CD79A and celiac disease: We also identified 29 additional patients who had initially elevated anti-TTG IgA concentrations with a normal first biopsy, but who underwent a second biopsy that was negative and therefore were not diagnosed with celiac disease (n = 6, 2%), had anti-TTG IgA concentration that normalized on repeat testing and therefore did not undergo repeat endoscopy (n = 16, 4%), or were lost to follow up (n = 7, 2%) (Fig. 1).