Impact of combination antiretroviral therapy on the risk of tuberculosis among persons with HIV infection

Screening for tuberculosis infection and effectiveness of preventive treatment among people with HIV in low-incidence settings

OBJECTIVE

To determine the yield of screening for latent tuberculosis infection (LTBI) among people with HIV (PWH) in low tuberculosis (TB) incidence countries (<10 TB cases per 100 000 persons).

DESIGN

A systematic review and meta-analysis were performed to assess prevalence and predictive factors of LTBI, rate of TB progression, effect of TB preventive treatment (TPT), and numbers needed to screen (NNS).

METHODS

PubMed and Cochrane Library were searched for studies reporting primary data, excluding studies on active or paediatric TB. We extracted LTBI cases, odds ratios, and TB incidences; pooled estimates using a random-effects model; and used the Newcastle-Ottawa scale for bias.

RESULTS

In 51 studies with 65 930 PWH, 12% [95% confidence interval (CI) 10-14] had a positive LTBI test, which was strongly associated with origin from a TB-endemic country [odds ratio (OR) 4.7] and exposure to TB (OR 2.9). Without TPT (10 629 PWH), TB incidence was 28/1000 person-years (PY; 95% CI 12-45) for LTBI-test positive versus 4/1000 PY (95% CI 0-7) for LTBI-test-negative individuals. Among 625 PWH (1644 PY) receiving TPT, 15 developed TB (6/1000 PY). An estimated 20 LTBI-positive individuals would need TPT to prevent one case of TB, and numbers NNS to detect LTBI or prevent active TB varied according to a-priori risk of LTBI.

CONCLUSION

The relatively high prevalence of LTBI among PWH and the strong correlation with origin from a TB-endemic country support risk-stratified LTBI screening strategies for PWH in low-incidence countries and treating those who test positive.

HIV-associated lung disease

Lung disease encompasses acute, infectious processes and chronic, non-infectious processes such as chronic obstructive pulmonary disease, asthma and lung cancer. People living with HIV are at increased risk of both acute and chronic lung diseases. Although the use of effective antiretroviral therapy has diminished the burden of infectious lung disease, people living with HIV experience growing morbidity and mortality from chronic lung diseases. A key risk factor for HIV-associated lung disease is cigarette smoking, which is more prevalent in people living with HIV than in uninfected people. Other risk factors include older age, history of bacterial pneumonia, Pneumocystis pneumonia, pulmonary tuberculosis and immunosuppression. Mechanistic investigations support roles for aberrant innate and adaptive immunity, local and systemic inflammation, oxidative stress, altered lung and gut microbiota, and environmental exposures such as biomass fuel burning in the development of HIV-associated lung disease. Assessment, prevention and treatment strategies are largely extrapolated from data from HIV-uninfected people. Smoking cessation is essential. Data on the long-term consequences of HIV-associated lung disease are limited. Efforts to continue quantifying the effects of HIV infection on the lung, especially in low-income and middle-income countries, are essential to advance our knowledge and optimize respiratory care in people living with HIV.

Factors Associated with the Effectiveness of Regimens for the Treatment of Tuberculosis in Patients Coinfected with HIV/AIDS: Cohort 2015 to 2019

(1) Background: Infection with the Human Immunodeficiency Virus (HIV) is a significant challenge for tuberculosis (TB) control, with increasing mortality rates worldwide. Moreover, the loss to follow-up is very high, with low adherence to treatment, resulting in unfavorable endpoints. This study aimed to analyze the effectiveness of TB treatment in patients coinfected with HIV/AIDS and its associated factors. (2) Methods: Patients coinfected with TB and HIV/AIDS at a Reference Hospital for infectious diseases were followed up for a maximum of one year from the start of TB treatment until cure or censorship (death, abandonment, and transfer) from 2015 to 2019. The Cox proportional model was used to identify risk factors for effectiveness. (3) Results: Of the 244 patients included in the cohort, 58.2% (142/244) had no treatment effectiveness, 12.3% (30/244) died, and 11.1% (27/244) abandoned treatment. Viral suppression at the onset of TB treatment (HR = 1.961, CI = 1.123-3.422), previous use of Antiretroviral Therapy (HR = 1.676, CI = 1.060-2.651), new cases (HR = 2.407, CI = 1.197-3.501), not using illicit drugs (HR = 1.763, CI = 1.141-2.723), and using the basic TB regimen (HR = 1.864, CI = 1.084-3.205) were significant variables per the multivariate Cox regression analysis. (4) Conclusion: TB treatment for most TB patients coinfected with HIV/AIDS was not effective. This study identified that an undetectable viral load at the beginning of the disease, previous use of ART, not using illicit drugs and not having previously taken anti-TB treatment are factors associated with successful TB treatment.

Prevalence of positive IGRAs and innate immune system in HIV-infected individuals in Japan

INTRODUCTION

Human immunodeficiency virus (HIV) infected individuals are at increased risk of developing active tuberculosis (TB). TB incidence remains higher than in non-HIV subjects after antiretroviral therapy (ART) initiation. This study was conducted to estimate the prevalence of positive IGRA, reflecting latent tuberculosis infection and/or a history of active TB, in HIV-infected individuals after ART initiation in Japan.

METHODS

Two IGRAs (Interferon (IFN)-γ release assays), QuantiFERON®-TB Gold Plus (QFT-Plus) and T-Spot®.TB (TSPOT), were used. We also analyzed the TB associated risk factors for the IGRAs results and the role of CD4⁺ T-cells, CD8⁺ T-cells and NK cells for producing IFN-γ. We also analyzed the risk factors for positive IGRA responses and the role of CD4⁺ T-cells, CD8⁺ T-cells and NK cells for producing IFN-γ.

RESULTS

One hundred eight-four subjects were prospectively enrolled. Median age was 49 years. The positivity rates of QFT-Plus and TSPOT were 7.6% [95%CI 4.6-12.4] and 2.7% [95%CI 1.2-6.2], respectively, with significant difference. TB-associated risk factors and NK cells ≥300/μL were selected as independently significant factors by multivariate logistic regression. The NK cell count revealed significant linear regression with IFN-γ production responding to TB-specific antigens.

CONCLUSIONS

The prevalence of positive IGRAs was 2.7%-7.6%. QFT-Plus would be practical for a higher positivity rate and reflect TB risk factors. The innate immune system, referring to IFN-γ production, plays an important role in the immune response to TB-specific antigens even after initiating ART.

Sociodemographic profiling of tuberculosis hotspots in Ethiopia, 2014-2017

BACKGROUND

Tuberculosis (TB) notification rates vary across regions in Ethiopia and districts within the Amhara Region. The Amhara Region is one of the main TB hotspot regions in the country. In this study we identified the spatial distribution of TB and characterized the sociodemographic factors of spatial clusters in the Amhara Region.

METHODS

An ecological spatial analysis of TB notifications from 2014 to 2017 was conducted to quantify the presence and location of spatial clusters of TB notifications at the district level within the Amhara Region. Global Moran's I statistics and local indicators of spatial association were used to explore the spatial clustering of TB notifications. Notifications from hotspots and low-risk districts were compared to identify significant sociodemographic factors using analysis of variance and Classification and Regression Tree analysis. The geographic information system and 'sp' packages of R software were used for spatial analysis.

RESULTS

From 2014 to 2017 the average notification rate of all forms of TB in the Amhara Region was 107/100 000 population (range 18-614 per 100 000 population). District-level TB notification rates were positively spatially autocorrelated, with Moran's I value ranging from 0.207 to 0.276 (p=0.01). Hotspot TB clusters were found in the northwest and central part of the region. The proportion of migrants (F(3,124)=23.21, p<0.001, d=1.4) was found to be the most important factor associated with hotspot TB clustering.

CONCLUSIONS

TB notification rates in the Amhara Region of Ethiopia over the past 4 y were significantly clustered. Distinguishing high-risk areas from low-risk areas and characterizing the proportion of migrants and other risk factors is important for targeted TB prevention and control in the region.

Inequality in uptake of isoniazid prevention therapy and Mantoux test among pregnant women with HIV in the Eastern Cape, South Africa

Background

HIV-associated tuberculosis (TB) is a major cause of death among pregnant women in South Africa. Isoniazid prevention therapy (IPT) strategy was implemented in South Africa concurrently with life-long antiretroviral therapy (ART) to reduce the TB-associated morbidity and mortality in individuals living with HIV. This study assessed the extent of the implementation of IPT and the performance of the Mantoux test by geographic settings of health facilities and residences of pregnant women living with HIV in the Eastern Cape, South Africa.

Methods

We conducted a data analysis of 1709 pregnant women enrolled in the new electronic database of the prevention of mother-to-child transmission programme of the East London Prospective Cohort Study. Relevant data on place of residence and antenatal care, performance of the Mantoux test and subsequent initiation of IPT were obtained. Descriptive and inferential statistics were employed to analyse the geographical variations and accessibility to Mantoux test and IPT.

