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Gastrointestinal Disorders
CELIAC DISEASE
Celiac disease is an autoimmune disease associated with total or sub-
total villous atrophy leading to malabsorption from the gut. As with
diabetes, antibodies associated with celiac disease can predict
progression to clinical disease and can be used to define the cause of
malabsorption. The disease is associated with endomysial antibodies
(tissue transglutaminase) and antibodies to gliadin and reticulin.
AGA
The presence of high levels of anti-gliadin antibodies (AGA) is indicative
of celiac disease. AGA sensitivity for celiac disease is reported between
95 – 100%. IgG type AGA are more sensitive but less specific and IgA
type AGA are less sensitive but more specific. AGA are detected also in
two thirds of dermatitis herpetiformis patients. Celiac disease patients
with selective IgA deficiency can only be detected by measuring IgG type
AGA.
Enzyme immunoassay for anti-gliadin antibodies show a specificity for
celiac disease of 80 – 90.5% for IgA class antibodies and of 100% for
IgG class antibodies. As for specificity, up to 21% of patients with other
gastrointestinal disorders show positivity for IgG anti-gliadin antibodies,
whereas IgA anti-gliadin antibodies were found only in 3% of them.
Combined IgG and IgA antibodies determination shows 96% sensitivity
and a specificity of 97%. The progress of the concentration of these
antibodies is also useful to monitor the fulfillment of a gluten free diet.
AEA / tTG
Antiendomysium antibodies (AEA) of the IgA class are found in patients
with active celiac disease or dermatitis herpetiformis. The diagnostic
sensitivity for celiac disease is 68-100% in untreated patients, and the
diagnostic specificity is 99-100% suggesting a high positive and negative
predictive value. IgA-AEA sensitivity for dermatitis herpetiformis is 70-80%
but increases to 100% when associated to gluten-sensitive enteropathy.
In the case of celiac disease patients presenting IgA deficiency, specific
antibodies can be detected by using IgG FITC/Evans (M) conjugate.
Tissue transglutaminase (tTG) is the prominent autoantigen in celiac
disease. Anti-tTG of the IgA class are found in patients with celiac disease
or dermatitis hepertiformis. Specificity of anti-tTG ELISA assay for celiac
disease is 94-100% and sensitivity is 92-100%. In the case of dermatitis
herpetiformis, specificity is 98% and sensitivity is 89%. Provided the high
incidence of IgA deficiency in celiac patients, is recommended to assay
the anti-tTG IgG when a negative result is obtained for the anti-tTG IgA.
ANTI-tTRANSGLUTAMINASE ANTIBODIES
44754
Anti-tTRANSGLUTAMINASE IgA ANTIBODIES
ELISA kit 96 T
Recombinant human antigen activated by calcium and gliadin
44798
Anti-tTRANSGLUTAMINASE IgG ANTIBODIES
ELISA kit 96 T
Recombinant human antigen activated by calcium and gliadin
ANTI-ENDOMYSIUM ANTIBODIES
44548
IFA – Complete kit, 12 slides x 4 wells
44715
IFA – Complete kit, 12 slides x 8 wells
44557
IFA – Slide Box, 12 slides x 4 wells
44710
IFA – Slide Box, 12 slides x 8 wells
Monkey Esophagus, distal section
ANTI-GLIADIN ANTIBODIES
44704
ANTI-GLIADIN ANTIBODIES (AGA-IgG/IgA)
ELISA kit 96 T
Gliadin
44884
ANTI-DEAMIDATED GLIADIN (DGP-IgG)
ELISA kit 96 T
Synthetic deamidated gliadin
44885
ANTI-DEAMIDATED GLIADIN (DGP-IgA)
ELISA kit 96 T
Synthetic deamidated gliadin
6
INFLAMMATORY BOWEL DISEASE
Determination of ASCA antibodies is useful in the diagnosis of
inflammatory bowel disease, particularly in the differentiation between
Crohn’s disease and ulcerative colitis, especially indeterminate
colitis, using a combination of perinuclear anti-neutrophil cytoplasmic
autoantibodies (p-ANCA) and ASCA tests.
ASCA
ASCA are strongly associated to Crohn’s disease (50%-80%), compared
to patients with ulcerative colitis (2%-14%) and to normal healthy
subjects (1%-7%). Approximately two-thirds of the Crohn’s disease
patients with ASCA IgG are also positive for ASCA IgA, but 0%-19% of
the patients have only ASCA IgA antibodies. In Crohn’s disease, up to
90% specificity has been reported in specimens positive for both ASCA
IgG and IgA antibodies, especially when concentration of both the IgG
and IgA ASCA antibodies is high.
ANTI-SACCHAROMYCES CEREVISIME ANTIBODIES IgG/IgA (ASCA)
44872
ELISA kit 96 T
Highly purified mannan from
Saccharomyces cerevisiae