Indirect immunofluorescence for anti-jejunum antibody detection in celiac disease: comparison among different antigenic substrates.
BACKGROUND
Although anti-endomysium antibodies (EmA) are the most reliable serological markers of celiac disease (CD), there is a need for low-cost methods for screening programs, as clinically silent disease is increasingly recognized.


OBJECTIVE
To evaluate the suitability of monkey, rat and rabbit jejunum as a substrate for the determination of anti-jejunum antibodies (JAB) in CD.


METHODS
JAB of IgA class were detected by indirect immunofluorescence on frozen sections of jejunum from monkeys, white rats and domestic rabbits. Sera from 61 untreated adults with biopsy-proven CD and EmA positivity in 57 out of 61 entered the study as true positives, while sera from 60 controls were considered as true negatives.


RESULTS
The sections of monkey jejunum showed the characteristic pattern of elongated villous fluorescence, a ring-like positivity of the cryptal basement membrane, an endomysium-like fluorescence along the smooth muscle layers in the tunica muscularis, while pericryptal fluorescence was not so evident on rat and rabbit jejunum. As compared to EmA positivity, the prevalence of JAB on monkey, rat and rabbit tissues was respectively 57/57, 54/57, 52/57. Two sera among 4 Ema negatives proved positive for JAB. No false positivity resulted from EmA and JAB on monkey jejunum, while a lower specificity was found for JAB on rat and rabbit substrates.


CONCLUSIONS
Although monkey, rat and rabbit small intestine appeared to be a suitable alternative substrate for determination of IgA-JAB, because of its lower cost and higher availability, it cannot replace monkey oesophagus, and be recommended for wide use.
Sategna-Guidetti
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Department of Internal Medicine, University of Turin, Italy.
Grosso
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SB
Grosso
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Bruno
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Grosso
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