Post-chemotherapy lymphopoiesis in patients with solid tumors is characterized by CD4(+) cell proliferation

Purpose: A phenolypic analysis of peripheral blood lymphocytes was carried out in order to investigate the lymphopenia developed in some patients with solid tumors treated with systemic chemotherapy. Patients and Methods. Per ipheral blood was obtained from 53 cancer patients receiving chemotherapy w ith more than grade 2 neutropenia, before treatment, during the nadir of ne utrophils and after bone marrow recovery. Cell phenotype was performed usin g monoclonal antibodies while cell proliferation, using 3HtdR uptake, was e valuated after cell stimulation with PHA-P and anti-CD3 moAb. Results: Post -chemotherapy myelosuppression and rhG-CSF-induced bone marrow recovery wer e associated with lymphopenia and lymphocytosis reaching pre-treatment valu es, respectively; both lymphopenia and lymphocytosis concerned all lymphocy te subpopulations. Lymphocytosis was positively correlated with the absolut e number of CD3(+), CD4(+) and CD20(+) cells; in addition the absolute numb er of HLA-DR+ and CD25(+) cells was also increased During bone marrow recov ery, the absolute number of CD25(+) cells was correlated with the increased number of both CD3(+)/CD25(+) and CD4(+)/CD25(+) but not of CD8(+)/CD25(+) or CD20(+)/CD25(+) cells. CD4+ lymphopenia (less than 400 cells/dl) was de tected in 58% and 21% of the patients during myelosuppression and bone marr ow recovery, respectively. PHA-P and anti-CD3 moAb failed to enhance lympho cyte proliferation in 60% and 44% of the patients during bone mar-row recov ery respectively. Conclusions: Post-chemotherapy CD4(+) cell repopulation i s an active phenomenon. However, in several patients CD4 lymphopenia, which could be associated with functional cell abnormalities, may persist during bone marrow recovery leading to impaired cell-mediated immunity.