After Treatment Decrease of Bone Marrow Tregs and Outcome in Younger Patients with Newly Diagnosed Acute Myeloid...

Area of Science:

• Immunology
• Hematology
• Oncology

Background:

• Defects in antileukemic immune cells, including regulatory T cells (Tregs), are implicated in acute myeloid leukemia (AML) development and persistence.
• Leukemic cells may recruit Tregs to bone marrow, fostering immune suppression and evading immune surveillance.

Purpose of the Study:

• To investigate the correlation between diagnostic bone marrow aspirate (BMA) regulatory T cells (Tregs) and overall response rate (ORR) in newly diagnosed AML patients.
• To evaluate changes in Treg counts after induction chemotherapy in AML patients and their association with treatment response.

Main Methods:

• Multiparametric flow cytometry was used to quantify Tregs (CD4+/CD45RA-/CD25high/CD127low) in diagnostic BMA from 39 younger AML patients (<65 years).
• Patients received standard induction chemotherapy; ORR (complete remission (CR)+CR with incomplete hematologic recovery (CRi)) was assessed.
• Treg levels were analyzed at diagnosis and post-treatment, correlating with ORR and molecular-cytogenetic factors.

Main Results:

• Diagnostic BMA Treg counts did not correlate with ORR in the overall study population.
• However, Treg counts significantly decreased in responder patients after treatment (p=0.039), while remaining unchanged in non-responders.
• Molecular-cytogenetic group (p=0.03) and NPM mutation (p=0.05) were significant predictors of ORR, independent of Tregs.

Conclusions:

• While diagnostic Treg levels are not predictive of initial AML treatment response, their significant reduction post-treatment in responders suggests a role in enhancing anti-leukemic immune responses.
• The findings imply that Treg depletion may be crucial for effective anti-AML immunity.
• Further studies with larger patient cohorts are needed to confirm the role of BMA Tregs in immune-AML interactions during diagnosis and post-treatment.