Results

The analysis shows that Mantoux test was performed on 803 pregnant women (47%) with significant geographical variation. After controlling for relevant covariates, pregnant women who resided in rural areas (AOR:0.63; CI: 0.47–0.84) compared to those who resided in urban areas were significantly less likely to receive Mantoux test. The rate of uptake of IPT was 79% with significant geographic variations. In the unadjusted model, rural place of residence (UOR:0.68; CI: 0.49–0.96) was independently associated with lower likelihood of uptake of INH prophylaxis; however, the effect was not significant after controlling for important covariates.

Conclusions

The high uptake rate of isoniazid prevention therapy in pregnant women living with HIV at the study sites is commendable; however, concerted efforts are needed to address the inequality gaps in the roll-out of IPT. Poor performance of Mantoux test is a serious concern and requires the attention of TB programme managers and other relevant authorities.

Drug therapy problems for patients with tuberculosis and HIV/AIDS at a reference hospital

OBJECTIVE

To determine the frequency of drug therapy problem in the treatment of patients with tuberculosis and HIV/AIDS.

METHODS

Data were obtained through a cross-sectional study conducted between September 2015 and December 2016 at a reference hospital in infectious diseases in Belo Horizonte (MG), Brazil. Sociodemographic, clinical, behavioral and pharmacotherapeutic variables were evaluated through a semi-structured questionnaire. Drug-related problems of pharmaceutical care were classified using the Pharmacotherapy Workup method. Factors associated with indication, effectiveness, safety and compliance drug therapy problem were assessed through multiple logistic regression.

RESULTS

We evaluated 81 patients, and 80% presented at least one drug therapy problem, with indication and adherence drug therapy problem being the most frequent. The factors associated with drug therapy problem were age, marital status, new case, ethnicity, time of HIV diagnosis and time to treat tuberculosis.

CONCLUSION

The frequency of drug therapy problem in coinfected patients was high and the identification of the main drug therapy problem and associated factors may lead the multiprofessional health team to ensure the use of the most indicated, effective, safe and convenient medicines for the patients clinical condition. Tuberculosis and HIV/AIDS coinfected individuals aged over 40 years are more likely to have drug therapy problems during treatment; in that, the most frequente are those that signal toward need of medication for an untreated health condition and non-compliance to treatment. Thus, older patients, unmarried or married, who have treated tuberculosis before, with a shorter time to tuberculosis treatment and longer time to diagnose HIV/AIDS, should receive special attention and be better followed by a multiprofessional health team because they indicate a higher chance of presenting Problems related to the use of non-adherent drugs.

Tuberculosis and HIV Coinfection–the Challenge in the Prevention, Detection and Treatment of Tuberculosis

Background:

Tuberculosis (TB) is still a major public health concern world-wide. The increasing global burden of TB is linked to HIV infection. HIV-TB coinfection has also conditioned clinical aspects of the TB. Since the HIV is beginning in the 1980s, the HIV infection poses a significant challenge in global TB control.

Objective:

In this review we focused on the challenges of epidemiological and clinical feature of tuberculosis presented by the HIV coinfection.

Method:

The article consists of a summary of the most important effects presented by the HIV coinfection on epidemiological and clinical feature of tuberculosis. The article analyzes and summary the causes for these challenges.

Results:

The major challenges to strategy of TB control and clinical feature of TB-HIV coinfection are presented in this paper.

Conclusion:

HIV/TB co-infection is synergic, interactive and reciprocal with significant impact. The infection of HIV and Mtb affect each other and the breakdown the immune function in TB/HIV coinfected individual. HIV infection has changed the strategy of TB control, however HIV increases global burden of TB, the reduction in the TB incidence rate is far from sufficient. Atypically clinical manifestations in TB/HIV co-infected patients and increased MDR-TB and XDR-TB contribute to the challenges in the diagnosis and treatment. Increased complexity of managing patients requires expertise in the clinical m knowledge. The focused efforts to control HIV-related TB are of great urgency. These findings will provide insight into the prevention, detection and treatment of tuberculosis and will guide advances towards tuberculosis control.

Prevalence and Risk Factors of Active TB among Adult HIV Patients Receiving ART in Northwestern Tanzania: A Retrospective Cohort Study

INTRODUCTION

Although ART has improved the outcome of people living with HIV/AIDS, still some patients develop TB while receiving ART. The literature on the magnitude of this problem is still scarce in our setting especially northwestern Tanzania. This study was designed to determine the prevalence of active TB among HIV patients on ART and assess its potential risk factors.

METHODS

A retrospective cohort study was done among adult HIV-positive patients initiated on ART at Bugando Medical Centre. Patients who were TB positive before ART initiation were excluded. Data regarding demographic, clinical, and laboratory information, TB status on receipt of ART, and time on ART were collected and analyzed using STATA 11 to determine the prevalence of TB and its associated factors.

RESULTS

In total, 391 patients were enrolled in this study. The median age was 39 (32-46) years, and a total of 129 (32.99%) participants had CD4 counts <200 cells/µl and 179 (45.78%) had WHO stage 3 and 4 illnesses. A total of 43 (11.0%) participants developed TB while receiving ART which was independently associated with male gender (OR = 2.9; p=0.007), WHO clinical stage 3 and 4 (OR = 1.4; p=0.029), baseline CD4 count <200 cells/µl (OR = 9.1; p < 0.001), and having not used IPT (OR = 3.1; p=0.05).

CONCLUSIONS

Active TB is prevalent among HIV patients while receiving ART in northwestern Tanzania which is independently associated with male gender, advanced HIV disease, and nonuse of IPT. Universal HIV testing could reduce late HIV diagnosis and hence reduce the risk of developing TB while receiving ART in our setting. Also IPT should be widely used for those who are negative for TB on screening.

A Comparison of Adverse Drug Reaction Profiles in Patients on Antiretroviral and Antitubercular Treatment in Zimbabwe

INTRODUCTION

Few studies describe the adverse drug event profiles in patients simultaneously receiving antiretroviral and anti-tubercular medicines in resource-limited countries.

OBJECTIVES

To describe and compare the adverse drug reaction profiles in patients on highly active antiretroviral therapy only (HAART), HAART and isoniazid preventive therapy (HHART), and HAART and antitubercular treatment (ATTHAART).

METHODS

We analysed individual case safety reports (ICSRs) for patients on antiretroviral therapy and antitubercular treatment submitted to the national pharmacovigilance centre during the targeted spontaneous reporting (TSR) programme from 1 September 2012 through 31 August 2016. All reports considered certain, probable or possible were included in the analysis.

RESULTS

A total of 1076 ICSRs were included in the analysis. Most of the reports were from the HAART only group (n = 882; 82.0%), followed by patients on HHART (n = 132; 12.3%), and ATTHAART (n = 62; 5.7%). The ATTHAART (35.5%) and HHAART (34.1%) had a higher frequency of hepatic disorders than the HAART group (5.0%) (p < 0.0001). A higher frequency of rash was reported in the HHAART (35.6%) and HAART groups (29.4%) than the ATTHAART group (14.5%) (p = 0.011). Peripheral neuropathy occurred more frequently in the ATTHAART group (19.3%) than other groups (p = 0.001) while Stevens-Johnson syndrome (14.7%; p < 0.001), gynaecomastia (18.2%; p < 0.001), and lipodystrophy (4.5%; p = 0.012) occurred more frequently in the HAART group. The HHAART group was associated with a higher frequency of psychosis (4.5%; p = 0.002).

CONCLUSION

Antiretroviral therapy was associated with a higher frequency of Stevens-Johnson syndrome, gynaecomastia, and lipodystrophy. Co-administration of antiretroviral and antitubercular medicines was associated with a higher frequency of drug-induced liver injury and peripheral neuropathy. Similarly, co-administration of isoniazid preventive therapy and antiretroviral drugs was associated with a higher risk for psychosis. There is a need to carefully manage TB/HIV co-infected patients, due to the higher risk of adverse drug reactions which may lead to poor treatment adherence and outcomes.

Reduction of HIV-associated excess mortality by antiretroviral treatment among tuberculosis patients in Kenya

Background

Mortality from TB continues to be a global public health challenge. TB ranks alongside Human Immunodeficiency Virus (HIV) as the leading infectious causes of death globally. HIV is a major driver of TB related morbidity and mortality while TB is the leading cause of mortality among people living with HIV/AIDS. We sought to determine excess mortality associated with HIV and the effect of antiretroviral therapy on reducing mortality among tuberculosis patients in Kenya.

Methods

We conducted a retrospective analysis of Kenya national tuberculosis program data of patients enrolled from 2013 through 2014. We used direct standardization to obtain standardized mortality ratios for tuberculosis patients compared with the general population. We calculated the population attributable fraction of tuberculosis deaths due to HIV based on the standardized mortality ratio for deaths among TB patients with HIV compared to TB patients without HIV. We used Cox proportional hazards regression for assessing risk factors for mortality.

