Interestingly, early stages of B‐cell development, including pro‐ and pre‐B‐cell stages, were most severely affected by zinc deficiency, whereas immature B cells (B220+IgM+IgD−) and mature B cells (IgM+IgD+) were more resistant to zinc deficiency, albeit still grossly impacted by severe zinc deficiency. Here, CD40LG is linked to Zinc deficiency.