Familial Risks and Heritability of Rheumatoid Arthritis: Role of Rheumatoid Factor/Anti-Citrullinated Protein Antibody Status, Number and Type of Affected Relatives, Sex, and Age

Abstract Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by joint inflammation and extra-articular manifestations. Many questions in the pathogenesis, clinical manifestation, and disease spectrum are answered after the discovery of the first autoantibody namely rheumatoid factor (RF). The finding of the second autoantibody named anti-citrullinated protein antibody (ACPA), which unearths the importance of protein citrullination process. It further provides the insight how immune cells and complement interact to perpetuate the inflammatory response. These two autoantibodies pave the way for our better understanding of RA. This review article focuses on the history, pathophysiology, and clinical association of these two autoantibodies in RA.

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POS0441 DEVELOPMENT OF RHEUMATOID ARTHRITIS AMONG ANTI-CITRULLINATED PROTEIN ANTIBODIES POSITIVE ASYMPTOMATIC INDIVIDUALS: A PROSPECTIVE OBSERVATIONAL STUDY

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.344 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 449.1-449

Author(s):

S. Mizuki ◽

K. Horie ◽

K. Imabayashi ◽

K. Mishima ◽

K. Oryoji

Keyword(s):

Rheumatoid Arthritis ◽

Risk Factors ◽

Observational Study ◽

Rheumatoid Factor ◽

Prospective Observational Study ◽

Enzyme Linked Immunosorbent Assay ◽

P Value ◽

Healthy Population ◽

Asymptomatic Individuals ◽

Citrullinated Protein

Background:In the idividuals with genetic and enviromental risk factors, immune events at mucosal surfaces occur and may precede systemic autoimmunity. Anti-citrullinated protein antibodies (ACPA) are present in the serum for an average of 3-5 years prior to the onset of rheumatoid arthritis (RA) during an asymptomatic period. In ACPA-positivite individuals, the additional presence of RA-related risk factors appears to add significant power for the development of RA. To date, there have been few reports in which clinical courses of ACPA-positive asymptomatic individuals were investigated prospectively.Objectives:To observe the clinical time course of ACPA-positive healthy population for the development of RA.Methods:Healthy volunteers without joint pain or stiffness, who attended the comprehensive health screening of our hospital, were enrolled in this prospective observational study. The serum ACPA levels were quantified by Ig-G anti-cyclic citrullinated peptide enzyme-linked immunosorbent assay with levels > 4.4 U/mL considered positive. ACPA-positive subjects were followed by rheumatologists of our department clinically or a questionnaire sent by mail for screening to detect arthritis.Results:5,971 healthy individuals without joint symptons were included. Ninty-two (1.5%) were positive for ACPA. Of these, 19 (20.7%) developed RA and two were suspected as RA by mail questionnaire. Their average age were 58-years, and women were 68%. The average duration between the date of serum sampling and diagnosis was 10.7 months. ACPA-positive individuals who developed to RA had higher serum ACPA and Ig-M rheumatoid factor levels than ACPA-positive individuals who did not (P value by Mann-Whitney U test: 0.002, 0.005, respectively).Conclusion:Among ACPA-positive asymptomatic individuals, 20% developed RA. The higher titer of ACPA and Ig-M rheumatoid factor levels are risk factors for devoloping RA.Disclosure of Interests:None declared

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