Interleukin-1 and interleukin-2 production by peripheral blood mononuclear cells in multiple sclerosis patients

The production of interleukin-1 (IL-1) and interleukin-2 (IL-2) by peripheral blood mononuclear cells (PBM) was assessed in multiple sclerosis (MS) patients in relapse, chronic progressive MS patients, patients with other neurological diseases (OND) and healthy subjects. Production was defined as the level of IL-1 and IL-2 in PBM supernatants. Neither spontaneous nor LPS-induced IL-1 production differed significantly in MS, OND patients or healthy individuals. On the other hand PHA-induced PBM IL-2 production was significantly less in MS patients in relapse (130 +/- 10.0 U/ml) than in chronic progressive MS patients (172 +/- 9.8 U/ml), OND patients (192 +/- 11.5 U/ml) and healthy subjects (215 +/- 13.8 U/ml) (P less than 0.02). Spontaneous IL-2 production was also diminished in MS patients in relapse (31 +/- 7.2 U/ml) as compared to chronic progressive MS patients (46 +/- 8.8 U/ml) and healthy subjects (49 +/- 11.1 U/ml) (P less than 0.01). Anti-Tac monoclonal antibody was used to study IL-2 receptor expression on the same sample of PBM that was used for IL-2 study. MS patients in relapse had significantly higher levels of IL-2 receptor-positive unstimulated PBM (6.0 +/- 2.2%) as compared to chronic progressive MS (2.0 +/- 0.9%), OND (2.5 +/- 1.1%) and healthy subjects (1.5 +/- 0.7%) (P less than 0.002). We postulate that reduced apparent IL-2 production by PBM of MS patients in relapse may result from immediate IL-2 binding to receptor expressed on activated T lymphocytes and internalization of IL-2-receptor complex.