Received: 15 June 2019
Accepted: 14 November 2019
First Online: 20 December 2019
Ethics approval and consent to participate
: All participants were properly informed on the nature of studies and specific procedures and gave signed written consent to participate. The consent forms and the plans for the research were approved by the Ethics Commission of the Institute of Clinical Immunology according to the formal requirements issued by the State Department of Health of Russian Federation.
: All participants and authors gave their consent for the publication of the study results, and a formal consent for publication was granted by the Research Council of the Institute of Clinical and Experimental Immunology. It is also confirmed that the work conforms to the principles of the WHO Helsinki declaration.
: The authors declare that they have no competing interests.