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Family members of patients with rheumatoid arthritis (RA) have an increased risk to develop the disease themselves. However, it is not clear which family members will eventually be affected. A Mexican study published in Arthritis & Rheumatology has now shown that the presence of specific antibodies in the blood is a tell-tale for the development for RA within five years.

The research encompassed 819 healthy family members of 252 RA patients, in whom the rheumatoid factor IgM-RF and the antibody anti-CCP2 were measured and who were followed up for five years. During this period, the family members were subjected to a questionnaire every four months, followed by an evaluation by a rheumatologist according to the ACR/EULAR criteria in case RA was suspected.

Participants who were positive for both antibodies were more likely to develop RA, with a positive predictive value (PPV) of 64 percent. Of the eleven family members with both antibodies, seven developed RA within the follow-up period. For detection of only anti-CCP2 (in 12 people) or only IgM-RF (in 16 people) the PPV was much lower with 58 and 0 percent respectively.

These results offer new perspectives on the treatment course of RA because of its possible early diagnosis. The sooner the inflammation of joints is treated, the less permanent damage will be inflicted on patients. The researchers do however bring forward the critical note that “the production of anti-CCP is strongly dependent on the genetic background of the patient”, which makes it uncertain to what degree the results are applicable to people outside of Mexico.

Sources: Arthritis & Rheumatology

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