Background: COVID-19, a disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), commonly presents as fever, cough, dyspnea, and myalgia or fatigue. Although the majority of patients with COVID-19 have mild symptoms, some are more prone to serious outcomes, including pneumonia, acute respiratory distress syndrome (ARDS), and even death. Hemophagocytic lymphohistiocytosis (HLH) is a severe, life-threatening inflammatory syndrome associated with intense cytokine release (also known as a “cytokine storm”). Similar to COVID-19, HLH is characterized by aggressive course leading to multi-organ failure. Main text: The purpose of this review article is to draw attention to the possibility of the complication of HLH in patients with the severe course of COVID-19. Indeed, some of the clinical characteristics observed in the more severe cases of COVID-19 are reminiscent of secondary HLH (which can be triggered by infections, malignancies, rheumatological diseases, or autoimmune/immunodeficiency conditions). The pathogenesis of SARS-CoV-2 infection also suggests that HLH or a similar hyperinflammatory syndrome is the cause of the severe course of the infection. Conclusion: The pathogenesis and clinical symptoms of severe COVID-19 indicate that an increased inflammatory response corresponding to HLH is occurring. Therefore, patients with severe COVID-19 should be screened for hyperinflammation using standard laboratory tests to identify those for whom immunosuppressive therapy may improve outcomes.

Efficacy and safety of tocilizumab (TCZ), an interleukin-6 receptor inhibitor, were demonstrated in juvenile idiopathic arthritis (JIA) with polyarticular course (pJIA) in the CHERISH trial. This observational, III phase study evaluated long-term treatment of TCZ in pJIA patients was conducted by members of the Pediatric Rheumatology International Trials Organization (PRINTO) from Poland and Russia. Forty-one patients, who had completed the CHERISH core study (104 weeks), were extensionally treated with TCZ (8 mg/kg, intravenous infusion every 4 weeks). Total treatment time was from 131 to 193 weeks. The long-term safety (the primary endpoint) and efficacy were evaluated. All patients achieved ACR70 response in the core study and continued to achieve at least ACR50 response up to week 24 of this study. The safety population comprised 46.41 patient-years (PY). Rates per 100 PY of adverse (AEs) and serious events (SAEs) were 181.0 and 6.46, respectively. Pharyngitis and respiratory tract infections were the most common AEs. Except one AE (severe neutropenia), all others were classified as mild (24.4%) or moderate (29.3%). The incidence of SAEs was low (7.3%). No new safety findings were observed. The safety profile of over 2.5-year treatment with TCZ is consistent with the pre-marketing CHERISH clinical trial. Presented data and continued efficacy response support the use of TCZ in pJIA. EUDRACT No: 2011-001607-12. https://clinicaltrials.gov/ct2/show/study/NCT01575769?term=ML27783

Biologicals are very effective for inhibiting disease progression in active juvenile idiopathic arthritis (JIA). To date, there have been no recommendations on how and when to stop therapy with TNF inhibitors. Our objective was to analyze characteristics and the disease course of JIA patients who discontinued etanercept due to achievement of inactive disease. Data of 39 patients with JIA from two clinical pediatric rheumatology centers in Bydgoszcz and Lublin (Poland) were analyzed retrospectively. All patients discontinued etanercept due to a remission on treatment. Etanercept was started after a mean 33.7 ± 36 (range 3–137) months of disease. The mean duration of therapy with etanercept was 34.7 ± 16.7 (range 6–72) months, with a mean duration of remission on medication 21.3 ± 9.6 (range 4–42) months before withdrawal of etanercept. The mean duration of remission after etanercept discontinuation was 14.2 ± 12.1 (range of 1–60) months. Only 12/39 (30.8 %) patients did not develop a disease exacerbation until the end of the study. Early flares, that is less than 6 months after termination of etanercept, were observed in 15/39 (38.5 %) patients. Twelve (30.8 %) patients restarted etanercept after exacerbation—all patients responded satisfactorily. Our data show that etanercept discontinuation in a substantial proportion of JIA patients results in early disease exacerbation. In many cases, reintroduction of etanercept is needed. Patients, in whom etanercept was restarted, responded satisfactorily.