CHARACTERIZATION OF ANTICYTOPLASMIC ANTIBODIES AND THEIR CLINICAL ASSOCIATIONS

Objectives-To characterise the cytoplasmic staining patterns identifie d by indirect immunofluorescence (IF) of human epithelial (HEp-2) cell s and the antigens recognised using additional serological techniques. To define the disease associations of anticytoplasmic antibodies. Met hods-Sera from 1173 patients were screened for cytoplasmic IF staining on HEp-2 cells and the patterns characterised. presence of antimitoch ondrial antibodies (AMA) was evaluated by a sensitive anti-pyruvate de hydrogenase complex enzyme linked immunosorbent assay (ELISA) (IgG) an d by immunoblotting. Detection of antibodies to extractable nuclear an tigens (ENA) was performed by double immunodiffusion and the presence of anti-ribosomal P antibodies was determined by immunoblotting. Resul ts-Cytoplasmic IF staining demonstrated in 75 sera (6.4%). Six differe nt patterns were recognised: coarse granular filamentous speckles (AMA , n=9); condensed large speckles (anti-golgi apparatus antibodies, n=3 ); cytoskeletal (n=9); centriolar (n=4); diffuse coarse speckles (n=33 ); and fine speckles (n=17). Of the nine sera with an AMA pattern, the presence of these antibodies was confirmed in seven by the ELISA (n=6 ) and on immunoblotting (n=7). One of the seven patients had primary b iliary cirrhosis, and two had scleroderma. Two patients with anti-golg i antibodies had rheumatoid arthritis and two with anticentriolar anti bodies had scleroderma. Of 33 sera that had cytoplasmic staining and w ere ANA negative, three were positive for anti-Re and two were positiv e for anti-Jo-1 antibodies. Conclusions-In general, defined cytoplasmi c IF patterns have no specific disease associations. However, the find ing of cytoplasmic fluorescence should not be ignored, as it may indic ate the presence of antibodies to ENA in the absence of nuclear staini ng.