Evaluation of Positive B- and T-Cell Gene Rearrangement Studies in Patients With Negative Morphology, Flow Cytometry, and Immunohistochemistry

Abstract

The significance of positive immunoglobulin (IG) or T-cell receptor (TCR) gene rearrangement studies in the context of otherwise normal ancillary findings is unknown. To examine long-term hematologic outcomes of individuals with positive gene rearrangement studies with otherwise unremarkable blood or bone marrow studies in parallel. Data from patients who underwent IG or TCR gene rearrangement testing at the authors' affiliated Veterans Affairs Hospital January 1, 2013 to July 6, 2018 were extracted from medical records. Date of testing, specimen source, and morphologic, flow cytometric, immunohistochemical, and cytogenetic characterization of the tissue source were recorded. Gene rearrangement results were categorized as test positive/phenotype positive (T+/P+), test positive/phenotype negative (T+/P-), test negative/phenotype negative (T-/P-), or test negative/phenotype positive (T-/P+) based on comparison to other studies and/or final diagnosis. Patient records were reviewed for subsequent diagnosis of hematologic malignancy for patients with positive gene rearrangements but no other evidence for a disease process. A total of 136 patients with 203 gene rearrangement studies were analyzed. For TCR studies, there were 2 T+/P- and 1 T-/P+ results in 47 peripheral blood assays, as well as 7 T+/P- and 1 T-/P+ results in 54 bone marrow assays. Regarding IG studies, 3 T+/P- and 12 T-/P+ results in 99 bone marrow studies were identified. None of the 12 patients with T+/P- TCR or IG gene rearrangement studies later developed a lymphoproliferative disorder. Positive IG/TCR gene rearrangement studies in the context of otherwise negative bone marrow or peripheral blood findings are not predictive of lymphoproliferative disorders.