CD20+ T CELLS IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL).

BUONINCONTRO BRENDA; SARAPURA MARTINEZ VALERIA JUDITH; CORDINI, GREGORIO; COLADO ANA; CASSARINO CHIARA; BERNATOWIEZ J; BEZARES RAIMUNDO FERNANDO; GARATE, GONZALO; BORGE MERCEDES; GIORDANO MIRTA; GAMBERALE ROMINA

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias; 2022

Reunión Anual de Sociedades de Biociencias, Buenos Aires 16-19 Noviembre 2022.

CD20 is classically a B cell marker, but dim expression of CD20 hasbeen noted on 0.1 to 7% of circulating T cells from healthy donors(HD). Compared to CD20- T lymphocytes, CD20+ T cells producegreater levels of IL-2, IL-4, IL-10 IL-17, TNF alfa and IFN gamma.They may have a pathogenic behavior in autoimmune diseases andCD20+ T-cell malignancies or a protective role in ovarian cancer andHIV infection. Their role in CLL has not been evaluated yet. CLL isthe most common adult B cell leukemia, in which T cells are keyplayers in the protective tumor microenvironment of lymphoid tissues.We aimed to study the subpopulation of CD20+ T cells in peripheralblood (PB) and bone marrow (BM) of CLL patients. CD20+T cells were defined by flow cytometry as CD20+CD19-CD3+ cellsin 53 PB and 9 BM samples from CLL patients and 27 PB samplesfrom age and sex matched HD. The percentage (%CD20+ T cells)was calculated considering CD3+ T cells as 100%. We found higher%CD20+ T cells in PB of CLL patients compared to HD (4.6±0.6 vs2.3±0.3, p<0.05). Similar results were found when the total amountof CD20+ T cells was evaluated (p<0.05). The %CD20+ T cells in ourCLL patients range from 0.1 to 21.7 %. No significant differenceswere observed in the %CD20+ T cells when patients were segregatedbased on the expression of the prognostic markers CD38,CD49d, the mutational status of the IGVH, their clinical stage, plateletscount or hemoglobin, beta-2-microglobulin and lactate dehydrogenasevalues. Interestingly, higher %CD20+ T cells were foundin the BM compartment compared to PB of the same patient (n=9,p<0.05).In conclusion, the %CD20+ T cells is higher in PB from CLL patientscompared to HD and even higher in BM. No association was foundbetween the %CD20+ T cells and clinical and biological data of theCLL patients. Functional studies are needed to evaluate the impactof CD20+ T cells on leukemic cell survival and activation.