Assays and methods for the detection of Crohn's disease
View Patent ↗The present invention provides devices and methods for aiding in the diagnosis of Crohn's disease. The devices and methods accurately identify whether a sample from an individual is associated with inflammatory bowel disease (IBD) or a clinical subtype thereof such as Crohn's disease (CD). The present invention is useful for determining whether a sample from an individual is an IBD sample, or differentiating between CD and ulcerative colitis (UC). Thus, the present invention provides an accurate diagnostic prediction of IBD or a clinical subtype thereof and prognostic information useful for guiding treatment decisions.
1. A diagnostic assay, said diagnostic assay comprising:
(a) determining the presence or absence of IgA anti-outer membrane protein A (anti-OmpA) antibodies in a sample by contacting said sample with an OmpA antigen or reactive fragment thereof, wherein said OmpA antigen or reactive fragment thereof is substantially-free of an OmpC antigen, under conditions suitable to form a complex of said OmpA antigen or reactive fragment thereof and IgA anti-OmpA antibody;
(b) contacting said complex with a labeled indicator antibody to form a labeled complex; and
(c) detecting the presence or absence of said labeled complex with a detection device, wherein the presence of said labeled complex is associated with Crohn's disease.
2. The assay of claim 1 , wherein said IgA anti-OmpA antibodies are detected with an enzyme-linked immunosorbent assay.
3. The assay of claim 1 , further comprising determining the presence or absence of IgA anti- Saccharomyces cerevisiae antibodies (ASCA) in said sample,
wherein the presence of IgA anti-OmpA antibodies or the presence of IgA ASCA in said sample is each independently associated with Crohn's disease.
4. The assay of claim 1 , further comprising determining the presence or absence of IgA ASCA in said sample,
wherein the presence of both IgA anti-OmpA antibodies and IgA ASCA in said sample is associated with Crohn's disease.
5. The assay of claim 3 , wherein the presence of IgA ASCA is determined by reactivity with purified yeast cell wall phosphopeptidomanan (PPM).
6. The assay of claim 5 , wherein said yeast cell wall PPM is prepared from ATCC strain #38926.
7. The assay of claim 1 , wherein said OmpA antigen is recombinant OmpA antigen.
8. The assay of claim 1 , wherein said sample is human serum.
9. An assay kit for improving the diagnosis of Crohn's disease, said assay kit comprising:
(a) a plate well containing an OmpA antigen or reactive fragment thereof, wherein said OmpA antigen or reactive fragment thereof is substantially-free of an OmpC antigen;
(b) a labeled anti-IgA antibody; and
(c) instructions for detecting the presence or absence of IgA anti-OmpA antibodies in a patient's sample.
10. The assay kit of claim 9 , wherein said sample is human serum.
11. An assay to aid in the detection of Crohn's disease comprising:
(a) contacting a sample with an OmpA antigen or reactive fragment thereof, wherein said OmpA antigen or reactive fragment thereof is substantially-free of OmpC antigen, under conditions suitable to transform said OmpA antigen or reactive fragment thereof into a complex comprising said OmpA antigen or reactive fragment thereof and IgA anti-OmpA antibody;
(b) contacting said complex with a labeled indicator antibody to transform said complex into a labeled complex; and
(c) detecting the presence of said IgA anti-OmpA antibodies in said sample.
12. The assay of claim 11 , wherein said sample is human serum.
13. The assay of claim 11 , wherein said assay is an ELISA assay.
14. The assay of claim 11 , wherein detecting the presence of said IgA anti-OmpA antibodies in said sample comprises the use of a detection device.
15. The assay of claim 14 , wherein said detection device comprises a spectrophotometer.
16. A method for performing an assay for improving the diagnosis of Crohn's disease, said method comprising:
(a) detecting the presence of IgA anti-OmpA antibodies in a patient's sample, wherein the IgA anti-OmpA antibodies are substantially-free of IgA anti-OmpC antibodies; and
(b) reporting the presence or absence of said IgA anti-OmpA antibodies in the patient's sample to improve the diagnosis of Crohn's disease.
17. The method of claim 16 , wherein the detecting step is performed using an ELISA.
18. The method of claim 17 , wherein the ELISA further comprises the steps of:
(a) contacting the sample with an OmpA antigen or reactive fragment thereof, wherein said OmpA antigen or reactive fragment thereof is substantially-free of an OmpC antigen;
(b) contacting the sample with a labeled anti-IgA antibody; and
(c) analyzing the sample using a spectrophotometer.