Objective To explore the levels and clinical significance of serum periostin (POSTN) and syndecan 4 (SDC4) in children with Henoch-Sch nlein purpura nephritis (HSPN).

Methods A total of 122 hospitalized children with Henoch-Schonlein purpura (HSP) in the Children's Hospital Affiliated to Soochow University from March 2019 to December 2021 were divided into HSPN group (n=74) and HSP group (n=48) according to whether complicated with renal damage, and 40 healthy children in the same period were selected as control group. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of serum POSTN and SDC4 in each group; the relationships of serum POSTN and SDC4 levels with onset age, gender, blood lipid, coagulation function, renal function, 24-hour urine protein quantification and renal pathological grading in children with HSPN were analyzed; the receiver operating characteristic (ROC) curve was used to analyze the values of serum POSTN and SDC4 levels in the early diagnosis of HSPN.

Results The levels of serum POSTN, SDC4, ratio of 24-hour urinary protein quantification to body mass, urinary microalbumin, creatinine and urea nitrogen in the HSPN group were significantly higher than those in the HSP group and the control group, and the levels of serum POSTN, SDC4, ratio of 24-hour urinaryprotein quantification to body mass, urinary microalbumin, creatinine and urea nitrogen in the HSP group were also significantly higher than those in control group (P < 0.05). There were significant differences in the levels of serum POSTN and SDC4 among HSPN children with different renal pathological grades (P < 0.05). In the children with HSPN, the levels of serum POSTN and SDC4 were positively correlated with the ratio of 24-hour urine protein quantification to body mass (P < 0.05), and the level of serum POSTN was also positively correlated with level of SDC4 (P < 0.05). The area under the curve of ROC curve for serum POSTN was 0.788, the sensitivity was 94.1%, and the specificity was 59.2%; the area under the curve of ROC curve for serum SDC4 was 0.842, the sensitivity was 84.5%, and the specificity was 69.2%.

Conclusion The levels of serum POSTN and SDC4 increase in children with HSPN, their expression levels are correlated with the pathological grading of renal tissue and the ratio of 24-hour urine protein quantification to body mass, and detection of serum POSTN and SDC4 levels is helpful for the early diagnosis of HSPN.