OBJECTIVE
To determine whether interleukin-1 alpha and 1 beta gene polymorphism is associated with rheumatoid arthritis disease activity and bone mineral metabolism, and whether there is any relationship between IL-1 beta and rheumatoid arthritis (RA) motif gene.
METHODS
IL-1 gene polymorphisms were analyzed in 65 RA patients who met American College of Radiology (ACR) criteria and 60 controls. From genomic DNA, 2 polymorphisms in each gene for IL1 alpha-889 and IL-1 beta + 3953 were typed by PCR-RFLP and HLA-DRB1 allele typing was also undertaken by PCR-SSOP. Some clinical and laboratory parameters were collected. The allelic frequencies and carriage rates were compared between RA patients and controls and between patients with active and quiescent disease. Comparison was also made between IL-1 polymorphism and parameters of bone mineral metabolism and between patients with the HLA-DRB1 RA motif plus IL-1 beta 2 and patients without the two alleles. Fisher test and the analysis of variance was used to analyze the data.
RESULTS
There was no significant difference in the frequency and carriage rate of IL-1 alpha polymorphisms between RA patients and the controls. The beta 2/2 genotype of IL-1 beta was more common in female RA patients compared with controls (P = 0.001). A lower carriage rate of IL-1 beta 2 occurred in male RA patients (P = 0.001). A higher carriage rate of IL-1 alpha 2 is associated with a higher ESR (P = 0.008), HAQ score (P = 0.03), and vit-D3 (P < 0.001), but conversely a lower SJC (p = 0.002), a lower RF (P = 0.002) and a lower BMD at the lumbar spine (P = 0.001). A higher frequency of IL-1 alpha 1 is associated with a lower CRP value (P = 0.009). An increased IL-1 beta 2 carriage is associated with active rheumatoid disease as indicated by a higher CRP (P < 0.001), ESR (P < 0.001) and pain score (P = 0.001) and a higher BMD at the lumbar spine (P = 0.007), lower vit-D3 and. Udpd/Crea level The presence of the HLA DRB1 RA motif and IL-1 beta allele 2 at same time did not contribute to disease activity.
CONCLUSION
Polymorphisms of the IL-beta gene may affect the RA occurrence. Carriage of IL-1 beta 2 polymorphisms is associated with more active disease in RA and the presence of both the IL-1 alpha 2 and the IL-1 beta 1 allele in RA influences bone resorption.