A novel EBV-related nucleo-cytoplasmic antigen in a null cell-line (HLN-STL-C) reactive to antibodies in the sera from patients with Sjögren's syndrome.

We have established a non-T- and non-B-cell line, HLN-STL-C(STL-C), which harbors the EBV genome, from the lymph node cells of a Japanese ATL patient. This cell line expresses a unique Epstein-Barr virus (EBV)-related nucleo-cytoplasmic (N-C) antigen which is detected by indirect immunofluorescence (IF) with the sera from patients with nasopharyngeal cancer (NPC), infectious mononucleosis (IM) or adult T-cell leukemia (ATL). One of the molecular components of this antigen is proved to be STL-C specific 125 kD molecule by immunoblot analysis (IB). To study the involvement of EBV in Sjögren's syndrome (SS), we examined the reactivity of the N-C antigen with the sera of SS patients by IF and IB. Among 24 cases examined, the sera of 21 cases (87.5%) positively stained the N-C antigen by IF. The staining patterns were divided into two types. Type I, (seven cases) showed positive staining for only N-C antigen, and Type II, (14 cases) was positive for N-C antigen associated with diffuse nuclear staining due to antinuclear antibodies in the SS patient's sera. Only one out of 11 non-Sjögren's patients' sera, which were almost all healthy controls, was positive for N-C antigen in this study. By IB, however, only two out of 15 IF-positive SS patients' sera reacted with STL-C specific 125 kD molecule. These results suggested the presence of heterogenous components in the N-C antigen. Our findings may support the hypothetical conception that EBV plays an etiological role in SS.