Lymphocyte subpopulations and IgG concentrations in cerebrospinal fluid and blood from patients with myasthenia gravis.

Twelve patients with myasthenia gravis (MG) were examined for cerebrospinal fluid (CSF) T lymphocytes and for peripheral blood lymphocyte subpopulations (E-, EAET-, EA- and EAC-rosette-forming cells). The patients had a significantly increased percentage of CSF T cells (88.2 +/- 8.7%) when compared with controls (78.0 +/- 9.1%). Absolute concentrations of CSF T cells were not significantly increased. In peripheral blood no significant change in lymphocyte subpopulations was observed, but there was a slight leucocytosis in the patient group. The patients had increased CSF IgG concentrations, CSF IgG to protein ratio, and CSF to serum IgG ratio, indicating an intrathecal production of IgG. No oligoclonal bands could be demonstrated in the agarose gel electrophoresis. The two patients with thymoma had anti-muscle antibodies in CSF and serum, with ratios of 1:256 and 1:1024, respectively. Serum IgG levels were increased, but not significantly, in the patient group. These results suggest an involvement also of the central nervous system in some patients with MG.