Results

Of 162,014 patients included in the analysis, 6% died. Mortality was 10.6 (95% CI: 10.4–10.8) times higher among TB patients than the general population; 42% of deaths were attributable to HIV infection. Patients with HIV who were not receiving ART had an over four-fold risk of death compared to patients without HIV (aHR = 4.2, 95% CI 3.9–4.6). In contrast, patients with HIV who were receiving ART had only 2.6 times the risk of death (aHR = 2.6, 95% CI 2.5–2.7).

Conclusion

HIV was a significant contributor to TB-associated deaths in Kenya. Mortality among HIV-infected individuals was higher among those not on ART than those on ART. Early initiation of ART among HIV infected people (a “test and treat” approach) should further reduce TB-associated deaths.

The Immune Interaction between HIV-1 Infection and Mycobacterium tuberculosis

The modulation of tuberculosis (TB)-induced immunopathology caused by human immunodeficiency virus (HIV)-1 coinfection remains incompletely understood but underlies the change seen in the natural history, presentation, and prognosis of TB in such patients. The deleterious combination of these two pathogens has been dubbed a "deadly syndemic," with each favoring the replication of the other and thereby contributing to accelerated disease morbidity and mortality. HIV-1 is the best-recognized risk factor for the development of active TB and accounts for 13% of cases globally. The advent of combination antiretroviral therapy (ART) has considerably mitigated this risk. Rapid roll-out of ART globally and the recent recommendation by the World Health Organization (WHO) to initiate ART for everyone living with HIV at any CD4 cell count should lead to further reductions in HIV-1-associated TB incidence because susceptibility to TB is inversely proportional to CD4 count. However, it is important to note that even after successful ART, patients with HIV-1 are still at increased risk for TB. Indeed, in settings of high TB incidence, the occurrence of TB often remains the first presentation of, and thereby the entry into, HIV care. As advantageous as ART-induced immune recovery is, it may also give rise to immunopathology, especially in the lower-CD4-count strata in the form of the immune reconstitution inflammatory syndrome. TB-immune reconstitution inflammatory syndrome will continue to impact the HIV-TB syndemic.

Effect of secondary preventive therapy on recurrence of tuberculosis in HIV-infected individuals: a systematic review

Human immunodeficiency virus (HIV)-infected individuals successfully treated for tuberculosis (TB) remain at risk of recurrence of the disease, especially in high TB incidence settings. We performed a systematic review, investigating whether secondary preventive therapy (sPT) with anti-TB drugs (preventive therapy in former TB patients with treatment success) is an effective strategy to prevent recurrence of TB in this patient group. We searched the databases PubMed, Cochrane Library, EMBASE, Web of Science and Google Scholar using the keywords HIV-infections, HIV, human immunodeficiency virus, AIDS, isoniazid, isoniazid preventive therapy (IPT), tuberculosis, TB, recurrence and recurrent disease, resulting in 253 potential publications. We identified eight publications for full text assessment, after which four articles qualified for inclusion in this systematic review. The quality of the included articles was rated using the GRADE system. All but one study were rated as having a high quality. In all included studies, sPT significantly decreased the incidence of recurrent TB in HIV-infected individuals to a substantial degree in comparison to non-treatment or placebo. Relative reductions varied from 55.0% to 82.1%. These data showed that the use of sPT to prevent recurrent TB in HIV-infected individuals was highly beneficial. These findings need to be confirmed in prospective studies with an adequate assessment of the effect of antiretroviral therapy (ART) and the occurrence of drug resistance.

Implementation and Operational Research: Declining Tuberculosis Incidence Among People Receiving HIV Care and Treatment Services in East Africa, 2007-2012

BACKGROUND

Antiretroviral therapy (ART) reduces the risk of Tuberculosis (TB) among people living with HIV (PLWH). With ART scale-up in sub-Saharan Africa over the past decade, incidence of TB among PLWH engaged in HIV care is predicted to decline.

METHODS

We conducted a retrospective analysis of routine clinical data from 168,330 PLWH receiving care at 35 facilities in Kenya, Tanzania, and Uganda during 2003-2012, participating in the East African region of the International Epidemiologic Databases to Evaluate AIDS. Temporal trends in facility-based annual TB incidence rates (per 100,000 person years) among PLWH and country-specific standardized TB incidence ratios using annual population-level TB incidence data from the World Health Organization were computed between 2007 and 2012. We examined patient-level and facility-level factors associated with incident TB using multivariable Cox models.

RESULTS

Overall, TB incidence rates among PLWH in care declined 5-fold between 2007 and 2012 from 5960 to 985 per 100,000 person years [P = 0.0003] (Kenya: 7552 to 1115 [P = 0.0007]; Tanzania: 7153 to 635 [P = 0.0025]; Uganda: 3204 to 242 [P = 0.018]). Standardized TB incidence ratios significantly decreased in the 3 countries, indicating a narrowing gap between incidence rates among PLWH and the general population. We observed lower hazards of incident TB among PLWH on ART and/or isoniazid preventive therapy and receiving care in facilities offering TB treatment onsite.

CONCLUSIONS

Annual TB incidence rates among PLWH significantly declined during ART scale-up but remained higher than the general population. Increasing access to ART and isoniazid preventive therapy and co-location of HIV and TB treatment may further reduce TB incidence among PLWH.

Isoniazid Prophylactic Therapy for the Prevention of Tuberculosis in HIV Infected Adults: A Systematic Review and Meta-Analysis of Randomized Trials

Background

Infection with Human Immunodeficiency virus (HIV) is an important risk factor for Tuberculosis (TB). Anti-Retroviral Therapy (ART) has improved the prognosis of HIV and reduced the risk of TB infected patients. Isoniazid Preventive Therapy (IPT) aims to reduce the development of active TB in patients with latent TB.

Objective

Systematically review and synthesize effect estimates of IPT for TB prevention in adult HIV patients. Secondary objectives were to assess the effect of IPT on HIV disease progression, all-cause mortality and adverse drug reaction (ADR).

Search Strategy

Electronic databases were searched to identify relevant articles in English available by September 11^th 2015.

Selection Criteria

Research articles comparing IPT to placebo or no treatment in HIV infected adults using randomized clinical trials.

Data Analysis

A qualitative review included study-level information on randomization and treatment allocation. Effect estimates were pooled using random-effects models to account for between-study heterogeneity.

Main Results

This review assessed ten randomized clinical trials that assigned 7619 HIV patients to IPT or placebo. An overall 35% of TB risk reduction (RR = 0.65, 95% CI (0.51, 0.84)) was found in all participants, however, larger benefit of IPT was observed in Tuberculin Skin Test (TST) positive participants, with pooled relative risk reduction of 52% [RR = 0.48; 95% CI (0.29, 0.82)] and with a prediction interval ranging from 0.13 to 1.81. There was no statistically significant effect of IPT on TB occurrence in TST negative or unknown participants. IPT also reduced the risk of HIV disease progression in all participants (RR = 0.69; 95% CI (0.48, 0.99)) despite no benefits observed in TST strata. All-cause mortality was not affected by IPT although participants who had 12 months of IPT tend to have a reduced risk (RR = 0.65; 95% CI(0.47, 0.90)). IPT had an elevated, yet statistically non-significant, risk of adverse drug reaction [RR = 1.20; 95% CI (1.20, 1.71)]. Only a single study assessed the effect of IPT in combination with ART in preventing TB and occurrence of multi-drug resistant tuberculosis.

Conclusions

IPT use substantially contributes in preventing TB in persons with HIV in general and in TST positive individuals in particular. More evidence is needed to explain discrepancies in the protective effect of IPT in these individuals.

Risk of tuberculosis among HAART receiving HIV patients attending an ART centre of West Bengal, India: a prospective cohort study

This prospective study was conducted to find out the incidence density rate and to identify the attributed risk factors of Tuberculosis development among ART receivers. All patients who were registered in a nodal ART centre of India within 1st January 2008-31st December 2008 and had been initiated ART in the year of 2008 were considered as a cohort and were followed up till 31st December 2012. This study was started with 169 ART receivers and ended with 129 patients. During total 631.1 person-years observation, 39 TB cases (31 pulmonary and 8 extra pulmonary) were diagnosed. TB incidence density rate reduced from 12.08/100 to 1.12/100 person-years during the follow up periods. Cox regression model revealed that patients having past history of Tuberculosis were at 5 times higher risk (Hazard ratio = 5.205; 95 % CI 2.439-11.106; p = 0.000). Patients with WHO clinical stage 3 or 4 at the time of enrolment had 2 times more risk of development of TB (Hazard ratio = 2.081; 95 % CI 1.502-2.884; p = 0.000). This study highlighted that special attention should be paid on earliest identification of TB among the HIV patients who had past history of TB or suffering from WHO clinical stage 3 or 4 to prevent the silent transmission and multidrug resistance development of Tuberculosis in the community.

