Antineutrophil cytoplasmic antibodies in primary Sjögren's syndrome: prevalence and clinical significance.

Objective: To evaluate the prevalence of cytoplasmic (c) and perinuclear (p) antineutrophil cytoplasmic antibodies (ANCA) in patients with primary Sjogren's syndrome (SS), and to correlate the presence of ANCA with extraglandular and immunological manifestations related to SS.

Methods: In a cross-sectional study, we included 82 consecutive patients (75 female and seven male; mean age 61 yr; range 33-87 yr) attending our unit. All patients fulfilled four or more of the diagnostic criteria for SS proposed by the European Community Study Group in 1993. Extraglandular manifestations such as arthralgia and/or arthritis, Raynaud's phenomenon, autoimmune thyroiditis, peripheral neuropathy, renal involvement and cutaneous vasculitis were also recorded. Serum samples were examined by indirect immunofluorescence (IIF) and by ELISA using as substrates myeloperoxidase (MPO) and proteinase 3 (PR3).

Results: ANCA were detected in nine (11%) patients: seven had pANCA and two an atypical pattern. These two atypical ANCA became cANCA when paraformaldehyde fixation was applied. ELISA findings showed that two patients had antibodies against MPO, and no patient had antibodies to PR3. The most common extraglandular manifestations in the ANCA-positive patients were articular involvement in six (66%) patients, peripheral neuropathy in five (55%), Raynaud's phenomenon in four (44%) and cutaneous vasculitis in four (44%). Of the four patients with cutaneous vasculitis and ANCA, two had a mononuclear inflammatory vascular disease (MIVD) in the biopsy specimen. When compared with patients without ANCA, those with these antibodies had a higher prevalence of cutaneous vasculitis (44% vs 8%, P = 0.01), Raynaud's phenomenon (44% vs 8%, P = 0.01) and peripheral neuropathy (55% vs 7%, P < 0.001).

Conclusion: ANCA positivity can be found in patients with primary SS and its detection is associated with the presence of clinical manifestations attributable to vascular involvement (cutaneous vasculitis, peripheral neuropathy and Raynaud's phenomenon).