Figure 3.

Altered T cell compartments in the setting of the ATM mutations. A) There are fewer naive CD4⁺CD62L⁺CD45RO⁻ T cells in the AT patient. Conversely, there is an elevated memory T cell compartment (CD45RO⁺) in the AT patient compared to the HD control. There is an increase in the central memory (CD62L⁺CD45RO₊) compartment, and the increased memory T cell frequency is particularly evident in the effector memory ( CD62L⁻CD45RO⁺) T cell population. B) Purified CD4⁺ T cells from two representative HD and the AT patient show expansion of CD4⁺CXCR5⁺PD-1^hi circulating Tfh (cTfh) cells in the peripheral blood of the AT patient. C) Despite an increase in the frequency of CD4⁺CXCR5⁺PD-1^hi cTfh cells, the ATM mutations do not affect levels of ICOS, which is important for Tfh cell differentiation and function. (ISO = isotype control). D) Purified CD4⁺ T cells from two representative HD and the AT patient show a decreased frequency of CD4⁺FOXP3⁺CD25⁺CD127^lo Tregs in the peripheral blood of the AT patient. E) Despite this, Treg suppressive capacity is preserved as shown in representative histograms of Treg-mediated suppression of autologous and heterologous CFSE-labeled Tresp cell proliferation on day 4.5 from the AT patient and a HD control. Percentages of Tresp cells undergoing division.