COVID-19 and the differences in physiological background between children and adults and their clinical consequences.

The SARS-CoV-2 pandemic has indeed been one of the most significant problems facing the world in the last decade. It has affected (directly or indirectly) the entire population and all age groups. Children have accounted for 1.7 % to 2 % of the diagnosed cases of COVID-19. COVID-19 in children is usually associated with a mild course of the disease and a better survival rate than in adults. In this review, we investigate the different mechanisms which underlie this observation. Generally, we can say that the innate immune response of children is strong because they have a trained immunity, allowing the early control of infection at the site of entry. Suppressed adaptive immunity and a dysfunctional innate immune response is seen in adult patients with severe infections but not in children. This may relate to immunosenescence in the elderly. Another proposed factor is the different receptors for SARS-CoV-2 and their differences in expression between these age groups. In infants and toddlers, effective immune response to viral particles can be modulated by the pre-existing non-specific effect of live attenuated vaccines on innate immunity and vitamin D prophylaxis. However, all the proposed mechanisms require verification in larger cohorts of patients. Our knowledge about SARS-CoV-2 is still developing.

Inhibitory immune checkpoint molecules and exhaustion of T cells in COVID-19.

COVID-19 (Coronavirus Disease) is an infectious disease caused by the coronavirus SARS-CoV-2 (Severe acute respiratory syndrome Coronavirus 2), which belongs to the genus Betacoronavirus. It was first identified in patients with severe respiratory disease in December 2019 in Wuhan, China. It mainly affects the respiratory system, and in severe cases causes serious lung infection or pneumonia, which can lead to the death of the patient. Clinical studies show that SARS-CoV-2 infection in critical cases causes acute tissue damage due to a pathological immune response. The immune response to a new coronavirus is complex and involves many processes of specific and non-specific immunity. Analysis of available studies has shown various changes, especially in the area of specific cellular immunity, including lymphopenia, decreased T cells (CD3+, CD4+ and CD8+), changes in the T cell compartment associated with symptom progression, deterioration of the condition and development of lung damage. We provide a detailed review of the analyses of immune checkpoint molecules PD-1, TIM-3, LAG-3 CTLA-4, TIGIT, BTLA, CD223, IDO-1 and VISTA on exhausted T cells in patients with asymptomatic to symptomatic stages of COVID-19 infection. Furthermore, this review may help to better understand the pathological T cell immune response and improve the design of therapeutic strategies for patients with SARS-CoV-2 infection.

Canakinumab as monotherapy for treatment of familial Mediterranean fever - first report in Central and Eastern Europe region.

Autoinflammatory disorders (AID) are characterized by spontaneous attacks of acute inflammation with a broad spectrum of clinical symptoms. Ongoing inflammation and reoccurrence of acute flares can lead to the development of amyloidosis. One group of AID is represented by monogenic periodic fever syndromes while familial Mediterranean fever (FMF) is the most common form of AID from this group. Its prevalence in Central and Eastern Europe was reported to be very low. We report a case of FMF patient with a very severe clinical course of FMF and intolerance to colchicine, which is a gold standard for FMF treatment. The clinical effect of the application of anakinra was insufficient and accompanied with side effects and low tolerability. Switching to canakinumab (human monoclonal antibody against IL-1ß) at dose of 150 mg every 4 weeks induced a rapid remission of the disease activity and inflammatory markers. However, due to relapse of acute flares after three weeks from application, the escalation of dose to 300 mg every 4 weeks induced a complete remission of symptoms and significantly improved the quality of life. This is the first report of successful canakinumab administration in FMF patient in Central and Eastern Europe, a region with very low incidence of FMF (Tab. 1, Ref. 16).