Peripheral blood CD19+B cell proportion at baseline predicts early complete response to belimumab treatment in patients with refractory lupus nephritis
Xinxin Xie, Yan Zhou, Quangang Zhu, Yun Liao, Zhongjian Chen, Weihua SongObjective
Belimumab has been proven to be effective for treating refractory lupus nephritis. However, the meaningful renal response is still far from satisfactory. This study sought to identify immunological biomarkers to stratify patients who are likely to benefit from belimumab therapy.
Methods
We retrospectively reviewed the medical records of patients with refractory lupus nephritis who received 6 months belimumab treatment. Complete response (CR), partial response (PR) and no response (NR) were evaluated, and the predictors of CR were identified.
Results
A total of 28 patients with refractory LN were enrolled. The proportions of CR, PR and NR at 6 months were 39.29%, 32.14% and 28.57%, respectively. The baseline CD19+B cell proportions were significantly higher in CR patients than those in non-CR patients (19.30% vs 10.72%, p<0.001). In the binary logistic regression, baseline CD19+B cell proportion was identified as a predictor of CR in both univariate analysis (OR 1.359, 95% CI 1.098 to 1.683, p=0.005) and exploratory multivariate analysis adjusting for 24-hour urinary protein (OR 1.349, 95% CI 1.092 to 1.665, p=0.005). Receiver operating characteristic showed that the cut-off level of CD19+B cell proportion was 15.12%, with a sensitivity of 90.90%, specificity of 88.20% and an area under curve of 0.888 (95% CI 0.759 to 1.000, p=0.001).
Conclusion
Findings support the baseline CD19+B cell proportion could be used to predict CR to treatment with belimumab in refractory lupus nephritis patients.