Changes in lung volumes and airway responsiveness following haematopoietic stem cell transplantation

¹ U.O. Medicina Preventiva e del Lavoro - Laboratorio di Fisiopatologia Respiratoria
² U.O. Ematologia 2, Azienda Ospedaliera Universitaria "San Martino"
³ U.O. Fisiopatologia Respiratoria, Di.M.I., Università di Genova, Genova, Italy

^* To whom correspondence should be addressed. E-mail: giovanni.barisione{at}hsanmartino.it.

	Abstract

Changes in lung volumes occur following haematopoietic stem cell transplantation (HSCT). Airway hyperresponsiveness was occasionally reported, without mechanistic explanation.

We studied 17 patients by standard methacholine (MCh) challenge before, and then 3 (n=16) and 12 (n=13) months after HSCT. Another 6 patients were challenged before and 3 months after HSCT using a modified challenge to investigate the effect of deep inhalations.

No patient developed bronchiolitis obliterans or bronchiolitis obliterans organising pneumonia (BOOP). At 3 months, forced vital capacity (FVC) was significantly reduced by 0.33±0.55 L, 1-s forced expiratory volume (FEV₁) by 0.31±0.50 L, total lung capacity (TLC) by 0.39±0.37 L and single-breath diffusing capacity (DL,CO) by 15±12%. At 12 months, TLC decreased by 0.43±0.36 L and DL,CO by 8±8%. With standard challenge, no significant changes in FEV₁ response to MCh were observed after HSCT but FVC decreased significantly less after than before HSCT, suggesting less air trapping. With modified challenge, deep inhalations reversed MCh-induced decrease in partial expiratory flow more after than before HSCT and this correlated (r=0.88) with TLC decrements.

In conclusion, an increase of airway responsiveness is unlikely after HSCT, at least in patients without pulmonary complications, and mechanisms opposing airway narrowing may blunt the bronchoconstrictor response.