Chemokines are involved in the pathogenesis of multiple sclerosis. The aim of the study was to evaluate the effects of immunosuppressive therapy on production of two proinflammatory chemokines--interleukin-8 (IL-8) and RANTES (regulated on activation, normal T cell expressed and secreted). Twenty-five patients with relapsing-remitting multiple sclerosis were treated with 2-chlorodeoxyadenosine (Cladribine), administered subcutaneously in 6 cycles repeated every 5 weeks. IL-8 and RANTES levels were measured by the enzyme-linked immunoassay (ELISA) method in serum and cerebrospinal fluid (CSF) before and after treatment. After Cladribine treatment the levels of IL-8 decreased significantly in CSF only, whereas the RANTES levels decreased significantly both in CSF and serum. Our results suggest that Cladribine therapy might modify the circulating level of RANTES.