Development and application of a simple LC-MS method for the determination of plasma rilpivirine (TMC-278) concentrations

Rilpivirine (TMC-278) is a second-generation non-nucleoside reverse transcriptase inhibitor that is high potent against both wild-type and drug-resistant HIV-1 strains. Therefore, rilpivirine is expected to treat therapy-experienced patients who failed to use current drugs due to the emergence of drug-resistant HIV mutants. The quantification of rilpivirine in human plasma is important to support clinical studies and determine pharmacokinetic parameters of rilpivirine in HIV-1 infected patients. Consequently, simple and easy system to determine plasma rilpivirine concentrations has been required. In this study, we developed a conventional LC-MS method to quantify plasma rilpivirine. Subsequently the method was validated by estimating the precision and accuracy for inter- and intraday analysis in the concentration range of 18-715 ng/ml. The calibration curve was linear in this range. Average accuracy ranged from 100.0 to 100.6%. Relative standard deviations of both inter- and intraday assays were less than 3.3%. Recovery of rilpivirine was more than 82.0%. These results demonstrate that our LC-MS method provides a conventional, accurate and precise way to determine rilpivirine in human plasma. This method can be used in routine clinical application for HIV-1 infected patients, and permits management of drug interactions and toxicity for rilpivirine

Regional Differences in the Prevalence of Major Opportunistic Infections among Antiretroviral-Naive Human Immunodeficiency Virus Patients in Japan, Northern Thailand, Northern Vietnam, and the Philippines

To identify regional differences in the distribution of opportunistic infections (OIs) among human immunodeficiency virus (HIV)-infected patients in Asia, the medical records of antiretroviral therapy (ART)-naive patients who attended the following tertiary hospitals from 2003 to 2011 were reviewed: Nagoya Medical Center (NMC, Nagoya, Japan), Lampang Hospital (LPH, Lampang, northern Thailand), Bach Mai Hospital (BMH, Hanoi, northern Vietnam), and Philippine General Hospital (PGH, Manila, Philippines). Logistic regression analyses were performed to identify associations between country of origin and risk of major OIs. In total, 1,505 patients were included: NMC, N = 365; LPH, N = 442; BMH, N = 384; and PGH, N = 314. The median age was 32 years, and 73.3% of all patients were male. The median CD4 count was 200 cells/μL. Most patients at NMC and PGH were men who have sex with men. Injection drug users were most common at BMH (35.7%). Mycobacterium tuberculosis (TB) was most common at PGH (N = 75) but was rare at NMC (N = 4). Pneumocystis pneumonia (PCP) prevalence was highest at NMC (N = 74) and lowest at BMH (N = 13). Multivariable logistic regression showed increased odds of TB at PGH (adjusted odds ratio [aOR] = 42.2, 95% confidence interval [CI] = 14.6?122.1), BMH (aOR = 12.6, CI = 3.9?40.3), and LPH (aOR = 6.6, CI = 2.1?21.1) but decreased odds of PCP at BMH (aOR = 0.1, CI = 0.04?0.2) and LPH (aOR = 0.2, CI = 0.1?0.4) compared with those at NMC. The cryptococcosis risk was increased at LPH (aOR = 6.2, CI = 0.9?41.0) compared with that at NMC. Cytomegalovirus (CMV) retinitis prevalences were similar in all countries. OI prevalence remained high among ART-naive patients in our cohort. The risks of TB, PCP, and cryptococcosis, but not CMV retinitis, differed between countries. Improved early HIV detection is warranted

Role of the Specific Amino Acid Sequence of the Membrane-Spanning Domain of Human Immunodeficiency Virus Type 1 in Membrane Fusion

Fusion between cell and virus membranes mediated by gp41 initiates the life cycle of human immunodeficiency virus type 1. In contrast to the many studies that have elucidated the structure-function relationship of the ectodomain, the study of the membrane-spanning domain (MSD) has been rather limited. In particular, the role that the MSD's specific amino acid sequences may have in membrane fusion as well as other gp41 functions is not well understood. The MSD of gp41 contains well-conserved glycine residues that form the GXXXG motif (G, glycine; X, other amino acid residues), a motif often found at the helix-helix interface of membrane spanning α-helices. Here we examined the role that the specific amino acid sequence of the gp41 MSD has in gp41 function, particularly in membrane fusion, by making two types of MSD mutants: (i) glycine substitution mutants in which glycine residues of the MSD were mutated to alanine or leucine residues, and (ii) replacement mutants in which the entire MSD was replaced with one derived from glycophorin A or from vesicular stomatitis virus G. The substitution of glycines did not affect gp41 function. MSD-replacement mutants, however, showed severely impaired fusion activity. The assay using the Env expression vector revealed defects in membrane fusion after CD4 binding steps in the MSD-replacement mutants. In addition, the change in Env processing was noted for MSD-replacement mutants. These results suggest that the MSD of gp41 has a relatively wide but not unlimited tolerance for mutations and plays a critical role in membrane fusion as well as in other steps of Env biogenesis

International micro-clades (IMCs) detected in the study population and outlier sequences.

<p>HPD: highest posterior density, tMRCA: time of most recent common ancestor, ND: not determined.</p

Cytokines and Chemokines Involved in Hepatitis B Surface Antigen Loss in Human Immunodeficiency Virus/Hepatitis B Virus Coinfected Patients

It has been reported that hepatic flare (HF), attributable to the development of immune reconstitution inflammatory syndrome (IRIS) in human immunodeficiency virus (HIV)/hepatitis B virus (HBV) coinfected patients, occurs frequently after the start of anti-retroviral therapy (ART). We have observed several cases of hepatitis B surface antigen (HBsAg) loss after IRIS. However, the factors leading to HBsAg clearance remain unknown. We measured CD4+ and CD8+ T cells, cytokines and chemokines in 16 patients coinfected HIV-1 and HBV with IRIS, and analyzed the factors leading to HBsAg clearance after IRIS. There was no significant difference in the CD4+ and CD8+ T cell counts between the HBsAg clearance and non-clearance groups, while the serum concentrations of almost all cytokines and chemokines in the HBsAg clearance group were higher than in the HBsAg non-clearance group at any time of observation. In particular, IP-10 at the ALT peak, GM-CSF and IL-12 one month after the ALT peak and TNF-α and GM-CSF after the ALT concentrations fell to within normal limits, were significantly higher in the HBsAg clearance group. It seems that HBsAg loss after IRIS requires continued immune responses against HBV, involving Th1 cytokines

Detailed phylogenetic structure of five large micro-clades.

<p>Open and solid circles indicate male and female cases, respectively. Circle color indicates geographic origin of the samples, followed by risk behavior, and nationality, if known. Dates at the sub-tree’s root show the tMRCA of each micro-clade. Numbers below each node show bootstrap values above 80%. JP = Japanese, KR = Korean, VN = Vietnamese, ID = Indonesian, TH = Thai, TW = Taiwanese, UN = unknown, IDVU = intravenous drug user.</p