A Rare Case of Leukocyte Chemotactic Factor 2 (ALECT2)-Associated Amyloidosis and Membranoproliferative Glomerulonephritis (MPGN)Associated with Cryoglobulinemia

Introduction: Membranoproliferative glomerulonephritis (MPGN) associated with cryoglobulinemia is an uncommon renal condition, often secondary to infectious or autoimmune etiologies. Hepatitis B infection less frequently manifests as cryoglobulinemia compared to hepatitis C. Concurrently, Leukocyte chemotactic factor 2 amyloidosis (ALECT2) is an exceedingly rare form of amyloidosis, characterized by the deposition of leukocyte chemotactic factor 2 protein in the kidneys, with a higher prevalence among individuals of Mexican descent. The simultaneous presence of MPGN from cryoglobulinemia and ALECT2 in a single kidney biopsy represents a rare diagnostic finding. Here, we present a unique case of a patient with hepatitis B induced MPGN associated cryoglobulinemia and concurrent ALECT2. Case Description: We present the case of a 68-year-old male with a medical history notable for hypertension, lower extremity rash with biopsy consistent with leukocytoclastic vasculitis, and post herpetic neuralgia who presented with chest pain and dyspnea attributed to a pericardial effusion and found to have acute kidney injury. Urinalysis revealed hematuria and proteinuria while urine microscopy demonstrated 3-4 dysmorphic red blood cells per high-powered field. Serological investigations revealed positive antinuclear antibodies, positive rheumatoid factor, trace cryoglobulin, and decreased C3 and C4 levels. Steroids were started for a suspected flare of overlap syndrome. Kidney biopsy histopathology revealed features consistent with MPGN Type II cryoglobulinemia and immunohistochemical staining confirmed ALECT2 presence within the amorphous deposits, positive for amyloidosis. The coexistence of MPGN and ALECT2 in the context of cryoglobulinemia secondary to hepatitis B infection was noted as exceedingly rare. The patient was started on Entecavir for hepatitis B treatment. Discussion: This case shows the diagnostic challenges posed by MPGN in the backdrop of active hepatitis B infection and cryoglobulinemia. The additional discovery of ALECT2 raises questions regarding its clinical implications and significance. Further research and case reports are imperative to unravel potential relationships and underlying mechanisms associated with ALECT2 and cryoglobulinemia.