Virsuses: Human Immunodeficiency Syndrome & Acquired Immunodeficiency Syndrome
Immunodeficiency syndromes
description
Transcript of Immunodeficiency syndromes
Immunodeficiency syndromes
Classification
• Primary:rare,B,T & combined B &T deficits• Secondary: in severe infection,
immunosupression(CT,RT) ,malnutrition,DM,renal failure, ageing, autoimmune diseases,malignancies, AIDS
AIDS Definition: disease caused by retrovirus
human immunodeficiency virus ( HIV).• Characterized by• Depletion of CD 4+ T lymphocytes• Profound immunosuppression• Opportunistic infection (caused by
organisms that are often non-pathogenic or low virulence)
• Secondary neoplasms & neurological manifestations
Epidemiology
• Incidence >42 million people HIV +• Africa,SE Asia• 5th commonest cause of death in 25-44 yrs• Homosexual /bisexual males • IV drug abusers*
• Recepients of blood& blood products• Heterosexual contacts• ???• Paediatric –mother to child transmission
Aetiology- HIV
• Retrovirus• Lentivirus family• HIV 1,HIV 2 • HIV 1 –subgroups • Major (M),outlier
(O),neither (N)• M –clades A-K (B SE
asia,C India)
Structure of HIV (Cont….)
• HIV genome contains• Gag• Pol• Env • Tat,rev,vif,nef,vpr, vpuImp for HIV pathogenicity &
targeted therapy
Pathogenesis of HIV infection & AIDS
• Viral transimission to blood (Infection of CD 4+ T cells )or macrophages,dendritic cells or CD4 + cells in mucosa
• Infection established in lymphoid tissues• Latent period • Active viral replication • ↓T lymphocytes & decreased immunity• AIDS
Entry/internalization of HIV in T cell, macrophage
• Binding of gp 120 to CD 4 +cells (T cells /macrophages/dendritic cells)
• Conformational change in gp 120• Binding of HIV gp 120 to coreceptors (CCR
5,CXCR 4) • Membrane penetration by gp 41• Membrane fusion• Virus enters the cells