RESUMO
BACKGROUND: Immune complex vasculitides may be subdivided into adult IgA small vessel vasculitis (aIgA-SVV, adult Henoch-Schönlein purpura) and non-IgA-SVV (hypersensitivity vasculitis, etc.). OBJECTIVES: We aimed to evaluate clinical and laboratory parameters of inpatients fulfilling the diagnostic criteria for aIgA-SVV and non-IgA-SVV. METHODS: 29 adult patients (≥ 20years) with aIgA-SVV according to the EULAR/PRINTO/PRES criteria and 53 adult patients with non-IgA-SVV according to the 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides were compared with respect to a variety of clinical and laboratory parameters using uni- and multivariable statistics. RESULTS: Compared to aIgA-SVV patients, the platelet-to-lymphocyte ratio was significantly higher in non-IgA-SVV patients. Serum C3 levels and mean corpuscular haemoglobin concentration observed in non-IgA-SVV patients were significantly lower compared to aIgA-SVV patients. Laboratory-based evidence for proteinuria and haematuria was significantly more common in patients with aIgA SVV. Only in patients with aIgA-SVV, proteinuria and haematuria significantly correlated with systemic immune-inflammation biomarkers. In patients with aIgA-SVV, higher LDH and CRP were strong independent predictors for the presence of proteinuria and proteinuria. In patients with non-IgA-SVV, female sex was a protective factor for proteinuria, while skin lesions on the upper extremities proved to be a significant independent predictor of haematuria. CONCLUSIONS: We detected several clinical and laboratory differences between patients with aIgA-SVV and non-IgA-SVV. In both groups, distinct predictors for renal involvement could be observed indicating that aIgA-SVV and non-IgA-SVV are very similar conditions but do not appear to present the same entity.