Diagnosis & treatment of tuberculosis in HIV co-infected patients.

Human immunodeficiency virus (HIV) associated tuberculosis (TB) remains a major global public health challenge, with an estimated 1.4 million patients worldwide. Co-infection with HIV leads to challenges in both the diagnosis and treatment of tuberculosis. Further, there has been an increase in rates of drug resistant tuberculosis, including multi-drug (MDR-TB) and extensively drug resistant TB (XDRTB), which are difficult to treat and contribute to increased mortality. Because of the poor performance of sputum smear microscopy in HIV-infected patients, newer diagnostic tests are urgently required that are not only sensitive and specific but easy to use in remote and resource-constrained settings. The treatment of co-infected patients requires antituberculosis and antiretroviral drugs to be administered concomitantly; challenges include pill burden and patient compliance, drug interactions, overlapping toxic effects, and immune reconstitution inflammatory syndrome. Also important questions about the duration and schedule of anti-TB drug regimens and timing of antiretroviral therapy remain unanswered. From a programmatic point of view, screening of all HIV-infected persons for TB and viceversa requires good co-ordination and communication between the TB and AIDS control programmes. Linkage of co-infected patients to antiretroviral treatment centres is critical if early mortality is to be prevented. We present here an overview of existing diagnostic strategies, new tests in the pipeline and recommendations for treatment of patients with HIV-TB dual infection.

Pharmacokinetics of lamivudine & stavudine in generic fixed-dose combinations in HIV-1 infected adults in India.

Background & objectives: Antiretroviral drug concentrations are important determinants of clinical response to a drug accounting for both toxicity and efficacy. Several factors such as age, ethnicity, body weight and patients’ immune status may influence antiretroviral drug concentrations. The aim of the study was to determine the influence of immunological status, sex and body mass index on the steady state pharmacokinetics of lamivudine (3TC) and stavudine (d4T) in HIV-infected adults, who were undergoing treatment with generic fixed dose combinations (FDC) of these drugs in India. Methods: Twenty seven HIV-1 infected patients receiving antiretroviral treatment (ART) for at least two weeks at the Government ART clinic at Tambaram, Chennai, took part in the study. Serial blood samples were collected predosing and at different time points after drug administration. Plasma 3TC and d4T levels were estimated by HPLC. Results: The patients’ immune status, sex or body mass index had no impact on the pharmacokinetics of 3TC. In the case of d4T, peak concentration was significantly lower in patients with CD4 cell counts < 200 cells/μl than those with ≥ 200 cells/ μl (P < 0.05), but were within the therapeutic range. The mean CD4 cell counts increased from 101 cells/μl at initiation of ART to 366 cells/μl at 12 months of treatment. Interpretation & conclusions: Blood levels of 3TC and d4T drugs that are part of generic FDCs commonly used by HIV-infected individuals in India were within the therapeutic range and not influenced by nutritional or immune status. There was a significant improvement in CD4 cell counts over 12 months of treatment. Indian generic FDCs manufactured and used widely in the developing world provide effective concentrations of antiretroviral drugs.

CCR2, MCP-1, SDF-1α & DC-sign gene polymorphisms in HIV-1 infected patients with & without tuberculosis.

Background & objectives: Variability in the clinical outcome of persons exposed to and infected with HIV-1 and tuberculosis (TB) is determined by multiple factors including host genetic variations. The aim of the present study was to find out whether chemokine, chemokine receptor and DC-SIGN gene polymorphisms were associated with susceptibility or resistance to HIV and HIV-TB in south India. Methods: CCR2 V64I (G/A), monocyte chemoattractant protein-1 (MCP-1) -2518 A/G, stromal cell derived factor-1α (SDF-1α) 3’UTR G/A and DC-SIGN gene polymorphisms were studied by polymerase chain reaction based methods in HIV-1 infected patients without TB (n=151), with pulmonary TB (PTB) (n=81) and extrapulmonary TB (n=31), 155 PTB patients without HIV and 206 healthy controls. Results: The genotype frequencies of CCR2 V64I, MCP-1 -2518 and DC-SIGN polymorphisms did not differ significantly between the study groups. A significantly increased frequency of GG genotype of SDF-1α polymorphism was observed among HIV+PTB+ patients compared to healthy controls (P=0.009, Pc=0.027). Interpretation & conclusions: Our data suggest that GG genotype of SDF-1α 3’UTR polymorphism may be associated with susceptibility to PTB in HIV-1 infected patients. A better understanding of genetic factors that are associated with TB could help target preventive strategies to those HIV patients likely to develop tuberculosis.

Immune reconstitution syndrome in a child with TB and HIV.

Immune reconstitution syndrome (IRS) is the transient worsening or appearance of new signs, symptoms or radiological manifestation of an opportunistic infection occurring after the initiation of Highly active antiretroviral therapy (HAART) and is not due to treatment failure or new infection. We describe a case of a HIV infected child with tubercular (mediastinal) lymphadenitis with worsening of clinical and radiological features on starting HAART.

Urine nevirapine as a predictor of antiretroviral adherence.

BACKGROUND & OBJECTIVE: Incomplete adherence is a major contributor to failure of antiretroviral therapy. Although the available methods to monitor adherence to therapy have proved to be predictive of outcomes, the results are variable. We assessed the feasibility of detecting nevirapine (NVP) in spot urine samples to monitor patient adherence to antiretroviral treatment and to study the urinary excretion of NVP in healthy volunteers after oral administration of a single dose of NVP (200 mg). METHODS: Spot urine samples were collected from 50 HIV-infected patients (36 on treatment regimen containing NVP and 14 on drugs other than NVP) and tested for NVP by HPLC in a blinded manner. Sixteen healthy volunteers (9 males and 7 females) were administered a single oral dose of 200 mg NVP and spot urine samples were collected on day '0' before drug administration, and thereafter every 24 h up to 9 days and tested for NVP. RESULTS: All the urine samples collected from patients undergoing treatment with NVP-containing regimens at different time points after drug administration tested positive for NVP. Thirteen out of 14 samples from patients not on NVP yielded a negative result. The drug was detected in the urine of healthy volunteers up to 9 days. The urinary excretion of NVP was prolonged in females than in males. INTERPRETATION & CONCLUSION: In view of its long half-life, NVP gets excreted in urine for a long period of time. Hence, testing spot urine samples for NVP may not be a useful measure to monitor patient adherence to treatment.

Immune reconstitution syndrome following initiation of antiretroviral therapy in a patient with HIV infection and multidrug-resistant tuberculosis.

Paradoxical exacerbation of the signs and symptoms of tuberculosis may occur not only after antituberculosis therapy, but also soon after the initiation of a potent combination of antiretroviral drugs in human immunodeficiency virus (HIV) serpositive patients with tuberculosis. We report a case of immune reconstitution syndrome in response to antiretroviral therapy in a HIV-positive patient on antituberculosis therapy for multidrug-resistant tuberculosis.