LAUSR

The present study focuses on the associations of serum immunoglobulin with disease activity, relapse/recurrence and renal involvement in Henoch‐Schönlein purpura (HSP) children. 1683 Chinese children with HSP were recruited from January 2015 to January 2021. Laboratory data of blood samples and urine tests were collected. Renal biopsy was performed by the percutaneous technique. Patients' histories associated with HSP onset were obtained by interviews and questionnaires. (1) IgA and IgE were dramatically elevated in HSP patients as compared to their normal values and subject to a 1.75–3.09 fold and a 1.97–2.61 fold increase, respectively. (2) No significant correlation of the disease activity with IgA and IgE was determined, respectively. (3) The serum IgA levels were significantly lower in patients with relapse/recurrence than that in patients without relapse/recurrence, which may be attributed to the transmission of IgA‐mediated immune complexes from blood to vessel walls. (4) No significant correlation was found between serum IgA, IgE levels and the pathological classification. HSP children have marked disorders of serum immunoglobulin profiles, characterized by significant increases in IgA and IgE. The detection of serum IgA may be applicable to predict relapse/recurrence of HSP whereas not associated with disease activity and renal involvement.