Instruct: Given a scientific claim, retrieve passages that support or refute the claim.
Query: Antiretroviral therapy increases rates of tuberculosis across a broad range of CD4 strata.
BACKGROUND Human immunodeficiency virus (HIV) infection is the strongest risk factor for developing tuberculosis and has fuelled its resurgence, especially in sub-Saharan Africa. In 2010, there were an estimated 1.1 million incident cases of tuberculosis among the 34 million people living with HIV worldwide. Antiretroviral therapy has substantial potential to prevent HIV-associated tuberculosis. We conducted a systematic review of studies that analysed the impact of antiretroviral therapy on the incidence of tuberculosis in adults with HIV infection. METHODS AND FINDINGS PubMed, Embase, African Index Medicus, LILACS, and clinical trial registries were systematically searched. Randomised controlled trials, prospective cohort studies, and retrospective cohort studies were included if they compared tuberculosis incidence by antiretroviral therapy status in HIV-infected adults for a median of over 6 mo in developing countries. For the meta-analyses there were four categories based on CD4 counts at antiretroviral therapy initiation: (1) less than 200 cells/µl, (2) 200 to 350 cells/µl, (3) greater than 350 cells/µl, and (4) any CD4 count. Eleven studies met the inclusion criteria. Antiretroviral therapy is strongly associated with a reduction in the incidence of tuberculosis in all baseline CD4 count categories: (1) less than 200 cells/µl (hazard ratio [HR] 0.16, 95% confidence interval [CI] 0.07 to 0.36), (2) 200 to 350 cells/µl (HR 0.34, 95% CI 0.19 to 0.60), (3) greater than 350 cells/µl (HR 0.43, 95% CI 0.30 to 0.63), and (4) any CD4 count (HR 0.35, 95% CI 0.28 to 0.44). There was no evidence of hazard ratio modification with respect to baseline CD4 count category (p = 0.20). CONCLUSIONS Antiretroviral therapy is strongly associated with a reduction in the incidence of tuberculosis across all CD4 count strata. Earlier initiation of antiretroviral therapy may be a key component of global and national strategies to control the HIV-associated tuberculosis syndemic. REVIEW REGISTRATION International Prospective Register of Systematic Reviews CRD42011001209 Please see later in the article for the Editors' Summary.
BACKGROUND Treatment regimens for active tuberculosis (TB) that are intermittent, or use rifampin during only the initial phase, offer practical advantages, but their efficacy has been questioned. We conducted a systematic review of treatment regimens for active TB, to assess the effect of duration and intermittency of rifampin use on TB treatment outcomes. METHODS AND FINDINGS PubMed, Embase, and the Cochrane CENTRAL database for clinical trials were searched for randomized controlled trials, published in English, French, or Spanish, between 1965 and June 2008. Selected studies utilized standardized treatment with rifampin-containing regimens. Studies reported bacteriologically confirmed failure and/or relapse in previously untreated patients with bacteriologically confirmed pulmonary TB. Pooled cumulative incidences of treatment outcomes and association with risk factors were computed with stratified random effects meta-analyses. Meta-regression was performed using a negative binomial regression model. A total of 57 trials with 312 arms and 21,472 participants were included in the analysis. Regimens utilizing rifampin only for the first 1-2 mo had significantly higher rates of failure, relapse, and acquired drug resistance, as compared to regimens that used rifampin for 6 mo. This was particularly evident when there was initial drug resistance to isoniazid, streptomycin, or both. On the other hand, there was little evidence of difference in failure or relapse with daily or intermittent schedules of treatment administration, although there was insufficient published evidence of the efficacy of twice-weekly rifampin administration throughout therapy. CONCLUSIONS TB treatment outcomes were significantly worse with shorter duration of rifampin, or with initial drug resistance to isoniazid and/or streptomycin. Treatment outcomes were similar with all intermittent schedules evaluated, but there is insufficient evidence to support administration of treatment twice weekly throughout therapy.
