In antiphospholipid syndrome (APS), which antibody combination confers the highest thrombotic risk (triple positivity)?

• A Anti-β2-glycoprotein I IgM alone
• B Anticardiolipin IgM alone
• C Lupus anticoagulant alone
• D Lupus anticoagulant + anticardiolipin IgG + anti-β2-glycoprotein I IgG ✓

Explanation

Triple positivity — simultaneous presence of lupus anticoagulant, anticardiolipin antibody IgG, and anti-β2-glycoprotein I IgG — confers the highest thrombotic and obstetric risk in APS, with annual thrombosis recurrence rates exceeding 5–10% per year even on anticoagulation. IgG isotypes are more pathogenic than IgM. Single-antibody positivity, especially IgM isotype or low-titre anticardiolipin, carries much lower risk and may not require anticoagulation. Risk stratification using the Global APS Score (GAPSS) incorporates these antibody profiles.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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