2',5'-oligoadenylate synthetase activity and T cell subset in the cerebrospinal fluid and peripheral blood of aseptic meningitis

2',5'-oligoadenylate synthetase activity, which is assumed to be induced by interferon, is reported to be one of the useful markers reflecting interferon activity. The enzyme activity of patients with aseptic meningitis and febrile convulsion were compared in order to evaluate interferon activity as one of the local immune-defense mechanisms of aseptic meningitis. The surface antigen of mononuclear cells in cerebrospinal fluid and peripheral blood of some patients with aseptic meningitis was also measured. The enzyme activity of patients with aseptic meningitis was 191.4 pmol/dL in the cerebrospinal fluid and 395.8 pmol/dL in the serum during the acute phase, while that of patients with febrile convulsion was 45.2 pmol/dL in the cerebrospinal fluid and 326.0 pmol/dL in the serum. The enzyme activity of the former patients significantly decreased during the recovery phase in both the cerebrospinal fluid and serum. CD3 positive cells in the peripheral blood were 56.3% of the total mononuclear cells during the acute phase and 65.2% during the recovery phase, whereas in the cerebrospinal fluid mononuclear cells, they were 87.1 and 85.5%, respectively. During the acute phase, CD4 positive cells were the predominant T lymphocyte subset in the cerebrospinal fluid cells, while CD8 positive cells were predominant during the recovery phase. The relative proportions of CD4 positive and CD8 positive cells during the acute and recovery phase in the cerebrospinal fluid mononuclear cells were quite high compared to the recovery phase, although that ratio of peripheral blood mononuclear cells was not changed throughout the course. It was concluded that T lymphocytes and increased 2',5'-oligoadenylate synthetase activity in the cerebrospinal fluid may be one of the important components in the local inflammatory process independent of the systemic host defense mechanism in aseptic meningitis.