Association of Feno with IgE Levels in Patients with Allergic Asthma

Background: Asthma is a chronic multifactorial disease characterized by inflammation with multiple triggers.  Inflamation of the airways is the main pathologic pathway in asthma, and not only determines the diagnosis and severity of symptoms, but is also useful to establish treatment and predict potential complications.  By measuring FeNO levels, an indirect level of pulmonary inflammation can be obtained since it is produced by alveolar macrophages in response cytokines.  One of the main known causes of this inflammatory response is an allergic reaction.  This allergic reaction sets off a cascade of biochemical events that leads to the expression of inflamatory mediators, preformed or de novo, and IgE being the principal of such mediators. The objective was evaluate the relationship between levels of FeNO and IgE to inflammation and allergy severity. 

Methods: 50 patients (72% female and 28% male) aged 12 to 50 years old, diagnosed with asthma were taken from the Allergy and Immunology department.  A complete medical history was performed, and the diagnosis was confirmed through a clinical history and spirometric criteria, according to GINA 2010.  All medications that could alter the inflammatory process were taken away for 15 days.  Lastly, total serum IgE levels were measured with electrochemiluminescence technique and the FeNO with standard procedures.  The data was further analyzed using a Pearson’s correlation test.

Results: 21% of the participants showed normal IgE values (<100 UI/Ml) and 33% of the participants had normal FeNO measurements (<20 ppm).  A 0.29 coefficient was measured using a Pearson’s correlation test, which suggests a low positive correlation between the two observed variables.

Conclusions:   The results showed a low correlation between the IgE and FeNO levels.  This result does not allow for a correlation between both parameters; which leads to a conclusion that high levels of IgE from an allergic reaction is not necessarily going to lead to a high FeNO, thus a pulmonary inflammation.   Additionally, it emphasizes the importance of the allergists and pneumonologists to work together when treating an asthma patient, given the multidisciplinary nature of this pathology.