Background: To compare the application value of serum and urinary β2-microglobulin in immunoglobulin A nephropathy (IgAN).
Methods: Two hundred thirteen patients were hospitalized at the First Affiliated Hospital of Bengbu Medical College in China because of physical abnormalities and diagnosed with IgAN by means of renal biopsy between January 2010 and December 2018. β2-MG levels in serum and urine were detected through immunoturbidimetric methods. The renal histopathology was quantified according to Katafuchi semi-quantitative standards and Lee’s grading.
Results: One hundred twenty-four patients were male and 89 cases were female, for a 1.39:1 male to female ratio. The average age was 38.25 ± 12.48 years old when patients received their first renal biopsy. The levels of serum β2-MG and urine β2-MG increased gradually with the aggravation of tubulointerstitial lesions. Results of correlation analysis showed that serum β2-MG had higher application value. Serum β2-MG levels were positively correlated with SCr and tubulointerstitial lesions (r = 0.840, 0.652, p = 0.000), negatively correlated with CG-eGFR (r = -0.680, p = 0.000). The results of multivariate logistic regression analysis showed that serum β2-MG was a marker of independent risk factor for the score of tubulointerstitial lesions ≥ 3 (OR = 6.649, p = 0.000). ROC analysis showed better diagnostic performance for serum β2-MG, with the optimal cutoffs in predicting tubulointerstitial score ≥ 1, score ≥ 4 and score ≥ 7 of 1.905 mg/L, 2.13 mg/L, and 4.49 mg/L, respectively.
Conclusions: Serum β2-MG is valuable in evaluating renal function and pathological lesions in IgAN patients and has significant predictive value in evaluating tubulointerstitial lesions. Serum β2-MG may be used as a non-invasive diagnostic indicator for predicting renal function and tubulointerstitial lesions in IgAN.