In some affected children, impaired cellular immunity to common recall antigens, with low numbers of circulating white blood cells were reported.

Functional studies have shown that CD45R0 cells respond in vitro to recall antigens, whereas CD45RA positive cells do not.

Irrespective of what maintains the size of the total peripheral T-cell pool, mechanisms that maintain a T-lymphocyte clone in cell division, and concomitantly expressing CD45R0, are likely to be the most important factors determining the frequency of T lymphocytes responsive to a given recall antigen.