Could serum pentraxin 3 levels and IgM deposition in skin biopsies predict subsequent renal involvement in children with Henoch–Schönlein purpura?

Background: The aim of this study was to evaluate the potential of serum pentraxin 3 (PTX3) values as an early predictor of subsequent renal involvement in patients with Henoch–Schönlein purpura (HSP) with no abnormalities on urinary examination and in renal function tests at disease onset. Methods: This was a prospective cohort study which included 60 pediatric patients with HSP (age range 3–15 years) who were diagnosed between February 2011 and October 2012 and 60 age- and sex-matched healthy controls. The patients were followed up for at least 18 months. Clinical findings were recorded for all patients at first examination, and blood samples for routine laboratory parameters and PTX3 value as well as skin biopsy specimens were obtained from each subject. Results: Of the 60 patients with HSP, 29 (48.3 %) developed subsequent renal involvement, of whom four underwent kidney biopsy. The mean serum PTX3 level of patients with subsequent renal involvement was significantly higher than those of patients without renal involvement and of the controls (2.20 ± 1.30 vs. 1.36 ± 0.85 and 1.03 ± 0.7 ng/ml, respectively; p = 0.004). Immunofluorescence evaluation of skin biopsy revealed that in addition to immunoglobulin A (IgA) deposition, the IgM deposition was significantly associated with subsequent renal involvement (p = 0.008). Conclusions: A high PTX3 level and IgM staining in skin biopsies from HSP patients may be harbingers of subsequent renal involvement. © 2014, IPNA