A
Comparative Analysis of Anti-Saccharomyces Antibodies (ASCA) and p35 and p36
Recombinant Clones for the Diagnosis of Crohn's Disease (CD)
I.
Shafran, C. Piromalli, S. Naser
BACKGROUND: Numerous studies have confirmed the utility of ASCA as a serological marker for CD. Recent investigations have identified the utility of another potential CD diagnostic serum marker, p35 and p36 recombinant clones specific for Mycobacterium avium ss. paratuberculosis. Our lab is currently investigating the utility of these serologic markers for the diagnosis of CD. AIM: To evaluate the accuracy of ASCA and both p35 and p36 serologic markers for the diagnosis of CD. METHODS: Serum samples were obtained from 62 patients with confirmed and documented CD. The sera samples were sent to Prometheus Laboratories to determine the IgA and IgG ASCA titers with the Prometheus IBD Diagnostic System. The serologic response to p35 and p36 were analyzed by Western blotting at the University of Central Florida. RESULTS: The ASCA titer levels for IgA and/or IgG were positive for 61% (38/62) of CD patients. The p35 and/or p36 recombinant clones were positive for 85% (53/62) of CD patients. The 24 CD patients not detected by ASCA were identified as positive by the p35 and/or p36 recombinant clones in 92% (22/24) of those CD patients missed by ASCA. The 9 CD patients not detected by p35 and/or p36 were identified by the ASCA serologic markers in 78%(7/9) of those CD patients missed by p35 and p36. CONCLUSION: This investigation further establishes the utility of p35 and p36 recombinant clones for the diagnosis of CD. These results also reveal added evidence to demonstrate the complimentary role that ASCA may have with p35 and p36 for increasing the sensitivity and specificity of these serologic tests. Larger studies are needed to investigate the combined use of these serologic markers for the diagnosis of CD and as predictive markers to facilitate the development of treatment strategies.
All content copyright ©1999 Dr. Ira Shafran, M.D.