Background: There is uncertainty about the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in individuals with rare inborn errors of immunity (IEI), a population at risk of developing severe coronavirus disease 2019. This is relevant not only for these patients but also for the general population, because studies of IEIs can unveil key requirements for host defense. Objective: We sought to describe the presentation, manifestations, and outcome of SARS-CoV-2 infection in IEI to inform physicians and enhance understanding of host defense against SARS-CoV-2. Methods: An invitation to participate in a retrospective study was distributed globally to scientific, medical, and patient societies involved in the care and advocacy for patients with IEI. Results: We gathered information on 94 patients with IEI with SARS-CoV-2 infection. Their median age was 25 to 34 years. Fifty-three patients (56%) suffered from primary antibody deficiency, 9 (9.6%) had immune dysregulation syndrome, 6 (6.4%) a phagocyte defect, 7 (7.4%) an autoinflammatory disorder, 14 (15%) a combined immunodeficiency, 3 (3%) an innate immune defect, and 2 (2%) bone marrow failure. Ten were asymptomatic, 25 were treated as outpatients, 28 required admission without intensive care or ventilation, 13 required noninvasive ventilation or oxygen administration, 18 were admitted to intensive care units, 12 required invasive ventilation, and 3 required extracorporeal membrane oxygenation. Nine patients (7 adults and 2 children) died.

As shown by analysis of mice and humans bearing DOCK8-inactivating mutations, DOCK8 plays a cell-autonomous role in survival of naive CD8 T cells, LFA-1 polarization toward the immune synapse, and CD8 T cell memory and recall responses following viral infection.

Macrophage activation syndrome (MAS), also known as secondary hemophagocytic lymphohistiocytosis, is a rare and potentially fatal complication of Kawasaki disease (KD). We report 2 cases, performed a literature search, and analyze the characteristics of MAS associated with KD. A total of 69 patients were evaluated, 34 reported the date of the diagnosis of MAS and KD, 6% had a diagnosis of MAS before KD, 21% had a simultaneous presentation, and 73% had the diagnosis of MAS after KD. Different treatment approaches were observed with corticosteroids administered in 87%, cyclosporine in 49%, etoposide (VP-16) in 39%, and monoclonal anti-TNF in 6% of cases. Coronary abnormalities were especially high in this group of patients (46%) and 9 patients died (13%). The persistence of fever with splenomegaly, hyperferritinemia, thrombocytopenia, and elevated aspartate aminotransferase (AST) should prompt the consideration of MAS complicating KD.

The presence of coronary aneurysms was significantly and positively correlated with male gender, IVIG resistance, inotrope treatment, cardiac failure, abdominal pain and neurological symptoms. IVIG-resistant patients had higher neutrophil : lymphocyte ratio. Abdominal symptoms, hypoalbuminemia and elevated C-reactive protein were present in almost all of the patients. Multisystem involvement with atypical presentation in KDSS is frequent. An important differential diagnosis is TSS. Mechanical ventilation, gastrointestinal and neurological symptoms were associated with IVIG resistance and the presence of coronary aneurysms. The first line of treatment includes IVIG and pulse corticosteroids; in severe cases, infliximab, anakinra, cyclosporine or plasmapheresis are alternative treatment options.

Patients with KD presenting in shock seem to have an increase in gastrointestinal manifestations, incomplete presentation, IVIG resistance, and worse cardiac outcomes. Larger, prospective, multicentre studies should be carried out to corroborate these findings.

Highlights1. What is already known about this topic? SARS-CoV-2 causes asymptomatic or mild infection in about 80% of humans, while an excessive immune response has killed millions. Differential susceptibility and risk factors became a concern early in the pandemic. Several monogenic defects that involve innate viral sensors or affect interferon response pathways, as well as autoantibodies against type 1 interferons, have been identified in 14% of patients with life-threatening COVID-19. The impact of the novel betacoronavirus infection in patients with known inborn errors of immunity is less clear. Case series and reports from different countries have suggested a minor impact or even a potential protective effect of the IEI for some patients.2. What does this article add to our knowledge? We describe findings and outcomes of COVID-19 in 31 pediatric and adult patients with known IEI from Mexico, 84% of whom survived. Pediatric patients had a higher hospitalization rate. Inpatient mortality was 40%, and ICU mortality was 63%. Six patients died of secondary bacterial infection or uncontrolled systemic inflammation, but not from overwhelming viral infection. One patient with an autoinflammatory disorder under treatment with anakinra had a catastrophic clinical course. Eighty percent of patients received IVIG as part of their treatment for acute SARS-CoV-2 infection.3. How does this study impact current management guidelines? We recommend continued and/or high-dose IVIG in patients with known IEI seeking care for COVID-19. Patients with autoinflammatory disorders, especially those with inflammasome dysregulation, should probably take extreme measures to prevent exposure, while doctors taking care of SARS-CoV-2 infected patients with immune deficiencies must do everything they can to prevent secondary bacterial infections. The high survival of patients with COVID-19 in the context of inborn errors of immunity worldwide (over 80%) might be the result of patientphysician awareness and special care.

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X-linked recessive ectodermal dysplasia with immunodeficiency is a rare primary immunodeficiency caused by hypomorphic mutations of the gene encoding the nuclear factor κB essential modulator (NEMO) protein. This condition displays enormous allelic, immunological, and clinical heterogeneity, and therapeutic decisions are difficult because NEMO operates in both hematopoietic and nonhematopoietic cells. Hematopoietic stem cell transplantation (HSCT) is potentially life-saving, but the small number of case reports available suggests it has been reserved for only the most severe cases. Here, we report the health status before HSCT, transplantation outcome, and clinical follow-up for a series of 29 patients from unrelated kindreds from 11 countries. Between them, these patients carry 23 different hypomorphic mutations. HSCT was performed from HLA-identical related donors (n = 7), HLA-matched unrelated donors (n = 12), HLA-mismatched unrelated donors (n = 8), and HLA-haploidentical related donors (n = 2). Engraftment was documented in 24 patients, and graft-versus-host disease in 13 patients. Up to 7 patients died 0.2 to 12 months after HSCT. The global survival rate after HSCT among NEMO-deficient children was 74% at a median follow-up after HSCT of 57 months (range, 4-108 months). Preexisting mycobacterial infection and colitis were associated with poor HSCT outcome. The underlying mutation does not appear to have any influence, as patients with the same mutation had different outcomes. Transplantation did not appear to cure colitis, possibly as a result of cell-intrinsic disorders of the epithelial barrier. Overall, HSCT can cure most clinical features of patients with a variety of mutations.