Mechanisms for reduced pulmonary diffusing capacity in haematopoietic stem-cell transplantation recipients

Lung diffusing capacity for CO (DLCO) is compromised in haematopoietic stem-cell transplantation (HSCT) recipients. We derived alveolar-capillary membrane conductance (D-M,D-CO) and pulmonary capillary volume (V-C) from DLCO and diffusing capacity for NO (DLNO). Forty patients were studied before and 6 weeks after HSCT. Before HSCT, DLNO and DLCO were significantly lower than in 30 healthy controls. D-M,D-CO was similar to 40% lower in patients than in controls (p < 0.001), whereas V-C did not differ significantly. After HSCT, DLNO and D-M,D-CO further decreased, the latter by similar to 22% from before HSCT (p < 0.01) while V-C did not change significantly. Lung density, serum CRP and reactive oxygen metabolites were significantly increased, with the latter being correlated (R-2 = 0.71, p < 0.001) with the decrement in DLNO. We conclude that DLNO and, to a lesser extent, DLCO are compromised before HSCT mainly due to a D-M,D-CO reduction. A further reduction of D-M,D-CO without V-C loss occurs after HSCF, possibly related to development of oedema, or interstitial fibrosis, or both. (C) 2014 Elsevier B.V. All rights reserved.