AB0721 CLINICAL AND LABORATORY CHARACTERISTICS, GENETIC FEATURES OF MACROPHAGE ACTIVATION SYNDROME IN CHILDREN WITH SYSTEMIC-ONSET JUVENILE IDIOPATHIC ARTHRITIS: A SINGLE CENTER EXPERIENCE

Background: Macrophage activation syndrome (MAS) is a life-threatening complication of systemic-onset juvenile idiopathic arthritis (sJIA) characterized by fever, hepatosplenomegaly, lymphadenopathy, coagulopathy, and rapid development multiple organ failure. MAS triggered viral bacterial infections, most often Epstein-Barr viruses, cytomegalovirus, influenza parainfluenza parvavirus B19, yersiniosis, salmonellosis, sepsis. Despite modern diagnostic treatment technologies, still remains formidable sJIA, it an aggressive course, heterogeneous clinical presentation, especially in conditions with genetically engineered biological drugs, ambiguous response to pathogenetic therapy accompanied mortality 5-10% patients. Objectives: To analyze the laboratory features children sJIA study genetic predisposition this syndrome. Methods: The included 24 patients who are being followed up rheumatology department National Medical Research Center Children’s Health, Moscow. presentation manifestations were assessed 24, described 7 using new generation sequencing further biostatistical processing obtained data. Results: Of patients, 23 (98%) had 16 (68%) rash, 17 (72%) - organomegaly, 4 (16%) polyserositis, 2 (7%) myalgia myopathy. All (100%) increase ferritin level more than 684 ng/ml, 98% them high lactate dehydrogenase (LDH) 97% triglycerides. In CBC, cytopenia was found 80% children: 54% erythrocytopenia, 74% leukopenia, 88% thrombocytopenia, 15% sharp decrease erythrocyte sedimentation rate. coagulogram 90% D-dimer, 85% fibrinogen. Hyponatremia presented 95% Thus, met criteria HLH-2004 protocol, adapted for sJIA. Genetic characteristics analyzed out 94 MAS. They Table 1. These have rare frequent variants, as well genes polymorphisms that associated macrophage number variants (n=7). Gene Patient № 1 №2 3 №5 №6 №7 LYST 0 6 NLRC4 NLRP12 5 10 12 NLRP3 8 TNFAIP3 UNC13D 18 26 XIAP Conclusion: has typical there manifestations: hyperferritinemia, cytopenia, hyponatremia, increased levels LDH triglycerides, based on which, diagnosis can be made. Patients at our center also predisposed condition. References: [1]Crayne CB, Albeituni S, Nichols KE, Cron RQ. Immunology Activation Syndrome. Front Immunol. 2019 Feb 1;10:119. doi: 10.3389/fimmu.2019.00119. PMID: 30774631; PMCID: PMC6367262. [2]Henderson LA, Syndrome Secondary Hemophagocytic Lymphohistiocytosis Childhood Inflammatory Disorders: Diagnosis Management. Paediatr Drugs. 2020 Feb;22(1):29-44. 10.1007/s40272-019-00367-1. 31732958; PMC7334831. [3]Ravelli A, Davì Minoia F, Martini Hematol Oncol Clin North Am. 2015 Oct;29(5):927-41. 10.1016/j.hoc.2015.06.010. Epub Aug 25. 26461152. Disclosure Interests: None declared