Five genetic markers in the interleukin 1 family in relation toinflammatory bowel disease

Background—An imbalance between theproinflammatory cytokine interleukin 1β (IL-1β) and theanti-inflammatory cytokine IL-1 receptor antagonist (IL-1ra) has beenpostulated as a pathogenic factor in inflammatory bowel disease (IBD).
Aims—To study allelic frequenciesof novel polymorphisms in the genes for IL-1β and IL-1ra in patientswith IBD and to assess the relation between ex vivo cytokine productionand allelic variants of the IL-1β and IL-1ra genes.
Subjects—Two hundred and seventyhealthy controls, 74 patients with ulcerative colitis (UC), 72 withCrohn's disease (CD), 40 with primary sclerosing cholangitis for theallelic frequencies, and 60 healthy individuals for the ex vivostimulation test.
Methods—Genotyping was performed bypolymerase chain reaction and subsequent cleavage with specificendonucleases (Mwo1, MspAI1, Alu1, Taq1, BsoF1) for five novelrestriction fragment length polymorphisms (RFLPs) in the genes forIL-1ra and IL-1β.
Results—No significant differences were found inthe allelic frequencies or allele carriage rates of the markers in theIL-1β and IL-1ra genes between CD, UC, and healthy controls. Noassociation between the genetic markers and cytokine production levelswas observed. Patients with UC carried the combination of both the infrequent allele of the Taq1 RFLP and the Mwo1 RFLP significantly morefrequently (35.2% in UC versus 71.1% in controls).
Conclusions—UC is associatedwith carriage of both infrequent alleles of the Taq1 and Mwo1 RFLPs.However, it could not be confirmed whether the association reflects apathogenic mechanism underlying UC.