Notably, MDD patients with self-reported sleep disturbance had a higher CD4<sup>+</sup> T cell percentage than those without such disturbance.<h4>Conclusions</h4>Our findings demonstrate that patients with MDD comorbid with sleep disturbances exhibit elevated proportions of CD4<sup>+</sup> T cells compared to those without such disturbance. This evidence concerns the gene CD4 and Sleep disturbance.