IGH/IGK gene rearrangement in the diagnosis of B-cell non-Hodgkin lymphoma: experience from three centers

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B-cell non-Hodgkin lymphomas (B-NHL) are a heterogeneous group of malignancies that pose significant diagnostic challenges due to their clinical and molecular diversity. Traditional detection methods (e.g., morphology and immunohistochemistry) could confirm most cases, but 10% remain difficult to diagnose. Comparatively, immunoglobulin clonality assessment has great potential to support the diagnosis of lymphocytic malignancies. This study retrospectively analyzed 996 patients with suspected B-NHL and reactive lymphoid hyperplasia (RLH) from three centers. Immunoglobulin heavy/light chain (IGH/IGK) gene rearrangements were detected using capillary electrophoresis, and results were compared with final diagnoses based on clinical follow-up. Among 978 cases with definitive diagnoses, 97.1% (369/380) of B-NHL patients showed IGH/IGK gene rearrangements, while 99.7% (596/598) of non-B-NHL patients were negative. The combined evaluation of morphology and IGH/IGK rearrangement improved the sensitivity from 70.8 to 98.2% and the accuracy from 81.7 to 92.1% over morphology alone. The combined assessment of morphology, immunohistochemistry and IGH/IGK rearrangement improved the sensitivity from 71.6 to 98.2% and the accuracy from 83.2 to 93.4% compared to the combined assessment of morphology and immunohistochemistry. Additionally, IGH rearrangements were more frequent than IGK rearrangements in B-NHL patients, with significant differences in rearrangement patterns among B-NHL subtypes. The IGH rearrangement was mainly found in small lymphocytic lymphomas, diffuse large B-cell lymphoma and follicular lymphoma; the IGK rearrangements were mainly found in B-cell lymphoblastic lymphomas and marginal zone lymphoma; the IGH and IGK rearrangements were mainly found in mantle cell lymphoma and multiple myeloma. In conclusion, IGH/IGK rearrangement analysis showed high consistency with final diagnoses, supporting its integration into routine clinical diagnostics to improve the accuracy of B-NHL diagnosis.

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