Anti-Ro/SSA antibodies. Association with a particulate (large speckledlike thread) immunofluorescent nuclear staining...

Twenty-one patients with clinical and histopathologic evidence of subacute cutaneous lupus erythematosus and one patient with Sjögren's syndrome and vasculitis had anti-Ro/SSA (Sjögren's syndrome A) antibodies as demonstrated by double immunodiffusion assay using a saline extract of human spleen as the source of antigen. These serum samples were negative when tested for other nuclear antigens, including native DNA, Sm, and RNP. When tested for antinuclear antibodies (ANAs) by immunofluorescence, only ten of 22 serum samples were ANA positive on mouse liver substrate, while 18 of 22 had a positive ANA when HEp-2 tumor cells were utilized. With imprints of human spleen as test substrate, all 22 serum samples yielded a positive ANA result and a particulate (large speckledlike thread) staining pattern. Absorption of two of these serum samples with human spleen extract containing Ro/SSA antigen inhibited both the particulate staining pattern using human spleen imprints and the anti-Ro/SSA precipitin line by double immunodiffusion. These studies suggest that anti-Ro/SSA antibodies and antibodies producing the particulate nuclear staining pattern on human spleen imprints are either one and the same or closely paralleling antibody systems.