Background: The reason for increased peripheral blood leukocyte (PBL) nitric oxide (NO) production in patients with multiple sclerosis (MS) is unknown.
Objective: To investigate whether PBL NO production is related to measures of oxidative stress.
Methods: PBL nitrite, diene conjugates (DC, a measure of undergone oxidative stress), antiradical activity (ARA) and antioxidant acitvity (AOA) were measured in 35 healthy control persons and 80 patients with MS. We investigated the correlation of these measures with a partial correlation analysis, with age as the control variable.
Results: There was a significant correlation in both MS patients and healthy control persons between PBL nitrite levels and PBL DC, ARA and AOA. The correlations were stronger in healthy control persons. An analysis by disease subtype showed that the correlations were present in patients with relapsing-remitting and secondary progressive MS, but absent in primary progressive MS.
Conclusions: PBL nitrite levels and measures of oxidative stress are closely related in MS-patients as well as in healthy control persons. Increased serum NO levels in MS may be the result of a physiologic reaction to overall oxidative stress. The differences in the strength of correlation between different disease subtypes may reflect differences in leukocyte biology.