Oxygen radical production in leukocytes and disease severity in multiple sclerosis.

This study investigated the relationship between the formation of NADPH oxidase-dependent oxygen radicals in peripheral blood leukocytes ('respiratory burst') and disease severity in patients with multiple sclerosis (MS). Oxygen radical production was induced by formyl-Met-Leu-Phe (fMLF), Trp-Lys-Tyr-Met-Val-Met-NH2 (WKYMVM) or phorbol myristate acetate (PMA) and was assessed by quantifying superoxide anion, i.e. the initial radical formed by the NADPH oxidase. Disease severity was evaluated using the Multiple Sclerosis Severity Score (MSSS). In patients with severe disease, the production of superoxide anion was significantly lower for all three inducers of radical formation (p=0.04-0.004). Our findings are supportive of a protective role of oxygen radicals in autoimmunity.