A gut biopsy of patient 3 showed subtotal villous atrophy of the duodenum as Marsh IIIb enteropathy with no CD20+ B cells and moderate to high amounts of CD3+, CD4+, and CD8+ intraepithelial cells compared with noncarriers (Supplemental Figure 3A and Supplemental Table 3). Here, CD8A is linked to Abnormal intestine morphology.