Does tuberculosis accelerate the progression of HIV disease? Evidence from basic science and epidemiology

Identification of cytokine signatures in HIV‑infected individuals with and without Mycobacterium tuberculosis co‑infection

Individuals with human immunodeficiency virus (HIV) infection are susceptible to immune system dysregulation, particularly during co-infection with Mycobacterium tuberculosis (MTB). Although there is an association between cytokine profiles and HIV-MTB co-infection, little is known about the cytokine-related host immune response mechanism to HIV-MTB co-infection. Therefore, the present study aimed to analyze expression of cytokines IL-17A, IFN-γ, TNF, IL-2, IL-10, IL-6 and IL-4 in individuals with HIV-MTB co-infection. A total of 30 patients with HIV and 40 with HIV-MTB co-infection were recruited into the present study, including those with active (A) (n=19) and latent (L)TB (n=21). HIV infection status was established based on national HIV guideline (Pedoman Nasional Pelayanan Kedokteran Tatalaksana HIV). ATB was confirmed using a positive acid-fast bacillus staining and culture of sputum; LTB status was established using IFN-γ release assay. Furthermore, the levels of cytokines IL-17A, IFN-γ, TNF, IL-10, IL-6, IL-4 and IL-2 were measured using flow cytometric bead array and CD4 cell count was performed by PIMA™ CD4 assay. IFN-γ, TNF, IL-10, IL-6 and IL-2 were able to significantly differentiate patients with HIV-ATB from those with HIV-LTB. Furthermore, in the patient subgroup with CD4 count <350 cells/µl, IFN-γ, IL-10 and IL-6 were able to differentiate between patients with HIV-ATB and HIV alone, as well as between patients with HIV-ATB and HIV-LTB. Based on these findings, the cytokine profiles are likely to be distinct between individuals with HIV infection with A- and LTB. Furthermore, the expression of CD4-positive T cells may influence the immune response in the body under HIV-MTB co-infection.

Prevalence and associated factors of HIV-TB co-infection among HIV patients: a retrospective Study

Background

TB/HIV co-infection is a major public health problem in many parts of the world. But the prevalence of co-infection was varies among countries.

This study was designed to assess prevalence of TB/HIV co-infection and to determine its factors.

Methods

A retrospective study was done among HIV-positive patients at Hiwot Fana hospital from December, 2014 to 2018. The study participants were selected by simple random sampling. Patients with incomplete chart reviews were excluded and demographic, clinical and laboratory information were analyzed using SPSS and STATA. Uni-vitiate and bivariate logistic regressions were applied.

Results

Five hundred fourteen patients were enrolled in this study. Of these, 187(37.4%) had TB. Bivariate logistic analysis showed that HIV patients with regards to marital status[AOR = 2.6; 95%CI = 1.19–2.89], education status [AOR = 3.74; 95%CI = 2.47–5.66], weight less than 50kg [AOR = 2.54; 95% CI = 1.35 – 4.81], CD4 level < 200cells/mm³ [AOR = 4.57; 95%CI = 2.38– 6.86] and patient who were at WHO clinical stage III [AOR = 7.8; 95%CI = 5.15 – 8.55] were significantly associated with TB/HIV co-infection.

Conclusion

The prevalence of TB among HIV patients was high and predicted by marital, education status, weight, CD4 cell count and WHO clinical stage III.

Concomitant administration of HAART aggravates anti-Koch-induced oxidative hepatorenal damage via dysregulation of glutathione and elevation of uric acid production

Anti-Koch and HAART have been shown to independently induce toxicity to the liver and kidney, albeit available data are few and inconsistent. The present study evaluates the impact of Anti-Koch and HAART, when administered singly and in combination, on hepatic and renal status, and the possible role of adenine deaminase (ADA)/xanthine oxidase (XO) pathway. Anti-Koch and HAART administration were observed to independently impair hepatic and renal functions, diminish glutathione content, and substantially increase lipid peroxidation (MDA) and nitrogen reactive specie (NO). Coherently, these drugs caused significant accumulation of polymorphonuclear leucocytes, up-regulated ADA/XO signaling, increased uric acid production, and enhanced DNA fragmentation in the liver and kidney. Anti-Koch treatment did not significantly alter hepatic and renal levels of nitric oxide nor induce DNA fragmentation in the kidney. Co-administration of anti-Koch and HAART aggravated the observed biochemical alterations. Findings from the histopathological studies of the liver and renal tissues were in agreement with observed biochemical alterations. In conclusion, this report is the first to reveal that anti-Koch and HAART, when administered singly or in combination, attenuate glutathione content and elevate uric acid production in the liver and kidney via upregulation of ADA/XO signaling with resultant oxidative and nitrosative stress, and increased DNA fragmentation.

Factors associated with initiation of antiretroviral therapy in the advanced stages of HIV infection in six Ethiopian HIV clinics, 2012 to 2013

Introduction

Most HIV-positive persons in sub-Saharan Africa initiate antiretroviral therapy (ART) with advanced infection (late ART initiation). Intervening on the drivers of late ART initiation is a critical step towards achieving the full potential of HIV treatment scale-up. This study aimed to identify modifiable factors associated with late ART initiation in Ethiopia.

Methods

From 2012 to 2013, Ethiopian adults (n=1180) were interviewed within two weeks of ART initiation. Interview data were merged with HIV care histories to assess correlates of late ART initiation (CD4+ count <150 cells/µL or World Health Organization Stage IV).

Results

The median CD4 count at enrolment in HIV care was 263 cells/µL (interquartile range (IQR): 140 to 390) and 212 cells/µL (IQR: 119 to 288) at ART initiation. Overall, 31.2% of participants initiated ART late, of whom 85.1% already had advanced HIV disease at enrolment. Factors associated with higher odds of late ART initiation included male sex (vs. non-pregnant females; adjusted odds ratio (aOR): 2.02; 95% CI: 1.50 to 2.73), high levels of psychological distress (vs. low/none, aOR: 1.96; 95% CI: 1.34 to 2.87), perceived communication barriers with providers (aOR: 2.42, 95% CI: 1.24 to 4.75), diagnosis via provider initiated testing (vs. voluntary counselling and testing, aOR: 1.47, 95% CI: 1.07 to 2.04), tuberculosis (TB) treatment prior to ART initiation (aOR: 2.16, 95% CI: 1.43 to 3.25) and a gap in care of six months or more prior to ART initiation (aOR: 2.02, 95% CI: 1.10 to 3.72). Testing because of partner illness/death (aOR: 0.64, 95% CI: 0.42 to 0.95) was associated with lower odds of late ART initiation.

Conclusions

Programmatic initiatives promoting earlier diagnosis, engagement in pre-ART care, and integration of TB and HIV treatments may facilitate earlier ART initiation. Men and those experiencing psychological distress may also benefit from targeted support prior to ART initiation.

Tuberculosis and HIV co-infection-focus on the Asia-Pacific region

Tuberculosis (TB) is the leading opportunistic disease and cause of death in patients with HIV infection. In 2013 there were 1.1 million new TB/HIV co-infected cases globally, accounting for 12% of incident TB cases and 360,000 deaths. The Asia-Pacific region, which contributes more than a half of all TB cases worldwide, traditionally reports low TB/HIV co-infection rates. However, routine testing of TB patients for HIV infection is not universally implemented and the estimated prevalence of HIV in new TB cases increased to 6.3% in 2013. Although HIV infection rates have not seen the rapid rise observed in Sub-Saharan Africa, indications are that rates are increasing among specific high-risk groups. This paper reviews the risks of TB exposure and progression to disease, including the risk of TB recurrence, in this vulnerable population. There is urgency to scale up interventions such as intensified TB case-finding, isoniazid preventive therapy, and TB infection control, as well as HIV testing and improved access to antiretroviral treatment. Increased awareness and concerted action is required to reduce TB/HIV co-infection rates in the Asia-Pacific region and to improve the outcomes of people living with HIV.