Aspartic peptidases of human pathogenic trypanosomatids: perspectives and trends for chemotherapy

Aspartic peptidases are proteolytic enzymes present in many organisms like vertebrates, plants, fungi, protozoa and in some retroviruses such as human immunodeficiency virus (HIV). These enzymes are involved in important metabolic processes in microorganisms/virus and play major roles in infectious diseases. Although few studies have been performed in order to identify and characterize aspartic peptidase in trypanosomatids, which include the etiologic agents of leishmaniasis, Chagas’ disease and sleeping sickness, some beneficial properties of aspartic peptidase inhibitors have been described on fundamental biological events of these pathogenic agents. In this context, aspartic peptidase inhibitors (PIs) used in the current chemotherapy against HIV (e.g., amprenavir, indinavir, lopinavir, nelfinavir, ritonavir and saquinavir) were able to inhibit the aspartic peptidase activity produced by different species of Leishmania. Moreover, the treatment of Leishmania promastigotes with HIV PIs induced several perturbations on the parasite homeostasis, including loss of the motility and arrest of proliferation/growth. The HIV PIs also induced an increase in the level of reactive oxygen species and the appearance of irreversible morphological alterations, triggering parasite death pathways such as programed cell death (apoptosis) and uncontrolled autophagy. The blockage of physiological parasite events as well as the induction of death pathways culminated in its incapacity to adhere, survive and escape of phagocytic cells. Collectively, these results support the data showing that parasites treated with HIV PIs have a significant reduction in the ability to cause in vivo infection. Similarly, the treatment of Trypanosoma cruzi cells with pepstatin A showed a significant inhibition on both aspartic peptidase activity and growth as well as promoted several and irreversible morphological changes. These studies indicate that aspartic peptidases can be promising targets in trypanosomatid cells and aspartic proteolytic inhibitors can be benefic chemotherapeutic agents against these human pathogenic microorganisms.

Incomplete restoration of Mycobacterium tuberculosis-specific-CD4 T cell responses despite antiretroviral therapy

OBJECTIVES

Despite antiretroviral therapy (ART), HIV-infected persons have increased risk of active tuberculosis (TB). PPD and combined ESAT-6 and CFP-10-specific-CD4 (EC-Sp-CD4) responses were examined over 96 weeks.

METHODS

HIV-infected, ART-naive Thai adults with CD4 T cell count ≤350 cells/μL starting ART were assessed at baseline, wk4, 8, 12, 24, 48 and 96. PPD and EC-Sp-CD4 T cells were detected by CD25/CD134 co-expression after stimulation with antigens.

RESULTS

Fifty subjects were enrolled, 39 were male, median age 32 yrs, median baseline CD4 T cell count 186 cells/μL and plasma HIV-viral-load 4.9log10 copies/mL. Seventeen were TB-sensitised. At baseline, 25 had positive PPD and 15 had positive EC-Sp-CD4 response. CD4 T cell count <100 cells/μL was less (P = 0.005) and TB-sensitisation was more likely (P = 0.013) to be associated with positive baseline PPD-Sp-CD4 response. At wk4, the number of subjects with positive PPD-Sp-CD4 response rose to 35 (P = 0.021). Mean PPD-Sp-CD4 T cells increased at wk4 (P = 0.017) in patients not classified as TB-sensitised. The number of subjects with positive EC-Sp-CD4 response did not change significantly post ART. In TB-sensitised patients, mean EC-Sp-CD4 T cells declined to below baseline from wk12 (P = 0.010) onwards. EC-Sp-CD4 responses were undetectable in 3 out of 17 TB-sensitised patients.

CONCLUSIONS

Restoration of responses to TB-antigens was incomplete and inconsistent under the employed experimental conditions and may account for persistent increased risk of TB despite ART.

Drug resistance profiles of Mycobacterium tuberculosis complex and factors associated with drug resistance in the Northwest and Southwest Regions of Cameroon

BACKGROUND

Anti-tuberculosis drug resistance continues to be a major obstacle to tuberculosis (TB) control programmes with HIV being a major risk factor in developing TB. We investigated anti-TB drug resistance profiles and the impact of socioeconomic as well as behavioural factors on the prevalence of TB and drug resistance in two regions of Cameroon with such data paucity.

METHODS

This was a hospital-based study in which 1706 participants, comprising 1133 females and 573 males consecutively enrolled from selected TB and HIV treatment centres of the Northwest and Southwest regions. Demographic, clinical and self-reported risk behaviours and socioeconomic data were obtained with the consent of participants using questionnaires. Culture and drug resistance testing were performed according to standard procedures.

RESULTS

The prevalence of resistance to at least one anti-TB drug was 27.7% and multi-drug resistance was 5.9%. Smoking, concurrent alcohol consumption and smoking, being on antiretroviral therapy for ≤ 12 months and previous household contact with TB patient were independently associated with tuberculosis prevalence, while only previous tuberculosis infection was associated with drug resistance in a univariate analysis.

CONCLUSION

The study showed a high prevalence of drug resistance TB in the study population with only previous TB infection associated with drug resistance in a univariate analysis. It also provides evidence in our context, of the role of alcohol and smoking in increasing the risk of developing TB, which is more likely in people living with HIV/AIDS. Therefore, it is important for public health authorities to integrate and intensify alcohol/smoking abstention interventions in TB and HIV control programs in Cameroon.

Global policy review of antiretroviral therapy eligibility criteria for treatment and prevention of HIV and tuberculosis in adults, pregnant women, and serodiscordant couples

OBJECTIVE

This article reviews the antiretroviral therapy (ART)initiation criteria from national treatment guidelines for 70 countries and determines the extent of consistency with the current World Health Organization (WHO) recommendations.

METHODS

Published ART guidelines were collected from the Internet, databases, and WHO staff. ART eligibility criteria for asymptomatic people, pregnant women, people with HIV-associated tuberculosis, serodiscordant couples, injecting drug users, men who have sex with men, and sex workers were abstracted from them. Multiple regression analysis was used to determine the relation between ART eligibility criteria, ART coverage, and various population characteristics and policy interventions.

RESULTS

Of the 70 countries, 42 (60%) follow WHO’s ART guidelines for asymptomatic people and 31 (44%) for pregnant women,recommending ART at CD4 count of ≤350 cells/mm(3). Twenty-three(33%) countries recommend ART for people with HIV-associated tuberculosis irrespective of CD4 count. Nineteen countries are also recommending or considering earlier ART above CD4 count ≤350 cell/mm(3) for asymptomatic people, pregnant women, and/or serodiscordant couples. Multiple linear regression analysis shows that HIV prevalence, year of publication of guidelines, and HIV expenditure are significantly associated with published ART eligibility criteria. On average, the ART coverage is similar irrespective of published guidelines being consistent with the WHO recommendation(P , 0.53).

CONCLUSIONS

Published guidelines from a significant number of countries are not following WHO recommendations. Although published guidelines may not reflect practice, it is important to adapt recommendations and services quickly to reflect the emerging science on the health and prevention benefits of earlier access to ART.

Granulomas of intestinal tuberculosis and Crohn's disease can be differentiated by CD73 cell surface marker expression: a pilot study

BACKGROUND

Intestinal tuberculosis (ITB) and Crohn's disease are similar granulomatous disorders. Granulomas are present in both and difficult to differentiate on histopathology alone. A recent study demonstrated recruitment of mesenchymal cells (MSCs) at the periphery of granulomas in lymph node tuberculosis which suppressed T cell responses. We hypothesized that granulomas of ITB would also recruit MSCs to evade host immune response.

AIM

The purpose of this study was to demonstrate MSC markers in granulomas of ITB and evaluate whether distribution of MSC markers could differentiate between granulomas of Crohn's and ITB.

METHODS

We initially retrospectively enrolled 17 patients with confirmed ITB (8) or Crohn's (9) with granulomas on histopathology. Tissues were evaluated by immunofluorescence for MSC markers CD29, CD90, CD73 and absence of haematopoietic markers CD31, CD34, CD45 and CD14. Double-staining was done to confirm presence of MSCs. Subsequently, 23 postoperative specimens of Crohn's (18) and ITB (5) were analyzed for validation.

RESULTS

Overall, 27 Crohn's and 13 ITB cases were assessed. CD29 and CD90 positive cells were noted around both ITB and Crohn's granulomas. MSC marker CD73 was expressed around the granulomas of ITB alone and was completely absent in the Crohn's. The subsequent assessment of granulomas in postoperative specimens of Crohn's and ITB also showed similar results.

CONCLUSION

Granulomas of ITB and Crohn's disease can be differentiated by CD73 MSC surface marker expression. The differential CD73 expression around ITB granuloma indicates that Mycobacterium tuberculosis evades host immunity by recruiting MSCs with CD73 expression. MSCs with increased CD73 expression could be the future for therapeutic intervention in Crohn's.

