Heavy Chain Deposition Disease: Clinicopathologic Characteristics of a Chinese Case Series.

RATIONALE & OBJECTIVE: Heavy chain deposition disease (HCDD) is a rare consequence of monoclonal immunoglobulin deposition disease that has not been well characterized in non-white populations. To explore the clinicopathologic characteristics and outcomes of HCDD in Chinese individuals, we report on a case series assembled in a single center in China. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: 25 patients with biopsy-proven HCDD were studied retrospectively. RESULTS: 14 men and 11 women with an average age of 50.3 years were studied. The patients presented with hypertension (76%), edema (96%), anemia (84%), serum creatinine level > 1.2mg/dL (68%), nephrotic-range proteinuria (56%), and microscopic hematuria (80%). One (4%) patient had multiple myeloma diagnosed. Serum immunofixation electrophoresis showed that 10 of 21 (48%) patients were positive for monoclonal immunoglobulin. Hypocomplementemia of C3 was found in 68% of patients. Nodular mesangial sclerosis was identified in all patients by using light microscopy. Using immunofluorescence, all 25 patients had deposition of heavy chains of immunoglobulin G class (γ1, 13; γ2, 2; γ3, 6; γ4, 2; γ1 and γ4, 1; and γ2 and γ4, 1). During an average of 40.1 months of follow-up of 20 patients, 65% had improved kidney function, 10% had worsening kidney function, and 25% progressed to kidney failure. Mean values for kidney and patient survival were 37.8 and 40.1 months, respectively. Kidney survival was higher among patients who received chemotherapy. LIMITATIONS: Retrospective study, single-center experience. CONCLUSIONS: In this case series of HCDD in a single center in China, the heavy chain deposits seen in the kidney biopies of all individuals were of immunoglobulin G class. Chemotherapy improved kidney function, especially among individuals in an early stage of the disease.