Plasma Levels of Neopterin and C-Reactive Protein (CRP) in Tuberculosis (TB) with and without HIV Coinfection in Relation to CD4 Cell Count

Background

While the risk of TB is elevated in HIV-positive subjects with low CD4 cell counts, TB may in itself be associated with CD4 lymphocytopenia. We investigated markers of immune activation (neopterin) and inflammation (CRP) in TB patients with and without HIV coinfection and their association with CD4 cell levels, and determined their predictive capacity as alternative markers of advanced immunosuppression.

Methods

Participants selected from a cohort of adults with TB at Ethiopian health centers (195 HIV+/TB+, 170 HIV-/TB+) and 31 controls were tested for plasma levels of neopterin and CRP. Baseline levels of neopterin and CRP were correlated to CD4 cell count before and after anti-TB treatment (ATT). The performance to predict CD4 cell strata for both markers were investigated using receiver operating curves.

Results

Levels of both biomarkers were elevated in TB patients (neopterin: HIV+/TB+ 54 nmol/l, HIV-/TB+ 23 nmol/l, controls 3.8 nmol/l; CRP: HIV+/TB+ 36 μg/ml, HIV-/TB+ 33 μg/ml, controls 0.5 μg/ml). Neopterin levels were inversely correlated (-0.53, p<0.001) to CD4 cell count, whereas this correlation was weaker for CRP (-0.25, p<0.001). Neither of the markers had adequate predictive value for identification of subjects with CD4 cell count <100 cells/mm³ (area under the curve [AUC] 0.64 for neopterin, AUC 0.59 for CRP).

Conclusion

Neopterin levels were high in adults with TB, both with and without HIV coinfection, with inverse correlation to CD4 cell count. This suggests that immune activation may be involved in TB-related CD4 lymphocytopenia. However, neither neopterin nor CRP showed promise as alternative tests for immunosuppression in patients coinfected with HIV and TB.

Incidence of tuberculosis and immunological profile of TB/HIV co-infected patients in Nigeria

BACKGROUND:

We obtained estimates of the incidence of tuberculosis (TB) among patients receiving HIV Treatment. We also modeled the relationship between incident TB and change in CD4 count over the follow-up period.

METHODS:

We analyzed the incidence of TB over 10 years from initiation of HIV treatment among 345 HIV treatment-naïve persons, who were enrolled in a cohort in Kano, Nigeria. We used Generalized Estimating Equation [GEE] to identify determinants of TB incidence and model the relationship between the occurrences of TB with change in CD4 count over the follow-up period. We created Kaplan-Meier curves stratified by anti-retroviral therapy (ART) treatment failure status to examine the effect of first line ART treatment failure on occurrence of TB.

RESULT:

During the 10-year period, 47(13.62%) had TB [incidence was 7.43 per (1,000) person year)]. It is associated with decreasing age (OR = 0.98), female gender (OR = 0.83), being on first line ART other than AZT (OR = 0.87), poor adherence (OR = 1.25), change in ART regimen (OR = 2.3) and ART treatment failure (OR = 1.51). Odds of TB occurrence was also associated with CD4 increment at 10 years (OR = 0.99). Those with TB/HIV co-infection tend to have statistically significant shorter time to failing first line ART regimen compared to those with HIV infection alone.

CONCLUSION:

There was high incidence of TB in the studied HIV cohort with a deleterious effect on the outcome of ART treatment. There is need for early TB screening and re-screening among all HIV patients.

Impact of tuberculosis treatment on CD4 cell count, HIV RNA, and p24 antigen in patients with HIV and tuberculosis

OBJECTIVES

To describe HIV RNA levels during tuberculosis (TB) infection in patients co-infected with TB and HIV. Moreover, to examine the p24 antigen profile during TB treatment.

METHODS

We examined the changes in CD4 cell count, HIV RNA, and p24 levels during anti-tuberculous therapy in a group of TB/HIV-1 co-infected and HIV-untreated patients from Guinea-Bissau.

RESULTS

A total of 365 TB patients were enrolled, of whom 76 were co-infected with HIV-1 and 19 were dually infected with HIV-1 + HIV-2. No significant changes in CD4, HIV RNA, or p24 levels were found during 8 months of TB treatment. HIV RNA levels correlated well with p24 (Spearman's R(2)=0.52, p<0.00001) and both markers were strong predictors of mortality. Initial HIV RNA levels correlated with a clinical TB severity index--the TBscore (Spearman's R(2)=0.23, p=0.02)--and the TBscore decreased dramatically during TB treatment although HIV RNA levels remained unchanged.

CONCLUSION

We found no significant changes in CD4, HIV RNA, or p24 antigen levels during 8 months of TB treatment among TB/HIV co-infected individuals, who did not receive antiretroviral treatment. The markers were unaffected by a strong improvement in TBscore and all three markers showed predictive capacity for mortality risk.

Prevalent and incident tuberculosis are independent risk factors for mortality among patients accessing antiretroviral therapy in South Africa

Background

Patients with prevalent or incident tuberculosis (TB) in antiretroviral treatment (ART) programmes in sub-Saharan Africa have high mortality risk. However, published data are contradictory as to whether TB is a risk factor for mortality that is independent of CD4 cell counts and other patient characteristics.

Methods/Findings

This observational ART cohort study was based in Cape Town, South Africa. Deaths from all causes were ascertained among patients receiving ART for up to 8 years. TB diagnoses and 4-monthly CD4 cell counts were recorded. Mortality rates were calculated and Poisson regression models were used to calculate incidence rate ratios (IRR) and identify risk factors for mortality. Of 1544 patients starting ART, 464 patients had prevalent TB at baseline and 424 developed incident TB during a median of 5.0 years follow-up. Most TB diagnoses (73.6%) were culture-confirmed. A total of 208 (13.5%) patients died during ART and mortality rates were 8.84 deaths/100 person-years during the first year of ART and decreased to 1.14 deaths/100 person-years after 5 years. In multivariate analyses adjusted for baseline and time-updated risk factors, both prevalent and incident TB were independent risk factors for mortality (IRR 1.7 [95% CI, 1.2–2.3] and 2.7 [95% CI, 1.9–3.8], respectively). Adjusted mortality risks were higher in the first 6 months of ART for those with prevalent TB at baseline (IRR 2.33; 95% CI, 1.5–3.5) and within the 6 months following diagnoses of incident TB (IRR 3.8; 95% CI, 2.6–5.7).

Conclusions

Prevalent TB at baseline and incident TB during ART were strongly associated with increased mortality risk. This effect was time-dependent, suggesting that TB and mortality are likely to be causally related and that TB is not simply an epiphenomenon among highly immunocompromised patients. Strategies to rapidly diagnose, treat and prevent TB prior to and during ART urgently need to be implemented.

Active tuberculosis is associated with worse clinical outcomes in HIV-infected African patients on antiretroviral therapy

Objective

This cohort study utilized data from a large HIV treatment program in western Kenya to describe the impact of active tuberculosis (TB) on clinical outcomes among African patients on antiretroviral therapy (ART).

Design

We included all patients initiating ART between March 2004 and November 2007. Clinical (signs and symptoms), radiological (chest radiographs) and laboratory (mycobacterial smears, culture and tissue histology) criteria were used to record the diagnosis of TB disease in the program’s electronic medical record system.

