Pharmacokinetics of rifabutin during atazanavir/ritonavir co-administration in HIV-infected TB patients.

BACKGROUND & OBJECTIVE: Rifabutin (RBT) is the rifamycin that is recommended to treat tuberculosis (TB) in HIV-infected individuals during combination antiretroviral therapy (ART) containing HIV protease inhibitors (PIs). We studied the pharmacokinetics of rifabutin at doses of 300 mg thrice weekly and 150 mg daily during concomitant atazanavir/ritonavir (ATZ/r) administration in adult HIV-infected TB patients treated in the Revised National TB Control Programme (RNTCP) in India. METHODS: This was a multi-centric study conducted in 45 adult HIV-infected TB patients, who were being treated for TB with a RBT-containing regimen and an antiretroviral treatment regimen with ATZ/r, at doses of 300 mg thrice-weekly (n = 36) or 150 mg daily (n = 9). Serial blood draws at pre-dosing and at 1, 2, 4, 6, 8, 12 and 24 hours after drug administration were done. Plasma RBT was estimated by high pressure liquid chromatography (HPLC). RESULTS: The peak concentration (Cmax) of both doses were within the therapeutic range (0.45-0.90 µg/ml) of RBT. Proportion of patients having Cmax above or below the therapeutic range and trough concentration (Cmin) below the minimum inhibitory concentration of RBT did not significantly differ between the two doses. TB treatment outcomes were also similar at both doses. CONCLUSIONS: This is the first and only study from India reporting on the pharmacokinetics of RBT at 300 mg thrice weekly and 150 mg daily doses. Both doses yielded similar plasma RBT concentrations, outcomes and were well tolerated. RBT can be administered at either doses during ATZ/r co-administration in HIV-infected patients with TB.

Association of Single Nucleotide Polymorphisms in TNFA and IL10 Genes with Disease Severity in Influenza A/H1N1pdm09 Virus Infections: A Study from Western India.

Susceptibility to severe influenza A/H1N1pdm09 virus is multifactorial. The present study was carried out in 246 patients infected with A/H1N1pdm09 virus to find out whether single nucleotide polymorphisms (SNPs) in the genes coding for proinflammatory and anti-inflammatory cytokines are associated with disease severity. Among the cases, 129 had mild disease, whereas 117 had severe disease. There were 27 fatal cases. TNFA rs1800629, IFNG rs2430561, IL10 rs1800872, IL10 rs1800896, and CCL2 rs1024611 SNPs were genotyped by polymerase chain reaction-based methods. A significantly higher frequency of TNFA rs1800629 "G/A" genotype was observed in severe and fatal cases compared with mild and survived cases, respectively. In a dominant mode, IL10 rs1800896 "G" allele was significantly negatively associated with disease severity. IL10 rs1800896 "C/A" genotype was significantly associated with fatality in influenza A/H1N1pdm09 infections. The results suggest that SNPs in the IL10 and TNFA genes might be associated with disease severity in influenza A/H1N1pdm09-infected patients.

Role of host immune response and viral load in the differential outcome of pandemic H1N1 (2009) influenza virus infection in Indian patients.

BACKGROUND: An unusually high number of severe pneumonia cases with considerable mortality is being observed with the pandemic H1N1 2009 virus infections globally. In India, all mild as well as critically ill cases were admitted and treated in the government hospitals during the initial phase of the pandemic. The present study was undertaken during this early phase of the pandemic. METHODOLOGY: The role of viral load and host factors in the pathogenesis were assessed by examining 26 mild (MP), 15 critically ill patients (CIP) and 20 healthy controls from Pune, India. Sequential blood and lung aspirate samples were collected from CIP. Viral load and cytokines/chemokine levels were determined from the plasma and lung aspirates of the patients. TLR levels were determined by staining and FACS analysis. Gene profiling was done for both cells in the lung aspirates and PBMCs using TaqMan Low Density arrays. Antibody titres and isotyping was done using HA protein based ELISAs. PRINCIPAL FINDINGS: 13/15 critically ill patients expired. All plasma samples were negative for the virus irrespective of the patient's category. Sequential lung samples from CIP showed lower viral loads questioning association of viral replication with the severity. Anti-rpH1N1-09-HA-IgG titres were significantly higher in critically ill patients and both categories circulated exclusively IgG1 isotype. Critically ill patients exhibited increase in TLR-3, 4, 7 and decrease in TLR-2 expressions. The disease severity correlated with increased plasma levels of IL1RA, IL2, IL6, CCL3, CCL4 and IL10. Majority of the immune-function genes were down-regulated in the PBMCs and up-regulated in the cells from lung aspirates of critically ill patients. No distinct pattern differentiating fatal and surviving patients was observed when sequential samples were examined for various parameters. CONCLUSIONS: Disease severity was associated with pronounced impairment of host immune response.