Hallmark of AIDS is reduction of

Ans: b (CD4)Ref: Harrison, 18th ed Pg. 1526HIV is an RNA virus. Hall mark of HIV infection is marked loss of CD4 + T cells and impairment in function of surviving T cells.HIV - High affinity binding of gp 120 protein to the host cell surface receptor CD4 molecule. CD4 molecule is seen on the surface of:T lymphocyte (mainly) Monocytes Macrophages Dendritic cells Langerhans cells.CXCR4 inhibitor used in HIV - MaravirocHIV uses 2 major co-receptor on CD4 for entry into a cell - CCR 5 & CXCR 4HIV genome has been recently found to be vulnerable to cellular factors that can block the progression of infection. It includes:a. TRIM 5 alpha protein in rhesus macaque cellsb. APOBEC Family of cellular Proteins. Any HIV infected individual with a CD4 + T cell count of < 200 pl/L has AIDS by definition, regardless of the presence of symptoms or opportunistic disease.HIV I has four groups;Group M (Major) is responsible for most of the infections worldwide. M Group is divided into several subtypes. Subtype C - m.c subtype in India & world Subtype A&D - Faster disease progression. Subtype D - Co-receptor usage (CXCR 4) Subtype C - Emergent resistant patterns.