N. Buchs et al., IL-4 VNTR gene polymorphism in chronic polyarthritis. The rare allele is associated with protection against destruction, RHEUMATOLOG, 39(10), 2000, pp. 1126-1131
Objective. To evaluate the occurrence of variants of the interleukin 4 (IL-
4) and IL-4 receptor (IL-4R) genes in patients with rheumatoid arthritis (R
A) and their possible contribution to joint destruction.
Methods. Allelic frequencies for polymorphisms in the IL-4 [variable number
of tandem repeat (VNTR) polymorphism in intron 3] and IL-4 receptor alpha
chain (transition at nucleotide 1902) genes were assessed in 335 RA patient
s and 104 controls. Clinical indices of disease activity, disability and jo
int destruction and plasma levels of IL-I beta, IL-1Ra and sCD23 were asses
sed to evaluate a possible functional effect.
Results. Carriage of the rare IL-4(2) allele was higher in patients with no
n-destructive RA (40%) than in those with destructive RA (22.3%: odds ratio
= 1.9. 95% confidence interval 1.1-3.5, P = 0.0006) and in controls (26%,
P = 0.002). Patients positive for this rare allele had significantly less j
oint destruction, assessed by the Larsen wrist index (P = 0.004) and a lowe
r erythrocyte sedimentation rate (P = 0.04). A significantly higher carriag
e rate of IL-4(2) was seen in HLA-DR4/DR1(-) patients with non-destructive
RA than in those with destructive RA. The IL-4 receptor polymorphism was no
t over-represented. Plasma levels of IL-1 beta, IL-1Ra and sCD23, known to
be modified by IL-4, were not different in individuals having different all
eles.
Conclusion. This IL-4 VNTR gene polymorphism may be a protective factor for
severe joint destruction in RA that could be used as a prognostic marker e
arly in the course of the disease.