2684. The Prospective Pilot Study of Infectious Complication Surveillance in Active Systemic Lupus Erythematosus Patients with Intense Immunosuppressive Therapy: Cellular Response and Clinical Outcomes

BACKGROUND: Despite a common complication, the real interplays between the infectious sequelae and systemic lupus erythematosus (SLE) with intense immunosuppressive therapy (IT) are not fully understood. OBJECTIVE: To identify the cellular biomarkers that justify the risk for overall infection in active SLE patients with intense IT. METHODS: An observational, prospective cohort pilot study was conducted in active SLE patients with intense IT aged >15 years from November 2017 March 2019 at Ramathibodi Hospital, Bangkok, Thailand. Clinical data and T-cell subpopulation analyses, at weeks 0 (at enrollment), 2, 4, 8, and 16 were obtained. Every patient was monitored over a 24-week period. The infections of interest were any emerging infections other than cytomegalovirus infection (CMV). Intense IT was defined as an induction therapy of active SLE disease with either the National Institute of Health or Euro-Lupus Nephritis Trial protocol regimens. RESULTS: A total of 23 active SLE patients were enrolled, 91.3% were female with the median age (interquartile range, IQR) of 27.7 (23.0–42.1) years old. The median SLE disease activity index (IQR) was 16 (10–20) and 73.9% had renal abnormality. At week 12, the prevalence of infection was 39.1% being bacterial infection in 77.8% and viral infection in 22.2%. There was no mortality in this study. Non-infection group had higher proportions of absolute lymphocyte count (ALC), CD3+ T cell, and CD3+CD56+ natural killer T (NKT) cell numbers compared with the infection group; [median of 1169.8 (694.4–1921.4) vs 716.1 (429.0–882.0) cells/µL; P = 0.044, 585.1 (245.1–669.2) vs. 204.9 (73.9–286.5) cells/µL; P = 0.017, and 50.5 (13.7–152.2) vs. 4.35 (2.44–52.9) cells/µL, P = 0.040, respectively]. Patients with NKT cells >9.31 cells/µL had longer median infection-free day of 25.3 days (19.7–25.3) vs. 2.0 days (1.7–4.0) in patients with lower NKT cell count (log rank P < 0.001). The Cox-proportional hazard ratio was 0.03, P = 0.003 (95% confidence interval 0.004–0.300). CONCLUSION: Bacterial infections are common in active SLE patients with intense IT. Monitoring of ALC, CD3+ T-cell, and NKT-cell counts can potentially be used as the infectious risk prognosticators. However, a study in a larger scale is encouraged to verify these findings. DISCLOSURES: All authors: No reported disclosures.