Elevated cerebrospinal fluid CD4 +/CD8 + T cell ratio in myasthenia gravis

Abstract

The proportions of CD2 +, CD4 + and CD8 + lymphocytes were determined with the 3-layer indirect immunoperoxidase technique in the cerebrospinal fluid (CSF) of 31 patients with myasthenia gravis (MG) and 21 control subjects without autoimmune or central nervous system (CNS) diseases. None of the MG patients were using immunosuppressive drugs and all were thymectomized shorly after CSF sampling. Analysis of the reference population showed that the percentage of CD4 + lymphocytes and accordingly the CD4 +/CD8 + T cell ratio is normally higher in CSF than in peripheral blood (PB). Compared to the controls, the mean percentage of CD4 + lymphocytes and the mean CD4 +/CD8 + ratio in CSF were significantly higher in MG patients. In addition, the CD4 +/CD8 + ratio was elevated in the CSF of 15 MG patients (48%) as a result of an elevation in the proportion of CD4 + and/or a decrease in CD8 + T cells. Among MG subjects the mean proportion of CD4 + lymphocytes was higher in the CSF of patients with also an elevated number of enlarged stimulated lymphoid cells in their CSF, which implies that these lymphocytes are often of the CD4 + phenotype. The percentage of CD4 + T cells in CSF was significantly higher in MG patients with a hyperplastic thymus or a thymoma than in those with an involuted thymus. Neither in MG patients nor in the reference population could an association be observed between CSF and PB lymphocyte subsets. In the controls this suggests that immunologic events of the CNS are normally not directly reflected in PB. In MG the results of this study indicate that, at least before therapeutic interventions on the immune system, a localized cellular immune reaction takes place within the CNS in a large proportion of the patients.