Interindividual phenotypic variations in CLL B lymphocyte maturation indication of different maturation blocks.

Peripheral blood lymphocytes from 8 patients with B-derived chronic lymphocytic leukaemia were stimulated by Staphylococcus aureus bacteria strain Cowan 1 with T cell mitogens PHA or PWM in 5-7 day suspension cultures. For the first group of patients proliferation and maturation tests were performed on T cell enriched and T cell depleted subpopulations, obtained from harvested lymphocytes at the end of cultures by the sheep red cell rosette technique. To re-examine mutual influences of cultivated T and B cells in the second group of experiments, lymphocytes from CLL patients and from 5 healthy individuals were investigated by the use of transmembrane cocultivation system after Feldman and Basten. The proliferative responses to lectin and to bacteria were assessed by 3HTdR-blastic and mitotic indices. The maturation process of B lymphocytes was examined by cytoplasmic Ig, studied by FITC-conjugated antisera. Results obtained with cocultivation system support the view that T cell replacing factor(s) were required for inducing prolonged growth and development of maturation of more numerous B lymphocytes in response to Staphylococcus aureus, a T cell independent, B specific polyclonal stimulator. Results analysed in different patients indicate various degrees of maturation of B cells including their differentiation towards a plasmacytoid cell, accompanied by various proliferative capacities of B and T lymphocytes. This functional analysis reflects the heterogeneity of B-CLL patients group.