B-cell development: a comparison between mouse and man.

A common variable immunodeficiency (CVID) patient, who carries mutations on both alleles of the gene encoding the surrogate light chain component lambda 5/14.1, shows a similar phenotype of B-cell deficiency as the lambda 5-deficient mutant mouse. As discussed here by Paolo Ghia and colleagues, this points to a remarkably similar developmental pathway of B cells in humans and mice.