[Subsets of peripheral blood lymphocytes and ageing in patients with SMON]

Recent clinical problems in patients with subacute myelo-optico-neuropathy (SMON) arise mainly from complications associated with the disease. Some of them show the association of autoimmune diseases. Furthermore, it has been reported that some kinds of autoantibody and hyperglobulinemia are frequently seen in patients with SMON. In order to examine whether ageing and clioquinol intoxication in the past may be implicated in the immunological system of the patients, we investigated subsets of peripheral blood lymphocytes including OKT3, OKT4, OKT8, OKIa1 and Leu7, in 31 patients with SMON, who lived in Nagano Prefecture. The levels of OKT8 (% positive cells), which are known to decrease with age actually increased with age in the peripheral blood of patients with SMON. The levels of OKT4 decreased with ageing, as did the OKT4/OKT8 ratios. The percentage of OKIa1 also significantly increased with age in the peripheral blood of patients with SMON compared to that of the controls (p less than 0.01 or p less than 0.001). It is considered unlikely that the effect of ageing on subsets of lymphocytes can be implicated in these immunological abnormalities of SMON patients, but it seems likely that the immune systems (B cell or T cell) of SMON patients are activated by factors other than ageing in subsets of lymphocytes.