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The development of pollinosis in children and adolescents is determined by the influence of genetic and environmental factors. The pathogenetic basis of pollinosis in children and adolescents is the differentiation of Th0 to Th2, activation of Th2cells and increasing of the production of IL-4, IL-5, IL-13, sIgE, activation of mast cells, basophils, eosinophils, with following development of IgE-mediated allergic reaction after exposure to pollen allergens and the manifestation of clinical symptoms of pollinosis (allergic rhinitis, allergic conjunctivitis, bronchial asthma). Children and adolescents with pollinosis often develop cross-allergic reactions to plant-based foods. Pathogenetic pharmacotherapy (antihistamines of the second generation, topical corticosteroids, antileukotrienes, decongestants) allows to achieve control over the symptoms of pollinosis. Subcutaneous and sublingual ASIT are high effective, they reduce the severity of symptoms of pollinosis, decrease the risk of developing bronchial asthma and severe clinical forms of pollinosis. The sublingual ASIT is more safe than subcutaneous ASIT.

Current review presents a brief overview of the immune system dysregulation during acute COVID-19 and illustrates the main alterations in peripheral blood CD4+ T-cell (Th) subsets as well as related target cells. Effects of dendritic cell dysfunction induced by SARS-CoV-2 exhibited decreased expression of cell-surface HLA-DR, CCR7 as well as co-stimulatory molecules CD80 and CD86, suggesting reduced antigen presentation, migratory and activation capacities of peripheral blood dendritic cells. SARS-CoV-2-specific Th cells could be detected as early as days 24 post-symptom onset, whereas the prolonged lack of SARS-CoV-2-specific Th cells was associated with severe and/or poor COVID-19 outcome. Firstly, in acute COVID-19 the frequency of Th1 cell was comparable with control levels, but several studies have reported about upregulated inhibitory immune checkpoint receptors and exhaustion-associated molecules (TIM3, PD-1, BTLA, TIGIT etc.) on circulating CD8+ T-cells and NK-cells, whereas the macrophage count was increased in bronchoalveolar lavage (BAL) samples. Next, type 2 immune responses are mediated mainly by Th2 cells, and several studies have revealed a skewing towards dominance of Th2 cell subset in peripheral blood samples from patients with acute COVID-19. Furthermore, the decrease of circulating main Th2 target cells basophiles and eosinophils were associated with severe COVID-19, whereas the lung tissue was enriched with mast cells and relevant mediators released during degranulation. Moreover, the frequency of peripheral blood Th17 cells was closely linked to COVID-19 severity, so that low level of Th17 cells was observed in patients with severe COVID-19, but in BAL the relative number of Th17 cells as well as the concentrations of relevant effector cytokines were dramatically increased. It was shown that severe COVID-19 patients vs. healthy control had higher relative numbers of neutrophils if compared, and the majority of patients with COVID-19 had increased frequency and absolute number of immature neutrophils with altered ROS production. Finally, the frequency of Tfh cells was decreased during acute COVID-19 infection. Elevated count of activated Tfh were found as well as the alterations in Tfh cell subsets characterized by decreased regulatory Tfh1 cell and increased pro-inflammatory Tfh2 as well as Tfh17 cell subsets were revealed. Descriptions of peripheral blood B cells during an acute SARS-CoV-2 infection werev reported as relative B cell lymphopenia with decreased frequency of nave and memory B cell subsets, as well as increased level of CD27hiCD38hiCD24 plasma cell precursors and atypical CD21low B cells. Thus, the emerging evidence suggests that functional alterations occur in all Th cell subsets being linked with loss-of-functions of main Th cell subsets target cells. Furthermore, recovered individuals could suffer from long-term immune dysregulation and other persistent symptoms lasting for many months even after SARS-CoV-2 elimination, a condition referred to as post-acute COVID-19 syndrome.

La 49 de pacienți cu tuberculoză pulmonară asociată cu toxocaroză, care au urmat tratament standard antituberculos, antiparazitar și imunocorectiv, a fost studiată dinamica indicilor răspunsului imun Th1 și Th2 și prezența corelației IL-5 cu eozinofilia și nivelurile ridicate de IgE. S-a stabilit că la pacienții cu tuberculoză pulmonară asociată cu toxocaroză se determină răspunsul imun de tip Th1 și Th2 cu deficit pronunțat de CD3 limfocite. S-a apreciat o corelație semnificativă între eozinofile și IL-5 (r = 0,77), eozinofile și IgE (r = 0,64) precum și între IgE și IL-5 (r = 0,53) ceea ce confirmă interrelația și interacțiunea puternică a parametrilor studiați în evoluția clinică a tuberculozei pulmonare asociată cu invazia toxocarotică. O singură cură de tratament antiparazitar nu este suficientă pentru a normaliza disfuncționalitățile descoperite.

Abstract. Results of cytokine network studies system in children with rotavirus infection are presented. Concentrations of cytokines were determined at both local and systemic levels. Analysis of cytokine levels was performed at initial terms (day 1 to 3), and in the course of disease (day 7 to 10). It was revealed that mild and mid-severe cases of rotavirus infection in the children are characterized by early increase in proinflammatory cytokines with restricted overshoot of proinflammatory cytokines at early recovery period. Meanwhile, the patients with severe forms of viral gastroenteritis exhibited high levels of proinflammatory cytokines. However, this balance was shifted towards anti-inflammatory cytokines during early reconvalescence.

Abstract. Over last years, huge efforts are made in order to improve analytic techniques for T lymphocyte subpopulations. Appropriate studies on T-helper cells are also subject to extensive research. These cellular compartments are substantially divided into various sub-classes. Such subpopulations, e.g., Th1, Th2, T-reg, Th17 and activated Т-helpers, were classified and characterized to sufficient degree. Recently, a lot of distinct data about specific receptors and functional properties of various Т-helper subpopulations was obtained. Applications of these results in laboratory research, without any doubt, will improve diagnostic quality when assessing functional alterations of immune system, as well as adequate therapy planning. (Med. Immunol., 2011, vol. 13, N 1, pp 7-16)