COMPARISON OF
SEROLOGIC MARKERS FOR THE DIAGNOSIS OF CROHN’S DISEASE
I.Shafran
M.D., C.Piromalli, F.El-Zaatari Ph.D., S.Naser Ph.D.; Dept. Molecular Biology,
UCF, Orlando,FL; Baylor College of Medicine, Houston,TX.
BACKGROUND: Considerable attention has been focused on the
anti-saccharomyces cervicae antibody (ASCA) as a serological marker for
Crohn’s disease. Recent investigations have identified the utility of another
potential Crohn’s diagnostic serum marker, p35 and p36 recombinant clones
specific for Mycobacterium avium ss.
paratuberculosis.
AIM: To determine and compare the diagnostic accuracy of
ASCA to both p35 and p36 serologic markers for the diagnosis of Crohn’s
disease.
METHODS: Serum samples were obtained from 27 patients with
Crohn’s disease. 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 63% (17/27) of the Crohn’s patients. The p35 and/or p36
recombinant clones were positive for 85% (23/27) of the Crohn’s patients. The
10 patients with negative ASCA titer levels for IgA and/or IgG each reacted
positively with p35 and/or p36 recombinant clones. The 4 patients with negative
reactivity to p35 and/or p36 each had positive ASCA titer levels for IgA and/or
IgG.
CONCLUSION: This study reveals 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 determine the enhanced
accuracy for diagnosing Crohn’s disease by combining the ASCA and p35 and p36
serologic markers.
All content copyright ©1999 Dr. Ira Shafran, M.D.