Background: Systemic lupus erythematosus (SLE) is a chronic multisystem rheumatic disease characterized by developing autoantibodies against nucleus antigen. It has a broad range of clinical symptoms and the potential to affect nearly all organs and tissues. Pulse dosage methylprednisolone (MEP) is the immunosuppression modality for life-threatening or organ-threatening SLE. However, it is challenging to estimate the MEP response rate. We combine clinical symptoms, routine laboratory examinations, and more specific protein examinations such as soluble B-cell activating factor (sBAFF), B-cell activating factor receptor (BAFF-R), and Interferon gamma-induced protein 10 (IP-10) to develop a formula that can predict the SLE Disease Activity Index 2K (SLEDAI 2K) score following a pulse dosage of methylprednisolone. Methods: In a prospective cohort study, patients with severe SLE with a SLEDAI 2K score of 12 or Lupus nephritis class III or IV according to WHO criteria were given methylprednisolone 500 mg/day for three consecutive days. Enzyme-linked immunosorbent assay (ELISA) tested blood samples for soluble (s) BAFF, IP 10, and flow cytometry for BAFF-R, CD-19. The SLEDAI 2K score was reevaluated after a pulse dose of methylprednisolone was administered. All statistical analyses were conducted using the Rstudio program. Results: Overall, 80 patients were included. Multivariate multiple regression analysis revealed that urine protein creatinine ratio (UPCR) (x1), CD19 percentage (x2), serum BAFF (x3), vasculitis (x4), and rash (x5) taken before MEP pulse were predictors for SLEDAI 2k score after pulse dose methylprednisolone in severe SLE with the formula 13.41+ (0.0008542 * x1) + -0.1829338 * x2) + (0.0008776 * x3) + (7.1801728 * x4) + (7.5429676 * x6). Conclusions: Formula to predict SLEDAI 2k score after MEP pulse was 13.41+ (0.0008542 * x1) + -0.1829338 * x2) + (0.0008776 * x3) + (7.1801728 * x4) + (7.5429676 * x6). Further validation is needed to be used in clinical practice.
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