In the lupus band test (DIF of non-lesional sun-protected skin), which immunoreactant pattern at the dermoepidermal junction is considered MOST specific for systemic lupus erythematosus?

• A Linear IgM alone
• B IgG + IgM + IgA + C3 in a granular band ✓
• C Linear IgA alone
• D IgG + C3 in a linear pattern

Explanation

The lupus band test shows a granular (not linear) deposition of multiple immunoreactants — IgG, IgM, IgA, and C3 — at the BMZ in normal-appearing non-sun-exposed skin in SLE. The presence of multiple immunoglobulin classes together at the BMZ ('full-house pattern') in non-lesional skin is highly specific for SLE. Single-class or linear patterns suggest other diagnoses.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.