[Relationship between NK Cell Reconstitution and aGVHD after Allo-HSCT]

Area of Science:

• Immunology
• Hematology
• Transplantation Medicine

Background:

• Acute graft-versus-host disease (aGVHD) is a major complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT).
• Natural killer (NK) cells play a crucial role in immune regulation and graft rejection.
• Understanding the dynamics of NK cells post-allo-HSCT is vital for managing aGVHD.

Purpose of the Study:

• To investigate the correlation between NK cell count and activity with the incidence and severity of aGVHD.
• To determine if NK cell metrics can serve as predictive markers for aGVHD outcomes.
• To explore the potential of NK cells as therapeutic targets in allo-HSCT recipients.

Main Methods:

• A cohort of 26 patients undergoing allo-HSCT was studied.
• Peripheral blood NK cell count and activity were assessed on day 30 post-transplantation using 4-color flow cytometry.
• aGVHD incidence and severity were evaluated clinically and pathologically.

Main Results:

• Patients with aGVHD exhibited significantly lower NK cell counts (655±216 cells/µl vs 1169±372 cells/µl, P=0.002) and activity (7.3±3.6% vs 9.0±3.6%, P=0.008) on day 30 compared to those without aGVHD.
• Higher grades of aGVHD (II-IV) were associated with markedly reduced NK cell counts (617±220 cells/µl vs 1081±399 cells/µl, P=0.001) and activity (4.2±1.7% vs 8.3±3.5%, P=0.001).
• Severe aGVHD (grade II-IV) correlated with increased relapse rates (57% vs 5%, P=0.010) and decreased 1-year progression-free survival (PFS) (43% vs 84%, P=0.010).

Conclusions:

• NK cell count and activity on day 30 post-allo-HSCT are significantly associated with aGVHD.
• These NK cell metrics show potential as predictive biomarkers for aGVHD.
• Modulating NK cell function could represent a novel therapeutic strategy for preventing or treating aGVHD.