Effects of alpha-interferon and steroids on CD23 expression and release in B-cell chronic lymphocytic leukemia

Istituto di Patologia Medica, Cattedra di Medicina Interna II, Universita di Trieste, Ospedale di Pordenone, Italy.

BACKGROUND. Since high CD23 expression and release have been reported in B-chronic lymphocytic leukemia (B-CLL), we investigated whether alpha-interferon or corticosteroids were able to modulate the expression and/or the release of this factor. METHODS. CD23 expression was determined with FITC-labelled anti-CD23 monoclonal antibody, and sCD23 release with a sandwich enzyme immunoassay. Twenty-one patients affected by B-CLL (stage A or B) were studied before and after three different treatment regimens (alpha-interferon, corticosteroids, alpha-interferon+corticosteroids). RESULTS. CD23 was highly expressed in the B-cells of all patients, and expression was not modified by any of the therapies, sCD23 release from leukemic cells was significantly greater (p < 0.00001) in untreated subjects than controls, and in vitro treatment with phorbol myristate acetate (PMA) led to a 10-fold increase (p < 0.0001) in sCD23 secretion. On the contrary, PMA did not increase sCD23 release in normal B cells. Treatment with corticosteroids (either alone or associated with alpha-interferon) reduced sCD23 secretion from leukemic cells, whereas alpha-interferon alone was not able to modify sCD23 release. CONCLUSIONS: Our data support the hypothesis that CD23 plays a role in the maintenance and progression of B-CLL and that the pharmacological modulation of this receptor/lymphokine could be useful in the therapy of B-CLL.