Expression Of S Baff, R Baff, And B Cells (Cd19+) As Potential Biomarker In Predicting Respons Treatment After Pulse Dose Metyl Prednisolone In Severe Sistemic Lupus Erithematosus

Background: B cell Activating Factors (BAFF) is a co stimulatory molecule that has become the target of recent SLE treatment. Pulse dose metyl prednisolone (MEP)has been widely used and is a standard protocol in management of severe and life threathening flare up. The aim of this study is to identify whethersoluble (S) BAFF along with its receptor,(R) BAFF and B Cells (CD19+) can become predictors of pulse dose metyl prednisolone (MEP) response treatment.
Method: Eighty subjects had been enrolled to this study. All subjects had SLE Disease Activity Index Score 2000 (SLEDAI 2K) score 12 or Lupus Nephritis Class 3 or 4 (WHO criteria) and decided to get pulse dose MEP. Prospective cohort study was conducted. All data as listed in SLEDAI 2k form were recorded before and after treatment. Enzyme-linked Immunoabsorbent Assay (ELISA) was used to measure S BAFF. Flowcytometry was used to measure BAFF Rand B cells (CD19+). Respons treatment was measured by SLEDAI 2K Responder Index (SRI) 50. Logistic Regression Analysis was used to identify the independent predictive factors for treatment response. Receiver Operating Characteristic (ROC) curve was used to find cut off point and Chi-sqare test to analyse proportion
difference and Relative Risk (RR) to treatment response
Results: There were 80 subjects enrolled in this study, all with high disease activity (mean SLEDAI 2k 30.04 ±10.8).The difference of SLEDAI 2K score before and after pulse dose MEP was 36%. SLEDAI 2K post MEP pulse > 36% of SLEDAI 2K pre treatment was considered SRI 36 Responder (SRI-36 R). SLEDAI 2K post pulse dose MEP < 36 % of SLEDAI 2K pre treatment was consider SRI -36 Non Responde (NR). Soluble BAFF 2459,47 pg/ml, R BAFF > 2817 MFI , and B cells (CD 19)> 29,2% have OR0.36; 2.17, and 2.16respectively but not statistically significant (p>0,05). Only R BAFF > 59,1 % have OR4.84with p value 0,03095% CI, in predicting SRI-36NR. Conclusions: BAFF R> 59,1% is a biomarker predictor of SRI-36 NR in pulse dose MEP with OR4,84, p value 0,030(95%CI).