There is little information about treatment outcome in patients with smear-negative pulmonary tuberculosis (PTB) or extrapulmonary tuberculosis (EPTB) treated under routine programme conditions in subsaharan Africa. A prospective study was carried out to determine treatment outcome in an unselected cohort of TB patients admitted to Zomba General Hospital, Malawi. Eight hundred and twenty-seven adult TB patients (451 men and 376 women) were registered between 1 July and 31 December 1995. Standardized treatment outcomes of treatment completion, death, default, and transfer to another district were assessed in relation to type of TB, human immunodeficiency virus (HIV) serostatus, age and gender. Two hundred and fifty-four patients (31%) died by the end of treatment, half of the deaths occurring in the first month. Death rates were 19% among 386 patients with smear-positive PTB, 46% among 211 patients with smear-negative PTB, and 37% among 230 patients with EPTB; 77% of the patients were HIV seropositive. Among new patients, HIV-positive patients had higher death rates than HIV-negative patients (hazard ratio [HR] 2.5; 95% confidence interval [95% CI] 1.6-3.8). Smear-negative patients had the highest death rates (HR 3.9; 95% CI 2.7-5.5 compared to smear-positive patients), followed by EPTB patients (HR 2.6, 95% CI 1.8-3.7 compared to smear-positive patients). Death rates increased with age but were similar in men and women. Adult patients in Malawi with smear-negative PTB and EPTB have low treatment completion and high death rates, related to high levels of HIV infection. National TB control programmes in areas of high HIV prevalence should no longer ignore treatment outcomes in patients with smear-negative PTB or EPTB.
Finding new treatment-shortening antibiotics to improve cure rates and curb the alarming emergence of drug resistance is the major objective of tuberculosis (TB) drug development. Using a matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging suite in a biosafety containment facility, we show that the key sterilizing drugs rifampicin and pyrazinamide efficiently penetrate the sites of TB infection in lung lesions. Rifampicin even accumulates in necrotic caseum, a critical lesion site where persisting tubercle bacilli reside. In contrast, moxifloxacin, which is active in vitro against a subpopulation of Mycobacterium tuberculosis that persists in specific niches under drug pressure and has achieved treatment shortening in mice, does not diffuse well in caseum, concordant with its failure to shorten therapy in recent clinical trials. We suggest that such differential spatial distribution and kinetics of accumulation in lesions may create temporal and spatial windows of monotherapy in specific niches, allowing the gradual development of multidrug-resistant TB. We propose an alternative working model to prioritize new antibiotic regimens based on quantitative and spatial distribution of TB drugs in the major lesion types found in human lungs. The finding that lesion penetration may contribute to treatment outcome has wide implications for TB.
Tuberculosis (TB) is an ancient disease, but not a disease of the past. After disappearing from the world public health agenda in the 1960s and 1970s, TB returned in the early 1990s for several reasons, including the emergence of the HIV/AIDS pandemic and increases in drug resistance. More than 100 years after the discovery of the tubercle bacillus by Robert Koch, what is the status of TB control worldwide? Here, we review the evolution of global TB control policies, including DOTS (directly observed therapy, short course) and the Stop TB Strategy, and assess whether the challenges and obstacles faced by the public health community worldwide in developing and implementing this strategy can aid future action towards the elimination of TB.
Tuberculosis (TB) is more prevalent in the world today than at any other time in human history. Mycobacterium tuberculosis, the pathogen responsible for TB, uses diverse strategies to survive in a variety of host lesions and to evade immune surveillance. A key question is how robust are our approaches to discovering new TB drugs, and what measures could be taken to reduce the long and protracted clinical development of new drugs. The emergence of multi-drug-resistant strains of M. tuberculosis makes the discovery of new molecular scaffolds a priority, and the current situation even necessitates the re-engineering and repositioning of some old drug families to achieve effective control. Whatever the strategy used, success will depend largely on our proper understanding of the complex interactions between the pathogen and its human host. In this review, we discuss innovations in TB drug discovery and evolving strategies to bring newer agents more quickly to patients.
