Biomarkers for inflammatory bowel disease and irritable bowel syndrome

1. A method for diagnosing whether a human subject is likely to have irritable bowel syndrome (IBS), comprising:

(a) contacting a mRNA-derived nucleic acid sample obtained from a human subject suspected of having IBS under hybridizing conditions with at least four nucleotide probes, wherein a first nucleotide probe consists of 15 or more contiguous nucleotides of SEQ ID NO:3 (BLCAP) or a full complement thereof, a second nucleotide probe consists of 15 or more contiguous nucleotides of SEQ ID NO:4 (TH1L) or a full complement thereof, a third nucleotide probe consists of 15 or more contiguous nucleotides of SEQ ID NO:9 (HIST1H2BK) or a full complement thereof, and a fourth nucleotide probe consists of 15 or more contiguous nucleotides of a nucleic acid selected from the group consisting of SEQ ID NO:6 (CALM3) or a full complement thereof and SEQ ID NO:5 (UBE2G1) or a full complement thereof;

(b) detecting formation of hybridization complexes between the probes and the nucleic acid targets in the nucleic acid sample, wherein the hybridization complexes provide a measure of gene expression of the nucleic acid targets; and

(c) diagnosing whether the human subject is likely to have IBS based on the measure of gene expression of the nucleic acid targets, wherein gene expression levels of the nucleic acid targets differentiate between IBS and normal.

2. The method of claim 1 , wherein the human subject suffers from one or more of abdominal pain, constipation, diarrhea, and a change in bowel habits.

3. The method of claim 1 , wherein the mRNA-derived nucleic acid sample is obtained from peripheral blood mononuclear cells red blood cell-depleted whole blood.

4. The method of claim 1 , further comprising analyzing gene expression of the nucleic acid targets by applying a weight to the number of hybridization complexes formed for each nucleic acid target.

5. A method for diagnosing whether a human subject is likely to have irritable bowel syndrome (IBS), comprising:

(a) contacting a mRNA-derived nucleic acid sample obtained from a human subject suspected of having IBS under amplifying conditions with at least four primer pairs, wherein a first primer pair selectively amplifies a detectable portion of SEQ ID NO:3 (BLCAP) or a full complement thereof, a second primer pair selectively amplifies a detectable portion of SEQ ID NO:4 (TH1L) or a full complement thereof, a third primer pair selectively amplifies a detectable portion of SEQ ID NO:9 (HIST1H2BK) or a full complement thereof, and a fourth primer pair selectively amplifies a detectable portion of a nucleic acid sequence selected from the group consisting of SEQ ID NO:6 (CALM3) and SEQ ID NO:5 (UBE2G1), wherein each primer in each primer pair consists of at least 15 contiguous nucleotides of its respective nucleic acid target;

(b) detecting amplification products generated by amplification of nucleic acid targets in the nucleic acid sample by the at least four primer pairs, wherein the amplification products provide a measure of gene expression of the nucleic acid targets; and

(c) diagnosing whether the human subject is likely to have IBS based on the measure of gene expression of the nucleic acid targets, wherein gene expression levels of the nucleic acid targets differentiate between IBS and normal.

6. The method of claim 5 , wherein the human subject suffers from one or more of abdominal pain, constipation, diarrhea, and a change in bowel habits.

7. The method of claim 5 , wherein the mRNA-derived nucleic acid sample is obtained from peripheral blood mononuclear cells red blood cell-depleted whole blood.

8. The method of claim 5 , further comprising analyzing gene expression of the nucleic acid targets by applying a weight to the number of amplification products formed for each nucleic acid target.