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Objectives: A perception derived from cross-sectional studies of small systemic lupus erythematosus (SLE) cohorts is that there is a marked discrepancy between antinuclear antibody (ANA) assays, which impacts on clinicians' approach to diagnosis and follow-up. We compared three ANA assays in a longitudinal analysis of a large international incident SLE cohort retested regularly and followed for 5 years., Methods: Demographic, clinical and serological data was from 805 SLE patients at enrolment, year 3 and 5. Two HEp-2 indirect immunofluorescence assays (IFA1, IFA2), an ANA ELISA, and SLE-related autoantibodies were performed in one laboratory. Frequencies of positivity, titres or absorbance units (AU), and IFA patterns were compared using McNemar, Wilcoxon and kappa statistics, respectively., Results: At enrolment, ANA positivity (≥1:80) was 96.1% by IFA1 (median titre 1:1280 (IQR 1:640-1:5120)), 98.3% by IFA2 (1:2560 (IQR 1:640-1:5120)) and 96.6% by ELISA (176.3 AU (IQR 106.4 AU-203.5 AU)). At least one ANA assay was positive for 99.6% of patients at enrolment. At year 5, ANA positivity by IFAs (IFA1 95.2%; IFA2 98.9%) remained high, while there was a decrease in ELISA positivity (91.3%, p<0.001). Overall, there was >91% agreement in ANA positivity at all time points and ≥71% agreement in IFA patterns between IFA1 and IFA2., Conclusion: In recent-onset SLE, three ANA assays demonstrated commutability with a high proportion of positivity and titres or AU. However, over 5 years follow-up, there was modest variation in ANA assay performance. In clinical situations where the SLE diagnosis is being considered, a negative test by either the ELISA or HEp-2 IFA may require reflex testing., Competing Interests: Competing interests: MYC has received consulting fees from Janssen and MitogenDx (less than US$10 000). AEC has received consulting fees from AstraZeneca, BristolMyersSquibb, and Glaxo Smith Kline (less than US$10 000 each). KCH has consulted for or collaborated on research projects with Janssen, Glaxo Smith Kline, Exagen Diagnostics, Eli Lilly, Merck Serono, Astra Zeneca and Neutrolis (less than US$10 000 each). CG has received consulting fees, speaking fees, and/or honoraria from AstraZeneca, Abbvie, Amgen, UCB, GlaxoSmithKline, Merck Serono and BMS (less than US$10 000 each) and grants from UCB. Grants from UCB were not to CG but to Sandwell and West Birmingham Hospitals NHS Trust. DDG received consulting fees, speaking fees, and/or honoraria from GlaxoSmithKline (less than $10 000). INB has received consulting fees, speaking fees and/or honoraria from Eli Lilly, UCB, Roche, Merck Serono, MedImmune (less than US$10 000 each) and grants from UCB, Genzyme Sanofi and GlaxoSmithKline. EMG has paid consultation with investment analysts Guidepoint Global Gerson Lerman Group.Dr. Kalunian has received grants from UCB, Human Genome Sciences/GlaxoSmithKline, Takeda, Ablynx, Bristol-Myers Squibb, Pfizer and Kyowa Hakko Kirin, and has received consulting fees from Exagen Diagnostics, Genentech, Eli Lilly, Bristol-Myers Squibb, and Anthera (less than US$10 000 each). MJF is Director of Mitogen Diagnostics Corporation (Calgary, AB Canada) and a consultant to Werfen International (Barcelona, Spain), Grifols (Barcelona, Spain), Janssen Pharmaceuticals of Johnson & Johnson and Alexion Canada (less than US$10 000 each). The remainder of the authors have no disclosures., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: The spectrum of antinuclear antibodies (ANAs) is changing to include both nuclear staining as well as cytoplasmic and mitotic cell patterns (CMPs) and accordingly a change is occurring in terminology to anticellular antibodies. This study examined the prevalence of indirect immunofluorescence (IIF) anticellular antibody staining using the Systemic Lupus International Collaborating Clinics inception cohort., Methods: Anticellular antibodies were detected by IIF on HEp-2000 substrate using the baseline serum. Three serologic subsets were examined: ANA positive (presence of either nuclear or mixed nuclear/CMP staining), anticellular antibody negative (absence of any intracellular staining), and isolated CMP staining. The odds of being anticellular antibody negative versus ANA or isolated CMP positive was assessed by multivariable analysis., Results: A total of 1,137 patients were included; 1,049 (92.3%) were ANA positive, 71 (6.2%) were anticellular antibody negative, and 17 (1.5%) had an isolated CMP. The isolated CMP-positive group did not differ from the ANA-positive or anticellular antibody-negative groups in clinical, demographic, or serologic features. Patients who were older (odds ratio [OR] 1.02 [95% confidence interval (95% CI) 1.00, 1.04]), of white race/ethnicity (OR 3.53 [95% CI 1.77, 7.03]), or receiving high-dose glucocorticoids at or prior to enrollment (OR 2.39 [95% CI 1.39, 4.12]) were more likely to be anticellular antibody negative. Patients on immunosuppressants (OR 0.35 [95% CI 0.19, 0.64]) or with anti-SSA/Ro 60 (OR 0.41 [95% CI 0.23, 0.74]) or anti-U1 RNP (OR 0.43 [95% CI 0.20, 0.93]) were less likely to be anticellular antibody negative., Conclusion: In newly diagnosed systemic lupus erythematosus, 6.2% of patients were anticellular antibody negative, and 1.5% had an isolated CMP. The prevalence of anticellular antibody-negative systemic lupus erythematosus will likely decrease as emerging nomenclature guidelines recommend that non-nuclear patterns should also be reported as a positive ANA., (© 2018, American College of Rheumatology.)