Multidrug-resistant tuberculosis (MDR-TB) is a growing public health problem. Due to long duration of therapy and concurrent use of multiple second-line drugs, adverse drug events (ADEs) are regarded as the most important clinical consideration in patients undergoing anti-MDR-TB treatment. To evaluate the frequency and type of treatment-related ADEs owing to MDR-TB therapy. The Cochrane Library, MEDLINE, and EMBASE were searched from inception through October 1, 2012, with additional manual search of International Journal of Tuberculosis and Lung Disease. Studies with available ADEs were selected if MDR-TB patients were treated with regimen including second-line drugs. Pooled estimations of incidence for each specific type of ADEs were calculated with 95% confidence intervals using random-effects model. Of the 5346 patients included, 2602 (57.3%) experienced at least 1 kind of ADE. The 3 most common side effects were gastrointestinal disorders (32.1%), ototoxicity (14.6%), and psychiatric disorders (13.2%). Subgroup analyses based on each characteristic (study population, previous tuberculosis treated, human immunodeficiency virus prevalence, and length of treatment) did not show any significant difference between groups. Additionally, among 1519 patients who developed ADEs with available data of impact on MDR-TB therapy, 70.4% required change of MDR-TB treatment. Adverse events were common among MDR-TB cases, occurring in more than half of the cases, with over two-thirds requiring change of anti-MDR-TB treatment. MDR-TB patients should be monitored closely and managed aggressively for side effects during therapy, especially for ototoxicity and psychiatric disorders.
BACKGROUND Many mathematical models have investigated the impact of expanding access to antiretroviral therapy (ART) on new HIV infections. Comparing results and conclusions across models is challenging because models have addressed slightly different questions and have reported different outcome metrics. This study compares the predictions of several mathematical models simulating the same ART intervention programmes to determine the extent to which models agree about the epidemiological impact of expanded ART. METHODS AND FINDINGS Twelve independent mathematical models evaluated a set of standardised ART intervention scenarios in South Africa and reported a common set of outputs. Intervention scenarios systematically varied the CD4 count threshold for treatment eligibility, access to treatment, and programme retention. For a scenario in which 80% of HIV-infected individuals start treatment on average 1 y after their CD4 count drops below 350 cells/µl and 85% remain on treatment after 3 y, the models projected that HIV incidence would be 35% to 54% lower 8 y after the introduction of ART, compared to a counterfactual scenario in which there is no ART. More variation existed in the estimated long-term (38 y) reductions in incidence. The impact of optimistic interventions including immediate ART initiation varied widely across models, maintaining substantial uncertainty about the theoretical prospect for elimination of HIV from the population using ART alone over the next four decades. The number of person-years of ART per infection averted over 8 y ranged between 5.8 and 18.7. Considering the actual scale-up of ART in South Africa, seven models estimated that current HIV incidence is 17% to 32% lower than it would have been in the absence of ART. Differences between model assumptions about CD4 decline and HIV transmissibility over the course of infection explained only a modest amount of the variation in model results. CONCLUSIONS Mathematical models evaluating the impact of ART vary substantially in structure, complexity, and parameter choices, but all suggest that ART, at high levels of access and with high adherence, has the potential to substantially reduce new HIV infections. There was broad agreement regarding the short-term epidemiologic impact of ambitious treatment scale-up, but more variation in longer term projections and in the efficiency with which treatment can reduce new infections. Differences between model predictions could not be explained by differences in model structure or parameterization that were hypothesized to affect intervention impact.
