Clinical-pathogenetic significance of middle mass molecules of different fractions in pulmonary expirates of patients with rheumatoid arthritis

Abstract

Objective — to establish the clinical and pathogenetic role of the isolation of the middle mass molecules of different fractions (aminopeptide — AF, peptide — PF, nucleotide — NF, chromatophore — CF) in exhaled breath concentrate (EBC) in pneumonitis in rheumatoid arthritis (RA) patients, their relationship with the parameters of respiratory moisture excretion, spirography and pressure in the pulmonary artery. 
 Materials and methods. EBC (pulmonary expirates) were studied in 31 patients with RA (mean age 46 years, the ratio of men to women 1 : 2), among whom moderate and high degree of disease activity was established in 67.7 % of cases, III and IV stages — in 54.8 %, the extra­articular form of the disease — in 61.3 %, systemic osteoporosis — in 83.9 %, seropositivity for rheumatoid factor — in 80.7 %, for antibodies to cyclic citrullined peptide — in 77.4 %. To determine the middle mass molecules in the expirates and blood serum, a screening method was used with the precipitation of proteins with trichloroacetic acid and the determination of the light absorption spectra of the acid­soluble fraction. 
 Results and discussion. Interstitial pneumonitis was diagnosed in 51.6 % of the number of RA patients, which was accompanied by fibrosing alveolitis in 18.8 % of cases, rheumatoid nodules in the lungs — in 12.5 %, obliterating bronchiolitis — in 6.3 %, with the ratio of restrictive, mixed and obstructive types of dysfunctions of external respiration 6 : 2 : 1, while the disease proceeded with a significant increase in AF indicators in 74.2 % of patients and the ratio «EBC/blood» (e/b) PF level in 77.4 % against the background of a decrease in AFe/b (at 71.0 %), NFe/b (at 54.8 %, CFe/b (at 74.2 %) and the ratio of surface tension caused by high­ and low­molecular substances in 83.9 %, and the composition of expirates was closely interrelated with the state of hemodynamics of the pulmonary circulation and bronchopermeability, depended on the rate and volume of respiratory moisture release, long­term use in the complex treatment of patients with an immunosuppressant of cytotoxic action, folic acid antagonist methotrexate. Conclusions. The nature of the respiratory excretion of middle mass molecules of different fractions determines the pathogenesis of pneumopathy in RA patients, which depends on the clinical, radiological and sonographic signs of the disease, and the study of EBC can be used to predict the course of the pathological process and monitor the effectiveness of therapeutic measures.