The absence of correlation between immunoregulatory T cells and induced lymphoproliferative response in treated B-chronic lymphocytic leukemia patients

Background. Many data suggest T cell functional impairment in B-cell chroni c lymphocytic leukemia (B-CLL). The mechanism responsible for this phenomen on is still unresolved. Methods. In 88 B-CLL patients (RAI II-IV) the relationship between immunore gulatory T cells and PHA induced lymphoproliferative response (LPR) was ana lysed before and after the therapy. The number of peripheral blood CD3+, CD 4+ and CD8+ T lymphocytes was determined by indirect immunofluorescence ass ay using monoclonal antibodies. LPR was estimated in whole blood culture me thod. Results. The absolute number of CD3+, CD4+ and CD8+ cells in untreated CLL patients was much higher than in healthy controls (n=26), but the percentag es of these subpopulations, CD4/CD8 ratio and LPR to PHA were significantly (p<0.00001) decreased. The chemotherapy induced a significant rise of CD3 and CD4+ percentages (p<0.006<p<0.022 respectively) in comparison to basel ine levels, but their levels remained significantly (p<0.00001) lower than the controls. The CD4/CD8 ratio was also elevated after the therapy (p<0.04 8) but remained below the normal value as well. The absolute number of CD3 and CD4+ T cells were normalized after treatment, while the CD8+ cells wer e still higher (p<0.044) than controls. The increase of LPR has been regist ered after treatment, but it failed to reach the control values. We could n ot find any correlation between the number of immunoregulatory T cells and induced LPR (r=0.07, for CD4+; r=0.09 for CD8+ cells). Conclusions. These data indicate some profound lymphoid cell defect in CLL patients affecting CD8+ proliferation as well as LPR.