Serum levels of TNF, IL-6 and sCD23 correlate with changes in lymphocyte count in patients with B-Cell chronic lymphocytic leukaemia receiving interferon-alpha therapy

The control of cell growth and differentiation in B-cell malignancies may be regulated by the autocrine production of cytokines, several of which have been implicated in the growth and survival of B-cells. The effect of interferon-alpha (IFN) therapy in these disorders may be to disrupt autocrine growth or survival loops. We have measured levels of circulating IL-1b, IL-6, TNF-a and soluble CD23 (sCD23) in 8 patients with Binet stage A B-cell chronic lymphocytic leukaemia (B-CLL) receiving IFN therapy, and compared these with changes in the lymphocyte count following IFN therapy. Two patients developed anti-interferon antibodies while on IFN therapy, and in both them, the changes in lymphocyte count correlated significantly with the titre of anti-interferon antibodies, as well as serum levels of IL-6, TNF-a and sCD23. In one patient there was significant correlation with levels of IL-1b. One patient, who stopped and restarted IFN therapy, demonstrated correlation between lymphocyte count and levels of IL-6 and sCD23. In a further two patients, there was correlation with levels of sCD23 alone, while the remaining three patients showed no correlation between lymphocyte count and the serum cytokines measured. These results suggest that IFN therapy may alter levels of circulating cytokines in some CLL patients and that these effects may be associated with disease progression.