Methods

We assessed the impact of TB disease on mortality, loss to follow-up (LTFU) and incident AIDS-defining events (ADEs) through Cox models and CD4 cell and weight response to ART by non-linear mixed models.

Results

We studied 21,242 patients initiating ART–5,186 (24%) with TB; 62% female; median age 37 years. There were proportionately more men in the active TB (46%) than in the non-TB (35%) group. Adjusting for baseline HIV-disease severity, TB patients were more likely to die (hazard ratio – HR = 1.32, 95% CI 1.18–1.47) or have incident ADEs (HR = 1.31, 95% CI: 1.19–1.45). They had lower median CD4 cell counts (77 versus 109), weight (52.5 versus 55.0 kg) and higher ADE risk at baseline (CD4-adjusted odds ratio = 1.55, 95% CI: 1.31–1.85). ART adherence was similarly good in both groups. Adjusting for gender and baseline CD4 cell count, TB patients experienced virtually identical rise in CD4 counts after ART initiation as those without. However, the overall CD4 count at one year was lower among patients with TB (251 versus 269 cells/µl).

Conclusions

Clinically detected TB disease is associated with greater mortality and morbidity despite salutary response to ART. Data suggest that identifying HIV patients co-infected with TB earlier in the HIV-disease trajectory may not fully address TB-related morbidity and mortality.

The effect of tuberculosis on mortality in HIV positive people: a meta-analysis

BACKGROUND

Tuberculosis is a leading cause of death in people living with HIV (PLWH). We conducted a meta analysis to assess the effect of tuberculosis on mortality in people living with HIV.

METHODS

Meta-analysis of cohort studies assessing the effect of tuberculosis on mortality in PLWH. To identify eligible studies we systematically searched electronic databases (until December 2008), performed manual searches of citations from relevant articles, and reviewed conference proceedings. Multivariate hazard ratios (HR) of mortality in PLWH with and without tuberculosis, estimated in individual cohort studies, were pooled using random effect weighting according to "Der Simonian Laird method" if the p-value of the heterogeneity test was <0.05.

RESULTS

Fifteen cohort studies were systematically retrieved. Pooled overall analysis of these 15 studies estimating the effect of tuberculosis on mortality in PLWH showed a Hazard Ratio (HR) of 1.8 (95% confidence interval (CI): 1.4-2.3). Subanalysis of 8 studies in which the cohort was not exposed to highly active antiretroviral therapy (HAART) showed an HR of 2.6 (95% CI: 1.8-3.6). Subanalysis of 6 studies showed that tuberculosis did not show an effect on mortality in PLWH exposed to HAART: HR 1.1 (95% CI: 0.9-1.3).

CONCLUSION

These results provide an indication of the magnitude of benefit to an individual that could have been expected if tuberculosis had been prevented. It emphasizes the need for additional studies assessing the effect of preventing tuberculosis or early diagnosis and treatment of tuberculosis in PLWH on reducing mortality. Furthermore, the results of the subgroup analyses in cohorts largely exposed to HAART provide additional support to WHO's revised guidelines, which include promoting the initiation of HAART for PLWH co-infected with tuberculosis. The causal effect of tuberculosis on mortality in PLWH exposed to HAART needs to be further evaluated once the results of more cohort studies become available.

Effect of treating co-infections on HIV-1 viral load: a systematic review

Co-infections contribute to HIV-related pathogenesis and often increase viral load in HIV-infected people. We did a systematic review to assess the effect of treating key co-infections on plasma HIV-1-RNA concentrations in low-income countries. We identified 18 eligible studies for review: two on tuberculosis, two on malaria, six on helminths, and eight on sexually transmitted infections, excluding untreatable or non-pathogenic infections. Standardised mean plasma viral load decreased after the treatment of co-infecting pathogens in all 18 studies. The standardised mean HIV viral-load difference ranged from -0.04 log(10) copies per mL (95% CI -0.24 to 0.16) after syphilis treatment to -3.47 log(10) copies per mL (95% CI -3.78 to -3.16) after tuberculosis treatment. Of 14 studies with variance data available, 12 reported significant HIV viral-load differences before and after treatment. Although many of the viral-load reductions were 1.0 log(10) copies per mL or less, even small changes in plasma HIV-RNA concentrations have been shown to slow HIV progression and could translate into population-level benefits in lowering HIV transmission risk.

Tuberculosis and survival of HIV-infected individuals by time since seroconversion

In a cohort of 1950 HIV-positive men with known dates of HIV seroconversion, 399 developed tuberculosis. Mortality rates following tuberculosis were greatly increased (hazard ratio, adjusted for age at seroconversion, 4.7, 95% confidence interval 3.7-6.1), and this ratio was similar at different times following seroconversion. Overall mortality was similar to that in western seroconverter cohorts with much lower rates of tuberculosis, suggesting that tuberculosis is more a marker of HIV progression than a cause of it.

Treatment of spondylodiscitis in human immunodeficiency virus-infected patients: a comparison of conservative and operative therapy

STUDY DESIGN

Multicenter retrospective case series.

OBJECTIVE

To determine relevant clinical presentation and outcome of human immunodeficiency virus (HIV)-positive patients with spondylodiscitis as a function of the treatment.

SUMMARY OF BACKGROUND DATA

This is the first study comparing the clinical outcome of HIV-positive patients with spondylodiscitis as a function of the treatment.

METHODS

We performed a national multicenter retrospective case series comparing operatively versus conservatively treated HIV-positive patients with spondylodiscitis presenting between 1991 and 2007.

RESULTS

Twenty patients were included in the study. The average age of the patients at the time of admission was 43.0 years. The sex ratio m:w resulted in 2.3:1. On admission, 50% of the patients were in CDC stage C3. The CD4 T-cell count was determined as being 237.5/microL on average. At the occurrence of spondylodiscitis HIV had been known for a mean 8.5 years. In altogether 75% of the cases a pathogen was found. In 3 cases, mixed infections were present. Half of the patients received surgery. In none of these patients a wound infection or a delay of wound healing could be observed. One patient died during in-patient stay. Eleven of the 19 patients could be followed up a mean 13 months after discharge. In the follow-up period further 3 patients died on an average of 45 months after discharge.

CONCLUSION

The occurrence of spondylodiscitis in HIV-positive patients is associated with a low CD4 T-cell count. The probability of mixed infections rises with a CD4 T-cell count <100/microL. The occurrence of spondylodiscitis in HIV-positive patients is accompanied by high mortality. Operative therapy of spondylodiscitis in HIV-positive patients is not associated with an increased surgical complication rate. HIV infection or AIDS should not have an influence on decision-making regarding conservative or operative therapy of spondylodiscitis.

Effect of tuberculosis on the survival of HIV-infected men in a country with low tuberculosis incidence

Evidence regarding the effect of tuberculosis (TB) on HIV disease progression at the population level remains inconclusive. We estimated the effect of incident TB on time to AIDS-related death, using a marginal structural Cox model. Between 1984 and 2005, 2882 HIV-infected men in the Multicenter AIDS Cohort Study contributed 21 914 person-years while followed for a median of 5.4 years. At study entry, the median CD4 cell count and HIV-1 RNA viral load were 533 cells/microl (interquartile range: 365-737) and 12, 953 copies/ml (interquartile range: 2453-48 540), respectively. This study was performed in a setting with a modest exposure to HAART; 8295 of 23 801 (35%) person-years were followed during the HAART era. Fifteen men incurred incident TB, yielding a TB incidence of 7 (95% confidence interval: 4-14) per 10 000 person-years and 1072 died of AIDS-related causes. Accounting for potential confounders, including CD4 cell count and viral load, the hazard of AIDS-related death was 2.4 times more for the person-time with TB compared to the person-time without TB (95% confidence interval: 1.2-4.7). Results underscore the importance of avoiding TB by using preventive interventions such as treatment of latent TB infection, particularly in populations with a large prevalence of HIV/TB co-infected individuals.

