Antineutrophil cytoplasmic antibody in patients with primary Sjogren's syndrome

The incidence, specificity and clinical significance of positivity for seru m antineutrophil cytoplasmic antibody (ANCA) was investigated Id 60 patient s with primary Sjogren's syndrome (SjS). The indirect immunofluorescence (I IF) technique and an enzyme-linked immunosorbent assay (ELISA) were used to measure ANCA. Purified myeloperoxidase (MPO), lactoferrin (LF), cathepsin- G (CTG) elastase (HLE) served as ANCA antigens for the ELISA. Ten (16.7%) o f the 60 SjS patients showed positivity by IIF or perinuclear, but not cyto plasmic, ANCA. Four of the 60 sera were shown to be positive for LF, four f or MPO, 0 for CTG and 0 for HLE by ELISA. There was no correlation between ANCA positivity and clinical features. ANCA in patients with SjS might be a n epiphenomenon of polyclonal B-cell activation.