Page 34 - Livre électronique du Congrès National de Pneumologie 2019

BLOOD EOSINOPHILIA FOR PHENOTYPING EOSINOPHILIC
ASTHMA : WHICH CRITERION TO CHOOSE?

C1

Introduction : The study of blood inflammatory pattern is an easy, lower cost, accessible and well-
tolerated method for phenotyping asthma as eosinophilic one. Eosinophilic inflammatory pattern is a
risk factor for poor asthma outcomes. However, there is no consensus about the cut off level for Blood
eosinophilia (BEo). The main reported cut-off levels were 300 and 400 cells/µl. Furthermore, a new
approach using a composite index that uses eosinophil/lymphocyte ratio and eosinophil/neutrophil
ratio, called ELEN index, has been advanced as a better surrogate for eosinophilic asthma.
Aim to determine which of the BEo at 300 , 400 cells/µl or the ELEN index is a better surrogate for
eosinophilic asthma and associated with poor asthma outcomes.

Methods

It is a cross sectional study including 102 subjects with asthma. A medical questionnaire assessing
asthma outcomes (symptoms control, severe exacerbations with hospitalization in the previous year),
a spirometry with bronchodilator test and a measurement of the bronchial nitric oxide (FeNO) were
performed. Complete peripheral blood counts were determined. Eosinophilic (Eo+) and non
eosinophilic (Eo-) were identified using the aforementioned three definitions. Statistical analysis was
performed using STATISTICA software. p0.05 was significant.

Results

The sample was aged 44.3±13.3 years and it was female dominated (70.6%). The eosinophilic pattern
was present in 29, 41 and 39% using the 300, 400 cut-offs and ELEN index, respectively.

✓ Using the three criteria, the Eo+ group had higher FeNO levels, a valid biomarker for bronchial
eosinophilic inflammation.
✓ Using the ELEN index but not the 300 and 400 cut-off levels, the Eo+ group had an impaired
lung function compared to the Eo- one, as shown by a reduced FEV1 (62±15 vs 69±16,
p=0.032 ) and more proximal obstructive ventilatory defect (66.7% vs 37.7%, p=0.029).
✓ Using the ELEN index as well as the 400 cut-off but not the 300 cut off, Eo+ had significantly
more hospitalizations during the previous year (20.5% vs 6.6%, p=0.036 using ELEN index
and 25% vs 7.9%, p=0.025 using the BEo at 400 cut-off).