Comparing BOS Incidence Between HCT Donor Types

By Patrick Daly - Last Updated: November 23, 2022

The use of antithymocyte globulin (ATG) for graft-versus-host disease (GVHD) prophylaxis has led to a similar rate of chronic GVHD (cGVHD) between hematopoietic cell transplantations (HCT) with haploidentical donors (HIDs) and human leukocyte antigen (HLA)-matched sibling donors (MSDs).

However, the incidence of bronchiolitis obliterans syndrome (BOS)—effectively lung cGVHD—between donor types is unclear, according to authors in Frontiers in Immunology. In their study, the investigators reported that patients who received HCT with graft sourced from a HID appeared to have a lower incidence of BOS compared with MSD transplants, which the authors suggested may be due to ATG and use of mixed grafts.

HUD HCT Shows Lower Rates of Pulmonary GVHD

Their findings were based on retrospective analyses of 1,405 patients with hematologic malignancies who underwent HCT. Patients were stratified according to donor type (HID, MSD, or matched-unrelated donor [MUD]), and researchers examined rates and risk factors of BOS.

Reportedly, the overall cohort had a 5-year cumulative incidence of BOS of 7.2%. Patients who received HID transplantation had a lower 5-year cumulative incidence compared with MSD transplantation (4.1% vs. 10.0%; P<.001) and a similar incidence compared with MUD (4.1% vs. 6.2%; P=.224).

Researchers found bronchiolitis obliterans syndrome was less frequent in HCT with haploidentical donors compared with MSD and MUDS.

In addition, patients who received ATG had a lower 5-year cumulative incidence of BOS compared with non-ATG patients in the overall cohort (4.6% vs. 11.2%; P<.001) and in the MSD group (4.1 vs. 11.2; P=.042).Patients with mixed–peripheral-blood stem cell plus bone marrow grafts had a lower 5-year cumulative incidence of BOS compared with those patients with only peripheral-blood stem cell grafts (4.2% vs. 9.1%; P=.001).

Protective factors for BOS included HID (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.2-0.6; P<.001), use of ATG (OR, 0.3; 95% CI, 0.2-0.7; P=.001), and mixed graft source (OR, 0.3; 95% CI, 0.1-0.8; P=.013).Comparatively, risk factors for BOS included acute GVHD (OR, 2.1; 95% CI 1.1-4.3; P=.035) and any cGVHD (OR, 10.1, 95% CI, 4.0-25.0; P<.001).

“In conclusion,” the authors summarized, “we suggested that HID transplantation based on ATG for GVHD prophylaxis presented a lower incidence of BOS than MSD transplantation. This study might provide a potential strategy for preventing BOS posttransplantation regardless of HID, MUD, or MSD transplantation.”

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