Active T cells and humoral immune variables in blood and cerebrospinal fluid in patients after acute unilateral idiopathic optic neuritis

The active T cell rosette test - that is determination of T lymphocytes with high affinity for sheep erythrocytes after incubation at 37°C for 1 h - defines a T cell subset that has been claimed to parallel cell-mediated immunocompetence in e.g. viral diseases. In 16 patients who have had acute unilateral idiopathic optic neuritis (ON), lower percentages of active T cells were found in CSF compared to blood, irrespective if the interval between the first bout of ON and the present study was 2 months or 26 years, and irrespective of degree of mononuclear pleocytosis or humoral immune variables in CSF. The same distribution of active T cells has previously been observed in multiple sclerosis (MS). The percentages of active T cells in peripheral blood from the patients with ON were normal. Determination of active T cell does not seem to discriminate those patients with ON who are likely to develop MS. One explanation could be that ON and MS have an etiologic agent in common but that a part of patients with ON have an until now undefined competence to limit the demyelinating process.