CD4 T cells are important in the protective immune response against tuberculosis. Two mouse models deficient in CD4 T cells were used to examine the mechanism by which these cells participate in protection against Mycobacterium tuberculosis challenge. Transgenic mice deficient in either MHC class II or CD4 molecules demonstrated increased susceptibility to M. tuberculosis, compared with wild-type mice. MHC class II-/- mice were more susceptible than CD4-/- mice, as measured by survival following M. tuberculosis challenge, but the relative resistance of CD4-/- mice did not appear to be due to increased numbers of CD4-8- (double-negative) T cells. Analysis of in vivo IFN-gamma production in the lungs of infected mice revealed that both mutant mouse strains were only transiently impaired in their ability to produce IFN-gamma following infection. At 2 wk postinfection, IFN-gamma production, assessed by RT-PCR and intracellular cytokine staining, in the mutant mice was reduced by >50% compared with that in wild-type mice. However, by 4 wk postinfection, both mutant and wild-type mice had similar levels of IFN-gamma mRNA and protein production. In CD4 T cell-deficient mice, IFN-gamma production was due to CD8 T cells. Thus, the importance of IFN-gamma production by CD4 T cells appears to be early in infection, lending support to the hypothesis that early events in M. tuberculosis infection are crucial determinants of the course of infection.
This paper seeks to establish the strength of association between contemporary tuberculosis (TB) in England and Wales and several potential aetiological factors. It presents an ecological analysis of standardised annual TB mortality rates for the 403 local authority districts between 1982 and 1992, disaggregated by age and sex. Social, demographic and ethnicity measures from the 1981 and 1991 censuses and standardised annual AIDS-related mortality rates for young men are used to calculate Poisson regression models. A strong association was found between all TB mortality groups and overcrowding at the household level. For women, no other measures improved the explanatory power of the models. In multiple regressions, both poverty and AIDS-related mortality explained additional variation in the model for younger men. The link between ethnicity and tuberculosis notifications was not reflected in this analysis of mortality. For all groups no evidence of a positive relationship with ethnicity was found, once overcrowding had been accounted for. The significance of household as opposed to district level crowding suggests that prolonged contact is required for disease transmission. Regression analysis indicates that it is the overcrowding and poverty among ethnic populations that is significant for their tuberculosis mortality. The fact that the relationship between AIDS and TB is confined to the group most typical of AIDS patients provides evidence that AIDS has little influence on the level of tuberculosis mortality in the wider population. Explanations for the observed relationship include preferential certification, migration for treatment and shortcomings in health care provision.
OBJECTIVE To conduct an economic analysis of the Hlabisa community-based directly observed therapy management strategy for tuberculosis and to project costs of three alternative strategies. SETTING Hlabisa health district, KwaZulu-Natal, South Africa. METHODS An economic analysis comparing the current tuberculosis management strategy in Hlabisa with three alternative strategies (the Hlabisa strategy prior to 1991 based on hospitalisation, the national strategy and sanatorium care) in terms of costs to both health service and patient and of cost-effectiveness. RESULTS The current Hlabisa strategy was the most cost-effective (R3799 per patient cured), compared with R98307 for the strategy used prior to 1991, R9940 for the national strategy, and R11145 for sanatorium care. Between 71% and 88% of treatment costs lie with the health service, and hospitalisation (R119 per day) is the most expensive item. Prolonged hospitalisation is extremely expensive, but community care is cheaper (community clinic visit, R28; community health worker visit, R7). The total cost of supervising a patient in the community under the current Hlabisa strategy was R503, equivalent to 4.2 days in hospital. Drug costs (R157) are equivalent to just 1.3 days in hospital. CONCLUSION Cost to both health service and patient can be substantially reduced by using community-based directly observed therapy for tuberculosis, a strategy that is cheap and cost-effective in Hlabisa. These findings have important national implications, supporting the goals of the new tuberculosis control programme.
