Background:ANCA associated vasculitides (AAV) are a heterogeneous group of rare diseases with unknown etiology and the broad clinical spectrum ranging from life-threatening systemic disease, through single organ involvement to minor isolated skin changes. Unfortunately the clinical classification, ANCA specificity or genetic characteristics alone is not able to categorize AAV patients in a satisfactory manner. As a consequence advanced statistical techniques were used to identify and stratify AAV subphenotypes [1, 2]. Here we have analyzed influence of the ANCA type on clinical manifestations and demographic characteristics in various types of AAV, based on data from the POLVAS registryObjectives:We decided to retrospectively analyze a large cohort of Polish AAV patients deriving from several referral centers – members of the Scientific Consortium of the Polish Vasculitis Registry (POLVAS) – and concentrate on demographic and clinical characteristics of anti-PR3 and anti-MPO positive patients regardless of their clinical diagnosis.Methods:We conducted a systematic multicenter retrospective study of adult patients diagnosed with AAV between Jan 1990 and Dec 2016. Patients were enrolled by 9 referral centers. We analyzed dichotomous variables: gender; ANCA status – anti-PR3+ or anti-MPO+, ANCA negative; organ involvement - skin, eye, ENT, respiratory, heart, GI, renal, urinary, CNS, peripheral nerves and polytomous variable (number of relapses), supported by quantitative covariates (e.g., age at diagnosis, CRP at diagnosis, maximal serum creatinine concentration ever)[3].Results:MPO-positive patients (both GPA and EGPA phenotype) were older at the time of diagnosis with a substantial percentage diagnosed > 65 years of age, and with high rate of renal involvement. Interestingly, while in the whole group of patients diagnosed with EGPA male to female ratio was 1:2, the MPO+ EGPA patients showed M:F ratio of 1:1.The analysis of ANCA negative AAV reveled significant differences in GPA, ANCA negative group is characterized with significantly lower frequency of renal involvement compared to rest GPA (11,5% vs 63,7%) p<0,05 what should be emphasized ANCA negative AAV never lead to ESRD (end stage renal disease) or even transient dialysis.Conclusion:ANCA specificity is indispensable as a separate variable in any clinically relevant analysis of AAV subcategories. MPO+ group is characterized by older age at time of diagnosis, male to female ration 1:1, kidney involvement, and shows more homogenous clinical phenotype than PR3+ AAV patients. In our group ANCA negative AAV never lead to ESRD (end stage renal disease) or even transient dialysis.References:[1]Mahr A, Specks U, Jayne D. Subclassifying ANCA-associated vasculitis: a unifying view of disease spectrum. Rheumatol Oxf Engl 2019;58:1707–9. https://doi.org/10.1093/rheumatology/kez148.[2]Wójcik K, Biedroń G, Wawrzycka-Adamczyk K, Bazan-Socha S, Ćmiel A, Zdrojewski Z et al. Subphenotypes of ANCA-associated vasculitis identified by latent class analysis. Clin Exp Rheumatol. 2020 Sep 1. Epub PMID: 32896241.[3]Wójcik K, Wawrzycka-Adamczyk K, Włudarczyk A, Sznajd J, Zdrojewski Z, Masiak A, et al. Clinical characteristics of Polish patients with ANCA-associated vasculitides—retrospective analysis of POLVAS registry. Clinical Rheumatology. 1 wrzesień 2019;38(9):2553–63.Disclosure of Interests:None declared
Myositis autoantibodies in a racially diverse population of children with idiopathic inflammatory myopathies