Antifilaggrin antibodies within normal range predict rheumatoid arthritis in a linear fashion.

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Antifilaggrin antibodies within " normal " range predict rheumatoid arthritis in a

linear fashion.

Aho K, Palosuo T, Heliovaara M, Knekt P, Alha P, von Essen R

National Public Health Institute, Helsinki, Finland.

OBJECTIVE: Increasing attention has been paid to the significance of

antifilaggrin antibodies (AFA) in rheumatoid arthritis (RA). We studied the

prediction of RA by AFA in serum specimens from the period prior to the onset of

clinical RA. METHODS: A case-control study was nested within a Finnish cohort of

19.072 adults who had neither arthritis nor a history of it at the baseline

examination during 1973-77. Pre-illness serum specimens for the assay of AFA by

ELISA, using filaggrin purified from human skin as the antigen, were available

from 124 of the 126 patients who had developed RA by late 1989. Of the incident

cases 89 were positive for rheumatoid factor (RF). Three controls per each

incident case were individually matched for sex, age, and municipality. RESULTS:

Pre-illness serum AFA level was found to be directly proportional to the risk of

RF positive RA. The odds ratio (95% confidence interval) in the highest quintile

compared to the lowest quintile was 5.4 (2.2-13.6). In the subgroup of subjects

positive for RF at baseline the figure was 24 (4.0-140). AFA did not predict the

development of RF negative RA. A close association of the same order of

magnitude between RF and AFA was noted in the pre-illness sera and in the

control sera. CONCLUSION: AFA still within the " normal " range predicts RA in a

linear fashion. AFA and RF are associated markers of the rheumatoid

immunological process.

PMID: 11128658, UI: 21011274