Pathology Cheat Sheet
Complexes and Immune Depletion
SLE and HIV pathology for NEET-PG: ANA and anti-dsDNA, wire-loop lesions, Libman-Sacks endocarditis, HIV gp120, CCR5, p24 antigen, and CD4 depletion here.
MedNext Academy | 3 min read
Complexes and Immune Depletion
SLE and HIV pathology for NEET-PG: ANA and anti-dsDNA, wire-loop lesions, Libman-Sacks endocarditis, HIV gp120, CCR5, p24 antigen, and CD4 depletion here.
The pathogenesis of systemic lupus erythematosus and the virology and immunopathology of HIV and AIDS.
High-yield lines
- Systemic lupus erythematosus is a multisystem autoimmune disease driven by autoantibodies against nuclear antigens.
- Antinuclear antibody is the sensitive screening test for lupus, while anti-double-stranded DNA and anti-Smith antibodies are highly specific.
- Lupus combines type II antibody-mediated cytopenias and type III immune-complex glomerulonephritis.
- Lupus nephritis shows wire-loop lesions from subendothelial immune complex deposition.
- Libman-Sacks endocarditis is the sterile verrucous valvular vegetation of lupus.
- HIV is an RNA retrovirus that infects CD4-bearing cells including helper T cells, macrophages, and dendritic cells.
- HIV gp120 binds CD4 and then a co-receptor, CCR5 for early macrophage-tropic strains and CXCR4 for late T-tropic strains.
- The p24 capsid antigen is the earliest detectable serological marker after HIV infection.
- Reverse transcriptase, integrase, and protease are HIV enzymes that are major drug targets.
- AIDS is defined by a CD4 count below 200 cells per microlitre or an AIDS-defining opportunistic illness.
- Progressive CD4 T-cell depletion is the central immunopathological process in HIV infection.
- HIV serology screens with ELISA and confirms with Western blot, with a window period before antibody positivity.
Mapped competency codes
- PA9.5
- PA9.6
Continue into the full chapter
This summary maps to PA9-immunopathology-and-aids.
Frequently Asked Questions
Which antibodies are most specific for systemic lupus erythematosus?
Anti-double-stranded DNA and anti-Smith antibodies are highly specific for lupus, whereas antinuclear antibody is sensitive but not specific.
How does HIV enter its target cell?
Its envelope glycoprotein gp120 binds the CD4 receptor and then a chemokine co-receptor, CCR5 for early macrophage-tropic strains or CXCR4 for late T-tropic strains.
What is the earliest detectable marker of HIV infection?
The p24 capsid antigen, which appears before antibodies during the window period and is used in fourth-generation combined antigen-antibody assays.
What defines AIDS in an HIV-infected patient?
A CD4 count below 200 cells per microlitre or the occurrence of an AIDS-defining opportunistic infection or malignancy.
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