SETTING Tuberculosis (TB) program, Damien Foundation Projects, Bangladesh. OBJECTIVE To summarize the outcome and its determinants of the first treatment for multidrug-resistant TB using a standardized regimen consisting of a minimum 9 months. DESIGN This was a prospective, observational study of a gatifloxacin (GFX) based directly observed regimen, mainly with initial hospitalization. The 4-month intensive phase was extended until sputum smear conversion. Patients were monitored using culture for up to 2 years after treatment completion. RESULTS Of the 515 patients who met the study inclusion criteria and were successively enrolled from 2005 to 2011, 84.4% had a bacteriologically favorable outcome. Due to extensive disease with delayed sputum conversion, only half of the patients completed treatment within 9 months; however, 95% were able to complete treatment within 12 months. Eleven patients failed or relapsed, and 93.1% of the 435 patients who were successfully treated completed at least 12 months post-treatment follow-up. The strongest risk factor for a bacteriologically unfavorable outcome was high-level fluoroquinolone (FQ) resistance, particularly when compounded by initial pyrazinamide (PZA) resistance. Low-level FQ resistance had no unfavorable effect on treatment outcome. Amplification of drug resistance occurred only once, in a patient strain that was initially only susceptible to kanamycin and clofazimine. CONCLUSION The excellent outcome of the Bangladesh regimen was largely maintained. Bacteriological treatment failures and relapses were rare, except among patients with high-level GFX resistance, notably in the presence of PZA resistance.
Tuberculosis and helminthic infections coexist in many parts of the world, yet the impact of helminth-elicited Th2 responses on the ability of the host to control Mycobacterium tuberculosis (Mtb) infection has not been fully explored. We show that mice infected with the intestinal helminth Nippostrongylus brasiliensis (Nb) exhibit a transitory impairment of resistance to airborne Mtb infection. Furthermore, a second dose of Nb infection substantially increases the bacterial burden in the lungs of co-infected mice. Interestingly, the Th2 response in the co-infected animals did not impair the onset and development of the protective Mtb-specific Th1 cellular immune responses. However, the helminth-induced Th2 environment resulted in the accumulation of alternatively activated macrophages (AAMs) in the lung. Co-infected mice lacking interleukin (IL) 4Rα exhibited improved ability to control Mtb infection, which was accompanied by significantly reduced accumulation of AAMs. Moreover, IL-4Rα(-/-) mice adoptively transferred with wild-type macrophages had a significantly higher Mtb load in their lungs compared with those that received IL-4Rα(-/-) macrophages, suggesting a direct contribution for the IL-4R pathway to the heightened susceptibility of co-infected animals. The Th2 response can thus enhance the intracellular persistence of Mtb, in part by mediating the alternative activation of macrophages via the IL-4Rα signaling pathway.
Recognizing that the current MDR-TB regimen is suboptimal and based on low-quality evidence, the Global MDR-TB Clinical Trials Landscape Meeting was held in December, 2014 to strategize about coordination of research and development of new treatment regimens for this disease that affects millions of people worldwide every year. Sixty international experts on multidrug-resistant tuberculosis (MDR-TB) met in Washington D.C. and Cape Town, South Africa to consider key MDR-TB trial-related issues, including: standardization of definitions; clinical trial capacity building and; regimens optimized to foster compliance, avoid the emergence of resistance and have clinical relevance for special populations, including children and those co-infected with HIV. Underpinning all of this is the generation of a sufficient evidence base to facilitate regulatory approval and improved normative guidance. Participants discussed treatment combinations currently being studied in Phase 2B and Phase 3 trials as well as other promising new regimens and combinations that may be evaluated in the near future. These include regimens designed specifically to enable shorter duration and all-oral treatment as a means of maximizing treatment completion. It is hoped that clear definition of these challenges will facilitate the process of identifying solutions that accelerate progress towards effective, non-toxic treatments that can be programmatically implemented.
The incidence of the acquired immunodeficiency syndrome (AIDS) in Malawi is one of the highest in Central Africa. Since tuberculosis is an important initial manifestations of the disease, consecutive patients admitted to the tuberculosis (TB) wards of Zomba General Hospital, Malawi, were asked for permission to undergo a human immunodeficiency virus (HIV)-antibodies test. In addition, two other studies were done: from September 1986 all medical in-patients, clinically suspected for immune deficiency and from April 1988 all blood donors were tested for HIV seropositivity. Seventy-five percent of the TB patients volunteered; 32 out of 125 (26%) were seropositive. In the high-risk age groups (20-40 years) this percentage rose to 32. Among the medical in-patients suspected of immune deficiency the seropositivity rose sharply from April 1987 to October 1988. Among the blood donors tested, 20% were seropositive.
