Presentation Patterns, Diagnostic Markers, Management Strategies, and Outcomes of IgD Multiple Myeloma: A Systematic Review of Literature

Renal insufficiency predicts worse prognosis in newly diagnosed IgD multiple myeloma patients

Objective

IgD multiple myeloma (MM) is a rare type of MM, accounting for about 1%-2% of all MMs. IgD MM always causes kidney damage and even leads to renal failure, which is the most common complication. This study aimed to explore the risk factors of renal damage and prognosis of IgD MM patients.

Design

From March 2018 to November 2021, 85 patients with IgD MM diagnosed for the first time at the First Affiliated Hospital of Zhengzhou University were included in this study. We collected information on clinical features and laboratory examinations. Patients were divided into the renal impairment (RI) (47/85) and non-renal impairment (no-RI) (38/85) groups. Binary logistic regression was used to explore risk factors of renal damage. The Chi-square test was used to analyze the difference in chemotherapy effect between the two groups. We also analyzed whether early dialysis was beneficial to acute renal failure (RF) in IgD MM patients. Finally, Kaplan-Meier was used to compare the survival of the two groups.

Results

In IgD MM, 55.3% of patients had renal damage as a complication, of which up to 59.6% presented with acute renal failure as the first manifestation. Serum β2-microglobulin (β2-MG) was an independent risk factor for renal damage in IgD MM (p = 0.002), but cytogenetic analysis suggested that it had no effect on patients' renal damage. There was also no significant difference in the effect of chemotherapy between the two groups (p = 0.255). In patients with acute renal failure, there was no significant difference between dialysis and no dialysis groups in the proportion of patients with improved renal function after treatment. The median overall survival (OS) of the RI group was significantly shorter than that of the no-RI group (p = 0.042). In the RI group, the median OS was 29 months, and in the no-RI group, the median OS was > 40 months.

Conclusion

Elevated serum β2-MG is an independent risk factor for renal damage. Compared with the no-RI group, patients in the RI group had poorer prognosis and shorter median OS. For patients with acute renal failure as the first manifestation, the treatment of primary disease is more meaningful than dialysis.

Monoclonal Gammopathies of Renal Significance: Renal Biopsy and Beyond

Monoclonal Gammopathies of Renal Significance (MGRS) are a rather heterogeneous group of renal disorders caused by a circulating monoclonal (MC) immunoglobulin (Ig) component, often in the absence of multiple myeloma (MM) or another clinically relevant lymphoproliferative disorder. Nevertheless, substantial kidney damage could occur, despite the "benign" features of the bone-marrow biopsy. One example is renal amyloidosis, often linked to a small clone of plasma cells, without the invasive features of MM. However, patients with amyloidosis may present with a nephrotic syndrome and renal failure, eventually leading to end-stage kidney disease. At the same time, other organs, such as the heart and the liver, may be severely damaged by Ig light chains or amyloid deposits, occasionally resulting in fatal arrhythmias and/or organ failure. Acute kidney injury (AKI) may as well result from massive excretion of MC proteins, with deposition disease in glomeruli or renal tubules, not rarely obstructed by luminal aggregates, or "casts". Proliferative glomerulonephritis with monoclonal Ig deposits is another, less frequent clinical presentation of an MGRS. The present review deals with the implications of MGRS for renal function and prognosis, and the potential of tools, such as the renal biopsy, for assessing clinical risk and guiding therapy of the underlying condition.