Evaluation diagnostic usefulness of immunoglobulin light chains (Ig kappa, Ig lambda) and incomplete IGH D-J clonal gene rearrangements in patients with B-cell non-Hodgkin lymphomas using BIOMED-2 protocol

Abstract

Evaluation diagnostic usefulness of immunoglobulin light chains (Ig kappa, Ig lambda) and incomplete IGH D-J clonal gene rearrangements in formalin-fixed, paraffin-embedded (FFPE) tissue of patients with B-cell non-Hodgkin lymphomas (B-NHL). This study was performed on samples from 70 patients with B-NHL, including two cases of follicular lymphoma (FL), 20 cases of diffuse large B-cell lymphoma (DLBCL), one case of mantle cell lymphoma (MCL), and 47 cases of B-cell neoplasm (non-classified), which had been previously assessed for complete IGH clonality, and failure to clarify gene rearrangements. We used a gold standard multiplex PCR protocol provided by European Biomedicine and Health (BIOMED-2) Concerted Action Project BMH4-CT98-3936 for improvement of diagnosis and analysis of clonality gene rearrangement in lymphoma malignancies. Our results revealed a total positive monoclonality of 89 % (62/70) in Ig kappa, Ig lambda, and 11.4 % (8/70) polyclonality in gene rearrangements assay. The samples with positive clonality consisting (Ig kappa: 45 %, Ig lambda: 55 %) in DLBCL, (Ig kappa: 100 %) in FL, (Ig lambda: 100 %) in MCL, and (Ig kappa: 47 %, Ig lambda: 36 %) in B-cell neoplasm non-classified. None of the incomplete IGH D-J immunoglobulin gene families (0 %) showed monoclonality, and all samples demonstrated polyclonality pattern. Our findings on FFPE tissue revealed that immunoglobulin light chains clonality gene rearrangements assays using BIOMED-2 protocol, could be considered a valuable and reliable method for clonality detection, particularly in cases of failure of complete IGH gene rearrangements analysis. Clonal Ig gene rearrangements assay is applicable for routine diagnostic testing of lymphoproliferative disorders and as a reliable method for differentiating between malignant and benign lymphoma disorders.