PREVALENCE OF SERUM AND SALIVARY ANTIBODIES TO HTLV-1 IN SJOGRENS-SYNDROME

There is accumulating evidence that human T-lymphotropic virus-1 (HTLV -1) infection contributes to the development of various inflammatory d isorders. To elucidate the relation between the infection and Sjogren' s syndrome, seroepidemiological and virological studies were conducted on patients with this syndrome in Nagasaki Prefecture, Japan, an area heavily endemic for HTLV-1. The HTLV-1 seroprevalence rate among the patients with Sjogren's syndrome (17/74, 23%) was significantly higher than that among blood donors (916/27 284, 3%), whereas the difference between patients with systemic lupus erythematosus and blood donors w as insignificant. Moreover, among Sjogren's syndrome patients the sero prevalence was high irrespective of age, unlike that among blood donor s, which rose with age. Titres of serum antibodies in the HTLV-1 serop ositive patients with Sjojgren's syndrome were similar to those among patients with HTLV-1-associated myelopathy/tropical spastic paraparesi s (HAM/TSP) and significantly higher than those among healthy carriers . IgM class antibodies were commonly detected in the serum of patients with Sjogren's syndrome. However, unlike that in HAM/TSP patients, th e viral load in peripheral-blood mononuclear cells was not necessarily high in the seropositive Sjogren syndrome group. Salivary IgA antibod ies to HTLV-1 were common among seropositive patients with Sjojgren's syndrome (5/7), which might be due to increased viral activity in the salivary glands. These antibodies were barely detectable in HAM/TSP pa tients (prevalence 1/10) or in healthy carriers (0/11). The findings s trongly suggest that HTLV-1 is involved in the pathogenesis of the dis ease in a subset of patients with Sjogren's syndrome in endemic areas.