Hepatitis B & hepatitis C in HIV-infection.

Human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) are the three most common chronic viral infections seen in the world. All three viruses share modes of transmission and hence co-exist in the same host at significantly high rates. HIV-induced immunosuppression has deleterious effects on the natural history, pathophysiology, diagnosis, therapeutic responses to hepatitis viruses. Responses to HBV vaccination are impaired in persons with HIV infection. Co-infection with the hepatitis viruses and HIV is likely to become a major health care catastrophe in the coming years. This review discusses the current trends in the understanding of the biology of co-infection and implications for treating these viruses effectively.

Natural killer cells in HIV-1 infection: role of NK cell-mediated non-cytolytic mechanisms in pathogenesis of HIV-1 infection.

Natural killer (NK) cells exhibit both cytolytic and non-cytolytic effector functions against HIV-infected targets. Their precise role in immunopathogenesis of HIV-1 infection is yet to be fully understood. This review addresses the non-cytolytic functions exhibited by NK cells, their potential role in pathogenesis of HIV-1 infection and the effect of HIV-1 viremia on NK cell functions. Activated NK cells are capable of secreting CC-chemokines and suppressing HIV-1 replication in a non-cytolytic fashion. However, HIV-1 viremia suppresses the ability of NK cells to secrete CC-chemokines. Suppression of HIV-1 viremia by highly active antiretroviral therapy (HAART) restores the ability of NK cells to secrete CC-chemokines and suppress endogenous HIV-1 replication by non-cytolytic mechanisms. Better understanding of the mechanisms involved in HIV-1-NK cell interactions would be helpful in delineating novel therapeutic strategics against HIV-1.