Reduction in skin disease in E/L/P triple-mutant mice compared with E/P double-mutant mice.

Introduction of the L-selectin mutation virtually eliminated the severe skin lesions that were observed in nearly all the E/P double mutants. (A) Three 15-month-old +/+ control mice (second filial generation of mixed C57BL/6 and 129/SvEv background). (B) Three 15-month-old E/L/P triple-mutant mice of mixed background. None of the more than 30 triple-null mice observed until 15 months of age showed any sign of skin lesions and all appeared generally healthy, as shown here. (C) The 3 mice in which lesions developed at 5 to 6 months of age. The few lesions observed in the triple-null mice (3 of 156 mice) were not as severe grossly or histopathologically as those in the E/P double-null mice.