OBJECTIVE To examine the effect of ethnicity on the relation between tuberculosis and deprivation. DESIGN Retrospective ecological study comparing incidence of tuberculosis in white and south Asian residents of the 39 electoral wards in Birmingham with ethnic specific indices of deprivation. SETTING Birmingham, 1989-93. SUBJECTS 1516 notified cases of tuberculosis. MAIN OUTCOME MEASURES Rates of tuberculosis and measures of deprivation. RESULTS Univariate analysis showed significant associations of tuberculosis rates for the whole population with several indices of deprivation (P<0.01) and with the proportion of the population of south Asian origin (P<0.01). All deprivation covariates were positively associated with each other but on multiple regression, higher level of overcrowding was independently associated with tuberculosis rates. For the white population, overcrowding was associated with tuberculosis rates independently of other variables (P=0.0036). No relation with deprivation was found for the south Asian population in either single or multivariable analyses. CONCLUSIONS Poverty is significantly associated with tuberculosis in the white population, but no such relation exists for those of Asian ethnicity. These findings suggest that causal factors, and therefore potential interventions, will also differ by ethnic group.
Nonreplicating and metabolically quiescent bacteria are implicated in latent tuberculosis infections and relapses following "sterilizing" chemotherapy. However, evidence linking bacterial dormancy and persistence in vivo is largely inconclusive. Here we measure the single-cell dynamics of Mycobacterium tuberculosis replication and ribosomal activity using quantitative time-lapse microscopy and a reporter of ribosomal RNA gene expression. Single-cell dynamics exhibit heterogeneity under standard growth conditions, which is amplified by stressful conditions such as nutrient limitation, stationary phase, intracellular replication, and growth in mouse lungs. Additionally, the lungs of chronically infected mice harbor a subpopulation of nongrowing but metabolically active bacteria, which are absent in mice lacking interferon-γ, a cytokine essential for antituberculosis immunity. These cryptic bacterial forms are prominent in mice treated with the antituberculosis drug isoniazid, suggesting a role in postchemotherapeutic relapses. Thus, amplification of bacterial phenotypic heterogeneity in response to host immunity and drug pressure may contribute to tuberculosis persistence.
BACKGROUND Since November 2009, WHO recommends that adults infected with HIV should initiate antiretroviral therapy (ART) at CD4+ cell counts of ≤350 cells/µl rather than ≤200 cells/µl. South Africa decided to adopt this strategy for pregnant and TB co-infected patients only. We estimated the impact of fully adopting the new WHO guidelines on HIV epidemic dynamics and associated costs. METHODS AND FINDING We used an established model of the transmission and control of HIV in specified sexual networks and healthcare settings. We quantified the model to represent Hlabisa subdistrict, KwaZulu-Natal, South Africa. We predicted the HIV epidemic dynamics, number on ART and program costs under the new guidelines relative to treating patients at ≤200 cells/µl for the next 30 years. During the first five years, the new WHO treatment guidelines require about 7% extra annual investments, whereas 28% more patients receive treatment. Furthermore, there will be a more profound impact on HIV incidence, leading to relatively less annual costs after seven years. The resulting cumulative net costs reach a break-even point after on average 16 years. CONCLUSIONS Our study strengthens the WHO recommendation of starting ART at ≤350 cells/µl for all HIV-infected patients. Apart from the benefits associated with many life-years saved, a modest frontloading appears to lead to net savings within a limited time-horizon. This finding is robust to alternative assumptions and foreseeable changes in ART prices and effectiveness. Therefore, South Africa should aim at rapidly expanding its healthcare infrastructure to fully embrace the new WHO guidelines.
