Toxocariasis is a parasitic disease (tissue helminthiasis) caused by the migration of Toxocara canis larvae in various organs and tissues, characterized by a long recurrent course and multiple allergic organ lesions. According to the literature, the morbidity from toxocariasis has increased by 300% over the past 50 years. The reasons for the widespread human larval toxocariasis are the progressive increase of dogs' number, both in cities and in rural areas; high extensive and intensive indices in toxocariasis in dogs; excessive pollution of the environment, especially the soil, by propagating stages of the pathogen, which contributes to the infection of people, especially children. The purpose of the study was to determine the state of humoral immunity and optimize the principles of diagnosis and prevention of toxocariasis in children based on the study of clinical, immunological and epidemiological features of the invasion, assessment of the severity of the general condition and natural resistance of the organism, as well as to justify immunomodulatory therapy. Material and methods. We conducted the study of cellular and humoral immunity in 40 children with toxocariasis at the age from 1 to 14 years and in 25 healthy children of the appropriate age. Children with toxocariasis suffer from an imbalance of immunological parameters, quantitative and functional changes of lymphocytes, violation of normal ratios of cellular subpopulations, dysimmunoglobulinemia, which is an evidence of varying degrees and direction of immunological reactivity and reduced body resistance to toxocariasis. Results and discussion. The imbalance and incoordination of the immunological parameters interaction can lead to various immune defects bringing to a variety of clinical and immunological manifestations of toxocariasis. It was established that the basis of the immune response in toxocariasis was the increased production of IgE-antibodies stimulating the participation of eosinophils in the formation of antiparasitic immunity. The content of IgE-antibodies and specific Ig E-antibodies in the blood of children with toxocariasis was significantly increased (p<0.05). Analysis of the frequency of immune parameters changes revealed that the vast majority of patients experience changes in immunological status. The peculiarities of immunological status changes are due to the fact that some immunity indices often exceed control, others are often reduced, and some mostly remained within normal limits. To comprehensive assessment of the humoral immunity state in patients with toxocariasis, taking into account the frequency of allergic reactions, a study of the concentration of circulating immune complexes, which is a combination of IgM and IgG antibodies with antigen and complement. The concentration of circulating immune complexes formation is a physiological reaction of the organism; normally they are destroyed by phagocytes. Immune complexes become pathogenic in various defects of phagocytosis. In the examined patients with toxocariasis, the concentration of circulating immune complexes values was within normal fluctuations. However, during the analysis of each index, we found out that only in half of the patients the content of concentration of circulating immune complexes in the blood was within normal limits, and in 37.8% of cases exceeded the norm. The study of immunological parameters in the dynamics (specific and general IgE-antibodies, humoral immunity coefficient, eosinophilia, concentration of circulating immune complexes) can be used as additional criteria not so much in the diagnosis, but to assess the severity of the general condition and natural resistance to the body and substantiation of immunomodulatory therapy. Conclusion. There is a progression of the imbalance of humoral immunity indices, quantitative and functional changes in lymphocytes in children with toxocariasis. They also have violations of normal ratios of cellular subpopulations, dysimmunoglobulinemia, which is a direct evidence of varying degrees of immunological reactivity and decreased body resistance.
Keywords: toxocariasis, humoral immunity, immunoglobulins, antibodies, children
Full text: PDF (Ukr) 287K