Skewing of the CD4(+) T-cell pool toward monofunctional antigen-specific responses in patients with immune reconstitution inflammatory syndrome in The Gambia

BACKGROUND

A common complication of starting antiretroviral therapy (ART) for human immunodeficiency virus (HIV) is the development of immune reconstitution inflammatory syndrome (IRIS) in approximately 25% of patients. Despite similarities with paradoxical reactions to tuberculosis and reversal reactions in leprosy, the exact mechanisms, and therefore potential determinants, of IRIS are still unknown.

METHODS

In this longitudinal cohort study, we analyzed 20 patients who developed IRIS following initiation of ART and 16 patients who did not, matched for ART time point. Peripheral blood mononuclear cells were stimulated overnight with a positive control antigen and 2 tuberculosis-specific antigens (purified protein derivative [PPD] and ESAT-6/CFP10), followed by polychromatic flow cytometry for analysis of cytokine production from CD4(+) and CD8(+) T cells.

RESULTS

Responses to PPD were significantly higher in IRIS patients compared to controls during the IRIS time point, but CD4(+) and CD8(+) T-cell responses to the positive control stimulation were significantly lower in IRIS patients at all time points. Furthermore, whereas control patients had rejuvenated polyfunctional T-cell responses by 3 months after ART, IRIS patients were strikingly monofunctional (generally interferon γ alone), even up to 6 months of ART in response to all stimulations.

CONCLUSIONS

Our findings suggest that the peripheral T-cell responses to the underlying pathogen are exaggerated in IRIS patients but that the overall quality of the peripheral T-cell pool is significantly reduced compared to non-IRIS patients. Furthermore, these effects are apparent at least up to 3 months after cessation of IRIS.

HIV-prevalence in tuberculosis patients in Germany, 2002-2009: an estimation based on HIV and tuberculosis surveillance data

Tuberculosis (TB) and HIV comorbidity is a major challenge in TB prevention and control but difficult to assess in Germany as in other countries, where data confidentiality precludes notifying the HIV status of TB patients. We aimed to estimate the HIV-prevalence in TB patients in Germany, 2002-2009, and to characterize the HIV/TB patients demographically. Data from the long-term observational open multicentre cohort ClinSurv HIV were used to identify incident TB in HIV-positive individuals. We assessed the cohort's coverage for the nationwide HIV-positive population by contrasting ClinSurv HIV patients under antiretroviral therapy (ART) with national HIV patient numbers derived from ART prescriptions (data by Insight Health; available for 2006-2009). The HIV-prevalence in TB patients was calculated as the number of HIV/TB cases projected for Germany over all culture-positive TB notifications. From 2002 to 2009, 298 of 15,531 HIV-positive patients enrolled in the ClinSurv HIV cohort were diagnosed with TB. A 21% cohort coverage was determined. The annual estimates of the HIV-prevalence in TB patients were on average 4.5% and ranged from 3.5% (95%CI 2.3-5.1%) in 2007 to 6.6% (95%CI 5.0-8.5%) in 2005. The most recent estimate for 2009 was 4.0% (95%CI 2.6-5.9%). The 298 HIV/TB patients were characterized by a male-to-female ratio of 2.1, by a median age of 38 years at TB diagnosis, and by 59% of the patients having a foreign origin, mainly from Subsahara Africa. We provide, to our knowledge, the first estimate of the HIV-prevalence in TB patients for Germany by joint evaluation of anonymous HIV and TB surveillance data sources. The identified level of HIV in TB patients approximates available surveillance data from neighbouring countries and indicates a non-negligible HIV/TB burden in Germany. Our estimation approach is valuable for epidemiological monitoring of HIV/TB within the current legal frameworks.

Tuberculosis in travellers

Tuberculosis (TB) incidence is increasing in many countries which are popular with international travellers. The development of active TB is a two-stage process; the risk of acquiring new TB infection depends primarily on the risk of contact with an individual with infectious TB, and the risk of disease on the immune status of the newly infected person. The risk of TB infection is low for most holiday-makers, but among long-term travellers to countries with high TB incidence, the risk may be similar to that experienced by the local population (0.5-2.5% per year); the risk to people working in health care is particularly high. Effective pre-travel advice involves assessing the traveller's risk of TB infection and disease. Recommendations on the prevention of TB in travellers vary between countries. Possible strategies include avoidance of exposure; BCG vaccination; and tuberculin skin testing before and after travel, with preventive therapy for those whose post-travel skin tests indicate recent infection. For those at highest risk of progression to disease, there may be value in preventive therapy during travel to reduce the risk of new TB infection. Further information on the contribution of recent travel to incident TB in industrialised countries would be valuable.

Undiagnosed tuberculosis among HIV clinic attendees: association with antiretroviral therapy and implications for intensified case finding, isoniazid preventive therapy, and infection control

OBJECTIVES

Initiation of antiretroviral therapy (ART) and the 3I's are strategies to prevent HIV-associated tuberculosis (TB). We describe factors associated with undiagnosed TB among HIV-infected patients attending an HIV clinic in South Africa and discuss implications for the 3 Is.

DESIGN

Convenience sample of HIV clinic attendees.

METHODS

HIV-infected participants were assessed for TB using a symptom screen, sputum-smear microscopy, sputum and blood mycobacterial culture, fine needle aspiration of enlarged lymph nodes, and chest radiography.

RESULTS

Four hundred twenty-two participants were enrolled. The median age and CD4+ T-cell count were 37 years [interquartile range (IQR): 31-44 years] and 215 cells per microliter (IQR: 107-347 cells/μL). Forty-seven percent had been on ART for a median duration of 8 months (IQR: 3.3-22.8 months). Three hundred sixty-one participants (85.6%) reported TB symptoms. Twenty-seven participants (6.4%) met criteria for bacteriologically confirmed TB and 50 (11.6%) for any form of TB. Bacteriologically confirmed TB was associated with CD4+ T-cell counts ≤100 cells per microliter (odds ratio: 5.05, 95% confidence interval: 1.69 to 15.12) when compared with CD4+ T-cell counts >200 cells per microliter and hemoglobin {hemoglobin < 10 g/dL [odds ratio 3.12 (95% confidence interval: 1.26 to 7.72)]}.

CONCLUSIONS

Undiagnosed TB among HIV-infected ambulatory patients was associated with low CD4+ T-cell counts regardless of ART status. TB screening algorithms which include CD4+ T-cell count and hemoglobin testing may be an effective way to identify HIV-infected clinic attendees at highest risk of undiagnosed TB. Isoniazid preventive therapy and TB infection control are essential for reducing occurrence of HIV-associated TB even after ART initiation.

Prevalence of pulmonary tuberculosis and immunological profile of HIV co-infected patients in Northwest Ethiopia

Background

In sub-Saharan Africa, as high as 2/3 of tuberculosis patients are HIV/AIDS co-infected and tuberculosis is the most common cause of death among HIV/AIDS patients worldwide. Tuberculosis and HIV co-infections are associated with special diagnostic and therapeutic challenges and constitute an immense burden on healthcare systems of heavily infected countries like Ethiopia. The aim of the study was to determine the prevalence of pulmonary tuberculosis and their immunologic profiles among HIV positive patients.

Methods

A cross sectional study was conducted among adult HIV-positive patients attending HIV/AIDS clinic of Gondar University Hospital. Clinical and laboratory investigations including chest x-ray and acid fast staining were used to identify tuberculosis cases. Blood samples were collected to determine CD4+ lymphocyte count. A structured questionnaire was used to collect socio-demographic characteristics of study subjects. The data was entered and analyzed using SPSS version 16 software.

Results

A total of 400 HIV positive study participants were enrolled. Thirty (7.5%, 95%CI: 5.2-10.6%) of the study participants were found to have pulmonary tuberculosis. In multivariate analysis, only CD4+ lymphocyte count (AOR = 2.9; 95% CI: 1.002-8.368) was found to be independently associated with tuberculosis-HIV co-infection. Individuals who had advanced WHO clinical stage were also statistically significant for co-infection. The mean CD4+ lymphocyte count of HIV mono-infected participants were 296 ± 192 Cells/mm3 and tuberculosis-HIV co-infected patients had mean CD4+ lymphocyte count of 199 ± 149 Cells/mm3 with p value of 0.007.

Conclusions

We found high prevalence of tuberculosis-HIV co-infection. Lower CD4+ lymphocyte count was found to be the only predicting factor for co-infection. Early detection of co-infection is very necessary to prolong their ART initiation time and by then strengthening their immune status.

Immunotherapy for TB

Mycobacterium tuberculosis was one of the first human pathogens to be identified as the cause of a specific disease – TB. TB was also one of the first specific diseases for which immunotherapy was attempted. In more than a century since, multiple different immunotherapies have been attempted, alongside vaccination and antibiotic treatment, with varying degrees of success. Despite this, TB remains a major worldwide health problem that causes nearly 2 million deaths annually and has infected an estimated 2 billion people. A major reason for this is that M. tuberculosis is an ancient human pathogen that has evolved complex strategies for persistence in the human host. It has thus been long understood that, to effectively control TB, we will need to address the ability of the pathogen to establish a persistent, latent infection in most infected individuals. This review discusses what is presently known about the interaction of M. tuberculosis with the immune system, and how this knowledge has been used to design immunotherapeutic strategies.