SETTING The rural health district of Hlabisa, KwaZulu-Natal, South Africa.   OBJECTIVES To assess the acceptability and effectiveness of traditional healers as supervisors of tuberculosis (TB) treatment in an existing directly observed treatment, short-course (DOTS) programme. DESIGN An observational study comparing treatment outcomes among new TB patients in the three intervention sub-districts offered the additional option of traditional healers for directly observed treatment (DOT) supervision with those in the remainder of the district offered the standard range of options for DOT supervision (health facility, community health worker and lay persons). A comparison was also made of treatment outcomes between different options for DOT supervision. RESULTS A total of 3461 TB patients were registered in Hlabisa District from April 1999 to December 2000, of whom 2823 were discharged from hospital to the ambulatory DOT programme. Treatment outcomes were known for 1816 patients in Hlabisa District (275 patients in the intervention area and 1541 patients in the control area). There was no significant difference (P < 0.5) in treatment outcome in the intervention and control areas (77% vs. 75%). Among 275 patients with known outcomes in the intervention area, 48 patients were supervised by traditional healers and 227 patients supervised by people other than traditional healers. Treatment completion was not significantly higher among patients supervised by traditional healers than among patients supervised by other categories of DOT supervisor (88% vs. 75%, P = 0.3841). Interviews with 41 of 51 traditional healer patients who had completed treatment revealed high levels of satisfaction with the care received. CONCLUSIONS Traditional healers make an effective contribution to TB programme performance in this pilot scheme in Hlabisa district. Further evaluation will be necessary as this approach is scaled up.
BACKGROUND Highly active antiretroviral therapy (HAART) is being scaled up in developing countries. We compared baseline characteristics and outcomes during the first year of HAART between HIV-1-infected patients in low-income and high-income settings. METHODS 18 HAART programmes in Africa, Asia, and South America (low-income settings) and 12 HIV cohort studies from Europe and North America (high-income settings) provided data for 4810 and 22,217, respectively, treatment-naïve adult patients starting HAART. All patients from high-income settings and 2725 (57%) patients from low-income settings were actively followed-up and included in survival analyses. FINDINGS Compared with high-income countries, patients starting HAART in low-income settings had lower CD4 cell counts (median 108 cells per muL vs 234 cells per muL), were more likely to be female (51%vs 25%), and more likely to start treatment with a non-nucleoside reverse transcriptase inhibitor (NNRTI) (70%vs 23%). At 6 months, the median number of CD4 cells gained (106 cells per muL vs 103 cells per muL) and the percentage of patients reaching HIV-1 RNA levels lower than 500 copies/mL (76%vs 77%) were similar. Mortality was higher in low-income settings (124 deaths during 2236 person-years of follow-up) than in high-income settings (414 deaths during 20,532 person-years). The adjusted hazard ratio (HR) of mortality comparing low-income with high-income settings fell from 4.3 (95% CI 1.6-11.8) during the first month to 1.5 (0.7-3.0) during months 7-12. The provision of treatment free of charge in low-income settings was associated with lower mortality (adjusted HR 0.23; 95% CI 0.08-0.61). INTERPRETATION Patients starting HAART in resource-poor settings have increased mortality rates in the first months on therapy, compared with those in developed countries. Timely diagnosis and assessment of treatment eligibility, coupled with free provision of HAART, might reduce this excess mortality.
Tuberculosis remains one of the world's leading infectious causes of death. Approximately 80% of all disease is due to postprimary (secondary) tuberculosis in the lung. Unfortunately, tissues of developing lesions are seldom available and there are no recognized models of postprimary tuberculosis. In the preantibiotic era when tissues were more abundant, several investigators described early postprimary tuberculosis as a lipid pneumonia quite different from the caseating granulomas commonly described today. We used histopathologic, immunohistochemical and acid fast stains to examine tissues from several people with untreated primary and postprimary tuberculosis and compared the findings with those of mice with reactivation tuberculosis. The results confirmed that developing postprimary tuberculosis begins as a lipid pneumonia accompanied by bronchial obstruction in which infection is restricted to foamy alveolar macrophages. Cavities result from a combination of caseation of tuberculous pneumonia and microvascular occlusion characteristic of delayed type hypersensitivity (DTH). Reactivation tuberculosis in the mouse begins as a similar tuberculous lipid pneumonia with bronchial obstruction and evidence for participation of DTH. Developing necrosis in both species is associated with localization of organisms within lipid droplets. These results suggest that reactivation tuberculosis in mice is a valuable model of developing human postprimary tuberculosis.
