CD4 and depressive symptom measurement: Since premature T cell senescence with similar impaired generation of CD4+ naïve T cells and overproduction of CD4+ and CD8+ memory T cells is also a characteristic of patients with Major Depressive Disorder (MDD) (Simon et al., 2023), we investigated whether depression was more prevalent in our group of outpatients with CVID and correlated to T cell senescence characteristics.