Antinuclear Antibody-Negative Systemic Lupus Erythematosus in an International Inception Cohort.
Arthritis Care Res
The spectrum of antinuclear antibodies (ANA) is changing to include both nuclear staining as well as cytoplasmic and mitotic cell patterns (CMPs) and accordingly a change in terminology to anti-cellular antibodies. This study examined the prevalence of indirect immunofluorescence (IIF) anti-cellular antibody staining using the Systemic Lupus International Collaborating Clinics inception cohort.Anti-cellular antibodies were detected by IIF on HEp-2000 substrate utilizing the baseline serum. Three serological subsets were examined: 1) ANA-positive (presence of either nuclear or mixed nuclear/CMP staining), 2) anti-cellular antibody-negative (absence of any intracellular staining), and 3) isolated CMP staining. The odds of being anti-cellular antibody-negative versus ANA or isolated CMP-positive was assessed by multivariable analysis.1137 patients were included; 1049/1137 (92.3%) were ANA-positive, 71/1137 (6.2%) were anti-cellular antibody-negative, and 17/1137 (1.5%) had isolated CMP. The isolated CMP group did not differ from the ANA-positive or anti-cellular antibody-negative group in clinical, demographic or serologic features. Patients who were older (OR 1.02 [95% CI: 1.00, 1.04]), of Caucasian race/ethnicity (OR 3.53 [95% CI: 1.77, 7.03]), or on high dose glucocorticoids at or prior to enrolment (OR 2.39 [95% CI: 1.39, 4.12]) were more likely to be anti-cellular antibody-negative. Patients on immunosuppressants (OR 0.35 [95% CI: 0.19, 0.64]) or with anti-SSA/Ro60 (OR 0.41 [95% CI: 0.23, 0.74]) or anti-UI-RNP (OR 0.43 [95% CI: 0.20, 0.93]) were less likely to be anti-cellular antibody-negative.In newly diagnosed SLE, 6.2% of patients were anti-cellular antibody-negative and 1.5% had isolated CMP. The prevalence of anti-cellular antibody-negative SLE will likely decrease as emerging nomenclature guidelines recommend that non-nuclear patterns should also be reported as a positive ANA. This article is protected by copyright. All rights reserved.
School of Medicine
General Internal Medicine