Evaluation of serum procalcitonin and C-reactive protein levels as biomarkers of Henoch-Schönlein purpura in pediatric patients

Henoch-Schönlein purpura (HSP) is a vasculitic disorder resulting from autoinflammatory-mediated tissue injury. Procalcitonin (PCT) and C-reactive protein (CRP) are two biomarkers of the immune response that recognize bacterial infection and inflammation, respectively. This study tested whether levels of PCT and CRP were associated with selected clinical features, disease severity, and organ damage in HSP. Eighty-nine pediatric patients with HSP were analyzed for clinical manifestations and organ damage. Serum CRP, PCT, and occult blood in the urine and stool (prior to steroid therapy) were measured. Disease severity was classified according to previously established clinical classifications. Sixty patients (67.4 %) had a low clinical score (LCS) of <4 (group A) while 29 patients (32.5 %) had a high clinical score (HCS) of ≥4 (group B). When patients were then classified by the presence of gastrointestinal bleeding, 66 (74.2 %) cases lacked alimentary tract hemorrhage (group C) while 23 (25.8 %) cases presented with gastrointestinal bleeding (group D). There were no significant differences in CRP (group A: median = 5.26, range = 1.00–77.60 vs. group B: median = 8.59, range = 1.00–144.00 mg/l; u = 1.397) or PCT levels (group A: median = 0.05, range = 0.05–0.24 vs. group B: median = 0.08, range = 0.05–1.02 ng/ml; u = 1.709) between groups A and B. When serum PCT levels were examined in relation to gastrointestinal bleeding, the levels of serum PCT were higher in group D than group C patients (group D: median = 0.09, range = 0.05–1.02 vs. group C: median = 0.05, range = 0.05–0.32 ng/ml; u = 2.849). It is important to note that the average PCT level was below the threshold for a systemic bacterial infection (0.5 ng/ml). We did not observe a correlation between CRP levels and the absence or presence of GI bleeding in groups C or D (group C: median = 4.66, range = 1.00–144.00 vs. group D: median = 9.44, range = 1.06–124.00 mg/l; u = 1.783), respectively. In all patients, there was a significant correlation between the concentrations of PCT and CRP (r = 0.721, p = 0.002). In patients with HSP, inflammatory markers are not uniformly associated with the disease and instead, show variable association depending on the clinical severity and level of organ damage. In patients with severe HSP, elevated serum PCT was significantly associated with gastrointestinal bleeding. In contrast, CRP was not a specific predictor for different clinical classifications of HSP, despite a similar pattern of concentration changes to PCT.