Multisystem Inflammatory Syndrome in Children (MIS-C) Associated With COVID-19 Infection in Morocco.

Introduction. This study aims to describe the clinical and paraclinical characteristics of Multisysteminflammatory syndrome in children (MIS-C). Methods. A retrospective study encompassing 52 children diagnosed with MIS-C according to the World Health Organization criteria, over a 3-year period at Abderrahim Harrouchi Hospital in Morocco. Results. The median age was 6 years (IQR: 1-14), with a sex ratio of 1.16 (28 boys and 24 girls). Clinical manifestations were predominantly characterized by fever in all cases (100%), respiratory and gastrointestinal symptoms in 30 cases (58%) and 23 cases (44%) respectively, and shock in 9 cases (17%). We noted a myocarditis in 6 cases (12%). The treatment comprised intravenous human Immunoglobulin combined with methylprednisolone in all patients (100%). Conclusion. The characteristics of our MIS-C patients were similar to those in the literature, but more studies are needed to confirm these results.

Case Report of Two Independent Moroccan Families with Syndromic Epidermodysplasia Verruciformis and STK4 Deficiency.

Epidermodysplasia verruciformis (EV) is a rare genodermatosis caused by ß-human papillomaviruses (HPV) in immunodeficient patients. EV is characterized by flat warts and pityriasis-like lesions and might be isolated or syndromic, associated with some other infectious manifestations. We report here three patients from two independent families, with syndromic EV for both of them. By whole exome sequencing, we found that the patients carry new homozygous variants in STK4, both leading to a premature stop codon. STK4 deficiency causes a combined immunodeficiency characterized by a broad infectious susceptibility to bacteria, viruses, and fungi. Auto-immune manifestations were also reported. Deep immunophenotyping revealed multiple cytopenia in the three affected patients, in particular deep CD4+ T cells deficiency. We report here the fourth and the fifth cases of the syndromic EV due to STK4 deficiency.

Human Genetic and Immunological Determinants of SARS-CoV-2 Infection and Multisystem Inflammatory Syndrome in Children.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces pneumonia and acute respiratory failure in Coronavirus Disease 2019 (COVID-19) patients with inborn errors of immunity to type I interferon (IFN-I). The impact of SARS-CoV-2 infection varies widely, ranging from mild respiratory symptoms to life-threatening illness and organ failure, with a higher incidence in men than in women. Approximately 3 to 5% of critical COVID-19 patients under 60 and a smaller percentage of elderly patients exhibit genetic defects in IFN-I production, including X-chromosome-linked TLR7 and autosomal TLR3 deficiencies. Around 15 to 20% of cases over 70 years old, and a smaller percentage of younger patients, present with preexisting autoantibodies neutralizing type I interferons. Additionally, innate errors affecting the control of the response to type I interferon have been associated with pediatric multisystem inflammatory syndrome (MIS-C). Several studies have described rare errors of immunity, such as XIAP deficiency, CYBB, SOCS1, OAS1/2, and RNASEL, as underlying factors in MIS-C susceptibility. However, further investigations in expanded patient cohorts are needed to validate these findings and pave the way for new genetic approaches to MIS-C. This review aims to present recent evidence from the scientific literature on genetic and immunological abnormalities predisposing individuals to critical SARS-CoV-2 infection through IFN-I. We will also discuss multisystem inflammatory syndrome in children (MIS-C). Understanding the immunological mechanisms and pathogenesis of severe COVID-19 may inform personalized patient care and population protection strategies against future serious viral infections.