R1 reticulin antibodies: markers of celiac disease in children on a normal diet and on gluten challenge.

R1 reticulin antibodies were found in sera from patients with childhood celiac disease (CCD). Although the overall sensitivity of R1 in the diagnosis of CCD was relatively low (16/43 = 37%), when only those cases in an active phase of the disease were considered, the sensitivity increased (16/24 = 67%). In spite of its low sensitivity, the R1 assay did show a high degree of specificity, as this antibody was not found in children with post-enteritis syndrome or in healthy controls. R1 antibodies, when found in active CCD, always turned out to be positive when tested on human liver as substrate. While this fact did not enhance the sensitivity of the test, it strengthened its specificity, since R1, found in pathological conditions other than CCD, was nearly always negative on human tissue. Although the R1 reticulin antibody test cannot replace jejunal biopsy in the diagnosis of CCD, its assay, particularly on human liver as substrate, can be considered a useful tool in the screening of celiac patients.