Distinctive features of positive anti-cell antibody tests (indirect immunofluorescence on HEp-2 cells) in patients with non-autoimmune diseases.

OBJECTIVE: The objective of this study was to determine whether characteristics of positive results in the indirect immunofluorescence assay on HEp-2 cells for anti-cell antibodies (HEp-2 IFA) differ between patients with non-autoimmune diseases (NADs) and patients with systemic autoimmune rheumatic diseases (SARDs). METHODS: Cross-sectional observational study comparing HEp-2 IFA test results in three groups: (a) 558 NAD patients comprising four subgroups (cancer ( n = 95), infectious diseases ( n = 148), psychiatric diseases ( n = 163), common non-infectious chronic diseases ( n = 152)); (b) 194 SARD patients; (c) 1217 healthy individuals (HIs). Sera were tested at 1:80 dilution and diluted to the end titer. Slides were analyzed by two independent blinded examiners. RESULTS: A positive HEp-2 IFA test occurred in 102 (18.3%) NAD patients, 170 (87.6%) SARD patients and 150 (12.3%) HIs. The four NAD subgroups did not differ regarding HEp-2 IFA frequency, titer or pattern. HEp-2 IFA titer was higher in NAD patients than in HIs and both had lower titer than SARD patients. Nuclear dense fine speckled pattern was more frequent in NAD patients and HIs than in SARD patients ( p < 0.001). Nuclear homogeneous and nuclear coarse speckled patterns were more frequent in SARD patients than in the other groups ( p < 0.001). The nuclear fine speckled pattern was prevalent in all three groups, but presented a gradient in titer across them; HIs and NAD patients had low and intermediary titers, which were significantly lower than in SARD patients ( p < 0.001). CONCLUSION: Positive HEp-2 IFA frequency, pattern and titer present differential features in NAD and SARD patients, and this attribute adds value to the test in the diagnosis of SARDs.

Geographic variation as a risk factor for digital ulcers in systemic sclerosis patients: a multicentre registry.

OBJECTIVE: To evaluate the influence of geographic variation on the risk of digital ulcer (DU) development in systemic sclerosis (SSc) patients. METHODS: This cross-sectional, multicentre study evaluated patients with SSc from centres located in different geographic regions of Brazil (subtropical and tropical climate zones). Demographic and clinical data were collected. RESULTS: The study included 141 patients with SSc (26 from the subtropical and 115 from the tropical zone). In total, 43 DUs were observed in 23 (16%) of the patients. By a simple logistic regression model, the presence of DUs was associated with a higher modified Rodnan skin score, previous necrosis or amputation of the extremities, flexion contracture of the fingers, active smoking, higher avascular score on capillaroscopy, higher severity of Raynaud's phenomenon, a higher Health Assessment Questionnaire Disability Index (HAQ-DI) score, a higher visual analogue scale score for Raynaud's phenomenon and overall disease, and the subtropical climate zone. Using multiple logistic regression, the presence of DUs was significantly associated with patients living in the subtropical climate zone [odds ratio (OR) = 5.4, p = 0.002], necrosis or amputation (OR = 5.2, p = 0.011), and a higher HAQ-DI score (OR = 2.6, p = 0.021). CONCLUSION: In this multicentre study in a continental country with different climates, patients with SSc living in a subtropical climate region had a 5.4 times higher risk of developing DUs than patients living in a warmer region (tropical climate), suggesting a more severe course of peripheral vasculopathy among patients living in geographic regions with relatively cold weather.