Breath analysis in gastrointestinal graft-versus-host disease after allogeneic hematopoietic cell transplantation.

Volatile organic compounds (VOCs) are generated during pathologic processes, and their assessment can be used to diagnose and monitor a variety of diseases. Given the role of the microbiome in graft-versus-host disease (GVHD), we hypothesized that microorganisms producing volatile metabolites may alter VOCs expelled in breath in patients with gastrointestinal (GI) GVHD. In this pilot study, exhaled breath samples were obtained from 19 patients with grade 2 to 4 acute GI GVHD, 10 patients with no GVHD at day 100, and 10 healthy control subjects; the samples were analyzed by using mass spectrometry. Overall, nine (47%) patients had grade 2 GVHD, eight (42%) patients had grade 3 GVHD, and two (11%) patients had grade 4 GVHD; 26% had upper GI, 21% had lower GI, and 53% had both upper and lower GI manifestations. Stepwise canonical discriminant analysis identified 5 VOCs distinguishing patients with and without GI GVHD: 2-propanol, acetaldehyde, dimethyl sulfide, isoprene, and 1-decene (Wilks' Λ, 0.43; F statistic, 6.08; P = .001). The model correctly classified 89% (17 of 19) and 90% (9 of 10) of patients with and without GI GVHD, respectively. Breath analysis is a feasible and promising noninvasive method to detect acute GI GVHD. Further study of serial breath analysis and the gut microbiome in a larger cohort are ongoing to validate these findings.

Comparative Effectiveness of Busulfan and Fludarabine versus Fludarabine and 400 cGy Total Body Irradiation Conditioning Regimens for Acute Myeloid Leukemia/Myelodysplastic Syndrome.

Allogeneic hematopoietic cell transplantation conditioning regimen intensity has varied for patients with acute myeloid leukemia and myelodysplastic syndrome. A comparative effectiveness analysis was performed to assess outcomes of busulfan and fludarabine (BuFlu) versus those of fludarabine and 400 cGy total body irradiation (FluTBI) conditioning. Thirty-three subjects received BuFlu and 38 received FluTBI. The BuFlu group received more red blood cell transfusions (P = .02) and had a longer time to platelet recovery (P = .004). There were no differences between the regimens regarding incidence of acute or chronic graft-versus-host disease (GVHD), quality of life, or 2-year outcome estimates for relapse (48; 95% confidence interval [CI], 30 to 64 and 50; 95% CI, 33 to 65), nonrelapse mortality (29; 95% CI, 14 to 45 and 29; 95% CI, 15 to 44), relapse-free survival (27; 95% CI, 13 to 43 and 29; 95% CI, 16 to 44), and overall survival (35; 95% CI, 19 to 51; and 37; 95% CI, 22 to 52), respectively. These comparable outcomes have implications for health care resource utilization. Future prospective investigation comparing these regimens with larger patient cohorts and additional strategies to prevent relapse and limit toxicities as well as cost-effectiveness analyses are warranted.