Renal pathology — MCQs

Question 21: Immunofluorescence staining pattern from a kidney biopsy from a 35-year-old patient presenting with proteinuria has been shown below. What is the most probable cause? (AIIMS Nov 2018)

• A. FSGS
• B. PSGN
• C. Lupus nephritis (Correct Answer)
• D. Goodpasture syndrome
• E. IgA nephropathy

Explanation: ***Lupus nephritis*** - The image likely shows a **"full house" immunofluorescence pattern** (deposits of IgG, IgA, IgM, C3, and C1q), which is characteristic of **lupus nephritis** [1]. - This pattern indicates immune complex deposition in the glomeruli, a hallmark of systemic lupus erythematosus affecting the kidneys [1]. *FSGS* - **Focal segmental glomerulosclerosis (FSGS)** typically shows **negative immunofluorescence** or only non-specific IgM and C3 in sclerotic areas [3,4]. - It does not present with the diffuse, multi-immunoglobulin deposition seen in the characteristic "full house" pattern. *PSGN* - **Post-streptococcal glomerulonephritis (PSGN)** characteristically shows a **"starry sky" or granular pattern** of C3 and IgG deposition, often with a dominant C3 [2]. - It does not typically show the full spectrum of immunoglobulins and complement components seen in lupus nephritis. *Goodpasture syndrome* - **Goodpasture syndrome** is characterized by a **linear deposition of IgG** along the glomerular basement membrane (GBM) on immunofluorescence [2]. - This pattern is distinct from the granular, multi-immunoglobulin deposition seen in immune complex-mediated diseases like lupus nephritis. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 532-533. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 915. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 530-531. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 531-532.