Spontaneous development of defects in multiple immune organs in ABIN1[D485N] mice. (A) Mean spleen weight (left) and body weight (middle) of WT and ABIN1[D485N] knockin mice with a typically enlarged spleen in 4-mo-old mutant mice (right). Bar, 1 cm. (B) Representative photomicrograph of hematoxylin and eosin–stained spleen sections from WT and ABIN1[D485N] mice. The red (R) and white (W) pulp are indicated. Bars, 0.05 mm. (C) Axillary, inguinal, and mesenteric LNs of 5-mo-old ABIN1[D485N] mice compared with WT mice. Bars, 1 cm. (D) Gut-associated lymphoid tissue (arrows) of the small intestine wall of ABIN1[D485N] (bottom) and WT (top) mice. Bars, 1 cm. (E) Hematoxylin and eosin–stained sections of Peyer’s patches (PP) in WT and ABIN1[D485N] mice. In the low-power view (top; bars, 0.5 mm), the arrows indicate Peyer’s patches in ABIN[D485N mice compared with WT mice. In the high-power view (bottom; bar, 0.05 mm), there are Peyer’s patches showing plasma cells (white arrows) and neutrophils (black arrow) in the ABIN1[D485N] mice. All mice used were 16–20 wk old. Data are representative of at least 12 mice (A–C) and 6 mice (D and E) of each genotype. Error bars show the mean ± SEM. **, P < 0.005 (two-tailed Students t test).