Immunoglobulin Profile of Multiple Myeloma in Kinshasa: A Preliminary Study from the INOVIE International Diagnostic Center in Democratic Republic of the Congo.

Abstract

Background:

Multiple myeloma is a plasma cell malignancy characterized by the clonal proliferation of bone marrow plasma cells and the production of monoclonal immunoglobulins. Characterization of the immunoglobulin profile is essential for diagnosis, disease classification, prognostic assessment, and therapeutic monitoring. However, data describing the immunoglobulin profile of multiple myeloma patients in sub-Saharan Africa remain limited. This study aimed to describe the electrophoretic and immunochemical profiles of patients with multiple myeloma in Kinshasa, Democratic Republic of the Congo.

Methodology:

A cross-sectional descriptive study with an exploratory analytical component was conducted at the INOVIE-AFRICA International Diagnostic Centre–DRC, Kinshasa, between July 2024 and August 2025. Thirty-three patients diagnosed with multiple myeloma according to the International Myeloma Working Group (IMWG) criteria underwent serum protein electrophoresis and serum immunofixation. Sociodemographic, clinical, radiological, and laboratory data were collected from medical records.

Results:

The mean age of the patients was 58.2 ± 13.6 years, and 54.5% were aged 60 years or older. Males predominated (63.6%). Anemia (57.6%) and bone pain (51.5%) were the most frequent clinical manifestations. Serum protein electrophoresis detected a monoclonal spike in 75.8% of patients, predominantly within the gamma globulin region (66.7%). Serum immunofixation demonstrated a monoclonal band in 93.9% of cases, confirming its superior diagnostic sensitivity. IgG-associated myeloma was the predominant immunochemical subtype, with IgG kappa accounting for 63.7% of cases and IgG lambda for 21.2%. Kappa light chains represented 74.2% of all monoclonal proteins identified by immunofixation. Patients with a detectable monoclonal spike were significantly older than those without a detectable spike (61.4 ± 12.4 vs. 48.0 ± 12.4 years; p = 0.012).

Conclusion:

Multiple myeloma in this cohort was predominantly characterized by secretory disease, with a marked predominance of IgG kappa monoclonal proteins. Serum immunofixation demonstrated greater diagnostic sensitivity than serum protein electrophoresis and proved essential for accurate immunoglobulin characterization.