Lung granulomas from Mycobacterium tuberculosis/HIV-1 co-infected patients display decreased in situ TNF production

Tuberculosis/HIV-1 co-infection is responsible for thousands of deaths each year, and previous studies have reported that co-infected individuals display major morphological alterations in tissue granulomas. The purpose of this study was to evaluate immunohistopathological characteristics in lung tissues from pulmonary TB/HIV-1-co-infected individuals. Following autopsy, tuberculosis-positive HIV-1-negative cases displayed granulomas with normal architecture, mainly composed of a mononuclear infiltrate with typical epithelioid, as well as giant cells, and exhibiting caseous necrosis. In contrast, lesions from the TB/HIV-1-co-infected group showed extensive necrosis, poorly formed granulomas, and a marked presence of polymorphonuclear cells. More importantly, TNF staining was greatly reduced in the TB/HIV-1-co-infected individuals. Our data suggest that HIV-1 infection alters the organization of pulmonary granulomas by modulating TNF and, possibly, cell trafficking, leading to an impaired anti-tuberculosis response.

HIV progression and predictors of mortality in a community-based cohort of Zambian adults

This article describes immunological HIV progression, mortality, and its predictors in 974 Zambian adults. During 3138 person-years of follow-up, 281 deaths occurred, and the overall mortality rate was 9.0 per 100 person-years. Thirty-six percent of patients were dead within 5 years of enrollment. The median survival in patients with baseline CD4 count ≥500 cells/mm³ was 5.62 years, with CD4 count between 200 and 499 cells/mm³ 5.46 years, and with CD4 count <200 cells/mm³ 3.89 years. The mortality rate increased significantly with older age (6.9 in patients <25 years, 9.3 in individuals aged 25-39 years, 10.2 in patients ≥40 years) and was higher in women (rate ratio 1.29). The median annual change of progression markers was -29.6 cells/mm³ for CD4 count, -3.0% for CD4 count percentage, 1.2 nmol/L for neopterin, -1.9 g/L for hemoglobin, and -70 cells/mm³ for total lymphocyte count. Hemoglobin and neopterin were as accurate as CD4 count to predict mortality.

Chlamydia pneumoniae infection in HIV-positive patients: prevalence and relationship with lipid profile

OBJECTIVES

The aims of this study were to evaluate the prevalence and impact of Chlamydia pneumoniae infection in HIV-positive patients and to establish the relationship between C. pneumoniae infection and lipid profile.

METHODS

Detection of C. pneumoniae was by polymerase chain reaction (PCR) on Peripheral Blood Mononuclear Cells (PBMCs) collected from 97 HIV-positive patients. Samples were collected after overnight fast in EDTA-treated tubes. On the same day, patients were also tested for routine chemistry, HIV viral load, CD3, CD8 and CD4 cell counts and lipid profile [cholesterol, high-density lipoproteins (HDLs), low-density lipoproteins (LDLs) and triglycerides].

RESULTS

The overall prevalence of C. pneumoniae was 39%. The prevalence of C. pneumoniae was inversely related to the CD4 lymphocyte count (P=0.03). In the naive group, C. pneumoniae-positive patients had both significantly higher HIV load (71 021+/-15 327 vs. 14 753+/-14 924 HIV-1 RNA copies/mL; P=0.03) and lower CD4 cell count (348.0+/-165.4 vs. 541.7+/-294.8; P=0.04) than C. pneumoniae-negative patients. Moreover, treatment-naive patients with C. pneumoniae infection had significantly higher mean levels of cholesterol (185.3+/-56.2 vs. 124.8+/-45.9 mg/dL; P=0.01), triglycerides (117.2+/-74.7 vs. 68+/-27.6 mg/dL; P=0.04) and LDL (122.4+/-60.1 vs. 55.6+/-58 mg/dL; P=0.05) than C. pneumoniae-negative patients.

CONCLUSIONS

These data indicate that, in HIV-positive subjects, C. pneumoniae infection is relatively frequent and is associated with both low CD4 cell count and high HIV load. Furthermore, C. pneumoniae appears to be associated with hyperlipidaemia and might therefore represent a further risk factor for cardiovascolar disease in HIV-positive patients.

Immunoadjuvant prednisolone therapy for HIV-associated tuberculosis: a phase 2 clinical trial in Uganda

Background. Human immunodeficiency virus (HIV)-infected patients with tuberculosis (TB) respond to effective antituberculous therapy, but their prognosis remains poor. Mounting evidence from clinical studies supports the concept of copathogenesis in which immune activation that is triggered by TB and mediated by cytokines stimulates viral replication and worsens HIV infection, especially when immune function is preserved.Methods. We performed a phase 2, randomized, double-blind, placebo-controlled clinical trial in Kampala, Uganda, to determine whether immunoadjuvant prednisolone therapy in HIV-infected patients with TB who have CD4(+) T cell counts >/=200 cells/ mu L is safe and effective at increasing CD4(+) T cell counts.Results. Short-term prednisolone therapy reduced levels of immune activation and tended to produce higher CD4(+) T cell counts. Although prednisolone therapy was associated with a more rapid clearance of Mycobacterium tuberculosis from the sputum, it was also associated with a transient increase in HIV RNA levels, which receded when prednisolone therapy was discontinued. The intervention worsened underlying hypertension and caused fluid retention and hyperglycemia.Conclusion. The benefits of prednisolone therapy on immune activation and CD4(+) T cell counts do not outweigh the risks of adverse events in HIV-infected patients with TB and preserved immune function.

Mycobacterial autofluorescence in Papanicolaou-stained lymph node aspirates: a glimmer in the dark?

This study was undertaken to determine the value of incorporating fluorescence into cytopathological evaluation of lymph node fine-needle aspiration (FNA) specimens suspected of harboring mycobacterial species. The study population consisted of 1,044 HIV-positive and -negative patients referred for FNA to the cytopathology unit of a South African medical school located in a very high HIV prevalence region. Each aspirate was assessed on routine Papanicolaou-stained slides for morphologic characteristics of mycobacterial infection. The same glass slides were then viewed under fluorescent microscopy to determine the presence or absence of mycobacterial autofluorescence. Using multivariate analysis, results of both cytology and fluorescence were compared with mycobacterial culture as the final arbiter of the presence of organisms. In this large clinical study, compared with culture, cytomorphology showed sensitivity of 84.9%, but low specificity of only 50.9%. Fluorescence demonstrated lower sensitivity of 65.9%, but improved specificity of 73.0%. Taken together, positivity of both cytology and fluorescence improved specificity to 81.8%. Fluorescent microscopy is rapid, inexpensive, and cost-effective; neither radioactive materials nor further staining are required. It is felt that this methodology would be of diagnostic benefit if used on morphologically suspicious samples in areas with a high prevalence of HIV and mycobacterial infections. Appropriate therapy could be commenced within hours of FNA, with reduction in the current number of patients lost to follow-up while awaiting results of culture. The technique is readily extended to other FNA types such as deep organ aspirates. Autofluorescence of organisms specifically requires usage of Papanicolaou staining; the technique cannot be used in histopathologic specimens stained with hematoxylin-eosin.

