Clinically Silent Sjögren Syndrome Presenting With Cryoglobulinemia

Cryoglobulinemia is an immune complex-mediated disorder that can be associated with autoimmune diseases, lymphoproliferative disorders, and chronic infections. Renal involvement can be a prominent manifestation and may occasionally be the initial clue to an underlying systemic condition. Here, we describe a 33-year-old woman who presented with pedal edema, intermittent arthralgia, hematuria, and impaired renal function. Kidney biopsy demonstrated characteristic intraluminal pseudothrombi with dominant immunoglobulin M deposition, consistent with cryoglobulinemic glomerulonephritis. Subsequently, serologic testing confirmed mixed cryoglobulinemia. Further evaluation revealed strong positivity for anti-Sjögren syndrome-related antigen-A and anti-Sjögren syndrome-related antigen-B antibodies, and a labial salivary gland biopsy fulfilled the 2016 American College of Rheumatology European Alliance of Associations for Rheumatology criteria for Sjögren syndrome, despite the absence of sicca symptoms. Treatment with corticosteroids and rituximab led to significant improvement in renal function. The clinical course was complicated by secondary thrombotic microangiopathy, which responded to plasma exchange. This report highlights the diagnostic value of kidney biopsy in uncovering occult systemic autoimmune disease and emphasizes that Sjögren syndrome may initially present with isolated renal manifestations. Early recognition is essential for the timely initiation of appropriate immunomodulatory therapy.