Fecal Calprotectin and the Complications of IgA-mediated Vasculitis: A Cohort Study

Abstract

Background: Immunoglobulin A (IgA)-mediated vasculitis, previously known as Henoch-Schönlein Purpura (HSP), is the most common vasculitis in children. It affects the skin, joints, gastrointestinal (GI) system, and kidneys. Calprotectin is a calcium-binding protein mainly found in neutrophils and macrophages, and its levels increase in settings of inflammation. Objectives: We conducted a study to investigate the role of calprotectin in prediction of HSP complications. Methods: In this cohort study, patients diagnosed with HSP by EULAR/PRINTO/PRES criteria and admitted to two referral children’s hospitals in Tehran, Iran, were enrolled. Fecal calprotectin levels were checked at the beginning of the presentation, and the patients were followed for GI and renal manifestations. Results: Out of the 100 patients who began to participate, 47 were eventually enrolled (25% girls). The age range was 2 to 18 years, with a mean of 6.5 ± 2.9 years. Hematuria was found in 21% and proteinuria in 17%. The Mann-Whitney test found an association between calprotectin and blood in stool (P = 0.03). No association was found between calprotectin and abdominal pain, sonography findings, hematuria, or proteinuria. The Pearson correlation test found a positive correlation between calprotectin level and leukocyte count (P = 0.003), neutrophil count (P = 0.002), and CRP (P = 0.03). Conclusions: Positive blood in stool was associated with fecal calprotectin levels in HSP, but hematuria and proteinuria were not. Considering the high cost of the calprotectin test, monthly follow-up with urine analysis appears to be a more logical approach. Neutrophil count and CRP were found to correlate with calprotectin levels, highlighting the nature of calprotectin as an acute inflammatory marker elevated during the acute phase of HSP disease.