Incidence of tuberculosis and early mortality in a large cohort of HIV infected patients receiving antiretroviral therapy in a tertiary hospital in Addis Ababa, Ethiopia

Preceding studies on morbidities and mortalities associated with TB in a cohort of HIV care indicate high incidence of TB development and premature death among patients on highly active antiretroviral treatment (HAART). This study aims to measure the rate of TB, TB mortality, and associated risk factors following commencement of HAART in a cohort of patients attending HIV care in Ethiopia. Patient information was gathered from the hospital register and analysed. TB incidence peaked within six months of HAART initiation, and dropped from 3.3/100 person-years in the first year to 0.4/100 person-years in the fifth year. At baseline, risk factors associated with TB included WHO clinical stage 3 HIV infection (adjusted hazard ratio (AHR) 2.53; 95% CI 1.70-3.70), WHO clinical stage 4 HIV infection (AHR, 3.86; 95% CI 2.54-5.86), and patients who were bed ridden >50% a day (AHR, 1.52; 95% CI 1.13-2.05). The rate of mortality was 6.9% (incidence 2.8 per 100 person-years) and 57% of deaths occurred in the first six months of HAART initiation. Multivariate Cox model indicated WHO clinical stage 4 HIV infection, CD4+ cell count <50 cells/μl, bed ridden >50% a day, and TB after HAART initiation as baseline independent predictors of mortality. Additional evidence shows that regular CD4+monitoring of patients before HAART initiation as well as earlier HAART initiation decreases death, and regular clinical staging decreases TB incidence.

Impact of antiretroviral therapy on tuberculosis incidence among HIV-positive patients in high-income countries

BACKGROUND

The lower tuberculosis incidence reported in human immunodeficiency virus (HIV)-positive individuals receiving combined antiretroviral therapy (cART) is difficult to interpret causally. Furthermore, the role of unmasking immune reconstitution inflammatory syndrome (IRIS) is unclear. We aim to estimate the effect of cART on tuberculosis incidence in HIV-positive individuals in high-income countries.

METHODS

The HIV-CAUSAL Collaboration consisted of 12 cohorts from the United States and Europe of HIV-positive, ART-naive, AIDS-free individuals aged ≥18 years with baseline CD4 cell count and HIV RNA levels followed up from 1996 through 2007. We estimated hazard ratios (HRs) for cART versus no cART, adjusted for time-varying CD4 cell count and HIV RNA level via inverse probability weighting.

RESULTS

Of 65 121 individuals, 712 developed tuberculosis over 28 months of median follow-up (incidence, 3.0 cases per 1000 person-years). The HR for tuberculosis for cART versus no cART was 0.56 (95% confidence interval [CI], 0.44-0.72) overall, 1.04 (95% CI, 0.64-1.68) for individuals aged >50 years, and 1.46 (95% CI, 0.70-3.04) for people with a CD4 cell count of <50 cells/μL. Compared with people who had not started cART, HRs differed by time since cART initiation: 1.36 (95% CI, 0.98-1.89) for initiation <3 months ago and 0.44 (95% CI, 0.34-0.58) for initiation ≥3 months ago. Compared with people who had not initiated cART, HRs <3 months after cART initiation were 0.67 (95% CI, 0.38-1.18), 1.51 (95% CI, 0.98-2.31), and 3.20 (95% CI, 1.34-7.60) for people <35, 35-50, and >50 years old, respectively, and 2.30 (95% CI, 1.03-5.14) for people with a CD4 cell count of <50 cells/μL.

CONCLUSIONS

Tuberculosis incidence decreased after cART initiation but not among people >50 years old or with CD4 cell counts of <50 cells/μL. Despite an overall decrease in tuberculosis incidence, the increased rate during 3 months of ART suggests unmasking IRIS.

Impact of previous ART and of ART initiation on outcome of HIV-associated tuberculosis

Background. Combination antiretroviral therapy (cART) has progressively decreased mortality of HIV-associated tuberculosis .To date, however, limited data on tuberculosis treatment outcomes among coinfected patients who are not ART-naive at the time of tuberculosis diagnosis are available. Methods. A multicenter, observational study enrolled 246 HIV-infected patients diagnosed with tuberculosis, in 96 Italian infectious diseases hospital units, who started tuberculosis treatment. A polytomous logistic regression model was used to identify baseline factors associated with the outcome. A Poisson regression model was used to explain the effect of ART during tuberculosis treatment on mortality, as a time-varying covariate, adjusting for baseline characteristics. Results. Outcomes of tuberculosis treatment were as follows: 130 (52.8%) were successfully treated, 36 (14.6%) patients died in a median time of 2 months (range: 0–16), and 80 (32.6%) had an unsuccessful outcome. Being foreign born or injecting drug users was associated with unsuccessful outcomes. In multivariable Poisson regression, cART during tuberculosis treatment decreased the risk of death, while this risk increased for those who were not ART-naive at tuberculosis diagnosis. Conclusions. ART during tuberculosis treatment is associated with a substantial reduction of death rate among HIV-infected patients. However, patients who are not ART-naive when they develop tuberculosis remain at elevated risk of death.

Tuberculosis risk before and after highly active antiretroviral therapy initiation: does HAART increase the short-term TB risk in a low incidence TB setting?

OBJECTIVE

To evaluate the short-term and long-term effects of highly active antiretroviral therapy (HAART) on tuberculosis (TB) risk compared with risk without HAART in a low TB incidence setting.

DESIGN

An observational cohort study among HIV-infected persons in care at the Comprehensive Care Center (Nashville, TN) between January 1998 and December 2008.

METHODS

A marginal structural model was used to estimate the effect of HAART on short-term (≤180 days) and long-term (>180 days) TB risk, with CD4⁺ lymphocyte count incorporated as a time-updated covariate.

RESULTS

Of 4534 HIV-infected patients, 34 developed TB (165 per 100,000 person-years; 20,581 person-years of follow-up). Seventeen cases occurred among persons not on HAART or >30 days after HAART discontinuation (212 per 100,000 person-years; 8019 person-years of follow-up). Seventeen occurred among persons on HAART (135 per 100,000 person-years; 12,562 person-years of follow-up); 10 in the first 180 days (402 per 100,000 person-years; 2489 person-years of follow-up); and 7 after more than 180 days (69 per 100,000 person-years; 10,073 person-years of follow-up). After adjusting for the most recent CD4⁺ lymphocyte count, the risk of TB in the first 180 days of HAART exposure relative to no HAART was 0.68 (0.14-3.22, P = 0.63).

CONCLUSIONS

In this low TB incidence setting, the TB rate in the first 180 days of HAART was almost twice as high as persons not on HAART. However, after adjusting for most recent CD4⁺ count, there was no significant difference in TB risk between these 2 groups. This suggests that low recent CD4⁺ lymphocyte count influences TB risk during the first 180 days of HAART.

An evaluation of factors associated with taking and responding positive to the tuberculin skin test in individuals with HIV/AIDS

BACKGROUND

The tuberculin skin test (TST) is still the standard test for detecting latent infection by M tuberculosis (LTBI). Given that the Brazilian Health Ministry recommends that the treatment of latent tuberculosis (LTBI) should be guided by the TST results, the present study sets out to describe the coverage of administering the TST in people living with HIV at two referral health centers in the city of Recife, where TST is offered to all patients. In addition, factors associated with the non-application of the test and with positive TST results were also analyzed.

METHODS

A cross-sectional study was carried out with HIV patients, aged 18 years or over, attending outpatient clinics at the Correia Picanço Hospital/SES/PE and the Oswaldo Cruz/UPE University Hospital, who had been recommended to take the TST, in the period between November 2007 and February 2010. Univariate and multivariate logistic regression analyses were carried out to establish associations between the dependent variable - taking the TST (yes/no), at a first stage analysis, and the independent variables, followed by a second stage analysis considering a positive TST as the dependent variable. The odds ratio was calculated as the measure of association and the confidence interval (CI) at 95% as the measure of accuracy of the estimate.

RESULTS

Of the 2,290 patients recruited, 1087 (47.5%) took the TST. Of the 1,087 patients who took the tuberculin skin test, the prevalence of TST ≥ 5 mm was 21.6% among patients with CD4 ≥ 200 and 9.49% among those with CD4 < 200 (p = 0.002). The patients most likely not to take the test were: men, people aged under 39 years, people with low educational levels and crack users. The risk for not taking the TST was statiscally different for health service. Patients who presented better immunity (CD4 ≥ 200) were more than two and a half times more likely to test positive that those with higher levels of immunodeficiency (CD4 < 200).

