Features of Omenn syndrome in an immunodeficient patient. (A) Desquamative erythroderma in P1 at the age of 9 months. (B-C) Immunohistologic staining of skin biopsies. (B) Anti-CD3 staining in a healthy control and P1. Arrows indicate clusters of infiltrating T cells. Morphometric quantification of 10 high-power fields revealed that CD3 staining covered 17% of the area in the patient compared with 1% in the healthy control. (C) Staining for CD4 and CD8. Ki67 staining reflects high proliferative activity in situ (right). (D) Hematoxylin and eosin (HE) stain (left) and anti-CD8 stain (right) of a lymph node biopsy of P1 and a healthy control. Arrows indicate a normal germinal center in the control (lacking in the patient) and the T-cell zone in the control (diffusely enlarged in the patient). (E) TCRγ rearrangement analysis of samples from blood, skin, and lymph node from P1 and blood of P2 and of a healthy control using primers for Vγ1-8 (upper row, blue), Vγ10 (upper row, black), and Vγ9 (lower row, black). Amplicon length (in bp) is plotted against the fluorescence intensity (arbitrary units). Size standards are indicated in orange.