Association between polymorphisms in the human chemokine receptor genes CCR2 and CX3CR1 and rheumatoid arthritis. 
Cell trafficking into the rheumatoid synovium is thought to play an important role in the inflammation seen in rheumatoid arthritis.  Chemokine receptors play a central role in this process, and several common variants are known, including the CCR2 variant, CCR2-64I, and two variants of the CX3CR1 gene, V249I and T280M. All three variants result in functional amino acid substitutions.  We studied the association of these chemokine receptor variants with susceptibility to and severity of rheumatoid arthritis in two Dutch patient populations; 282 consecutive rheumatoid arthritis patients from a rheumatology outpatient clinic, and a cohort of 101 female rheumatoid arthritis patients, followed closely for a 12-year period, from whom hand and feet X-rays taken at three year intervals were scored and analyzed in this study.  Although there was a trend towards increased severity of disease in patients carrying CX3CR1 variants, this was not independent of known risk factors.  We found no evidence for a significant independent role for the CCR2 and CX3CR1 variants in the susceptibility to or severity of rheumatoid arthritis.