Abstract Introduction Allogeneic hematopoietic stem cell transplantation (HSCT) can be complicated by pulmonary graft-versus-host disease (GVHD), an expression of the conflict between two immune systems. It generally manifests during the first two years following transplantation, in the form of bronchiolitis obliterans syndrome (BOS), characterized by the onset of irreversible obstructive ventilatory dysfunction. The long-term course of the respiratory disease and the factors involved in this progression after transplantation have not been determined. Methods Retrospective collection of medical data from allogeneic HSC transplant patients followed for BOS in Foch’s Hospital pulmonology department of and presenting with persistent obstructive airway disease more than 3 years after transplantation. Calculation of annualized exacerbation rate and annual decline in FEV1. Comparison of these characteristics with those of a cohort of patients followed for COPD, matched for sex, age, smoking, FEV1 at baseline, and follow-up duration. Results 41 patients were included in the BOS cohort: 24 men (60%), median age 53 years IQR 40;57, BOS diagnosis made at 14.6 months 9.23;24.37 after allograft, time between BOS diagnosis and the start of follow-up 22.2 months 11.1;26.7, FEV1 at the start of follow-up 1.62 L 1.26;1.99 or 55%theo 49%;63%. 41 patients were included in the matched cohort of COPD patients. The median follow-up duration was 7.6 years 5.46;11.54 for BOS and 9 years 7;13 for COPD. Patients followed for BOS showed a significant decline in FEV1, mainly during the first 5 years: a mean decline of -54 ml/year and -1%/year. In comparison, the FEV1 decline in COPD patients was -6 ml/year and -0%/year (p = 0.0046). The annualized rate of bronchial exacerbations was 1.11/year (SD 0.78) in the BOS cohort, while it was 0.47/year (SD 0.6) in the COPD cohort (p = 0.032). When the cohorts were adjusted for the annual exacerbation rate, the slope of decline in FEV1 was no longer significantly different between BOS and COPD patients (p = 0.08). All BOS patients were receiving inhaled therapy, 37% were receiving at least two systemic immunosuppressors at the start of follow-up, and 43% were still receiving at least one after 5 years. Six BOS patients (14,6%) died during follow-up, as did four COPD patients (9.7%). Conclusion BOS long-term progression (3 years) after allograft transplantation is characterized by a FEV1 decline and a rate of bronchial exacerbations significantly higher than those observed in a cohort of COPD patients. Exacerbations are determining factors in functional outcomes, potentially favored by a high level of immunosuppression. This abstract is funded by: no funding source
Salvator et al. (Fri,) studied this question.