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Regarding Danielle Papageorgiou's recent summary:
It's not gluten that takes a long time to leave the body but the antibodies to it.  They appear to stay longest the older you are when diagnosed (and the longer you have been exposed to gluten).  In a child they may be absent in less than 6 months while they might persist in older person for over 2  years.
Incidentally regarding causes of CD: we do know the cause - (some part of) gluten.  Indeed it is about the only autoimmune disease where the cause IS known and it is precisely because of this that scientists are studying CD so intently now (and the current 'T' cell research on this is promising).  It is hoped that by finding the exact role gluten plays in CD a model will be produced that helps unlock the secrets of other far more mysterious (and serious) autoimmune diseases like rheumatoid arthritis for which the cause are NOT yet known.  The ultimate goal is a better understanding of autoimmunity in general and any benefit to coeliacs is largely coincidental. 
CD is a "genetic" disease in the sense that you need the right genes to get it, although all the exact genes and are still not known. Moreover, the most recent research on the prevalence of CD in Italy and the UK revealing similar rates (slightly over 1%) in adults and children, suggests CD is likely to be "acquired" early in life, with or without overt symptoms. 
Charlotte
Oxford, UK

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