Trial Information

Study on Systemic and Airway Cytokines and Oxidative Stress in Patients Undergoing Haemopoietic Stem Cell Transplantation (HSCT)

Haemopoietic stem cell transplantation (HSCT) has revolutionized the treatment of both
haematological and perhaps some solid malignancies. However, despite recent technological
advancements, HSCT is still associated with significant mortality and morbidities.

Apart from various infective complications in early stage post-HSCT, bronchiolitis
obliterans syndrome (BOS) has been a well-known late complication that can result in high
mortality. It has been mostly associated with those who develop chronic graft-versus-host
disease after allogeneic HSCT. Clinically, the diagnosis of BOS is largely based on
demonstration of obstructive lung function abnormalities and air-trapping in computed
tomography scan of thorax. Pathologically, bronchiolitis obliterans is characterized by both
inflammatory and fibrotic reactions in the small bronchioles leading to subsequent
obliteration. Upon diagnosis of BOS post-HSCT, inhaled corticosteroid (with or without
bronchodilators) is commonly prescribed as anti-inflammatory agent, though with undocumented
clinical efficacy. Unfortunately, there is still a lack of reliable biomarkers that can
predict or allow early detection of BOS, preferably in the early and potentially reversible
stage of development of BOS.

Apart from measuring circulating biomarkers in blood, exhaled breath condensate (EBC) has
recently emerged as a non-invasive sampling method for real-time analysis and evaluation of
oxidative stress biomarkers in the lower respiratory tract airways, especially in various
lung diseases including asthma, chronic obstructive pulmonary disease, and lung cancer. As
bronchiolitis obliterans is predominantly a disease of the small bronchioles, it is highly
likely to be associated with changes in various inflammatory and oxidative stress biomarkers
in EBC. However, the role of measuring EBC biomarkers in predicting the occurrence of BOS
after HSCT has not been studied. Therefore, the current study aims to evaluate the temporal
changes of various oxidative stress biomarkers and cytokines in EBC and blood in patients
with haematological conditions who undergo allogeneic HSCT, with regard to the subsequent
development of BOS.