Auto-antibodies against type I IFNs in > 10% of critically ill COVID-19 patients: a prospective multicentre study

Type I interferon autoantibody footprints reveal neutralizing mechanisms and allow inhibitory decoy design

Autoantibodies neutralizing type I interferons (IFN-Is; IFNα or IFNω) exacerbate severe viral disease, but specific treatments are unavailable. With footprint profiling, we delineate two dominant IFN-I faces commonly recognized by neutralizing IFN-I autoantibody-containing plasmas from aged individuals with HIV-1 and from individuals with severe COVID-19. These faces overlap with IFN-I regions independently essential for engaging the IFNAR1/IFNAR2 heterodimer, and neutralizing plasmas efficiently block the interaction of IFN-I with both receptor subunits in vitro. In contrast, non-neutralizing autoantibody-containing plasmas limit the interaction of IFN-I with only one receptor subunit and display relatively low IFN-I-binding avidities, thus likely hindering neutralizing function. Iterative engineering of signaling-inert mutant IFN-Is (simIFN-Is) retaining dominant autoantibody targets created potent decoys that prevent IFN-I neutralization by autoantibody-containing plasmas and that restore IFN-I-mediated antiviral activity. Additionally, microparticle-coupled simIFN-Is were effective at depleting IFN-I autoantibodies from plasmas, leaving antiviral antibodies unaffected. Our study reveals mechanisms of action for IFN-I autoantibodies and demonstrates a proof-of-concept strategy to alleviate pathogenic effects.

Adult Long Coronavirus Disease 2019: Definition, Prevalence Pathophysiology, and Clinical Manifestations

Long coronavirus disease 2019 (COVID-19) is a multisystem disorder with variable manifestations and duration. One in 10 people with a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection will develop some manifestation of long COVID-19. Currently, there is no one single etiologic factor for the symptoms and signs of long COVID-19 beyond exposure to the SARS-CoV-2 virus. There are multiple theories about the pathophysiology ranging from viral persistence, reactivation, autoimmunity, and immune depletion. Certain risk factors have been identified including female sex, severe acute/hospitalized COVID-19, previous infections with SARS-CoV-2, and absence of vaccinations.

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.

Autoantibodies in hospitalised patients with COVID-19

Objectives

CD209L and its homologous protein CD209 act as alternative entry receptors for the SARS-CoV-2 virus and are highly expressed in the virally targeted tissues. We tested for the presence and clinical features of autoantibodies targeting these receptors and compared these with autoantibodies known to be associated with COVID-19.

Methods

Using banked samples (n = 118) from Johns Hopkins patients hospitalised with COVID-19, we defined autoantibodies against CD209 and CD209L by enzyme-linked immunosorbent assay (ELISA). Clinical associations of these antibodies were compared with those of patients with anti-interferon (IFN) and anti-angiotensin-converting enzyme-2 (ACE2) autoantibodies.

Results

Amongst patients hospitalised with COVID-19, 19.5% (23/118) had IgM autoantibodies against CD209L and were more likely to have coronary artery disease (44% vs 19%, P = 0.03). Antibodies against CD209 were present in 5.9% (7/118); interestingly, all 7 were male (P = 0.02). In our study, the presence of either antibody was positively associated with disease severity [OR 95% confidence interval (95% CI): 1.80 (0.69-5.03)], but the association did not reach statistical significance. In contrast, 10/118 (8.5%) had IgG autoantibodies against IFNα, and 21 (17.8%) had IgM antibodies against ACE2. These patients had significantly worse prognosis (intubation or death) and prolonged hospital stays. However, when adjusting for patient characteristics on admission, only the presence of anti-ACE2 IgM remained significant [pooled common OR (95% CI), 4.14 (1.37, 12.54)].

Conclusion

We describe IgM autoantibodies against CD209 and CD209L amongst patients hospitalised with COVID-19. These were not associated with disease severity. Conversely, patients with either anti-ACE2 IgM or anti-IFNα IgG antibodies had worse outcomes. Due to the small size of the study cohort, conclusions drawn should be considered cautiously.

