Circulating CD89-IgA complex does not predict deterioration of kidney function in Korean patients with IgA nephropathy

• Published in: Clinical chemistry and laboratory medicine Vol. 56; no. 1; pp. 75 - 85
• Main Authors: Jhee, Jong Hyun, Kang, Hye-Young, Wu, Meiyan, Nam, Bo Young, Chang, Tae-Ik, Jung, Su-Young, Park, Seohyun, Kim, Hyoungnae, Yun, Hae-Ryong, Kee, Youn Kyung, Yoon, Chang-Yun, Park, Jung Tak, Yoo, Tae-Hyun, Kang, Shin-Wook, Han, Seung Hyeok
• Format: Journal Article
• Language: English
• Published: Germany De Gruyter 27.11.2017; Walter De Gruyter & Company
• Subjects: Antigen-antibody complexes; Biomarkers; Biopsy; CD89; CD89 antigen; Confidence intervals; Enzyme-linked immunosorbent assay; Epidermal growth factor receptors; estimated glomerular filtration rate (eGFR); Glomerular filtration rate; IgA nephropathy; Immunoglobulin A; Pathogenesis; Patients; Risk; Statistical analysis; CD89; IgA nephropathy; estimated glomerular filtration rate (eGFR)
• ISSN: 1434-6621; 1437-4331
• DOI: 10.1515/cclm-2017-0090

Soluble CD89 (sCD89)-IgA complex plays a key role in the pathogenesis of IgA nephropathy (IgAN). However, there is a lack of evidence supporting this complex as a good biomarker for disease progression. This study aimed to evaluate the usefulness of sCD89-IgA complex for risk stratification of IgAN. A total of 326 patients with biopsy-proven IgAN were included. sCD89-IgA complex was measured by sandwich-enzyme-linked immunosorbent assay. The study endpoints were a 30% decline in estimated glomerular filtration rate (eGFR). sCD89-IgA complex levels were inversely and weakly associated with eGFR at the time of biopsy (r=-0.12, p=0.03). However, the significance between the two factors was lost in the multivariate linear regression after adjustment of clinical factors (β=0.35, p=0.75). In a multivariate Cox model, the highest (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.35-1.61; p=0.45) and middle (HR, 0.93; 95% CI, 0.46-1.89; p=0.84) tertiles of sCD89-IgA complex levels were not associated with an increased risk of developing a 30% decrease in eGFR. Furthermore, the decline rates in eGFR did not differ between groups and C-statistics revealed that the sCD89-IgA complex were not superior to clinical factors in predicting disease progression. This study found no association between sCD89-IgA complex levels and disease progression in IgAN. Although sCD89 can contribute to the formation of immune complexes, our findings suggest that the sCD89-IgA level is not a good predictor of adverse outcomes and has limited clinical utility as a biomarker for risk stratification in IgAN.