A case of renal γ2 heavy-chain deposition disease accompanied by rapid progressive renal failure.

Background: The recently described heavy-chain deposition disease (HCDD) is a comparatively rare monoclonal immunoglobulin disorder characterized histopathologically by glomerular and tubular basement membrane deposition of nonamyloidotic monoclonal heavy chains without associated light chains.
Method: We have described a case of γ2-HCDD presenting with proteinuria, microhematuria, severe hypertension, and rapidly progressive renal failure, which serum creatinine level was only 1.52 mg/dL in early stage HCDD, and the clinicopathologic features of this case have been compared with other reported cases of γ2-HCDD.
Results: Renal biopsy disclosed nodular sclerosing glomerulopathy. Immunofluorescence analysis revealed IgG2 (2+) heavy chain and C3 (+) in the mesangium and along the capillary walls and tubular basement membranes without IgA, IgM, κ and λ light chains. Electron microscopy revealed electron-dense deposits along the glomerular and tubular basement membranes as well as in the mesangium. Moreover, regardless of therapy, the condition of the patient progressively deteriorated, with less than 3 months of renal survival.
Conclusion: Rapid progressive renal failure was a common feature in both cases of γ2-HCDD. We propose that a possible link exists between prognosis of renal HCDD and the subclass of heavy chain deposited in the kidney.