SARS-CoV-2 infection in patients with inborn errors of immunity due to DNA repair defects

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 3-5% 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 15-20% 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.

Severity of SARS-CoV-2 infection in children with inborn errors of immunity (primary immunodeficiencies): a systematic review

BACKGROUND

Inborn errors of immunity (IEIs) are considered significant challenges for children with IEIs, their families, and their medical providers. Infections are the most common complication of IEIs and children can acquire coronavirus disease 2019 (COVID-19) even when protective measures are taken.

OBJECTIVES

To estimate the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children with IEIs and analyse the demographic parameters, clinical characteristics and treatment outcomes in children with IEIs with COVID-19 illness.

METHODS

For this systematic review, we searched ProQuest, Medline, Embase, PubMed, CINAHL, Wiley online library, Scopus and Nature through the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guideline for studies on the development of COVID-19 in children with IEIs, published from December 1, 2019 to February 28, 2023, with English language restriction.

RESULTS

Of the 1095 papers that were identified, 116 articles were included in the systematic review (73 case report, 38 cohort 4 case-series and 1 case-control studies). Studies involving 710 children with IEIs with confirmed COVID-19 were analyzed. Among all 710 IEIs pediatric cases who acquired SARS-CoV-2, some children were documented to be admitted to the intensive care unit (ICU) (n = 119, 16.8%), intubated and placed on mechanical ventilation (n = 87, 12.2%), suffered acute respiratory distress syndrome (n = 98, 13.8%) or died (n = 60, 8.4%). Overall, COVID-19 in children with different IEIs patents resulted in no or low severity of disease in more than 76% of all included cases (COVID-19 severity: asymptomatic = 105, mild = 351, or moderate = 88). The majority of children with IEIs received treatment for COVID-19 (n = 579, 81.5%). Multisystem inflammatory syndrome in children (MIS-C) due to COVID-19 in children with IEIs occurred in 103 (14.5%). Fatality in children with IEIs with COVID-19 was reported in any of the included IEIs categories for cellular and humoral immunodeficiencies (n = 19, 18.6%), immune dysregulatory diseases (n = 17, 17.9%), innate immunodeficiencies (n = 5, 10%), bone marrow failure (n = 1, 14.3%), complement deficiencies (n = 1, 9.1%), combined immunodeficiencies with associated or syndromic features (n = 7, 5.5%), phagocytic diseases (n = 3, 5.5%), autoinflammatory diseases (n = 2, 3%) and predominantly antibody deficiencies (n = 5, 2.5%). Mortality was COVID-19-related in a considerable number of children with IEIs (29/60, 48.3%). The highest ICU admission and fatality rates were observed in cases belonging to cellular and humoral immunodeficiencies (26.5% and 18.6%) and immune dysregulatory diseases (35.8% and 17.9%) groups, especially in children infected with SARS-CoV-2 who suffered severe combined immunodeficiency (28.6% and 23.8%), combined immunodeficiency (25% and 15%), familial hemophagocytic lymphohistiocytosis (40% and 20%), X-linked lymphoproliferative diseases-1 (75% and 75%) and X-linked lymphoproliferative diseases-2 (50% and 50%) compared to the other IEIs cases.

CONCLUSION

Children with IEIs infected with SARS-CoV-2 may experience higher rates of ICU admission and mortality in comparison with the immunocompetent pediatric populations. Underlying immune defects does seem to be independent risk factors for severe SARS-CoV-2 infection in children with IEIs, a number of children with SCID and CID were reported to have prolonged infections-though the number of patients is small-but especially immune dysregulation diseases (XLP1 and XLP2) and innate immunodeficiencies impairing type I interferon signalling (IFNAR1, IFNAR2 and TBK1).

Genetic and immunologic evaluation of children with inborn errors of immunity and severe or critical COVID-19

BACKGROUND

Most severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals are asymptomatic or only exhibit mild disease. In about 10% of cases, the infection leads to hypoxemic pneumonia, although it is much more rare in children.

OBJECTIVE

We evaluated 31 young patients aged 0.5 to 19 years who had preexisting inborn errors of immunity (IEI) but lacked a molecular diagnosis and were later diagnosed with coronavirus disease 2019 (COVID-19) complications.

METHODS

Genetic evaluation by whole-exome sequencing was performed in all patients. SARS-CoV-2-specific antibodies, autoantibodies against type I IFN (IFN-I), and inflammatory factors in plasma were measured. We also reviewed COVID-19 disease severity/outcome in reported IEI patients.

RESULTS

A potential genetic cause of the IEI was identified in 28 patients (90.3%), including mutations that may affect IFN signaling, T- and B-cell function, the inflammasome, and the complement system. From tested patients 65.5% had detectable virus-specific antibodies, and 6.8% had autoantibodies neutralizing IFN-I. Five patients (16.1%) fulfilled the diagnostic criteria of multisystem inflammatory syndrome in children. Eleven patients (35.4%) died of COVID-19 complications. All together, at least 381 IEI children with COVID-19 have been reported in the literature to date. Although many patients with asymptomatic or mild disease may not have been reported, severe presentation of COVID-19 was observed in 23.6% of the published cases, and the mortality rate was 8.7%.

CONCLUSIONS

Young patients with preexisting IEI may have higher mortality than children without IEI when infected with SARS-CoV-2. Elucidating the genetic basis of IEI patients with severe/critical COVID-19 may help to develop better strategies for prevention and treatment of severe COVID-19 disease and complications in pediatric patients.