Cytokine disbalance at herpesvirus myocarditis

Abstract

Viral myocarditis is a heterogeneous group of diseases not only by etiologic factors, which belong to different families of Vira kingdom, but is also characterized by a unique mechanism of inflammatory process and cytokine levels specific for each of them. According to numerous researches in сardio-immunology, at herpesvirus infection of the cardiovascular system occur both systemic and localized violations of the immune response. Unfortunately, the accessible literature did not provide the data analysis of complex cardio-immunological research that would take into account the features of herpesvirus myocarditis clinical course. This grounds relevance of immunodiagnosis directed on the exposure of dysimmunities by study of indices of general and local immunity with the estimation of the immune status in patients depending on the stage of exasperation or relapse of chronic herpetic infection in the complex of diagnostic tests. The purpose of our research was to determine features of the state of the immune system with the complex analysis of cytokine profile data, immune and interferon statuses in subacute and chronic forms of herpesvirus myocarditis.  Materials and methods. 87 myocarditis patients who were receiving inpatient treatment in medical establishments of  Kharkiv were examined. The average age was (M ± m) 36 ± 3,46 years old. The diagnosis of myocarditis was established according to the order № 436 by the Ministry of Healthcare of Ukraine from 03.07.2006 of clinical findings protocol. In accordance with the term of myocarditis clinical course, the patients were divided in two sub-groups: 44 patients with subacute (from 2 to 6 months), and 43 patients with chronic (over 6 months) clinical course of viral myocarditis. The control group correlated with patients of basic group by age and gender and consisted of 40 practically healthy persons without implications of cardial pathology. Definition of cytokine concentration: IL-2, IL-4, IL-6, IL-10, INF-γ, TNF-α in blood serum was conducted by the method of solid-phase enzyme-linked immunosorbent assay, population structure of lymphocytes with different antigenic determinants (CD3⁺, CD4⁺,CD8⁺, CD16/56, CD19⁺, СD95⁺) was determined by monoclonal antibodies by cytofluorimetric assay. Obtained data processing was conducted with the use of parametric and non-parametric methods of biostatistics by programs EXEL-2003^® and Biostatistics 4.03.  Results and discussion. The data obtained indicates the disbalance in their system, which above all is characterized by a considerable level increase of pro-inflammatory IL-6 up to 134,09 ± 22,72 pg/ml (control level 11,83 ± 1,64 pg/ml) and in relation to moderate growth of levels of IL-2 та TNF-α at subacute myocarditis. Such increase in level of IL-6 can take place due to the change of pro-inflammatory effect to anti-inflammatory in a remote period. In a complex with IL-10 IL-6 limits the secretion of TNF-α. For this reason, its level remains high at chronic herpesvirus myocarditis and exceeds the level of the control group by over 8 times. In addition, there is an increase of levels of anti-inflammatory IL-4, IL-10 cytokines at the chronic form of herpesvirus myocarditis course by 2,9 and 3,1 times respectively. At the same time, the level of IL-10 increased not only in comparison with the level of the control group but also almost 2 times exceeded the proper index at subacute myocarditis. Instead of the predicted INF-γ level rise, its decline was discovered, in patients with subacute course the index value was the lowest. This phenomenon can be the result of mast cells activity and in its turn influences the synthesis of collogen and processes of myocardium remodeling.  Analysis of sub-population composition of lymphocytes discovered the increase in number of CD3+CD95+ lymphocytes of peripheral blood at myocarditis, especially in the group of patients with subacute herpesvirus myocarditis with its level exceeding the index of the control group by 3,3 times, and at chronic course – by 2,7 times. We consider that determination of CD95+ expression already has a prognostic value during the first signs of cardiac insufficiency. An increase in level of the indicated receptor is the evidence of active rejection process of defective and infected cardiomyocytes, which clinical displays are signs of cardiac insufficiency and decline of myocardium retractive ability.  Conclusion. Thus, determination of cytokine in blood serum at infectious myocarditis of herpesvirus nature has a high diagnostic value and can compete with invasion and instrumental methods of diagnostics. Disbalance in the system of cytokines at herpesvirus myocarditis is a universal reaction of the immune system which is characterized by the increased levels of pro-inflammatory cytokines against the moderate decline of anti-inflammatory, and the increase in concentration of ІL-10 in combination with the level of lymphocytes of membrane phenotype CD3+CD95+ can be used as a diagnostic criterion of chronization course of disease. Understanding the pathogenesis of viral myocarditis at cellular level matters for the development and optimization of methods of laboratory diagnostics and forms a basis for determining prognosis of a disease course and choice of treatment tactic.