AIDS in Africa: the impact of coinfections on the pathogenesis of HIV-1 infection

The intimate relationship between the HIV-1 life-cycle and the activation state of cells supporting viral replication results in a dynamic interaction between coinfections and HIV-1 replication in dually infected people. The immunologic impact of recurrent coinfections has the potential to increase viral replication, viral genotypic heterogeneity and CD4 T lymphocyte loss, leading to accelerated decline in immune function, reduced survival and increased HIV-1 transmission risk. These effects may play a particularly significant role in the HIV-1 epidemic in sub-Saharan Africa. The mechanisms underlying these effects on virus-host dynamics are reviewed and data describing the impact of tuberculosis, malaria, schistosomiasis and genital ulceration on HIV-1 infection are presented.

Improved outcomes of HIV-1-infected adults with tuberculosis in the era of highly active antiretroviral therapy

OBJECTIVES

To compare the survival and treatment responses to antiretroviral therapy between HIV-1-infected patients with active TB (TB patients) and without (non-TB patients) in the era of highly active antiretroviral therapy (HAART).

DESIGN

8-year prospective observational study at a university hospital.

METHODS

A total of 125 (17.5%) TB patients (median CD4 cell count at TB diagnosis, 37 x 10(6) cells/l) and 591 non-TB patients (CD4 cell count at enrolment, 79 x 10(6) cells/l) were prospectively observed between June 1994 and October 2002. Virologic and immunologic responses were assessed in 230 antiretroviral-naive non-TB patients and 46 TB patients who concurrently initiated antituberculous therapy and HAART. The clinical outcome was evaluated by comparing incidence of new AIDS-associated opportunistic illnesses (OIs) and survival of all TB and non-TB patients. RESULTS Among antiretroviral-naive patients, CD4 cell count increase (71 versus 64 x 10(6) cells/l, P = 0.70) and proportions of patients achieving undetectable plasma viral load [20 of 46 versus 107 of 230, relative risk (RR), 0.93; 95% confidence interval (95% CI), 0.65-1.34; P = 0.71] at week 4 of HAART were similar between the 46 TB and 230 non-TB patients, as was the virologic failure during HAART (RR, 1.49; 95% CI, 0.92-2.41; P = 0.14). The risk for HIV progression to new OIs was also similar between the two groups (adjusted RR, 1.16; 95% CI, 0.764-1.77). The adjusted hazard ratio for death of TB patients compared with non-TB patients was 1.18 (95% CI, 0.65-2.32) before HAART era and 0.89 (95% CI, 0.57-1.69) in HAART era.

CONCLUSIONS

Our data indicated that virologic, immunologic, and clinical responses to HAART and prognosis of HIV-1-infected TB patients who were concurrently treated with antituberculous therapy and HAART were similar to those of non-TB patients.

Cutting edge: in vivo induction of integrated HIV-1 expression by mycobacteria is critically dependent on Toll-like receptor 2

Mycobacterial infection has been implicated as a possible factor in AIDS progression in populations where HIV-1 and Mycobacterium tuberculosis are coendemic. In support of this concept, we have previously shown that HIV-1-transgenic (Tg) mice infected with mycobacteria display enhanced viral gene and protein expression. In this study, we demonstrate that the induction of HIV-1 observed in this model is dependent on Toll-like receptor 2 (TLR2), a pattern recognition receptor known to be involved in mycobacteria-host interaction. Spleen cells from HIV-1-Tg mice deficient in TLR2 (Tg/TLR2(-/-)) were found to be completely defective in p24 production induced in response to live M. tuberculosis or Mycobacterium avium as well as certain mycobacterial products. Importantly, following in vivo mycobacterial infection, Tg/TLR2(-/-) mice failed to display the enhanced HIV-1 gag/env mRNA and p24 protein synthesis exhibited by wild-type Tg animals. Together, these results argue that TLR2 plays a crucial role in the activation of HIV-1 expression by mycobacterial coinfections.

Tuberculosis

Approximately one-third of the world population is infected with Mycobacterium tuberculosis, the organism that causes tuberculosis (TB). After a brief resurgence beginning in the mid-1980s, the incidence of TB is once again declining in the United States. Health care workers, including dentists and their staff, however, remain at risk for occupational acquisition of the disease. This risk can be managed by educating dental health care workers about the oral and systemic manifestations of TB and the mechanisms by which it is spread so that appropriate measures may be taken in the office to minimize the opportunity for disease transmission.

Impact of tuberculosis on HIV disease progression in persons with well-documented time of HIV seroconversion

Tuberculosis (TB) enhances HIV replication in vitro, but its impact on HIV progression at the population level is not established. Studies from industrialized and nonindustrialized countries show contradictory results as to whether TB accelerates HIV progression, although no studies have been conducted in persons with well-documented seroconversion times. Data from HIV seroconverters from 19 cohorts were analyzed to examine the effect of TB on HIV progression comparing persons with TB and persons without TB infected by HIV for the same length of time. TB and other AIDS-defining conditions (ADCs) were fitted as time-dependent covariates, adjusting for age, sex, transmission category, calendar year at risk, and cohort, using Cox proportional hazards models and allowing for late entry. Of 4398 seroconverters, 1294 (29%) developed AIDS. TB accounted for 72 (5.6%) of initial ADCs and for 105 (5.7%) of all ADCs. Survival from HIV seroconversion shows that compared with AIDS-free subjects, the risk of death associated with TB as an initial ADC (hazard ratio [HR] = 23.23, 95% CI: 14.60-36.96) does not differ from that associated with Kaposi sarcoma (HR = 23.47, 95% CI: 16.66-33.05) or esophageal candidiasis (OC)/Pneumocystis carinii pneumonia (PCP) (HR = 30.97, 95% CI: 24.38-39.34) but is lower than that for opportunistic infections other than TB, OC/PCP (HR = 46.83, 95% CI: 37.86-47.94) and high-grade non-Hodgkin lymphomas/invasive cervical carcinoma (HR = 92.71, 95% CI: 60.83-141.3). The lowest risk of death was seen, as expected, in AIDS-free subjects. HIV progression is not inherently faster in subjects who develop TB compared with other individuals with AIDS who have been infected by HIV for the same length of time in countries where TB treatment is widely available.

Cotrimoxazole prophylaxis for opportunistic infections in adults with HIV

BACKGROUND

The prevention and early treatment of infections are the mainstay of the medical management of the majority of people with HIV infection, who live in low income countries without access to antiretroviral drugs. Cotrimoxazole is cheap and effective against a wide range of organisms. However, routine prophylactic treatment is difficult to deliver in low-resource settings, and could also lead to increased resistance to the drug.

OBJECTIVES

To assess the effects of routinely administered cotrimoxazole on death and illness episodes in HIV infected adults.

SEARCH STRATEGY

We searched the Cochrane HIV/AIDS Group register, the Cochrane Controlled Trials Register, MEDLINE, LILACS, AIDSLINE, AIDSTRIALS and AIDSDRUGS databases, and proceedings and abstracts from AIDS and tuberculosis (TB) conferences (search date July 2001). We checked reference lists for trials and other pertinent articles, and contacted pharmaceutical companies and experts in the field.

SELECTION CRITERIA

Randomised or quasi randomised trials comparing routinely administered cotrimoxazole versus placebo or no treatment in adults (age greater than 13 years).

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial eligibility and quality, and extracted data. Where data were incomplete or unclear trial authors were contacted for further details.

MAIN RESULTS

Four trials involving 1476 people were identified. Three trials (1416 people) studied heterosexual men and women in West Africa. A fourth trial was of homosexual men on chemotherapy for Kaposi's sarcoma, in the United States. Meta-analysis of the three African trials showed a significant beneficial effect of cotrimoxazole for death: relative risk 0.69 (95% confidence interval 0.55 to 0.87); for morbid events: 0.76 (0.64 to 0.9); and for hospitalisation: 0.66 (0.48 to 0.92). There was no significantly greater risk of adverse effects: relative risk 1.28 (0.47 to 3.51). Effects were similar in people with early and advanced HIV disease. Insufficient evidence was found on effects in areas with higher bacterial resistance or in people on antiretroviral therapy.

