Clinical and immunological features and prognosis of different phenotypes of occupational asthma

Introduction. Occupational asthma is a complex and heterogeneous disease. Development of personalized treatment and prevention tactics becomes feasible due to phenotyping, which means identifying of markers to combine cases of occupational asthma with similar manifestations (clinical, instrumental, laboratory) and prognosis to phenotypes.

The study aims to determination and comparative analysis of spirographic and immunological parameters for different phenotypes of occupational asthma.

Materials and methods. In this study, we included 170 patients with different phenotypes of occupational asthma and 50 participants in control group. The spirographic examination was performed using computer spirograph with determination of the following parameters: forced vital capacity (FVC), forced expiratory volume during the first second (FEV1), Tiffeneau-Pinelli index (FEV1/FVC), peak expiratory flow (PEF), maximal expiratory flow at 75%, 50%, 25% of the forced vital capacity (MEF75%VC, MEF50%VC, MEF25%VC). Quantification of the immunoglobulins IgA, IgM, and IgG in human serum was conducted by Mancini method; levels of IgE, C-reactive protein and fibronectin were determined using a solid-phase enzyme immunoassay. Fibrinogen concentration in plasma was measured by an automatic coagulometer. Haptoglobin concentration in serum was determined by spectrophotometry. 

Results. According to spirometry and laboratory results obtained, there is a strong evidence, that the phenotype "occupational asthma — occupational chronic obstructive pulmonary disease" has the lowest values in pulmonary function tests and the most significant changes in immunoglobulins, fibronectin and acute phase proteins levels among other studied phenotypes of occupational asthma.

Conclusions. Dynamic determination of spirometric, immunological parameters, fibronectin and proteins of the acute phase of inflammation in workers at risk for the formation of occupational bronchial asthma may be recommended to be carried out once every 6 months, followed by the isolation of disease phenotypes. This will optimize diagnostics, therapeutic and preventive tactics, as well as predict the course of this pathology.

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