Introduction: An oligoclonal pattern on serum immunofixation electrophoresis (SIFE), is defined by the presence of more than two monoclonal bands on the gel. It results from the proliferation of small clones of plasma cells within the bone marrow. Material and methods: It is a retrospective study from July 1, 2024, to July 31, 2025, analyzing results of SIFE performed on Hydrasis Sebia at Mohammed VI National Laboratory. When serum capillary zone electrophoresis (CZE) was also present, abnormalities were noted. Results: The study found 22 cases of oligoclonal pattern. Majority of patients are older than 50 years old (72,5%). Most frequent isotype is IgG associated with light kappa and lambda chains (55%). Corresponding serum CZE all included an abnormality in the gamma globulin area. Discussion: An oligoclonal pattern or profile results from the proliferation of small plasma cells clones. These abnormalities are common in elderly subjects due to the immune system’s impairment. The detection of oligoclonal bands is easy but must remain precautious. Etiologies associated with such profiles include autoimmune, infectious diseases or malignant pathologies (lymphomas, plasma cells leukemia). A contributive interpretation could include a detailed report of the bands found on the gel in order to allow the detection of any ulterior modification of the clonality. Conclusion: An appropriate interpretation of an oligoclonal profile can only be done according to patient’s clinical history. It is recommended to repeat the SIFE to allow an early diagnosis of any monoclonal gammopathy.

Multiple myeloma is a little-known disease in young adults, it is rarely reported before the age of 30, even less if it is light chains. We report a case illustrating one of these exceptional situations. It has characteristics as organic sounding extended and favorable response to treatment despite diagnostic delay. We wanted to take the opportunity to raise awareness about the possibility of myeloma in adults at any age.