REVIEWER'S CONCLUSIONS

In the trials included in the review, cotrimoxazole prophylaxis had a beneficial effect in preventing death and illness episodes in adults with both early and advanced HIV disease. However, the wider applicability of these findings is unclear, in particular to areas with higher background bacterial resistance to cotrimoxazole. Further trials would be required in differing settings to widen applicability.

Tuberculosis control in Alberta. A federal, provincial and regional public health partnership

The number of cases of tuberculosis in Alberta or Canada may not be large, but the public health and medical costs of just a few cases can be prohibitive. For example, the costs of managing cases of multidrug-resistant tuberculosis and their contacts, can exceed the entire annual budget of a program. This was evident in New York City in the late 1980s and early 1990s, when $1 billion in public funds were spent reversing a major resurgence of drug-resistant and susceptible tuberculosis. In Canada, the Walkerton Inquiry has identified an apparent failure of provincial public policy to adequately address public health needs. This has resulted in decreased public confidence and potential liabilities for the policy-makers. In the design of the Tuberculosis Control Program of Alberta, the notion of a quasicentralized or quasidecentralized program is rejected. Rather there is an appeal to the notion of a partnership of responsibility that recognizes jurisdictional and non-jurisdictional public health, case management and epidemiologic realities, the integral contribution of each level of government and the need to be accountable to the public's health and purse. For levels of government not to properly discharge their responsibilities may be perceived as an abrogation of the public trust and a disregard of the Tuberculosis Control Policy Package and operational directives of the World Health Organization.

HIV-1/AIDS and the control of other infectious diseases in Africa

The effect of HIV-1 on other infectious diseases in Africa is an increasing public health concern. In this review, we describe the role that three major infectious diseases--malaria, sexually transmitted diseases (STDs), and tuberculosis--have had in the HIV-1 epidemic. The high prevalence of untreated STD infections has been a major factor facilitating the spread of HIV-1 in Africa; with the synergistic interaction between HIV-1 transmission and genital herpes being of special concern for control of both diseases. Increased susceptibility to tuberculosis after infection with HIV-1 has led to a rising incidence and threat of increased transmission of tuberculosis. Clinical malaria occurs with an increased frequency and severity in HIV-1-infected individuals, especially during pregnancy. As with tuberculosis, STDs, and other communicable HIV-1-associated diseases, the net effect of HIV-1 might include increased rates of malaria transmission across communities. In addition to enhancing access to HIV-1 prevention and care, public health surveillance and control programmes should be greatly intensified to cope with the new realities of infectious disease control in Africa.

Pulmonary manifestations of HIV/AIDS in the tropics

The most significant pulmonary opportunistic infections in the tropics are TB and pneumococcal pneumonia. Guidelines for the diagnosis and management of these and other pulmonary manifestations of HIV are discussed. Ultimately, unless concerted efforts are made to treat underlying HIV infection in regions most devastated by AIDS, the impact of these diseases will continue to grow.

Chemoprophylaxis for tuberculosis and survival of HIV-infected patients in Brazil

OBJECTIVE

To study the impact of chemoprophylaxis for tuberculosis on the survival of HIV-infected patients with a positive tuberculin skin test.

DESIGN

Prospective observational cohort study.

SETTING

Outpatient clinic of a university hospital, in Rio de Janeiro, Brazil.

PATIENTS

Two-hundred and ninety-seven patients with a positive tuberculin skin test (reaction > or = 5mm) who were admitted to the cohort between January 1991 and December 1994. Follow-up ended on September 30, 1998.

INTERVENTION

The use of chemoprophylaxis for tuberculosis.

MAIN OUTCOME MEASURES

Death was the primary outcome variable. The occurrence of tuberculosis was studied as a secondary outcome. Cox regression models were used in these analyses.

RESULTS

The median follow-up time was 43.6 months. Chemoprophylaxis was used by 128 (43%) of the patients. The use of chemoprophylaxis was associated with a reduction in risk for tuberculosis (hazard ratio, 0.38; 95% confidence interval, 0.14-1.04; P = 0.05). In a regression model adjusted for baseline CD4 cell count, chemoprophylaxis was associated with longer survival (hazard ratio, 0.24; 95% confidence interval, 0.09-0.65; P = 0.002).

CONCLUSIONS

Anti-tuberculosis chemoprophylaxis was associated with a substantially prolonged survival among purified protein derivative-positive HIV-infected patients in Brazil. These data have important implications for the clinical care of patients with HIV infection in areas of the world with a high prevalence of Mycobacterium tuberculosis infection.

Distribution of the human immunodeficiency virus coreceptors CXCR4 and CCR5 on leukocytes of persons with human immunodeficiency virus type 1 infection and pulmonary tuberculosis: implications for pathogenesis

Expression of CXCR4 was significantly reduced from normal on all cell subsets of persons with pulmonary tuberculosis (TB group), with HIV-1 infection (HIV group), and those with both infections (HIV/TB group), except for on monocytes in the HIV group. The reductions were most notable in the two TB groups. Interestingly, the duration of antituberculosis treatment was significantly negatively correlated with the expression of CXCR4 on CD4+ and CD8+CD45RO+ cells, monocytes and NK cells, viral load, and proportions of CD38-expressing CD8+ lymphocytes, in HIV/TB patients. By contrast, CCR5 expression on most cell subsets analyzed was increased in all the disease groups, except for on monocytes in the two TB groups. There was no change in CCR5 expression on CD4+ cells when based on the disease groupings. However, higher proportions of CD4+CD45RA+ and CD8+ lymphocytes as well as B cells expressing CCR5 correlated with advancing HIV-1 disease, as did decreased proportions of CXCR4-expressing CD4+CD45RA+ cells.

A systematic review of the epidemiologic interactions between classic sexually transmitted diseases and HIV: how much really is known?

BACKGROUND

Many studies have explored the role of "classic" sexually transmitted diseases (STDs) in determining the pattern of HIV epidemics. However, the many different STDs may contribute in different ways, at different magnitudes.

GOAL

To review available studies on the bidirectional interactions of HIV and STDs to explore the extent of current knowledge on the different influences of the varied STDs in heterosexual HIV epidemics.

METHODS

Longitudinal studies on susceptibility and controlled studies on infectiousness and duration of disease identified on electronic databases through reference lists and citation indices up to the end of 1999 were systematically reviewed, including meta-analyses assessing the influence of STDs on susceptibility to HIV.

RESULTS

Studies have a clear publication bias with a significant result that hinders robust interpretation. However, genital ulcerative disease appears to have a greater impact than nonulcerative disease, and men are more affected than women by the effects of STDs on susceptibility to HIV. There is evidence that STDs increase the infectiousness of HIV from men to women, whereas the evidence is more equivocal for the infectiousness of women. Few studies identify the impact of different STDs, and there is a marked lack of studies investigating the impact of HIV infection on the transmission of other STDs.

CONCLUSIONS

A large body of work has measured the association between STDs and HIV. However, publication bias and gaps in the focus of studies mean that a detailed, quantitative understanding of the interaction requires much more attention.

