Tl. Mcdowell et al., A GENETIC ASSOCIATION BETWEEN JUVENILE RHEUMATOID-ARTHRITIS AND A NOVEL INTERLEUKIN-1-ALPHA POLYMORPHISM, Arthritis and rheumatism, 38(2), 1995, pp. 221-228
Objective. The genetic factors that predispose to the development of j
uvenile rheumatoid arthritis (JRA) and its complications are not compl
etely understood. The cytokine interleukin-1 (IL-1) has been implicate
d in the pathogenesis of JRA and other inflammatory diseases. This stu
dy was performed to test whether polymorphisms of the IL-1 alpha gene
might be associated with JRA. Methods. We sequenced the 5' regulatory
region (containing the promoter) of the human IL-1 alpha gene in 18 no
rmal subjects. This revealed a C (IL-1A1) to T (IL-1A2) transition pol
ymorphism at position -889. We studied the frequencies of both alleles
in patients with JRA (n = 269) and controls (n = 99). Results. An inc
reased gene carriage of IL-1A2 was found in patients with early-onset,
pauciarticular JRA (EOPA-JRA; n = 103) compared with controls (0.66 v
ersus 0.49; P = 0.01, odds ratio [OR] = 2.1). Within this subset of JR
A, the association with IL-1A2 was particularly strong in the patients
in whom chronic iridocyclitis developed (n = 28) compared with those
without chronic iridocyclitis (0.89 versus 0.57; P = 0.002, OR = 6.2).
Within the group of EOPA-JRA patients, IL-1A2 was also associated wit
h elevation of the erythrocyte sedimentation rate (P < 0.0025). Conclu
sion. This is the first report of a cytokine gene association with JRA
, and we conclude that IL-1 alpha itself, or a gene for which the IL-1
alpha polymorphism is a marker, may contribute to the pathogenesis of
EOPA-JRA and the ocular complications found in this group.