Long-term follow-up after autologous stem cell transplantation for light- and heavy-chain deposition disease.

Monoclonal Ig deposition disease (MIDD) is a broad and uncommon entity, including light chain deposition disease (LCDD), light- and heavy-chain deposition disease and heavy-chain deposition disease.1 Overall, the kidney is the major target organ, the clinical picture being most frequently characterised by nephrotic syndrome, hypertension and renal failure.2 Light-chain Fanconi syndrome due to proximal tubular involvement may also occur, and typically manifests with type II renal tubular acidosis, hypophosphatemia, glycosuria and hypouricemia. Heart, liver and other organs are less frequently involved.3, 4 In approximately one-third of patients with MIDD the underlying clone of monoclonal plasma cells cannot be routinely detected.2 However, recent availability of serum free light chain (FLC) assay has allowed to demonstration of the presence of increased monoclonal FLC in virtually all patients.5 Treatment strategies in these patients have been highly variable, ranging from steroids with or without chemotherapy2 to high-dose therapy followed by autologous stem-cell transplantation (ASCT).5, 6 We retrospectively analyzed the outcomes of 8 consecutive patients who were admitted to our Institute from 1993 to 2006 and received a diagnosis of MIDD, as confirmed by kidney biopsy. Additional investigations to confirm the diagnosis included light microscopy, congo red staining, immunofluorescence with anti-κ and anti-λ antibodies and EM; immunohistochemistry with antibodies directed against plasma cell-associated Ags was performed, when appropriate.