A sandwich enzyme immunoassay for wheat gliadin.

A sandwich double antibody solid-phase enzyme immunoassay (EIA) that can detect and quantitate gliadin is described. Quantitative analysis could be carried out in the range of 5-400 ng/ml and the assay was more sensitive than inhibition EIA. Gliadin possessed weak cross-reactivity with oats, maize and rice prolamines. In the presence of anti-gliadin antibody (serum from a patient with active coeliac disease) gliadin could not be detected, but the sensitivity of the assay was restored by heat treatment of the serum. This EIA can therefore be employed to assess the gliadin content of biological fluids where specific antibody may coexist.

In vitro gliadin antibody production by peripheral blood mononuclear cells from patients with coeliac disease.

In vitro spontaneous IgG gliadin antibody production was shown in peripheral blood mononuclear cell (PBMC) cultures from 12/14 patients with active coeliac disease; in most cases no increase and sometimes a marked reduction of the in vitro synthesis was observed after pokeweed mitogen (PWM) addition. Lower levels of gliadin antibodies were also detected in PBMC cultures from 7/12 coeliac patients in remission; in all the cases the synthesis was increased by PWM. In vitro production was confirmed by higher levels in 7-day culture supernatants than in 0-day frozen-thawed cell pellets and by the inhibitory effect of cycloheximide. Spontaneous release of antibodies occurred within the first 3 days of culture, while PWM-induced antibody production reached a plateau after 7-9 days. The analysis of the in vitro gliadin antibody production is a promising technique to assess the regulatory mechanisms involved in the humoral immune response to gliadin.

Passage of gliadin into human breast milk.

Samples of breast milk were taken from 53 women following the ingestion of 20 g of gluten. The samples were analysed for the presence of gliadin by a double-antibody sandwich enzyme immunoassay. Gliadin (5-95 ng/ml) was detected in 54/80 samples collected at various stages of lactation. Maximum levels in milk were found 2-4 hours after ingestion; gliadin could not be detected in serum. The transfer of gliadin from mother to infant might be critical for the development of an appropriate specific immune response to gliadin later in life.

An analysis of cereals that react with serum antibodies in patients with coeliac disease.

Sera from six children with active coeliac disease, and elevated titres against gliadins and from six age-matched controls, were examined for IgG antibodies against different cereal proteins by a solid-phase radioimmunoassay. Antibodies to the major wheat proteins and the prolamines of other cereals were present in low titre in all control sera. In coeliac sera, significantly higher titres were found against A-gliadin, as well as against hexaploid and tetraploid wheat whole gliadins. Gliadin peptic-tryptic digest retained a significant antigenic activity, completely lost by peptic-tryptic-pancreatic digest. High titres were also found when coeliac sera were tested against wheat glutenins, albumins, and globulins, as well as against barley, oats, and maize prolamines; rice prolamines gave lower titres. Serum from whole gliadins and A-gliadin immunized rabbits showed a similar spectrum of reactivity against prolamines as coeliac sera. Our results indicate a dissociation between immunogenic properties of cereal proteins and toxicity in coeliac disease.

[Diagnostic value of changes in the Q wave induced by exertion]. / Valore diagnostico delle modificazioni dell'onda Q indotte dallo sforzo.

In order to evaluate the diagnostic value of exercise-induced Q wave changes and its relationship with the extent of coronary involvement and presence and location of a previous myocardial infarction, we examined the stress electrocardiograms of 188 consecutive patients with chest pain. Coronary arteriography shoved single vessel disease (SV) in 28 patients and multivessel disease (MV) in 130 patients; a previous myocardial infarction was present in 64 patients. The Q wave amplitude was measured as average of ten values in CM5 at rest and at peak exercise; a Delta-Q less than 0, i.e. reduction or no change of Q wave at peak exercise, was considered a positive response for coronary artery disease. The Delta-Q criterion shoved a significantly better sensitivity than ST depression, as a whole, but this improvement was nullified when patients with anterior myocardial infarction were excluded; as well specificity of Delta-Q although better than ST, did not allow a significant improvement for the diagnostic value of stress test. We also evaluated the diagnostic accuracy for multivessel coronary artery disease of both criteria positive was 78% whereas the negative predictive value of both criteria negative was 91%. We concluded that the exercise-induced Delta-Q less than 0 is a good indicator of coronary artery disease, although not superior to ST depression; the negativity of both criteria seems to be highly reliable for the exclusion of multivessel coronary artery disease.

Evaluation of exercise-induced Q-wave amplitude changes and their clinical value.

We studied the influence of exercise level, severity of coronary artery disease (CAD), presence of previous myocardial infarction (MI), anterior or diaphragmatic, on the clinical value of exertional Q wave changes (Delta-Q). We retrospectively evaluated the exercise electrocardiograms of 62 patients without angiographic evidence of CAD and 133 patients with CAD; 28 of them had single (SVD) and 105 multivessel disease (MVD). Forty-one patients had a previous diaphragmatic MI and 23 anterior. The sensitivity, specificity and predictive value of Delta-Q were compared to the ST criterion. The exercise level affected Delta-Q. ST and Delta-Q had similar specificity and predictive values. The extent of CAD did not affect the sensitivity of Delta-Q and this method was better than ST to detect SVD patients. The Delta-Q criterion was equally as efficient as ST in MVD patients without MI and with diaphragmatic MI. The loss of septal forces on resting electrocardiograms made useless Delta-Q analysis on patients with anterior MI. The improvement of sensitivity in SVD patients by Delta-Q might be of clinical value since these latter are frequently not diagnosed by the ST criterion.