Objective: Anti-C1q has been associated with systemic lupus erythematosus (SLE) and lupus nephritis in previous studies. We studied anti-C1q specificity for SLE (vs rheumatic disease controls) and the association with SLE manifestations in an international multicenter study., Methods: Information and blood samples were obtained in a cross-sectional study from patients with SLE (n = 308) and other rheumatologic diseases (n = 389) from 25 clinical sites (84% female, 68% Caucasian, 17% African descent, 8% Asian, 7% other). IgG anti-C1q against the collagen-like region was measured by ELISA., Results: Prevalence of anti-C1q was 28% (86/308) in patients with SLE and 13% (49/389) in controls (OR = 2.7, 95% CI: 1.8-4, p < 0.001). Anti-C1q was associated with proteinuria (OR = 3.0, 95% CI: 1.7-5.1, p < 0.001), red cell casts (OR = 2.6, 95% CI: 1.2-5.4, p = 0.015), anti-dsDNA (OR = 3.4, 95% CI: 1.9-6.1, p < 0.001) and anti-Smith (OR = 2.8, 95% CI: 1.5-5.0, p = 0.01). Anti-C1q was independently associated with renal involvement after adjustment for demographics, ANA, anti-dsDNA and low complement (OR = 2.3, 95% CI: 1.3-4.2, p < 0.01). Simultaneously positive anti-C1q, anti-dsDNA and low complement was strongly associated with renal involvement (OR = 14.9, 95% CI: 5.8-38.4, p < 0.01)., Conclusions: Anti-C1q was more common in patients with SLE and those of Asian race/ethnicity. We confirmed a significant association of anti-C1q with renal involvement, independent of demographics and other serologies. Anti-C1q in combination with anti-dsDNA and low complement was the strongest serological association with renal involvement. These data support the usefulness of anti-C1q in SLE, especially in lupus nephritis., (© The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

We report a woman with systemic lupus erythematosus (SLE) with diffuse proliferative glomerulonephritis and anti-dsDNA antibodies whose serum contained autoantibodies specific for the phosphorylated form of RNA polymerase II (RNAP IIO), Su and ribosomal P antigen, as well as anti-topoisomerase I antibodies, a marker for scleroderma (SSc). Over 6 years, the patient exhibited clinical manifestations consistent with SLE without clinical evidence of scleroderma. The reactivity of her serum autoantibodies with the phosphoproteins ribosomal P, topoisomerase I, and RNAP IIO is consistent with recognition of autoepitopes comprised in part of phosphate groups. This may explain the unexpected coexistence of marker autoantibodies for SLE and scleroderma, possibly with implications for the mechanisms of autoantibody generation.

Sera of 209 patients with rheumatic disease demonstrated 3 patterns of immunofluorescence (IF) on ethanol fixed neutrophils (PMN) and a promyelocytic cell line (HL60): (1) cytoplasmic on PMN, negative on HL60 cells, (2) nuclear or perinuclear on PMN, negative on HL60 and (3) nuclear or perinuclear on both PMN and HL60 cells. Pattern 1 was observed in sera of patients with Wegener's granulomatosis, but also in several patients with other rheumatic diseases. Pattern 2 was observed in sera of patients with systemic vasculitis or rheumatoid arthritis (RA). Antimyeloperoxidase activity was detected in sera from patients with systemic vasculitis that produced Pattern 2, but rarely in sera of patients with RA that produced the same IF pattern. Pattern 3 was observed in sera that contained antinuclear antibodies as detected by IF on HEp-2 cells.

Levels of soluble interleukin 2 receptors (IL-2R) have been found to be elevated in the serum of patients with systemic lupus erythematosus (SLE) and are considered an indication of immune system activation in this disease. To assess the relationship between soluble IL-2R levels and other serological markers, we compared levels of soluble IL-2R and anti-double stranded DNA (anti-dsDNA) antibodies in SLE sera. In a cross sectional study of 34 patients with SLE, soluble IL-2R levels were elevated compared with healthy individuals (1126 U/ml vs 235 U/ml, p less than 0.0001), and a significant correlation between levels of soluble IL-2R and anti-dsDNA antibodies was present (r = 0.543, p = 0.0009). In a longitudinal study of 10 additional patients, the time courses of soluble IL-2R levels and anti-dsDNA antibody measurements were similar in 3 patients. In 7 patients, substantial differences in the levels of soluble IL-2R and anti-dsDNA antibodies over time were observed, including marked changes in anti-dsDNA antibody levels that were accompanied by only minor changes in soluble IL-2R levels, and soluble IL-2R measurements that were persistently elevated despite generally low anti-dsDNA antibody levels. Our results indicate that soluble IL-2R levels may not always parallel other serological markers of SLE, suggesting measurement of different facets of immune system activation by various assays.