Sickle cell disease (SCD) children and adults with asthma have an increased rate of vaso-occlusive crisis, acute chest syndrome episodes, and premature mortality when compared to those without asthma. We hypothesised that either asthma diagnosis and/or bronchodilator treatment may aggravate SCD via their modulating effect on autonomic nervous system.

Heart rate variability during pulmonary function tests (spirometry, static volumes, DLCO/DLNO, exhaled NO at multiple flow rates) including salbutamol administration will be evaluated in patients with SCD (n=60) receiving asthma treatment or not, as compared to asthmatic children without SCD (n=30) matched for ethnicity

Inclusion Criteria:

• age from 8 to 16 years (≥ 8 years and < 16 years) (spirometry and DLCO study feasible)
• Sub-Saharan African or Caribbean ethnic origin.
• child with sickle cell disease referred for monitoring of respiratory function in the framework of its sickle cell disease and whether or not it presents a possible disease asthmatic (asthma treatment prescribed in the past year)
• or asthmatic child (typical functional signs + history of exacerbation severe hospitalized or reversible obstructive pulmonary disorder) not sickle cell
• addressed for respiratory function monitoring

Exclusion Criteria:

• Refusal to participate (lack of consent)
• Sickle cell child of North African origin

Subjects of African or Caribbean ethnicity who were 8 to 16 years of age and were referred to the Pulmonary function Testing unit for the follow-up of their disease : SCD or asthma