UNMASKING THE UNUSUAL: KIDNEY BIOPSY IN SYSTEMIC LUPUS ERYTHEMATOSUS

8 Feb 2025 12 a.m. 12 a.m.

WCN25-AB-1130, Poster Board= SAT-133

Introduction:

Systemic Lupus Erythematosus (SLE) is an autoimmune disease associated with chronic inflammation, affecting multiple organs. Lupus nephritis is a major risk factor for overall mortality and morbidity in SLE. Thus, prompt diagnosis and early treatment in such patients is crucial. Here, we describe two case reports of patients of SLE, who present with atypical renal manifestations.

Methods:

CASE-1: A 50-year-old female, known diabetic and hypertensive for 2 years, presented with the complaints of generalized edema for 15 days. Her routine investigations were suggestive of anemia with thrombocytopenia, with a hemoglobin of 10.8 gram/dL, a platelet count of 54,000/microliter, and a rising serum creatinine of 5.5 mg/dL. Urine microscopy revealed only traces for proteins (10 mg/dL). Ultrasonography of the abdomen suggested normal kidney size but had increased parenchymal echogenicity. Her ANA and anti-dsDNA were positive, and her serum Kappa free light chains were highly positive, with a serum Kappa/Lambda (FLC) ratio > 100.

CASE-2: A 60-year-old elderly female who presented with worsening shortness of breath for 7 days. Her complete blood count indicated anemia and thrombocytopenia, with a hemoglobin of 10.3 g/dl and a platelet count of 74,000/microliter. Serum creatinine had risen to 3.1 mg/dL and a 24-hour urinary sample collection suggested 8 g/24 hour of proteinuria. The autoimmune panel showed ANA and anti-dsDNA positivity. Ultrasonography of the abdomen revealed increased parenchymal echogenicity in bilateral kidneys.

Results:

Case 1 Kidney Biopsy: showed linear deposits of kappa along the walls of tubules, blood vessels, and capillary glomerular walls. The findings were consistent with kappa light chains monoclonal immunoglobulin deposition disease primarily affecting the tubulointerstitial compartment with focal acute tubular injury (Figure 1 and Figure 2).

Figure 1: Periodic acid–Schiff (PAS) stain showing mild increase in mesangial matric and cellularity. Figure 2: Immunofluorescence stain showing Kappa positivity in the protein reabsorption granules and deposits in walls of blood vessels.

Case 2 kidney biopsy: showed enlarged glomeruli with an increase in mesangial matrix and cellularity, with positive immunostaining for DNAJB9 in mesangium and peripheral capillary walls. Fibrillary dense deposits with diameters varying from 19.8 mm to 30.6 mm were identified, consistent with the diagnosis of fibrillary glomerulonephritis (Figure 3 and Figure 4).

Figure 3: DNAJB9 immunohistochemical stain in mesangial matrix. Figure 4: Electron Microscopy microphotographs showing fibrillary deposits in substance of basement membrane.

Conclusions:

In patients with systemic lupus erythematosus, we have discussed two atypical and rare renal associations. Both monoclonal gammopathy of renal significance (MGRS) and fibrillary glomerulonephritis (FGN) have a rare association with patients with SLE and are also associated with further worsening of renal functions and a poor prognosis. Accurate histopathological identification is essential to determining the optimal treatment approach in these patients.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.