CONCLUSIONS

Considering that the TST is recommended by the Brazilian health authorities, coverage for taking the test was very low. The most serious implication of this is that LTBI treatment was not carried out for the unidentified TST-positive patients, who may consequently go on to develop TB and eventually die.

Costs and consequences of additional chest x-ray in a tuberculosis prevention program in Botswana

RATIONALE

Isoniazid preventive therapy is effective in reducing the risk of tuberculosis (TB) in persons living with HIV (PLWH); however, screening must exclude TB disease before initiating therapy. Symptom screening alone may be insufficient to exclude TB disease in PLWH because some PLWH with TB disease have no symptoms. The addition of chest radiography (CXR) may improve disease detection.

OBJECTIVES

The objective of the present analysis was to compare the costs and effects of the addition of CXR to the symptom screening process against the costs and effects of symptom screening alone.

METHODS

Using data from Botswana, a decision analytic model was used to compare a "Symptom only" policy against a "Symptom+CXR" policy. The outcomes of interest were cost, death, and isoniazid- and multidrug-resistant TB in a hypothetical cohort of 10,000 PLWH.

MEASUREMENTS AND MAIN RESULTS

The Symptom+CXR policy prevented 16 isoniazid- and 0.3 multidrug-resistant TB cases; however, because of attrition from the screening process, there were 98 excess cases of TB, 15 excess deaths, and an additional cost of U.S. $127,100. The Symptom+CXR policy reduced deaths only if attrition was close to zero; however, to eliminate attrition the cost would be U.S. $2.8 million per death averted. These findings did not change in best- and worst-case scenario analyses.

CONCLUSIONS

In Botswana, a policy with symptom screening only preceding isoniazid-preventive therapy initiation prevents more TB and TB-related deaths, and uses fewer resources, than a policy that uses both CXR and symptom screening.

Tuberculosis in patients receiving antiretroviral treatment: incidence, risk factors, and prevention strategies

OBJECTIVE

To determine tuberculosis (TB) incidence rates and risk factors among individuals receiving antiretroviral treatment (ART).

DESIGN

Observational cohort in Johannesburg, South Africa.

METHODS

Incident TB was classified as early (less than 6 months of ART) or late (greater than 6 months of ART) incident TB. CD4 cell counts, viral load, body mass index, and hemoglobin were measured 6-monthly. Hazard ratios for factors associated with early and late incident TB were assessed using Cox proportional hazards regression.

RESULTS

During 13,416 person-years of follow-up, 501 TB cases occurred among 7536 individuals, corresponding to a 10% risk in the first 4 years of ART and an overall incidence rate of 4.2 cases/100 person-years. The highest incidence rate (21.7 per 100 person-years) was observed in the first 3 months of ART among people with CD4 count below 50 cells/mm3. Low baseline CD4 count, anemia, and low body mass index were the strongest risk factors for early incident TB. Low updated CD4 count, low updated body mass index, anemia, and high viral load on ART were strong risk factors for late incident TB.

CONCLUSIONS

Severity of HIV disease and unfavorable response to ART are associated with early and late incident TB, respectively. Early ART initiation and intensified TB screening at ART initiation are crucial to reduce incident TB.

The implementation of isoniazid preventive therapy in HIV clinics: the experience from the TB/HIV in Rio (THRio) study

OBJECTIVE

The TB/HIV in Rio (THRio) study was launched in September 2005 to assess the impact of integrated tuberculosis (TB) and HIV treatment strategies in 29 HIV clinics in Rio de Janeiro, Brazil.

DESIGN

THRio is a cluster-randomized trial (CRT) to determine whether routine screening for and treatment of latent TB in HIV clinic patients with access to antiretroviral therapy will reduce TB incidence at the clinic level. THRio is part of the Consortium to Respond Effectively to AIDS/TB Epidemic that is implementing research studies to assess the impact of bold, new public health paradigms for controlling the AIDS/TB epidemic.

METHODS

Twenty-nine public primary HIV clinics were randomly assigned a date to begin implementing TB screening procedures and provision of isoniazid preventive therapy (IPT) for TB/HIV coinfected patients. Final analysis of the CRT is expected in 2011.

RESULTS

Starting at date of tuberculin skin test (TST)/IPT implementation at each clinic through August 2010, 1670 HIV-infected patients initiated IPT, of which 215 are still receiving treatment. Of the remaining 1455 patients, 1230 (85%) completed therapy and only 20 (1.2%) patients initiating IPT reported adverse reactions leading to discontinuation of therapy. IPT completion was higher among HIV-infected patients receiving HAART (87%) than those not yet receiving HAART (79%, P < 0.01). Times to TST and IPT have markedly decreased postintervention, but remain considerably long. The richness of the THRio database has resulted in several analyses of this expansive cohort of HIV-infected patients that are reviewed here.

CONCLUSIONS

The national implementation of TST and IPT for HIV-positive patients in Brazil has been invigorated partly due to THRio's baseline results. Expanded use of IPT in HIV patients in Rio de Janeiro is achievable with high adherence and low adverse events, although this effort requires a package of activities including training, advocacy and reorganization of services.

Human immunodeficiency virus and tuberculosis coinfection in children: challenges in diagnosis and treatment

The burden of childhood tuberculosis (TB) is influenced by the human immunodeficiency virus (HIV) epidemic and this dangerous synergy affects various aspects of both diseases; from pathogenesis and the epidemiologic profile to clinical presentation, diagnosis, treatment, and prevention. HIV-infected infants and children are at increased risk of developing severe forms of TB. The TB diagnosis is complicated by diminished sensitivity and specificity of clinical features and diagnostic tools like the tuberculin skin test and chest x-ray. Although alternative ways of pulmonary sampling and the development of interferon-γ assays have shown to lead to some improvement of TB diagnosis in HIV-infected children, new diagnostic tools are urgently needed. Coadministration of anti-TB treatment and antiretroviral drugs induces severe complications, and this highlights the need to define optimal treatment regimens. Practical implementation of these regimens in TB control programs should be combined with isoniazid preventive therapy in TB-exposed HIV-infected children. The risk of severe complications after Bacille Calmette-Guérin vaccination of HIV-infected children emphasizes the need for new nonviable vaccines. This article reviews the current status of pediatric HIV-TB coinfection with specific emphasis on the diagnosis and treatment.

Tuberculosis risk factors and mortality for HIV-infected persons receiving antiretroviral therapy in South Africa

OBJECTIVE

To determine important risk factors for and impact of tuberculosis on survival in HIV-infected patients starting antiretroviral therapy (ART) in South Africa.

DESIGN

Prospective trial of 1771 HIV-infected patients with either CD4 cell count less than 200 cells/microl or a prior AIDS-defining illness, enrolled in randomized trial of four antiretroviral regimens.

METHODS

Data collected from patient records.

RESULTS

A history of tuberculosis at study entry was reported by 27% of patients and correlated with poor baseline health status. A history of tuberculosis at baseline was associated with subsequent tuberculosis and death during ART, but was not itself an independent risk factor for poor outcome. Tuberculosis was diagnosed during ART in 14% of patients and was more frequent during the first 3 months. Tuberculosis during therapy was independently associated with increased hazard of other AIDS-defining events and death, regardless of when during ART tuberculosis occurred. ART that consistently suppressed circulating viremia reduced but did not eliminate tuberculosis risk.

CONCLUSION

In HIV-infected patients who started ART at low CD4 cell counts, tuberculosis at baseline was a predictor of death, but was not independent of other factors indicating poor baseline health status. Tuberculosis during follow-up was, in contrast, an independent predictor of death even after adjustments for baseline risk factors, including CD4 cell count and viral load. Virologic failure during ART was associated with a 55% increase in risk of tuberculosis. Thus, tuberculosis is a major marker for poor outcome both at baseline and during ART and is not completely eliminated by fully suppressive ART.

Tuberculosis vaccines: present and future

There has never been a greater need for a new protective tuberculosis vaccine. Bacille Calmette-Guerin remains the cornerstone of any vaccine strategy, but improving its immunogenicity and efficacy has now become an urgent global health priority. This review discusses the main vaccines currently in clinical development and other novel vaccine strategies in the pipeline. It addresses the key questions in vaccine design, including antigen selection, route of vaccine delivery and immune correlates of vaccine-induced protection. There is an opportunity to identify such correlates from ongoing and future Phase II/III trials and, as these emerge, they can be used to validate the most relevant and predictive animal models with which to develop the next generation of new vaccines.

Tuberculosis in Europe: a problem of drug resistance or much more?

