Predictive markers of survival in HIV-seropositive and HIV-seronegative Tanzanian patients with extrapulmonary tuberculosis

Hepatitis B Co-Infection is Associated with Poorer Survival of HIV-Infected Patients on Highly Active Antiretroviral Therapy in West Africa

BACKGROUND

Hepatitis B has been reported to be high in HIV-infected African populations. However, the impact of this co-infection on the survival of HIV-infected Africans on long-term highly active antiretroviral therapy (HAART) remains poorly characterised. We investigated the impact of HBV/HIV co-infection on survival of HIV infected patients undergoing antiretroviral therapy in a West African population.

METHODS

This was a clinic-based cohort study of HIV-infected adults enrolled in Nigeria, West Africa. Study subjects (9,758) were screened for hepatitis B and hepatitis C at HAART initiation. Kaplan-Meier survival and Cox proportional hazards models were used to estimate probability of survival and to identify predictors of mortality respectively, based on hepatitis B surface antigen status. All patients had signed an informed written consent before enrolment into the study; and we additionally obtained permission for secondary use of data from the Harvard institutional review board.

RESULTS

Patients were followed up for a median of 41 months (interquartile range: 30-62 months) during which, 181 (1.9%) patients died. Most of the deaths; 143 (79.0%) occurred prior to availability of Tenofovir. Among those that were on antiretroviral therapy, hepatitis B co-infected patients experienced a significantly lower survival than HIV mono-infected patients at 74 months of follow up (94% vs. 97%; p=0.0097). Generally, hepatitis B co-infection: HBsAg-positive/HIV-positive (Hazards Rate [HR]; 1.5: 95% CI 1.09-2.11), co-morbid tuberculosis (HR; 2.2: 95% CI 1.57-2.96) and male gender (HR; 1.5: 95% CI 1.08-2.00) were significantly predictive of mortality. Categorising the patients based on use of Tenofovir, HBV infection failed to become a predictor of mortality among those on Tenofovir-containing HAART.

CONCLUSIONS

HBsAg-positive status was associated with reduced survival and was an independent predictor of mortality in this African HIV cohort on HAART. However, Tenofovir annulled the impact of HBV on mortality of HIV patients in the present study cohort.

Incidence and predictors of mortality and the effect of tuberculosis immune reconstitution inflammatory syndrome in a cohort of TB/HIV patients commencing antiretroviral therapy

BACKGROUND

Tuberculosis-HIV (TB-HIV) coinfection remains an important cause of mortality in antiretroviral therapy (ART) programs. In a cohort of TB-HIV-coinfected patients starting ART, we examined the incidence and predictors of early mortality.

METHODS

Consecutive TB-HIV-coinfected patients eligible for ART were enrolled in a cohort study at the Mulago National Tuberculosis and Leprosy Program clinic in Kampala, Uganda. Predictors of mortality were assessed using Cox proportional hazards analysis.

RESULTS

Three hundred and two patients [median CD4 count 53 cells/μL (interquartile range, 20-134)] were enrolled. Fifty-three patients died, 36 (68%) of these died within the first 6 months of TB diagnosis. Male sex [hazard (HR): 2.19; 95% confidence interval (CI): 1.19 to 4.03; P = 0.011], anergy to tuberculin skin test [HR: 2.59 (1.10 to 6.12); P = 0.030], a positive serum cryptococcal antigen result at enrollment (HR: 4.27; 95% CI: 1.50 to 12.13; P = 0.006) and no ART use (HR: 4.63; 95% CI: 2. 37 to 9.03; P < 0.001) were independent predictors of mortality by multivariate analysis. Six (10%) patients with TB immune reconstitution inflammatory syndrome died, and in most, an alternative contributing cause of death was identified.

CONCLUSIONS

Mortality among these TB-HIV-coinfected patients was high particularly when presenting with advanced HIV disease and not starting ART, reinforcing the need for timely and joint treatment for both infections. Screening for a concomitant cryptococcal infection and antifungal treatment for patients with cryptococcal antigenemia may further improve clinical outcome.

