Peripheral blood leukocyte NO production in MS patients with a benign vs progressive course.

BACKGROUND Nitric oxide (NO) may play a role in tissue destruction and axonal degeneration in multiple sclerosis (MS). OBJECTIVE To investigate NO production by peripheral blood leukocytes (PBL) in patients with a benign and progressive course of MS. METHODS PBL were isolated from 25 patients with a benign course of MS (BMS), 33 with secondary progressive MS (SPMS), 21 with primary progressive MS (PPMS), and 29 healthy individuals. Leukocyte supernatants were assayed for nitrite concentration, which is an index of NO generation, using the Griess reaction. Serum levels of tumor necrosis factor (TNF)alpha and interleukin (IL)-12 were measured using ELISA. RESULTS Compared to healthy controls, nitrite concentrations were higher in patients with BMS (p < 0.001), SPMS (p < 0.001), and PPMS (p < 0.05). There were no significant differences among the three clinical subgroups of MS. There was a correlation between nitrite concentrations and serum levels of IL-12 (p = 0.04), but not of TNFalpha. CONCLUSION Increased NO production by PBL in patients with MS is independent of the disease course.