POS0078 CROSS-SECTIONAL ANALYSIS OF INTERFERON SIGNATURE IN PEDIATRIC SYSTEMIC LUPUS ERYTHEMATOSUS
Authors: R. Raupov, E. Suspitsin, E. Kalashnikova, N. Lybimova, E. Kuchinskaya, R. Mulkidzhan, A. Kosmin, M. Kostik
Journal: Annals of the Rheumatic Diseases (2021)

Background: the role of interferon pathways in the pathogenesis of systemic lupus erythematosus (SLE) has been proven over the past years. Existing data suggest that interferon score (IFN I score) may serve as a useful marker of disease activity and patient clinical characteristics. Objectives: to compare characteristics of pediatric SLE patients with high and normal IFN I score. Methods: 40 SLE patients (33 girls, 7 boys) under 18 years old were included in the cross-sectional study. In all cases the diagnosis was made using Systemic Lupus International Collaborating Clinics (SLICC) classification criteria. The data on clinical manifestations, disease activity by SLEDAI and ECLAM, laboratory findings in the onset of the disease and at the moment of interferon signature assessment were evaluated. Interferon signature was assessed by real-time PCR quantitation of 5 IFN I-regulated transcripts; median expression of ≥2 was considered as a threshold. The patients were divided into 2 groups depending on the level of interferon score: high (group1, n=31) and normal (group2, n=9). Results: The mean age of the disease onset was 12 (9.5; 14.0) years. The most common symptoms were skin lesions (85%), arthritis (67.5%), fever (55%), mucosa (45%), CNS (37.5%) and kidney (30%) involvement. Anemia, leukopenia and thrombocytopenia were observed in 62.5%, 27.5% and 50% of cases, while 87.5% and 70% of patients had ANA positivity and dsDNA antibodies at the onset. The comparison between the groups with increased and normal IFN I-signature is presented in Table 1. Table 1. Parameters Group 1 (High IFN-s) Group 2 (Normal IFN-s) p-value Girls, n (%) 25 (80.7) 8 (88.9) 0.567 The onset age, years 12.0(10.0; 14.0) 11.0 (9.0; 13.0) 0.353 Time to IFN-signature study, months from onset 18.3 (7.0; 26.5) 0.97 (0.87;1.73) 0.987 Skin involvement, n (%) 12 (38.7) 4 (44.4) 0.837 CNS involvement, n(%) 8 (25.8) 1 (11.1) 0.353 Arthritis, n(%) 11 (35.5) 2 (22.2) 0.455 Anemia, n(%) 9 (29.0) 2 (22.20 0.687 Leucopenia, n(%) 9 (29.0) 1 (11.1) 0.274 ANA-positivity, n (%) 27 (87.1) 5 (55.6) 0.037 anti dsDNA antibodies, n(%) 12 (38.7) 2 (22.2) 0.361 Rheumatoid factor, n (%) 11 (35.5) 0 (0.0) 0.036 Hypocomplementemia, n (%) 18/28 (64.3) 2/6 (33.3) 0.162 Ferritin level, mkg/l 112.0 (39.0; 271.0) 21.0 (5.3; 23.7) 0.0008 Hematuria, n (%) 10 (32.3) 0 (0.0) 0.049 Proteinuria, n (%) 11 (35.5) 0 (0.0) 0.036 SELENA-SLEDAI, points 9 (2;15) 1 (0; 4) 0.073 ECLAM, points 3.0 (1.0; 6.0) 1.0 (0.0; 1.5) 0.048 Treatment with Rituximab or Cyclophosphamide, n (%) 22 (71.0) 3 (33.3) 0.040 GCS dose 0,2 mg/kg achievement for 6 months, n (%) 9/21 (42.9) 5/6 (83.3) 0.080 Conclusion: high IFN I-signature correlated with kidney involvement, ANA and RF-positivity, ferritinemia, proteinuria and hematuria. Patients with high IFN I-signature received more aggressive treatment and needed longer glucocorticosteroid (GCS) treatment. More meticulous dynamic evaluation of IFN-signature is needed to clarify its role as a predictive and prognostic marker. Acknowledgements: This work was supported by the RSF grant № 20-45-01005. Disclosure of Interests: None declared.