Auto-Abs neutralizing type I IFNs in patients with severe Powassan, Usutu, or Ross River virus disease

Arboviral diseases are a growing global health concern. Pre-existing autoantibodies (auto-Abs) neutralizing type I interferons (IFNs) can underlie encephalitis due to West Nile virus (WNV) (∼40% of patients) and tick-borne encephalitis (TBE, due to TBE virus [TBEV]) (∼10%). We report here that these auto-Abs can also underlie severe forms of rarer arboviral infections. Auto-Abs neutralizing high concentrations of IFN-α2, IFN-β, and/or IFN-ω are present in the single case of severe Powassan virus (POWV) encephalitis studied, two of three cases of severe Usutu virus (USUV) infection studied, and the most severe of 24 cases of Ross River virus (RRV) disease studied. These auto-Abs are not found in any of the 137 individuals with silent or mild infections with these three viruses. Thus, auto-Abs neutralizing type I IFNs underlie an increasing list of severe arboviral diseases due to Flaviviridae (WNV, TBEV, POWV, USUV) or Togaviridae (RRV) viruses transmitted to humans by mosquitos (WNV, USUV, RRV) or ticks (TBEV, POWV).

Effect of SARS-CoV2 infection on disease flares in patients with systemic lupus erythematosus: a case-control study

OBJECTIVES

To study the effect of SARS-CoV2 infection on flares of systemic lupus erythematosus (SLE).

METHODS

Patients who fulfilled the ACR/SLICC criteria for SLE and had documented COVID-19 between February and November 2022 were identified retrospectively from our hospital COVID-19 registry. SLE controls who did not have SARS-CoV2 infection were randomly matched for age, sex and the time of infection in a 2:1 ratio with those infected. The primary outcome of interest was clinical flare of SLE within 90 days of COVID-19. The rate of SLE flares (mild/moderate or severe) was compared between SARS-CoV2-infected SLE patients and controls.

RESULTS

Ninety-one SLE patients with COVID-19 (age 48.6 (14.0) years; 95.6% women) and 182 SLE controls (age 48.7 (13.8) years; 95.6% women) were studied. Eleven of 91 (12.1%) SARS-CoV2-infected patients had serious manifestations. One (1.1%) patient died and 7 (7.7%) developed severe complications. Within 90 days of SARS-CoV2 infection, 14 (15.4%) patients developed mild/moderate clinical SLE flares and two (2.2%) patients had severe SLE flares. The incidence of SLE flares in SARS-CoV2-infected patients was significantly higher than in those without the infection (17.6% vs 5.5%; odds ratio 3.67 [95% CI: 1.59, 8.46]; P = 0.001). The changes in anti-dsDNA and complement levels, however, were not significantly different between the two groups. Among SARS-CoV2-infected SLE patients, those with clinical SLE flares had significantly lower C3 values (P = 0.004) before the infection than those without.

CONCLUSION

Clinical flares within 90 days were significantly more common in SLE patients infected with SARS-CoV2 than matched non-infected SLE controls.

Similar Kinetics of Pulmonary SARS-CoV-2 Load in Intensive Care Unit Patients with COVID-19 Pneumonia with or Without Autoantibodies Neutralizing Type I Interferons

PURPOSE

The pathogenesis of life-threatening coronavirus disease 2019 (COVID-19) pneumonia in ICU patients can involve pre-existing auto-antibodies (auto-Abs) neutralizing type I interferons (IFNs). The impact of these auto-Abs on SARS-CoV-2 clearance in the lower respiratory tract (LRT) is unclear.

METHODS

We performed a retrospective study in 99 ICU patients with COVID-19 pneumonia between March and May 2020. LRT SARS-CoV-2 load (intensity and duration) was analyzed according to the presence or not of circulating auto-Abs neutralizing type I IFNs.

