Immunology confusion pairs
22 Immunology topics students commonly mix up on Step 1, each with the fastest separator, a side-by-side comparison, and a free practice question.
- Type I hypersensitivity vs Non-IgE hypersensitivity patternsType I is immediate IgE mast-cell allergy; non-IgE patterns are type II fixed-antigen antibody, type III immune complexes, or type IV…
- Innate immunity vs Adaptive immunityInnate is immediate pattern recognition without memory; adaptive is specific lymphocyte response with memory.Video
- T-cell maturation vs B-cell maturationT cells mature in thymus and are MHC selected; B cells mature in bone marrow and later refine antibodies in germinal centers.
- CD4 T-cell function vs CD8 T-cell functionCD4 helper T cells: read MHC class II and release cytokines; CD8 cytotoxic T cells: read MHC class I and kill infected or tumor cells.
- Th1 and Th2 differentiation vs Th17 and Treg differentiationTh1 is macrophage/IFN-gamma; Th2 is IgE/eosinophils; Th17 is neutrophils; Treg is immune suppression/tolerance.
- MHC class I vs MHC class IIMHC I presents endogenous antigen to CD8 on nucleated cells; MHC II presents exogenous antigen to CD4 on professional APCs.Video
- IgG and IgM vs Other immunoglobulin rolesIgG is serum/memory/placenta/opsonin; IgM is first/complement pentamer; other roles are IgA mucosa, IgE allergy/helminths, and IgD naive…
- Active immunization vs Passive immunizationActive immunization makes the host generate memory; passive immunization gives ready-made antibody with immediate temporary protection.
- Live attenuated vaccines vs Non-live vaccine platformsLive attenuated vaccines replicate and are avoided in severe immunodeficiency; non-live platforms do not replicate and include killed,…
- Hyperacute transplant rejection vs Acute and chronic transplant rejectionHyperacute is preformed antibody minutes-hours; acute is T-cell/antibody days-months; chronic is intimal fibrosis months-years.
- Graft-versus-host disease vs Host-versus-graft rejectionGVHD is donor immune cells attacking host; host-versus-graft is recipient immune system attacking graft.
- Severe combined immunodeficiency vs Other primary and mixed immunodeficiency syndromesSCID is combined T- and B-function failure; the comparison syndromes localize to B-cell maturation, class switching, platelets/eczema,…
- Job syndrome vs Chronic granulomatous diseaseJob is high IgE/eczema/cold abscesses/retained teeth; CGD is defective oxidative burst with catalase-positive infections.Video
- Chediak-Higashi syndrome vs Leukocyte adhesion deficiencyChediak-Higashi is giant granules and albinism; LAD is no pus, delayed cord separation, and neutrophil adhesion failure.
- C1 esterase inhibitor deficiency vs Terminal and central complement deficienciesC1-INH deficiency is bradykinin angioedema without hives; complement deficiencies present as recurrent Neisseria, pyogenic, or…
- C3 deficiency vs C5-9 deficiencyC3 deficiency is broad severe pyogenic and immune-complex risk; C5-9 deficiency is recurrent Neisseria.
- ANA and lupus-specific antibodies vs Anti-histone drug-induced lupus antibodyANA screens; anti-dsDNA nephritis/activity and anti-Smith specificity support SLE; anti-histone plus drug exposure supports drug-induced…
- c-ANCA pattern vs p-ANCA patternc-ANCA/PR3: granulomatosis with polyangiitis (GPA); p-ANCA/MPO: microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis.
- Anti-CCP antibody vs Rheumatoid factorAnti-CCP is the more specific RA antibody; RF is sensitive-ish but nonspecific IgM against IgG Fc.
- Anti-Jo-1 myositis antibody vs Anti-Mi-2 and anti-SRP myositis antibodiesAnti-Jo-1 is antisynthetase lung/hands; Mi-2 is classic dermatomyositis; SRP is severe necrotizing myopathy.
- Goodpasture antibody disease vs ANCA-associated vasculitis antibodiesGoodpasture is anti-GBM linear IgG; ANCA vasculitis is PR3/MPO pauci-immune small-vessel disease.
- T-cell growth and Th2/eosinophil cytokines vs Inflammatory, regulatory, and macrophage-activating cytokinesIL-2 grows T cells, IL-4/5 are Th2 allergy/parasite helpers, IL-6 acute phase, IL-10 brakes, TNF inflames, IFN-gamma activates macrophages.