Methisoprinol restoration of leukocyte chemotaxis inhibition by blocking factors in immunoproliferative diseases.

The ability of methisoprinol to antagonize the serum-inhibiting activity present in the sera of patients affected by immunoproliferative diseases (Hodgkin's disease and multiple myeloma) was investigated. Using a chemotaxis test, it was found that whereas donor leukocytes preincubated in patient sera exhibited impaired chemotaxis, the presence of methisoprinol (500 micrograms/ml) during the preincubation caused a significant recovery of this leukocyte function. Since the results exclude the assumption of a non-specific stimulation of cell motility, two hypotheses appeared possible for the action of methisoprinol: either an antagonistic activity against the blocking factor at the receptor or the metabolic level, or a direct inactivation of this factor. The clinical implications, with regard to the prophylaxis of infections and a better response to chemotherapy, are discussed.