Gamma gap as a prognostic marker of treatment response in patients with multiple myeloma.

Background: Multiple myeloma (MM) is defined by the excessive growth of cancerous plasma cells in the bone marrow, resulting in the production of an abnormal monoclonal paraprotein and signs of damage to vital organs. The diagnosis of multiple myeloma can be complex. This paper centers on the diagnosis of MM and examines the role of the gamma gap (GG) in prompting tests to assess treatment effectiveness.

Methods: Sixty individuals newly diagnosed with MM were selected from medical facilities in Iraq, specifically Baghdad Hospital/Medical City and Hematological Center, between November 2022 and March 2023. Additionally, 30 healthy participants were included as a comparison group. The assessment of suspected MM patients involves confirming the presence of a monoclonal paraprotein using serum electrophoresis (SEPG) and immunofixation (SIF), as well as analyzing free light chains (FLC). Spectrophotometric methods were used to measure total serum protein and albumin levels and calculate the globulin-to-albumin ratio by subtracting serum albumin from total serum protein.

Results: In most MM cases the monoclonal immunoglobulin (as M-spike) was identified and quantified by SPEP. Based on the findings from IFE detection, the prevalence of M-spike, particularly type IgG, was observed in 45 cases (83.3%), of which 40% were type κ, 24.6% were type λ, and 19.3% were of an unknown type. Additionally, type IgA was the second most prevalent (10 cases, 16.7%), with 14.3% being type κ and 1.7% being type λ. Moreover, the results indicated a significant association between GG and M-spike, as well as a strong correlation between GG and pre- and post-treatment M-spike levels. The area under the curve was deemed acceptable (AUC = 0.735, p = 0.0001), demonstrating high diagnostic accuracy (86.2) in distinguishing MM patients before and after treatment.

Conclusion: The evaluation of GG in the serum of MM patients demonstrated elevated levels, which were significantly associated with patients post-treatment. Therefore, our findings have significant implications for the use of GG as a prognostic indicator for monitoring treatment response in MM patients.