Contribution of immune activation to the pathogenesis and transmission of human immunodeficiency virus type 1 infection

The life cycle of human immunodeficiency virus type 1 (HIV-1) is intricately related to the activation state of the host cells supporting viral replication. Although cellular activation is essential to mount an effective host immune response to invading pathogens, paradoxically the marked systemic immune activation that accompanies HIV-1 infection in vivo may play an important role in sustaining phenomenal rates of HIV-1 replication in infected persons. Moreover, by inducing CD4+ cell loss by apoptosis, immune activation may further be central to the increased rate of CD4+ cell turnover and eventual development of CD4+ lymphocytopenia. In addition to HIV-1-induced immune activation, exogenous immune stimuli such as opportunistic infections may further impact the rate of HIV-1 replication systemically or at localized anatomical sites. Such stimuli may also lead to genotypic and phenotypic changes in the virus pool. Together, these various immunological effects on the biology of HIV-1 may potentially enhance disease progression in HIV-infected persons and may ultimately outweigh the beneficial aspects of antiviral immune responses. This may be particularly important for those living in developing countries, where there is little or no access to antiretroviral drugs and where frequent exposure to pathogenic organisms sustains a chronically heightened state of immune activation. Moreover, immune activation associated with sexually transmitted diseases, chorioamnionitis, and mastitis may have important local effects on HIV-1 replication that may increase the risk of sexual or mother-to-child transmission of HIV-1. The aim of this paper is to provide a broad review of the interrelationship between immune activation and the immunopathogenesis, transmission, progression, and treatment of HIV-1 infection in vivo.

Maternal mortality associated with tuberculosis-HIV-1 co-infection in Durban, South Africa

OBJECTIVES

To document the impact of tuberculosis and HIV-1 on maternal mortality.

DESIGN

Prospective study, 1997 and 1998; retrospective analysis, 1996.

PARTICIPANTS

Known maternal deaths, defined as the death of a mother within a year post-delivery, were studied in Durban, KwaZulu Natal. The HIV-1 status, presence of tuberculosis, maternal clinical features and perinatal outcomes were documented. The overall as well as HIV-1 and tuberculosis-specific maternal mortality rates for the hospital were calculated. The attributable fraction of deaths as a result of HIV-1 was calculated in the overall group and in those with tuberculosis co-infection.

RESULTS

A total of 50 518 deliveries and 101 maternal deaths were recorded. Of the deaths, 29.7% (30/101) were HIV-1 infected. The overall mortality rate was 200/100 000; for HIV-1-infected women this was 323.3/100 000, HIV-1-negative mothers, 148.6/100 000 live births. The attributable fraction of overall deaths as a result of HIV-1 was 15.9% Fourteen of the 15 mothers with tuberculosis were HIV-1 co-infected. The mortality rate for tuberculosis and HIV-1 co-infection was 121.7/1000; for tuberculosis without HIV-1 co-infection, 38.5/1000. Fifty-four per cent of maternal deaths caused by tuberculosis were attributable to HIV-1 infection. Thirty-five per cent of maternal deaths were associated with stillbirths; perinatal outcomes were no different between groups of mothers with tuberculosis, HIV-1 or neither infection.

CONCLUSION

Tuberculosis and HIV-1 are emerging as significant contributors to maternal mortality in KwaZulu Natal. Any attempt to improve maternal health must also include careful screening and investigation for tuberculosis in high-risk pregnant women.

Changing clinical presentation and survival in HIV-associated tuberculosis after highly active antiretroviral therapy

OBJECTIVE

To assess changes in clinical presentation and outcome of HIV-associated tuberculosis (TB) before and after widespread implementation of highly active antiretroviral therapy (HAART).

METHODS

We reviewed clinical charts of HIV-infected patients with culture-confirmed pulmonary TB in two referral clinical centers in Rome, Italy. The 67 patients diagnosed in 1995 to 1996 were compared with 51 patients diagnosed in 1997 to 1998. To analyze factors associated with survival we used a Cox model including antiretroviral therapy as a time-dependent covariate.

RESULTS

Patients diagnosed in 1997 to 1998 were more likely to have TB as the first AIDS-defining illness (78% versus 58%, p <.05), to have HIV diagnosed <2 months before TB (33% vs. 7%, p <.005) and to have typical chest radiograph pattern (45% vs. 25%, p <.05), and had a higher CD4(+) count (median 105 vs. 43, p <.005). Survival at 1 year was 80% for patients diagnosed in 1997 to 1998 vs. 65% for those diagnosed in 1995 to 1996 (p by log-rank =.02). After adjusting at multivariate analysis, time period of diagnosis was not confirmed as associated with survival (hazard ratio, 1.05; 95% confidence interval, 0.39--2.81). Age, CD4+ cell count <25/mm(3), and AIDS-defining illnesses before TB diagnosis were all associated with an higher risk of death, whereas a decreased risk of death was observed in patients starting a triple combination antiretroviral therapy after TB diagnosis (hazard ratio, 0.14; 95% confidence interval, 0.03--0.57).

CONCLUSIONS

Cases of HIV-associated TB occurring in patients with advanced immunosuppression and presenting with atypical radiologic appearance tend to be relatively less common in the HAART era. HAART is a major factor in prolonging survival in these patients.

Long-term effect of preventive therapy for tuberculosis in a cohort of HIV-infected Zambian adults

OBJECTIVE

To determine the long-term effect of preventive therapy (PT) for tuberculosis on the rates of tuberculosis, mortality and HIV progression.

METHODS

In a randomized controlled trial, 1053 HIV-positive Zambian adults received isoniazid (H) for 6 months, rifampicin plus pyrazinamide (RZ) for 3 months, or a placebo. CD4 percentage, neopterin, absolute lymphocyte count and haemoglobin were measured from enrolment (absolute CD4 cell counts from 12 months after enrolment). Because PT reduced the incidence of tuberculosis, eligible placebo subjects were offered H. Here, tuberculosis and mortality rates are compared in the three original arms (intention to treat) using data beyond the end of the trial (average follow-up 3 years; maximum 7 years).

RESULTS

There were 102 cases of tuberculosis and 281 deaths (rates 3.6 and 9.0/100 person-years, respectively). There was no significant difference between the tuberculosis rates in the H and RZ groups at any time. The effect of H/RZ on tuberculosis diminished over time (P = 0.011) but the cumulative risk of tuberculosis in the first 2.5 years was significantly lower in the H/RZ group than the placebo group (rate ratio 0.55; 95% confidence interval 0.32-0.93; P = 0.028). There was no significant effect of PT on mortality or progression markers. Tuberculosis was associated with an increased mortality (adjusted rate ratio 1.96; 95% confidence interval 1.21-3.18; P = 0.006).

CONCLUSIONS

Both PT regimens protect against tuberculosis for at least 2.5 years but appear to have no effect on HIV progression or mortality. These results may be used in cost-effectiveness models of PT.

Alteration in CD29(high) CD4(+) lymphocyte subset is a common feature of early HIV disease and of active tuberculosis

Peripheral CD4 T-cell depletion has been observed in human immunodeficiency virus (HIV)-negative patients with pulmonary tuberculosis (TB). To investigate more accurately this alteration, we studied peripheral blood CD45RA(+) and CD29(high) CD4 subsets in 79 TB patients with (HIV(+)TB(+)) or without (HIV(-)TB(+)) HIV infection, 85 HIV-infected patients without TB (HIV(+)TB(-)), and 43 healthy controls, all living in West Africa. The high proportion of CD4(+)CD29(high) T cells observed in controls was dramatically decreased in CDC-A stage HIV(+)TB(-) patients. CD45RA(+) CD4(+) T cells were depleted during the CDC-B stage. Both the percentage and the absolute count of CD29(high)CD4(+) T cells were decreased in HIV(-)TB(+) and HIV(+)TB(+) patients versus controls, but CD45RA(+)CD4(+) T cells were not decreased in TB patients without HIV-infection. Although distinct alterations in the CD4(+) T-cell homeostasis are involved in TB(-) versus HIV-infected subjects, our data suggest that the CD29(+)CD4(+) T-cell depletion observed during the early HIV disease contributes to the risk of active TB, by reducing the pool of T cells able to relocalize to the sites of the M. tuberculosis multiplication.

