Life-threatening infections (42.5%), caused by various pathogens, were the most serious threats faced by CD40L-deficient patients, while neutropenia (57.5%) remained the most common complication.
We describe a unique hemizygous CD40LG mutation which was discovered in a 12-year-old boy with chronic severe neutropenia, a normal IgG level, and absence of sinopulmonary or opportunistic infections.
Thus, it is possible that both the neutropenia and the NK cell deficiency are due to lack of growth-promoting signals normally delivered by the CD40 ligand.