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 chronic lymphocytic leukemia (B-CLL). The mechanism responsible for this phenomenon is still unresolved.

METHODS

In 88 B-CLL patients (RAI II-IV) the relationship between immunoregulatory T cells and PHA induced lymphoproliferative response (LPR) was analysed before and after the therapy. The number of peripheral blood CD3+, CD4+ and CD8+ T lymphocytes was determined by indirect immunofluorescence assay using monoclonal antibodies. LPR was estimated in whole blood culture method.

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 percentages 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 baseline levels, but their levels remained significantly (p < 0.00001) lower than the controls. The CD4/CD8 ratio was also elevated after the therapy (p < 0.048) 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 were still higher (p < 0.044) than controls. The increase of LPR has been registered after treatment, but it failed to reach the control values. We could not 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.