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

Assessment of renal outcome following therapy in monoclonal immunoglobulin deposition disease: Emphasizing the need for a consensus approach

Monoclonal immunoglobulin deposition disease (MIDD), often associated with plasma cell dyscrasias, predominantly affects the kidneys. In this disease, hematologic response (HR) to treatment can be reliably assessed by International Myeloma Working Group (IMWG) consensus criteria, while uniform criteria for assessing renal response are lacking. We report a retrospective analysis of renal outcomes among 34 patients with MIDD. With most patients treated with bortezomib and autologous stem cell transplantation, 26 of 28 (94%) achieved very good partial HR or better. We demonstrate that both IMWG (based on estimated glomerular filtration rate, eGFR) and amyloid (based on proteinuria) criteria are needed to capture renal response: among 28 evaluable patients, 6 (21%) had isolated proteinuria, while 13 (46%) had isolated decreased eGFR. Using both criteria, which were concordant in patients with both decreased eGFR and proteinuria, 22 of 28 patients (79%) achieved a renal response, including 2 of 7 discontinuing dialyses. All 6 patients (100%) with isolated proteinuria and 7 of 13 (54%) with isolated decreased eGFR achieved renal response, suggesting that isolated proteinuria is an early manifestation of MIDD associated with reversible renal damage. Baseline eGFR predicted renal response (p = .02 by quartile) and survival (p = .02), while HR (CR vs. non-CR) did not, probably because of high HR rate. With a median follow-up of 110 months, the median overall survival was 136 months (95% CI: 79-NR) and median renal survival had not been reached. Prospective studies using uniform renal response criteria are needed to optimize the management of MIDD.

Long-term renal survival of γ3-heavy chain deposition disease: a case report

Background

Monoclonal immunoglobulin deposition disease (MIDD) is characterized by the non-amyloid deposition of monoclonal immunoglobulin fragments in the basement membranes. Heavy chain deposition disease (HCDD) is a type of MIDD. HCDD is an extremely rare disease, and only three cases have been reported in Japan up to the present. The prognosis of HCDD is very poor, and optimal treatment has not been established. Only a few cases of HCDD with favorable long-term renal prognosis have been reported to date.

Case presentation

The authors describe a 61-year-old woman who presented with massive proteinuria, progressive kidney impairment, and hypocomplementemia. Kidney biopsy was performed for a precise diagnosis. On light microscopy, glomerules were lobulated and presented with nodular sclerosing glomerulopathy with membranoproliferative glomerulonephritis-like features. Immunofluorescence studies were positive for IgG, C3, and C1q within the mesangial nodules and in a linear distribution along the capillary walls without associated deposition of light chains. Staining for IgG showed the presence of linear deposits along tubular basement membranes. The analysis of the IgG subclass stain demonstrated intense positivity for IgG3 only. Electron microscopy revealed non-organized electron-dense deposits in the expanded mesangial area and inner aspect of the glomerular basement membranes. In accordance with the histological findings, we diagnosed γ3-HCDD. There was no evidence of plasma cell dyscrasia as a result of bone marrow aspiration. Serum and urine monoclonal proteins were not detected by immunoelectrophoresis and immunofixation electrophoresis. The serum free light chain ratio was within normal range. At first, prednisolone was administrated at a dose of 40 mg/day. However, a therapeutic effect was not observed. Urinary protein was not decreased and renal function further deteriorated. Therefore, melphalan plus prednisolone (MP) therapy was initiated. After 4 courses of MP therapy, the clinical parameters, including proteinuria, serum creatinine, albumin, and complement level (C3 and C4) were ameliorated. To date, the patient has been followed for 28 months, and long-term renal survival has been observed.

Conclusions

In this case, hematologic disease such as multiple myeloma was not detected; however, MP therapy was effective. Recently, the novel concept of monoclonal gammopathy of renal significance (MGRS) has been reported. MIDD, which includes HCDD, is one category of MGRS. In MGRS, aggressive chemotherapy may induce favorable renal outcomes.

How I treat monoclonal gammopathy of renal significance (MGRS)

Recently, the term monoclonal gammopathy of renal significance (MGRS) was introduced to distinguish monoclonal gammopathies that result in the development of kidney disease from those that are benign. By definition, patients with MGRS have B-cell clones that do not meet the definition of multiple myeloma or lymphoma. Nevertheless, these clones produce monoclonal proteins that are capable of injuring the kidney resulting in permanent damage. Except for immunoglobulin light chain amyloidosis with heart involvement in which death can be rapid, treatment of MGRS is often indicated more to preserve kidney function and prevent recurrence after kidney transplantation rather than the prolongation of life. Clinical trials are rare for MGRS-related kidney diseases, except in immunoglobulin light chain amyloidosis. Treatment recommendations are therefore based on the clinical data obtained from treatment of the clonal disorder in its malignant state. The establishment of these treatment recommendations is important until data can be obtained by clinical trials of MGRS-related kidney diseases.