Cellular hypersensitivity to gluten derived peptides in coeliac disease.

Wheat gluten derived antigens have been tested for their ability to inhibit the migration of leucocytes from healthy subjects and patients with coeliac disease. Three preparations of a water soluble fraction (Frazer's fraction III, FIII) of partial peptic tryptic digests of wheat gluten had different effects in a direct (one stage) assay. Subfractions B and B2 caused migration inhibition of leucocytes from patients with treated coeliac disease but not of leucocytes from healthy volunteers or patients with Crohn's disease or ulcerative colitis. This migration inhibition seems to be specific for gluten fractions because maize zein fraction B, beta-lactoglobulin and ovalbumin did not cause it. The sensitivity of coeliac leucocytes to fraction B is not related to factors present in coeliac serum as the migration of leucocytes from healthy individuals preincubated with coeliac sera was not inhibited. Puromycin diminished inhibition by fraction B, which was active at 1.2 micrograms/ml in an indirect (two stage) migration inhibition assay; this is consistent with a process involving elaboration of lymphokine(s). More highly purified fractions of B2, P1-P4 were prepared by reverse phase high performance liquid chromatography (HPLC) and showed differing potency in direct and indirect assays, with P4 being the most active fraction. Inhibition of migration by gluten derived peptides appears to result from the release of lymphokine by leucocytes specifically from coeliac patients.

Antigenic reactivity of peptides derived from wheat gluten with sera from patients with coeliac disease.

Fraction B from a peptic-tryptic digest of gluten from Scout 66 wheat has already been shown to cause histological damage to the jejunal mucosa of coeliac patients. Peptide fractions, designated P1-P4, have been prepared from it by a combination of gel filtration (producing an intermediate fraction pseudo-B2: psi B2) and reverse-phase high pressure liquid chromatography. An enzyme-linked immunosorbent assay (ELISA) has been used to measure IgG antibodies to fraction B in sera from untreated coeliac patients, patients with inflammatory bowel disease (IBD) and healthy individuals. The coeliac group had significantly higher (P less than 0.05) antibody levels to fraction B than either of the control groups [medians: coeliac disease (n = 21), 0.247; IBD (n = 17) 0.019; healthy controls (n = 13) 0.020]. Five coeliac sera which gave high absorbance values in the ELISA were chosen and preincubated with fraction B in a range of concentrations, before assay by ELISA: a dose-dependent inhibition of binding was found. Two sera which gave high ELISA values were preincubated with fractions B2 and P1-P4. B2, P1, P2 and P4 gave a dose-dependent inhibition, with P1 being the most potent. Absolute values were different for the two sera but the same relative pattern of reactivity was observed for each. With the serum giving the higher ELISA value the concentration of fraction (microgram/ml) giving a 50% inhibition of binding when 0.5 ml was added to 0.5 ml of a 1/500 dilution of the serum (IC50) was 2.6 for fraction B, 61 for P1, 155 for B2 and 285 and 295 for P4 and P2 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Specificity of leucocyte migration inhibition test in coeliac disease. A reassessment using different gluten subfractions.

Production of leucocyte migration inhibition factor by peripheral blood leucocytes in response to challenge with gluten fractions has been proposed as a reliable in vitro test for the diagnosis of coeliac disease. We have performed the leucocyte migration inhibition test with two different gluten fractions, GFIII and B2, in untreated and treated coeliac patients, patients with other intestinal diseases (abnormal controls) and healthy controls, and evaluated the sensitivity, specificity and positive and negative predictability of the test for the diagnosis of coeliac disease. Using GFIII as antigen leucocyte migration was significantly inhibited, compared to healthy controls, not only in treated and untreated coeliacs but also in abnormal controls. Using B2 gluten subfraction as antigen only treated coeliacs and abnormal controls differed significantly from healthy controls. The elevated number of abnormal controls showing migration inhibition consistently affected the diagnostic value of the test, which did not vary using B2 subfraction instead of GFIII as antigen. Our study confirms previous observations of gluten sensitization, as detected by leucocyte migration inhibition, in coeliac patients but strongly questions the claim that coeliac disease can be diagnosed on the basis of a positive leucocyte migration inhibition test without the need for intestinal biopsy.

Specific IgG subclass antibodies, IgE and IgG S-TS antibodies to wheat gluten fraction B in patients with coeliac disease.

Antibodies were measured in the sera of fifteen patients with untreated coeliac disease and twenty-eight patients with inflammatory bowel disease. Increased levels of specific IgG, IgG1, IgG2, and IgG4 antibody to wheat gluten fraction B, measured by an enzyme-linked immunosorbent assay, were shown in the coeliac disease group, but not in the inflammatory bowel disease group. No specific IgE antibody to fraction B was detected but 33% of the patients with coeliac disease had specific short-term sensitizing (anaphylactic) IgG antibody activity (IgG S-TS) to fraction B. There was no correlation between the IgG2 or IgG4 specific antibody and the presence of IgG S-TS activity.

Carnitine as a possible adjunct in parenteral feeding.

Carnitine is necessary for the transport of fatty acids across the inner mitochondrial membrane, and depletion in response to Intralipid infusion has previously been demonstrated. This study investigates whether orally administered L-carnitine increases tolerance to a lipid load given intravenously. Eight patients with active inflammatory bowel disease, being treated with intravenous prednisolone, were studied. Intralipid was infused on two occasions. Triglycerides and ketone bodies rose in a reproducible manner. Carnitine did not influence these changes. Carnitine excretion rose after an oral dose indicating that carnitine was absorbed, but carnitine excretion was increased in the steroid-treated individuals and rose after oral prednisolone in two healthy subjects. It is concluded that under the conditions of this study oral carnitine is without demonstrable effect on the handling of an intravenous lipid load.