MEMBRANE EXPRESSION OF IL-1-ALPHA IN CHRONIC B-LYMPHOCYTIC LEUKEMIA

Patients with B chronic lymphocytic leukemia (B-CLL) demonstrate a hig h variability in disease activity, from a benign monoclonal lymphocyto sis to a rapidly fatal condition. Progressive B-CLL is related to a hi gh expression of different growth factor receptors on the leukemic cel ls and to a high proliferative in vitro response to Staphylococcus aur eus strain Cowan 1 (SAC). As the expression of membrane IL-1 alpha (mI L-1 alpha) indicates B lymphocyte activation, we have investigated mIL -1 alpha on cells from patients at different stages of the disease. To tal cellular levels of IL-1 alpha were measured by flow cytometry of p ermeabilized cells and compared with CD5, CD19, CD25 and IgM expressio n on the cell surface. mIL-1 alpha is upregulated, both in leukemic an d normal lymphocytes, in response to sIgM cross-linking with SAC or ph orbol ester activation. A significantly higher expression of mIL-1 alp ha was found in cells from patients with a clinically benign form of t he disease.