Airway and alveolar nitric oxide production, lung function, and pulmonary blood flow in sickle cell disease.
BACKGROUND
Children with sickle cell disease (SCD) often have obstructive lung function abnormalities which could be due to asthma or increased pulmonary blood volume; it is important to determine the underlying mechanism to direct appropriate treatment. In asthmatics, exhaled nitric oxide (FeNO) is elevated. FeNO, however, can also be raised due to increased alveolar production. Our aim, therefore, was to determine if airway or alveolar NO production differed between SCD children and ethnic and age-matched controls.


METHODS
Lung function, airway NO flux and alveolar NO production, and effective pulmonary blood flow were assessed in 18 SCD children and 18 ethnic and age-matched controls.


RESULTS
The SCD children compared to the controls had a higher respiratory system resistance (P = 0.0008), alveolar NO production (P = 0.0224), and pulmonary blood flow (P < 0.0001), but not airway NO flux. There was no significant correlation between FeNO and respiratory system resistance in either group, but in the SCD children, there were correlations between alveolar NO production (P = 0.0006) and concentration (P < 0.0001) and pulmonary blood flow.


CONCLUSIONS
Airway NO flux was not elevated in the SCD children nor correlated with airways obstruction, suggesting that airways obstruction, at least in some SCD children, is not due to asthma.
Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.|National Institute for Health Research Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK.
Alan
A
Lunt
Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
Na'eem
N
Ahmed
Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
Gerrard F
GF
Rafferty
Department of Haematology, King's College Hospital NHS Foundation Trust, London, UK.
Moira
M
Dick
Department of Haematology, King's College Hospital NHS Foundation Trust, London, UK.|Division of Cancer Studies, King's College London, London, UK.
David
D
Rees
Department of Haematology, King's College Hospital NHS Foundation Trust, London, UK.
Sue
S
Height
Department of Haematology, King's College Hospital NHS Foundation Trust, London, UK.|Division of Cancer Studies, King's College London, London, UK.
Swee Lay
SL
Thein
Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.|National Institute for Health Research Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK.
Anne
A
Greenough
D000293:Adolescent; D000402:Airway Obstruction / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D000403:Airway Resistance; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000175:diagnosis; D015415:Biomarkers / Q000378:metabolism; D001783:Blood Flow Velocity; D001944:Breath Tests; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D011652:Pulmonary Circulation; D012129:Respiratory Function Tests; D012307:Risk Factors
D015415:Biomarkers; D009569:Nitric Oxide