Tuberculosis and HIV disease: two decades of a dual epidemic

The HIV epidemic is currently in its third decade without any sign of abating. Tuberculosis (TB) is responsible for a third of all AIDS deaths, 99% of which occur in developing countries. The two epidemics fuel each other, together making up the leading infectious causes of mortality worldwide. Tuberculosis-HIV coinfection presents special diagnostic and therapeutic challenges and constitutes an immense burden on the health care systems of heavily infected countries. Despite major gains that have been made in the past two decades, important questions still remain. To cope with the challenge of TB-HIV coinfection, further research in the design of diagnostic tests for tuberculosis, detection of drug resistant Mycobacterium tuberculosis strains in HIV-positive people, as well as development of more effective therapeutic agents and vaccines are urgently needed. It has become evident that this dual epidemic will persist unless comprehensive measures are instituted through the provision of sufficient funding in addition to expanding and strengthening current control strategies adopted by governments and international organizations.

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.

Evolution of serum beta2-microglobulin concentrations during treatment of tuberculosis patients

A total of 36 human immunodeficiency virus-seronegative patients were studied in order to evaluate serum beta2-M levels in immunocompetent patients with tuberculosis who were receiving treatment. Six measurements of several clinical and laboratory parameters were carried out at different intervals during the 6 months of treatment. The mean serum beta2-M at presentation was 149 nmol/l and 4 patients had values above the upper normal limit. Significant decreases in the mean serum beta2-M concentration were observed in the follow-up determinations in the patients as a whole (p = 0.002), in the patients with normal (p = 0.039) and in the patients with increased beta2-M at presentation (p = 0.037). beta2-M significantly correlated with erythrocyte sedimentation rate (p = 0.002). The statistically significant decrease observed in patients with both normal and increased beta2-M values at presentation, suggests that the immunological dysfunction responsible for the increase in beta2-M involves most, if not all, patients with tuberculosis. The measurement of beta2-M in conjunction with other clinical and laboratory parameters could be helpful in evaluating the response to therapy, particularly in those patients with increased beta2-M at presentation.

Tuberculous lymphadenitis, a diagnostic problem in areas of high prevalence of HIV and tuberculosis

The human immunodeficiency virus (HIV) epidemic is associated with a marked increase of tuberculosis cases. The influence of HIV on diagnostic methods for tuberculous lymphadenitis is less clear. In an environment of high HIV and tuberculosis prevalence in Blantyre, Malawi, a prospective study compared results of basic procedures diagnosing tuberculous lymphadenitis with the outcome of histology and/or culture. One hundred out-patients, aged 15-55 years, with extra-inguinal lymphadenopathy not responding to general antibiotics, entered the study. Among 52 cases, with whom all procedures were carried out in accordance with the protocol, 38 (73%) were diagnosed as tuberculous lymphadenitis; 84% of the latter (32/38) were seropositive for HIV. Needle aspirate and biopsy smears stained by the Ziehl-Neelsen technique contributed little to detecting tuberculosis, 8% and 11% respectively. In contrast, macroscopic caseation of excised lymph nodes showed a high yield of 82%, which was similar to histology, and higher than that of Löwenstein-Jensen culture (61%). The study suggested that HIV positivity of tuberculous lymphadenitis patients decreased the possibility of histology and culture both being indicative of tuberculosis (odds ratio 0.10; P = 0.06). Consequently histology results, often used as the single definitive method, failed to diagnose 18% (7/38) of tuberculosis cases. However, it was reassuring that 4 simple methods, which can safely be carried out at district level, could be expected to diagnose 80-95% of tuberculous lymphadenitis cases in a timely and cost-effective manner.

PCR detection of mycobacteraemia in tanzanian patients with extrapulmonary tuberculosis

In 191 Tanzanian patients admitted to hospital with suspected extrapulmonary tuberculosis (TB), TB was diagnosed in 158 patients; the remaining 33 patients had neither microbiological nor clinical evidence of TB. Mycobacterium tuberculosis was detected in the blood of 25 patients, in 92% by a polymerase chain reaction (PCR) technique and in 52% by culture of buffy coat cells. The presence of mycobacterial DNA or Mycobacterium tuberculosis bacteria in peripheral blood (positive culture) was significantly associated with HIV infection; it was detected in 22 (21.4%) of 103 HIV-seropositive patients compared to only 3 (3.5%) of 55 HIV-seronegative patients (p < 0.009). In two-thirds of the patients with mycobacteraemia, TB can be detected by simple smears from other organ sites. In patients with suspected extrapulmonary tuberculosis in whom smears from the infected site are negative or not available, PCR on blood will confirm the diagnosis within 24 hours in one third of the cases.