Development of the R263K Mutation to Dolutegravir in an HIV-1 Subtype D Virus Harboring 3 Class-Drug Resistance.

Dolutegravir (DTG), a second-generation integrase strand-transfer inhibitor (INSTI), is equivalent or superior to current non-nucleotide reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and first-generation INSTI-based antiretroviral regimens (ARVs). It has the potential to make big improvements in HIV control globally and within patients. This is perhaps the most "precious" HIV drug available. The integrase mutation R263K has been observed in tissue culture experiments and in patients treated with dolutegravir monotherapy in clinical trials. Globally, adherence and monitoring may be less than optimal and therefore DTG resistance more common. This is particularly important in low-middle-income countries, where patients may remain on failing regimens for longer periods of time and accumulate drug resistance. Data on this mutation in non-subtype B infections do not exist. We describe the first report of the R263K integrase mutation in a dolutegravir-exposed subtype D-infected individual with vertically acquired HIV. We have used deep sequencing of longitudinal samples to highlight the change in resistance over time while on a failing regimen. The case highlights that poorly adherent patients should not be offered dolutegravir even as part of a combination regimen and that protease inhibitors should be used preferentially.

Genetic diversity of integrase (IN) sequences in antiretroviral treatment-naive and treatment-experienced HIV type 2 patients.

Two potent integrase inhibitors (IN-Is), raltegravir (RAL, MK-0518) and elvitegravir (EGV, GS-9137), have been shown to be potent inhibitors for HIV-1 and resistance mutations have been identified in HIV-1 clinical trials. In this study, sequences from 11 HIV-2 patients were examined for IN polymorphisms. The primary mutations associated with RAL and EGV resistance were not detected despite the genetic variability among clinical isolates. Our study provides basic information on genotypic susceptibility of HIV-2 to RAL and EGV and supports the suggestion that RAL and EGV could be considered as a new therapeutic option for treating HIV-2-infected patients.

Detection of hepatitis B virus antigens in liver tissue. A relation to viral replication and histology in chronic hepatitis B infection.

The expression of hepatitis B virus antigens was studied by double staining liver tissue with appropriate antisera and correlated with serum hepatitis B viral DNA and histology in 28 patients with disease related to chronic hepatitis B virus infection. The cellular localization of hepatitis B core and hepatitis B e antigens generally coincided, but there were important differences at a subcellular level. Thus, hepatitis B e antigen was detected in nuclei and/or cytoplasm but strong cytoplasmic hepatitis B e antigen was associated with a high serum hepatitis B viral DNA (P = 0.0017) but not with active liver disease. Hepatitis B core antigen could also be detected in nuclei and/or cytoplasm, but strong cytoplasmic hepatitis B core antigen expression, exceeding that of hepatitis B e antigen, was associated with active liver disease (P = 0.041) and not with serum hepatitis B virus DNA. The proportion of hepatocytes expressing hepatitis B surface antigen correlated inversely with the serum titer (P = 0.0017), whereas hepatitis B surface and nucleocapsid antigens were usually expressed independently. The data support the hypothesis that cytoplasmic hepatitis B core antigen and not hepatitis B e antigen is the target for immune system-mediated cytolysis of hepatocytes. Cytoplasmic hepatitis B e antigen is not associated with liver damage but is instead associated with high levels of hepatitis B virus replication.

Differential distribution of hepatitis B core and E antigens in hepatocytes: analysis by monoclonal antibodies.

Current knowledge on the expression of HBeAg in hepatocytes is incomplete because of difficulties in obtaining monospecific antisera devoid of anti-HBc reactivity. In this study, we have examined by immunofluorescence the expression of HBcAg and HBeAg in cryostat liver sections from 25 chronic carriers of HBsAg using monoclonal antibodies. Although virtually all liver biopsies displayed concordance for HBeAg and HBcAg expression, the pattern of fluorescence differed markedly. Thus, monoclonal anti-HBc gave nuclear staining in all 13 reactive biopsies, while cytoplasmic staining was observed in only two of these. In contrast, monoclonal anti-HBe showed cytoplasmic reactivity coexisting with nuclear reactivity in 10 of 13 reactive biopsies. Hepatitis B virus DNA polymerase activity in the serum appeared to correlate better with the presence of HBcAg in hepatocytes rather than HBeAg. These results provide further evidence that HBeAg is expressed both in the nuclei and in the cytoplasm of infected hepatocytes. The observation that the number of cells expressing HBeAg exceeds those expressing HBcAg in carriers with active virus replication would suggest that assembly of core particles occurs in only a proportion of infected hepatocytes expressing HBeAg.