A high seroprevalence of HTLV-I in female Sjögren's syndrome (SS) patients has been reported in Nagasaki, Japan, an area that is heavily endemic for HTLV-I infection. Salivary IgA class antibodies to HTLV-I were common among HTLV-I seropositive patients with SS. This study was undertaken to elucidate the pathogenesis of SS caused by HTLV-I infection.
The clinical features and histological findings of SS and the prevalence of serum autoantibodies in 10 patients with HTLV-I associated myelopathy (HAM) who were consecutively admitted into Nagasaki University School of Medicine, were compared with those of 20 HTLV-I seropositive and 20 HTLV-I seronegative patients with SS.
Ocular and oral manifestations of SS were commonly detected in HAM patients. These patients also had extraglandular manifestations including recurrent uveitis, arthropathy, interstitial pneumonitis, Raynaud's phenomenon, and inflammatory bowel disease. All patients with HAM histologically showed a mononuclear cell infiltration in the labial salivary glands. Six of 10 patients had a mononuclear cell infiltration with a focus score of 1 or greater. According to the preliminary criteria for SS proposed by the European Community, definitive SS was diagnosed in six patients and probable SS in two patients. Serum gamma globulin and IgG values were increased in HAM patients. Patients with HAM had lower prevalence of rheumatoid factor, antinuclear antibody, and anti-SS-A (Ro) antibody than those of HTLV-I seropositive and HTLV-I seronegative SS patients. However, there was no significant difference in the prevalence of these antibodies among HAM patients with definitive SS, HTLV-I seropositive and HTLV-I seronegative SS patients. The CD3+CD4+ T cells preferentially infiltrated into the salivary glands in HAM patients as well as the salivary glands of patients with HTLV-I seropositive and seronegative patients. It seems probable that peripheral blood mononuclear cells from HAM patients preferentially infiltrated into the salivary glands, and that these cells produced the autoantibodies as well as anti-HTLV-I antibody.
The results strongly support the idea that HTLV-I is involved in the pathogenesis of the disease in a subset of patients with SS in endemic areas.