Gastroenterology, 1996; 111: 318-324
The final paragraph says:
In conclusion, our data show that approximately half of the siblings of patients with celiac disease show signs of sensitization to gluten as they mount an inflammatory local response to rectal gluten challenge. The genetic background and the clinical meaning of such gluten sensitivity need to be established. Further studies, particularly at the jejunal level, are necessary before deciding if any action is to be taken in this subset of first-degree relatives.