Objective. To assess the association between endothelin concentration in patients with ANCA-associated vasculitis or systemic connective tissue diseases and blood-inflammatory parameters, immunological markers as well as clinical expression of diseases.
Material and methods. A retrospective study was performed from February 2010 to February 2018 in Vilnius University Santaros Klinikos to analyze the medical records of 28 patients, in whose blood serume ANCA were detected and endothelin concentration was estimated. An indirect immunofluorescence method was used to detect ANCA, and the direct multifaceted sandwich type imuno was used to measure endothelin concentrations. The statistical analysis was performed using the SPSS v23.0 software package, the significance of the data was checked according to Chi-square, Fisher and t-criteria for two independent samples, the difterence was considered statistically significant at p<0.05.
Results. An increase in endothelin concentration was detected for all subjects, with an average of 17.24±3.9 pg/mL. The distribution of c-ANCA and p-ANCA among patients was 1:2, higher endothelin concentrations were detected in patients with p-ANCA (the difference of means: 19.77±23.3 pg/mL and 9.66±4.75 pg/mL).
Moderate and statistically significant correlation was found between endothelin and CRB concentrations (p = 0.018, r=0.512). There was no correlation between endothelin and CRB concentrations within pacients in systemic connective tissue disease and c-ANCA groups. Correlation with other blood parameters or other immunological markers has not been detected.
In most cases the following organs and organ systems were damaged: 50% joints, 39% kidneys, 32% lung and skin, 25% digestive tract, 21% of muscles. In the vasculitis group, higher endothelin concentrations were estimated for patients with impaired renal and lung function, whereas in the systemic connective tissue disease group - for patients who complained of muscle weakness and constitutional symptoms. In the c-ANCA group, a higher endothelin concentration was found in cases of fever, joint, muscle, lung or kidney damage, and p-ANCA - in cases of skin lesions. Statistically significantly lower endothelin concentrations were estimated in patients who were detected with p-ANCA and had gastrointestinal tract damage (p=0.04).
Conclusions. Endothelin concentration has a significant and moderate correlation with CRB concentration and can be used as a predictor for the acute phase of the disease. Although endothelin concentrations may increase during various conditions and diseases, as an immunological marker ET-1 is more specific for the vasculitis or p-ANCA-related diseases.
