Clinicopathologic Study Focuses on Potential Immunophenotypic Precursor to CLL
Posted: Thursday, April 29, 2021
Researchers set out to affirm that B-cell clones discovered in tissue biopsies, without overt lymphoma, may represent a tissue counterpart to peripheral blood monoclonal B-cell lymphocytosis (MBL), herein termed tMBL. Gabriel K. Habermehl, MD, of the Department of Laboratory Medicine, Cleveland Clinic, posed a possible connection between tMBL and chronic lymphocytic leukemia (CLL). “We know that most, if not all, cases of CLL are preceded by MBL. The natural history of CLL-type MBL has been characterized with the rate of progression to CLL requiring treatment to be approximately 1% per year, and the only independent risk factor associated with progressive lymphocytosis is the absolute B-cell count.”
In this study, published in the Archives of Pathology & Laboratory Medicine, 54 cases were identified (35 lymph nodes, 3 splenic, and 16 soft-tissue/viscera). A total of 46 cases were CLL-type, 2 were atypical CLL, and 6 were non-CLL. Of note, tMBL was detectable by immunohistochemistry in 14 cases (26%, all CLL-type). Concurrent blood flow cytometry, available in 10 cases, showed 4 with low-count MBL (3 CLL-type, 1 non-CLL-type), 5 with high-count MBL (all CLL-type), and 1 negative for the clonal population.
Regarding clinical follow-up, 43 of the 54 cases had clinical follow-up data available. With a median time of 51 months (range, 3–158.1 months), the 5-year overall survival rate was 86%. There were six deaths during the follow-up period. Two patients had disease progression (CLL-type tMBL progressed to CLL, 68.7 months; and non-CLL–type tMBL progressed to diffuse large B-cell lymphoma, 5.9 months).
“It may be prudent to closely follow all non-CLL tMBL cases owing to the apparent shorter overall survival rate within this group,” the authors suggested.
Disclosure: For full disclosures of the study authors, visit meridian.allenpress.com.