[What role does eosinophil cationic protein have in the evaluation of asthma severity?]

The revival of the concept of asthma as being a chronic inflammatory disease has led to the development of methods to monitor and control the underlying inflammatory process. The eosinophil is one of the main protagonists in this process, the control of the proteins that are released by the eosinophil when it is activated (more specifically the ECP) could provide valuable information for this purpose. However, the great complexity of the asthmatic inflammation obliges us to take into account a series of considerations, aiming at nor attributing nor expecting information from the ECP that it cannot provide. The ECP has been used in the diagnosis of asthma, in the prognosis of wheezing infants, as a marker for the exposure to the allergen, to evaluate the results of the provocation tests, with the clinical and functional seriousness of asthma, to control the effect of different anti-inflammatory treatments as well as to monitor the performance of these treatment, etc. However, it is necessary to take into account the fact that this marker is a reflection of the activation of the eosinophil, without specifying where the said activation has been produced and therefore there are studies that document increase of the ECP in relation to other conditions besides asthma (rhinitis, atopic dermatitis, the mother's addiction to tobacco, parasitosis, atopia, etc.). On the other hand there is a certain overlapping of the ECP values of patients with the active illness and with normal controls. Even patients with strong signs of asthma on occasions show normal ECP values, which could reflect that, in some cases, the eosinophilic inflammation may not be a relevant factor or, at least, it isn't a predominant one. On the other hand, when the asthma is being controlled, the determination of the ECP in induced sputum, could have a more precise diagnosis, while it could be a more exact reflection of the inflammation that exists on a local level, although this is a fact that needs to be proved subsequently. The principal usefulness of the ECP is for the individual follow up and control of each specific patient. Whatever the case, and given that the underlying asthmatic inflammation is a very complex process, in order to control it, a suitable combination of different markers is needed, which predictably improves the reliability of the diagnosis and prognosis and allows for a more precise control of the asthmatic inflammation.