Abstract
It has been proposed that the immunoglobulins in some naturally occurring macroamylases may primarily directed to animal amylase. This would suggest that there may also be an antibody to animal amylase with inability to bind endogenous amylases in circulation. On the basis of this assumption, an antibody to porcine pancreatic amylase (PPA) was investigated in sera from patients with inflammatory bowel disease (IBD): ulcerative colitis (UC) and Crohn's disease (CD), because serum antibodies to various dietary antigens have been demonstrated to be a significantly prevalent in patients with IBD. This investigation took advantage of the abilities of serum to inhibit specific activity of added PPA and to form an artificial macroamylase with the PPA. As expected, such antibodies to PPA were detected frequently in patients with CD (19/50, 38%), rarely in patients with UC (1/50, 2%) and not at all in normal controls (0/30). There were two different types of antibodies differing in their reaction with PPA; one was an enzyme-inhibiting antibody and another an enzyme-noninhibiting antibody. The former seemed to be of monoclonal or oligoclonal IgG whereas the latter was of polyclonal IgG and IgA or polyclonal IgG alone, and both were detected in almost cases. The presence of the antibodies specific for CD suggests that the antibodies may play an etiological role in CD, of which the etiology is still unknown.
