Long term follow-up of patients with Bronchiolitis obliterans Syndrome after hematopoietic stem cell transplantation

Abstract

Introduction: Bronchiolitis Obliterans Syndrome (BOS) after allogeneic hematopoietic stem cell transplantation (HSCT) is a progressive, chronic lung disease in which persistent inflammation leads to obstruction of the small airways. The incidence of BOS rises due to steady increases in utilization of HSCT. Mortality of BOS is high, and prompt recognition and treatment is mandatory. This study describes the long-term course of BOS in four children post HSCT.

Method: All paediatric patients with HSCT between 2000–2017 were reviewed. All patients with BOS were included in the study. Lung function parameters and biometric data were investigated over a period of 3.9–9.9y (median 4.9). In total, 169 available lung function tests were evaluated and changes in lung function parameters were analyzed. All side effects due to systemic steroid treatment were reviewed.

Result: Of 526 patients, 236 (44.8%) suffered from acute GvHD. Mortality data were related to number of organs involved: GvHD one organ n= 172, mortality (29 %); GvHD two organs n=46, mortality (34.8%) and GvHD>3 organ n=18 mortality (61.1%). Of these survivors four developed chronic BOS with lung function impairment (FVC <60%, FEV1 < 50%, FVC/FEV1 < 70, RV/TLC > 150%). Three presented with typical signs of BOS on computer tomography and broncho-alveolar lavage with neutrophils.

Conclusion: Chronic BOS of the lung presenting with progressive loss of lung function is a rare but devastating condition and one of the major causes of mortality in HSCT. Inconspicuous CT patterns and normal BAL post HSCT do not exclude severe chronic BOS. Further research is required to develop therapeutic concepts in HSCT survivors with BOS.