Tuberculosis has re-emerged as a public health concern in high-income countries in the last few decades. The European region accounts for only 5% of world TB cases. The incidence of new TB cases in Europe varies from very low rates in Scandinavian countries (six to eight cases/100,000 population) to rates as high as 231 cases/100,000 population in Tajikistan; the Russian Federation is eleventh among the 22 high-burden TB countries. The estimated detection rate of new sputum smear-positive pulmonary cases and the treatment success rate in 2007 were poor compared with other WHO regions: 51% of cases were diagnosed and 70% of them completed a full course of anti-TB therapy, which is still a long way from the World Health Assembly targets (detection of 70% of infectious cases and successful treatment of 85% of them). The low success rate is largely attributable to the increasing number of drug-resistant TB cases: Eastern European countries are among those with the highest rates of multidrug-resistant (MDR)-TB (TB resistant to rifampicin and isoniazid) in the world. By the end of September 2009, at least one case of extensively drug-resistant TB (named XDR-TB and defined as a MDR-TB strain with additional resistance to any fluoroquinolone, and to at least one of three injectable drugs used in anti-TB treatment) had been reported by 25 countries in the WHO European Region. In Western Europe, TB continues to cause disease among elderly native-born individuals, although high-risk groups including immigrants, prisoners, HIV-infected persons and drug addicts significantly contribute to the overall burden. Improved TB control in Europe requires a large coordinated effort by all stakeholders, including governments, governmental and non-governmental institutions, as well as the academic and private sectors and affected communities.

The burden and characteristics of tuberculosis/human immunodeficiency virus (TB/HIV) in South Korea: a study from a population database and a survey

BACKGROUND

Although, in South Korea, human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS) keeps increasing and tuberculosis(TB) burden is still significant, there have been few reports on TB/HIV cases. In this study, we investigated the burden and characteristics of TB/HIV patients in South Korea, an area with intermediate burden of TB and a low prevalent area with HIV/AIDS.

METHODS

We identified patients with TB and cases with HIV between January 1 2001 and December 31 2005, from nationwide reporting system (TBnet and HIV/AIDS registry) through an electronic record linkage method. A questionnaire survey was also conducted and determined the rate of diagnosis of HIV among TB cases in public health units in 2005.

RESULTS

The number of cases with both HIV and TB was 137 (0.07% among 197,562 TB cases) and the newly detected TB/HIV cases per 100,000 population was increasing annually: 2001, 0.025; 2002, 0.031; 2003, 0.025; 2004, 0.071; 2005, 0.095. Males between 20 and 59 years of age accounted for 87.6% of TB/HIV patients. Compared with patients with TB alone, those with TB/HIV had a higher percentage of extrapulmonary TB (8.0% vs 19.0%; p < 0.0001). The standardized prevalence ratio (SPR) of HIV among patients with TB was 18.46 (95% CI, 15.50-21.83). SPR of HIV among male TB patients aged 20-59 and extrapulmonary TB cases was 39.64 (95% CI, 32.87-47.40) and 43.21 (95% CI, 28.22-63.31) respectively. Through a questionnaire survey of public health units, six patients (0.08%) were confirmed as having HIV among 7,871 TB patients in public health centers in 2005, which is similar to the result from the study through nationwide reporting systems.

CONCLUSIONS

The prevalence rate of TB/HIV patients is still low but increasing in South Korea. Physicians should consider performing HIV tests among TB patients, especially in higher-risk groups, such as young males with extrapulmonary TB in South Korea.

Influence of HIV infection on mortality in a cohort of patients treated for tuberculosis in the context of wide access to HAART, in Rio de Janeiro, Brazil

OBJECTIVE

To analyze the influence of HIV serostatus on mortality related to tuberculosis (TB) in the context of wide access to highly active antiretroviral therapy (HAART) in a middle-income country.

METHODS

Prospective cohort study including patients who started antituberculous therapy between April 2000 and July 2005 at a referral center in Rio de Janeiro, Brazil.

RESULTS

Two hundred seven patients were enrolled, 106 were seropositive for HIV. There were 21 TB-related deaths in HIV-positive subjects (24.7 deaths per 100 patient-years) and 2 (2.5 deaths per 100 patient-years) among HIV-negative patients (rate ratio = 9.76, P < 0.001). Among HIV-infected subjects, TB-related mortality tended to be lower in patients treated with HAART [hazard ratio (HR) = 0.58, P = 0.06]. However, mortality among patients treated with HAART was still significantly increased as compared with HIV-negative patients (HR = 6.6, P = 0.014). In a Cox regression model adjusted for disseminated TB (P = 0.04), and treatment with antituberculous regimens not containing rifampicin (P = 0.11), mortality was significantly higher among seropositive patients not on HAART compared with HIV-negative subjects (HR = 6.30, P = 0.024). Among subjects treated with HAART, there was a nonsignificant increase in mortality (rate ratio = 3.48, P = 0.14).

CONCLUSIONS

HIV infection still has a substantial impact on TB-related mortality in the context of wide access to HAART in a middle-income country.

Antiretroviral therapy for control of the HIV-associated tuberculosis epidemic in resource-limited settings

Great progress has been made over the past few years in HIV testing in patients who have tuberculosis (TB) and in the scale-up of antiretroviral therapy. More than 3 million people in resource-limited settings were estimated to have started antiretroviral therapy by the end of 2007 and 2 million of these were in sub-Saharan Africa. However, little is known about what impact this massive public health intervention will have on the HIV-associated TB epidemic or how antiretroviral therapy might be used to best effect TB control. This article provides an in-depth review of these issues.

Mortality from HIV and TB coinfections is higher in Eastern Europe than in Western Europe and Argentina

BACKGROUND AND OBJECTIVES

Tuberculosis (TB) is a leading cause of death in HIV-infected patients worldwide. We aimed to study clinical characteristics and outcome of 1075 consecutive patients diagnosed with HIV/TB from 2004 to 2006 in Europe and Argentina.

METHODS

One-year mortality was assessed in patients stratified according to region of residence, and factors associated with death were evaluated in multivariable Cox models.

RESULTS

At TB diagnosis, patients in Eastern Europe had less advanced immunodeficiency, whereas a greater proportion had a history of intravenous drug use, coinfection with hepatitis C, disseminated TB, and infection with drug-resistant TB (P < 0.0001). In Eastern Europe, fewer patients initiated TB treatment containing at least rifamycin, isoniazid, and pyrazinamide or combination antiretroviral therapy (P < 0.0001). Mortality at 1 year was 27% in Eastern Europe, compared with 7, 9 and 11% in Central/Northern Europe, Southern Europe, and Argentina, respectively (P < 0.0001). In a multivariable model, the adjusted relative hazard of death was significantly lower in each of the other regions compared with Eastern Europe: 0.34 (95% confidence interval 0.17-0.65), 0.28 (0.14-0.57), 0.34 (0.15-0.77) in Argentina, Southern Europe and Central/Northern Europe, respectively. Factors significantly associated with increased mortality were CD4 cell count less than 200 cells/microl [2.31 (1.56-3.45)], prior AIDS [1.74 (1.22-2.47)], disseminated TB [2.00 (1.38-2.85)], initiation of TB treatment not including rifamycin, isoniazid and pyrazinamide [1.68 (1.20-2.36)], and rifamycin resistance [2.10 (1.29-3.41)]. Adjusting for these known confounders did not explain the increased mortality seen in Eastern Europe.

CONCLUSION

The poor outcome of patients with HIV/TB in Eastern Europe deserves further study and urgent public health attention.

Tuberculosis among people with HIV infection in the United Kingdom: opportunities for prevention?

OBJECTIVE

To investigate the incidence of, and risk factors for, tuberculosis among HIV clinic attendees in the United Kingdom.

DESIGN AND METHODS

Observational cohort study of 27 868 individuals in the United Kingdom Collaborative HIV Cohort collaboration, 1996-2005.

RESULTS

Among individuals not taking combination antiretroviral therapy (cART), tuberculosis incidence was considerably higher among individuals of black African vs. white or other ethnicities {incidence rates 9.9 [95% confidence intervals (CIs) 7.2, 12.6], 2.5 [95% CI 1.8, 3.0] and 4.4 [95% CI 2.7, 6.0] episodes per 1000 person-years, respectively}. Tuberculosis incidence decreased with time after starting cART; among black Africans, incidence was consistently higher and remained substantial (5.3 per 1000 person-years) at 24 months and longer after starting cART. The strongest independent risk factors for tuberculosis after cART start were most recent CD4 cell count: adjusted rate ratios (aRR) 10.65 (95% CI 6.11, 18.57), 3.40 (95% CI 2.05, 5.65), 1.77 (95% CI 1.06, 2.96) and 1.84 (95% CI 1.09, 3.12) for individuals with CD4 cell counts less than 50, 50-199, 200-349 and 350-499 cells/microl, respectively, compared with at least 500 cells/microl; and black African vs. white ethnicity [aRR 2.93 (95% CI 1.89, 4.54)]. HIV risk group, shorter time on cART, later calendar period and unsuppressed viral load were also independently associated with incident tuberculosis.

CONCLUSIONS

Tuberculosis incidence among people attending UK HIV clinics is substantial, particularly among those with non-white ethnicity and low CD4 cell counts, even after starting cART. Earlier HIV diagnosis is needed in order to implement interventions to prevent tuberculosis; tuberculosis preventive therapy should be considered in addition to cART.