HIV care in non-industrialised countries

The HIV/AIDS epidemic is now most rapidly expanding in the non-industrialised world. As more and more poor people fall sick and die prematurely, the issue of care for the HIV-infected person living in a resource-poor country is of paramount importance. Rational and comprehensive care packages need to be based on proper understanding of the natural history of infection and accurate measurement of the HIV/AIDS disease burden. In the early stages of infection, disease progression is the same in non-industrialised nations as it is in industrialised countries. Once virulent diseases start, survival is short largely because of limited access to inadequate health care. Therefore, early HIV-related disease, as well as AIDS, are targets for care. Needs are diverse but can be considered as more of the same (e.g. to cope with additional cases of TB generated by HIV) and those new services such as voluntary counselling and testing and palliative care. Budgets are limited everywhere, but prioritisation can be promoted through drawing up a hierarchy of care needs. Specific HIV/AIDS services and the provision of anti-retroviral therapy come after basic services are implemented. Affordable ways to use disease-modifying drugs need to be pursued that are relevant to non-industrialised countries and which do not promote AIDS exceptionalism.

Tuberculosis (TB) and HIV infection are independently associated with elevated serum concentrations of tumour necrosis factor receptor type 1 and beta2-microglobulin, respectively

The aim of this study was to identify immune markers that are independently associated with HIV infection or TB in vivo. Using commercially available assays, we measured concentrations of five immune markers in sera from 175 out-patients attending medical clinics in Cote D'Ivoire and Ghana, West Africa. Patients were categorized into groups with TB only (TB+HIV-, n = 55), TB and HIV co-infection (TB+HIV+, n = 50), HIV infection only (TB-HIV+, n = 35), or neither infection (TB-HIV-, n = 35). TB+HIV+ and TB-HIV+ groups were matched for blood CD4+ lymphocyte count. Mean +/- s.d. concentrations of beta2-microglobulin were similarly increased in both the TB-HIV+ (5.3+/-2.1 microg/ml, P<0.0001) and the TB+HIV+ (5.0+/-1.5 microg/ml, P<0.0001) groups compared with the TB-HIV- group (2.2+/-1.8 microg/ml), but were only slightly increased in the TB+HIV- group (3.2+/-1.8 microg/ml, P = 0.01). In contrast, mean serum concentrations of soluble tumour necrosis factor receptor type I (sTNF-RI) were similarly elevated in the TB+HIV- (1873+/-799 pg/ml, P<0.0001) and TB+HIV+ (1797+/-571 pg/ml, P<0.0001) groups compared with uninfected subjects (906+/-613 pg/ml), but there was only a small increase in sTNF-RI in the TB-HIV+ group (1231+/-165 pg/ml, P = 0.03). Both TB and HIV infection were associated with substantial elevation of serum concentrations of soluble CD8, soluble CD54, and sTNF-R type II. Analysis of additional samples from groups of TB+HIV- and TB+HIV+ patients receiving anti-TB treatment showed significant and equal reductions in mean serum sTNF-RI concentrations, but no significant change in mean beta2-microglobulin. Thus, serum beta2-microglobulin and sTNF-RI serve as relatively independent markers of HIV infection and TB, respectively, in studies of co-infected persons.

Tuberculosis, malnutrition and wasting

Malnutrition predisposes to tuberculosis, and tuberculosis causes 'consumption'. Starting from current advances and historic findings in epidemiology and immunology, we can hope to decipher the effects of macro- and micronutrient deficiency upon tuberculosis, the contribution of immune response to the pathogenesis of wasting, and the best approach to its treatment.

Impact of pulmonary tuberculosis on survival of HIV-infected adults: a prospective epidemiologic study in Uganda

BACKGROUND

Retrospective cohort studies of tuberculosis suggest that active tuberculosis accelerates the progression of HIV infection. The validity of these findings has been questioned because of their retrospective design, diverse study populations, variable compliance with anti-tuberculous therapy and use of anti-retroviral medication. To assess the impact of tuberculosis on survival in HIV infection we performed a prospective study among HIV-infected Ugandan adults with and without tuberculosis.

METHODS

In a prospective cohort study, 230 patients with HIV-associated tuberculosis and 442 HIV-infected subjects without tuberculosis were followed for a mean duration of 19 months for survival. To assess changes in viral load over 1 year, 20 pairs of tuberculosis cases and controls were selected and matched according to baseline CD4 lymphocyte count, age, sex and tuberculin skin test status.

RESULTS

During the follow-up period, 63 out of of 230 tuberculosis cases (28%) died compared with 85 out of 442 controls (19%), with a crude risk ratio of 1.4 [95% confidence interval (CI), 1.07-1.87]. Most deaths occurred in patients with CD4 lymphocyte counts < 200 x 10(6) cells/l at baseline (n = 99) and occurred with similar frequency in the tuberculosis cases (46%) and the controls (44%). When the CD4 lymphocyte count was > 200 x 10(6)/l, however, the relative risk of death in HIV-associated tuberculosis was 2.1 (95% CI, 1.27-3.62) compared with subjects without tuberculosis. For subjects with a CD4 lymphocyte count > 200 x 10(6)/l, the 1-year survival proportion was slightly lower in the cases than in the controls (0.91 versus 0.96), but by 2 years the survival proportion was significantly lower in the cases than in the controls (0.84 versus 0.91; P < 0.02; log-rank test). For subjects with a CD4 lymphocyte count of 200 x 10(6) cells/l or fewer, the survival proportion at 1 year for the controls was lower than cases (0.59 versus 0.64), but this difference was not statistically significant (P = 0.53; logrank test). After adjusting for age, sex, tuberculin skin test status, CD4 lymphocyte count, and history of HIV-related infections, the overall relative hazard for death associated with tuberculosis was 1.81 (95% CI, 1.24-2.65). In a nested Cox regression model, the relative hazard for death was 3.0 (95% CI, 1.62-5.63) for subjects with CD4 lymphocyte counts > 200 x 10(6)/l and 1.5 (95% CI, 0.99-2.40) for subjects with a CD4 lymphocyte count of 200 x 10(6)/l or fewer.

CONCLUSION

The findings from this prospective study indicate that active tuberculosis exerts its greatest effect on survival in the early stages of HIV infection, when there is a reserve capacity of the host immune response. These observations provide a theoretical basis for the treatment of latent tuberculous infection in HIV-infected persons.

Adult tuberculosis overview: African versus Western perspectives

Tuberculosis is currently an enormous global health problem. In industrialized countries in Western Europe and North America, tuberculosis case rates are low and an increasing proportion of cases now occur in foreign-born individuals and in marginalized populations, including the homeless, prisoners, drug users, and persons with human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS). In contrast, the burden of tuberculosis in sub-Saharan Africa continues to grow, largely fueled by the HIV pandemic and poor public health infrastructure. Use of the World Health Organization's (WHO) directly observed therapy, short course (DOTS) strategy has been successful in improving outcomes and preventing the emergence of acquired drug resistance in several African countries; however, case rates are increasing throughout most of the region. It is clear that control of tuberculosis in Africa is closely linked to control of HIV and AIDS. Substantial external donor support and innovative approaches to enhance interactions between HIV/AIDS prevention and treatment efforts and tuberculosis control programs will be needed to improve the current tuberculosis situation in Africa. The purpose of this review is to provide a synopsis of recent developments in these areas and to serve as a reference source for interested readers.