Potential of Periostin as a Tissue and Urinary Biomarker in Lupus Nephritis and IgA Nephropathy Patients

Total of 50 lupus nephritis and IgA nephropathy patients who met the inclusion criteria were included in this study. The information sheet and informed consent will be obtained before collecting the patient's data. All patients were interviewed for collecting demographic data and laboratory testing were reviewed from patient's record. Kidney tissue and urine sample were collected at the biopsy date from patients.Kidney tissue were stained with hematoxylin and eosin (H&E), Masson's trichrome solution and immunohistochemistry for periostin. The location of periostin staining in kidney tissue were assessed by renal pathologist.

The total of 50 urine samples from patients and 50 urine samples from healthy controls were measured for periostin level by enzyme-linked immunosorbent assay. The Mann-Whitney rank-sum test was used for comparing urine periostin level between patients and healthy controls and also other variables between patients with urine periostin detection and without urine periostin detection. Spearman correlation coefficients were used test correlations between urine periostin level in patients and other variables. Receiver operating characteristic curves was generated to calculate the area under the curve and find the best cutoff value of urine periostin level for distinguishing patients from healthy controls. P-values < 0.05 were considered statistically significant.