Study on the impact of CD4+ T cells and their subsets on relapse in AML patients during remission

This study investigates the impact of minimal residual disease (MRD) on relapse in patients with acute myeloid leukemia (AML), focusing on its interaction with immune cells function. A total of 49 AML patients were enrolled in this prospective study and categorized into four groups: MRD^-positive with relapse, MRD^-positive without relapse, MRD^-negative with relapse, and MRD^-negative without relapse. Peripheral blood T lymphocyte subpopulations were analyzed using ten-color flow cytometry. CD4⁺ T cells were co-cultured with leukemia cell lines to assess the impact of CD4⁺ T cells on leukemia cell proliferation, apoptosis, and cytokine release. In MRD^-positive patients, relapsed individuals exhibited significantly higher levels of CD4⁺ T cells, regulatory T (Treg) cells, and CD4⁺CD45RA⁺ naïve T cells compared to non-relapsed patients (P < 0.0001, P = 0.0016, and P = 0.0066, respectively). Conversely, in MRD^-negative patients, relapsed individuals showed a significantly lower percentage of Treg cells (P = 0.0068). Furthermore, we observed that CD4⁺ T cells were associated with enhanced leukemia cell proliferation and reduced apoptosis, along with markedly increased IL-10 expression. The available data raise the possibility that CD4⁺ T cell-derived IL-10 participates in immune microenvironment regulation, a process that may have implications for MRD maintenance and disease recurrence in AML.