Intestinal lesions of BD expressed interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha and interleukin (IL)-12 mRNA, indicating Th1 skewed responses in vivo. mRNA of Txk, a Tec family tyrosine kinase specific to Th1 cells, was expressed in the lesions, suggesting its contribution to the Th1-dominant responses.
No significant difference was observed in the distribution of TNF-alpha promoter region polymorphisms between patients with Behçet's disease and controls.
This genetic proximity to a gene that is already widely implicated in disease susceptibility led us to investigate the association between TNF promoter polymorphisms and susceptibility to BD.
In this study, we investigated genetic polymorphisms of TNF alpha -308 G/A, TNF beta +252 G/A, and TNFR2 196 R/M in 94 Korean BD patients and age- and sex-matched healthy controls to investigate the role of TNF and TNF receptor polymorphisms in BD.
However, polymorphic analyses of the TNFB gene and Tau-a microsatellite between the HLA-B and TNF genes indicate that the pathogenic gene of BD is not the HLA-B51 gene itself but another gene located around the HLA-B gene.
These results indicated that a non-HLA gene located around the TNF gene region centromic of the HLA-B gene was a candidate to control the genetic susceptibility to Behçet's disease.