A method for detecting multidrug-resistant Mycobacterium tuberculosis by using a reduction of resazurin is described. Eighty clinical isolates were evaluated against isoniazid and rifampin; results at 7 days were compared with those of the proportion method. Specificity and sensitivity were excellent. The method is simple, inexpensive, and rapid and might be used with other antituberculosis drugs.
Tuberculosis, a major health problem in developing countries, has reemerged in recent years in many industrialized countries. The increased susceptibility of immunocompromised individuals to tuberculosis, and many experimental studies indicate that T cell-mediated immunity plays an important role in resistance. The lymphokine interferon gamma (IFN-gamma) is thought to be a principal mediator of macrophage activation and resistance to intracellular pathogens. Mice have been developed which fail to produce IFN-gamma (gko), because of a targeted disruption of the gene for IFN-gamma. Upon infection with Mycobacterium tuberculosis, although they develop granulomas, gko mice fail to produce reactive nitrogen intermediates and are unable to restrict the growth of the bacilli. In contrast to control mice, gko mice exhibit heightened tissue necrosis and succumb to a rapid and fatal course of tuberculosis that could be delayed, but not prevented, by treatment with exogenous recombinant IFN-gamma.
Adult T-cell leukaemia lymphoma (ATLL) is an aggressive disease caused by the human T-lymphotropic virus 1 (HTLV-I) with a short survival. Responses to interferon alpha (IFN-alpha) and zidovudine (AZT) have been documented but not with long-term follow-up. We treated 15 ATLL patients with IFN and AZT. Eleven patients had acute ATLL, two had lymphoma and two smouldering ATLL, with progression. The main features were: organomegaly (14), skin lesions (10), high white blood cell (WBC) count (11) and hypercalcaemia (9). Eleven patients had previously received chemotherapy and one had received an autograft. At the time of the study, seven patients had progressive disease and eight were in partial or complete clinical remission. Responses (PR) lasting 2+ to 44+ months were seen in 67%; 26% did not respond (NR) and one patient was not evaluable. Hypercalcaemia predicted a poor outcome but differences were not significant. Eight of the 15 patients have died 3-41 months from diagnosis. Median survival for the 15 patients was 18 months. Survival of the NR ranged from 4 to 20 months; six PR patients are alive 8-82 months from diagnosis. The differences in survival between NR (median: 6 months) and PR (55% of patients alive at 4 years) were statistically significant (P = 0.002). In conclusion, IFN and AZT improves the outcome of ATLL patients and helps maintain responses.
Late presentation remains a major concern despite the dramatically improved prognosis realized by ART. We define a first presentation for HIV care during the course of HIV infection as 'late' if an AIDS-defining opportunistic disease is apparent, or if CD4+ T-cells are <200/microl. In the Western world, approximately 10 and 30% of HIV-infected individuals still present with CD4+ T-cells <50 and <200/microl, respectively; estimates are substantially higher for developing countries. Diagnosis and treatment of opportunistic diseases and intense supportive in-hospital care take precedence over ART. Benefits of starting ART without delay, that is, when opportunistic diseases are still active, include faster resolution of opportunistic diseases and a decreased risk of recurrence. The downside of starting ART without delay could include toxicity, drug interactions and immune reconstitution inflammatory syndrome (IRIS). Among asymptomatic or oligosymptomatic individuals presenting late, where ART and primary prophylaxis are initiated, approximately 10-20% will become symptomatic from drug toxicity or undiagnosed opportunistic complications, including IRIS, which require appropriate therapies. In this review we describe late presentation to HIV care, the scale of the problem, the evaluation of a late-presenting patient and challenges associated with initiation of potent antiretroviral therapy (ART) in the setting of acute opportunistic infections and other comorbidities.