Kinetics of protein a activation of mononuclear cells from patients with chronic lymphocytic leukemia — I. CLL B-cells are not intrinsically unresponsive to staphylococcal protein A

The response of lymphocyte subpopulations to staphylococcal Protein A (SPA) was studied in patients with B-cell chronic lymphocytic leukemia (CLL) and normal volunteers. The kinetics of the proliferative response, optimal dose and sera requirements were determined. Of 92 experiments conducted in 60 patients, SPA induced peripheral blood mononuclear cells (PBMC) proliferation in 81.5% of cases studied. The mean proliferative response of CLL PBMC was significantly lower than normal PBMC, 5823 vs. 30,364 cpm. However, enriched CLL B-cells failed to respond to SPA compared to normal enriched B-cells, with mean cpm 444 vs. 6438 respectively. As PBMC from CLL consist of increased proportions of B-cells and decreased proportions of T-cells, enriched CLL B-cells were cultured at 1 : 1 ratio with autologous or allogeneic normal T-cell enriched fractions. CLL B-lymphocytes were stimulated by SPA when cultured in the presence of T-lymphocytes, indicating a T-helper defect in the B-CLL proliferative response to SPA, rather than an intrinsic inability of CLL B-cells to proliferate. These observations are of import for further studies of CLL B-lymphocyte function, cytogenetics, and establishment of CLL B-cell lines in culture.