Cell subsets in blood as a biomarker for Bronchiolitis Obliterans Syndrome (BOS)

Lung transplantation is a last treatment option for patients with an end stage
lung disease. Unfortunately, long-term survival after lung transplantation is
severely limited by chronic lung allograft dysfunction, which usually manifests
as bronchiolitis obliterans syndrome (BOS). About 50% of all lung
transplantation patients dies within the first five years after
transplantation. In addition, BOS reduces the quality of life and increases
the cost of treatment. Clinically BOS manifests as an obstruction of the
airways and shortness of breath with a progressive and fatal course. The
pathogenesis is driven by allo-immune and nonallo-immune mechanisms that can
occur alone and simultaneously. Histologically it was shown that during BOS the
allograft is inflitrated by leukocytes, followed by a process of injury, repair
and extensive fibrosis where various leukocyte subsets are involved. This is
the main reason why we are very interested in the dynamics and differentiation
status of certain groups of leukocytes in the peripheral blood. Particulary
monocytes surrounding the development of BOS. Infiltration and differentiation
of certain fractions during inflammation and repair probably determines
whether the immune response will lead to a pathological disorder.

The objective of this study is to determine the composition and functional
capacity of leukocyte fractions in the blood of lung transplantation patients.
As a possible biomarker for BOS. It is expected that in patients with BOS the
frequency and functional capacity of leukocyte fractions is changed in
comparison with lung transplant patients without BOS.Phenotypical changes in
blood, cytokine production capacity and differetiation potential of monocytes
that are recruited during BOS are possible infomational en functional
biomarkers. Therefore these leukocytes could also provide insight into the
causal pathogenesis of BOS. Results from this research could be a valuable
addition to the general understanding of BOS pathophysiology, and the role of
monocytes in the process of inflammation and fibrosis.

The proposed research is an observational study and is achievable within the
timeframe of one year.

Not applicable
Participants will not undergo any extra treatment or burden for this study. The
blood is collected with informed consent, and the vena-puncture is already made
for regular follow-up care.