SPLICE VARIANTS OF HUMAN IL-23 RECEPTOR (IL-23R) mRNA AND USE OF A DELTA 9 ISOFORM IN PREDICTING INFLAMMATORY BOWEL DISEASES

Abstract

There is disclosed the cloning and identification of human IL-23R splice variants caused by alternative splicing of the IL-23R mRNA in human. Alternative mRNA forms occur through skipping one, multiple full exons or partial exons, within the IL-23R gene. A total of twenty-five (25) different IL-23R transcripts were identified. A novel exon deletion (exon 9) isoform in the interleukin 23 receptor is disclosed, denoted as Δ9. The present application also describes a quantitative assay to measure different IL-23R isoform. Detection of Δ9 isoform of IL-23R is predominantly present in colon and cervical tissues. A decrease in Δ9 is observed in inflamed colon tissues in Crohn's patients. There is disclosed a method of predicting Crohn's disease by measuring Δ9 isoform of IL-23R.

What is claimed is: 
     
         1 . A method of quantifying the expression level of IL-23R mRNA variant (Δ8,9) in a biological sample, said Δ8,9 consists of a nucleotide sequence of SEQ ID NO: 22, said method comprises the steps of:
 (a) isolating a mRNA from a biological sample; 
 (b) preparing a cDNA from said isolated mRNA; 
 (c) amplifying a portion of said cDNA containing exon 8,9 to yield an amplicon; and 
 (d) analyzing said amplicon by fragment analysis to quantify said Δ8,9 expression level in said biological sample. 
 
     
     
         2 . The method of  claim 1 , wherein said biological sample is derived from a human. 
     
     
         3 . The method of  claim 1 , wherein said biological sample is a cell, tissue, or biological fluid. 
     
     
         4 . The method of  claim 3 , wherein said tissue is colon tissue. 
     
     
         5 . The method of  claim 4 , wherein said colon tissue is an ascending colon tissue. 
     
     
         6 . The method of  claim 4 , wherein said colon tissue is a descending colon tissue. 
     
     
         7 . The method of  claim 3 , wherein said tissue is cervix. 
     
     
         8 . The method of  claim 3 , wherein said biological fluid is whole blood. 
     
     
         9 . The method of  claim 3 , wherein said cell is peripheral blood mononuclear cell. 
     
     
         10 . The method of  claim 1 , wherein said step (c) is performed using a forward primer and a reverse primer, said forward primer having a nucleotide sequence set forth in SEQ ID NO: 27, and said reverse primer having a nucleotide sequence set forth in SEQ ID NO: 28.