RESULTS

Among the 99 included patients, 38 (38%) were positive for auto-Abs neutralizing type I IFNs, with 5 (5%) harboring auto-Abs neutralizing IFN-α2 at any concentration, while 33 (33%) had auto-Abs neutralizing only IFN-ω at the lower concentration. SARS-CoV-2 load in the LRT and duration of viral shedding, were similar in patients with or without auto-Abs neutralizing type I IFNs. Patients with auto-Abs had the same mortality than those without auto-Abs, despite greater occurrence of renal failure and ECMO support, and longer duration of mechanical ventilation and ICU stay.

CONCLUSION

In summary, 5% of patients with critical COVID-19 pneumonia carried auto-Abs neutralizing IFN-α2, while about 1/3 harbored auto-Abs neutralizing low concentrations of IFN-ω. The detection of either type of auto-Abs did not impact LRT viral clearance and mortality, although it was associated with greater morbidity and a longer hospitalization. These findings suggest that similar albeit hitherto unknown mechanisms of disease drive critical COVID-19 pneumonia in patients without auto-Abs against type I IFNs.

A sensitive assay for measuring whole-blood responses to type I IFNs

Human inborn errors of the type I IFN response pathway and auto-Abs neutralizing IFN-α, -β, and/or -ω can underlie severe viral illnesses. We report a simple assay for the detection of both types of condition. We stimulate whole blood from healthy individuals and patients with either inborn errors of type I IFN immunity or auto-Abs against type I IFNs with glycosylated human IFN-α2, -β, or -ω. As controls, we add a monoclonal antibody (mAb) blocking the type I IFN receptors and stimulated blood with IFN-γ (type II IFN). Of the molecules we test, IP-10 (encoded by the interferon-stimulated gene (ISG) CXCL10) is the molecule most strongly induced by type I and type II IFNs in the whole blood of healthy donors in an ELISA-like assay. In patients with inherited IFNAR1, IFNAR2, TYK2, or IRF9 deficiency, IP-10 is induced only by IFN-γ, whereas, in those with auto-Abs neutralizing specific type I IFNs, IP-10 is also induced by the type I IFNs not neutralized by the auto-Abs. The measurement of type I and type II IFN-dependent IP-10 induction therefore constitutes a simple procedure for detecting rare inborn errors of the type I IFN response pathway and more common auto-Abs neutralizing type I IFNs.

Molecular determinants of cross-species transmission in emerging viral infections

SUMMARYSeveral examples of high-impact cross-species transmission of newly emerging or re-emerging bat-borne viruses, such as Sudan virus, Nipah virus, and severe acute respiratory syndrome coronavirus 2, have occurred in the past decades. Recent advancements in next-generation sequencing have strengthened ongoing efforts to catalog the global virome, in particular from the multitude of different bat species. However, functional characterization of these novel viruses and virus sequences is typically limited with regard to assessment of their cross-species potential. Our understanding of the intricate interplay between virus and host underlying successful cross-species transmission has focused on the basic mechanisms of entry and replication, as well as the importance of host innate immune responses. In this review, we discuss the various roles of the respective molecular mechanisms underlying cross-species transmission using different recent bat-borne viruses as examples. To delineate the crucial cellular and molecular steps underlying cross-species transmission, we propose a framework of overall characterization to improve our capacity to characterize viruses as benign, of interest, or of concern.

An easy assay to detect autoantibodies neutralizing cytokines in subjects with critical infections

Autoantibodies against type I interferon (IFN) are associated with a worse outcome in COVID-19. The measurement of cytokine-neutralizing autoantibodies has been limited, hindering understanding of their role in clinical practice. We showed that an easy and reliable assay can be reproduced and validated to measure the neutralizing potency of autoantibodies directed to type I or type II IFN. Identifying of anti-cytokine autoantibodies might reflect on early treatments for subsequent infections, such as with antivirals or virus-neutralizing monoclonal antibodies.

Yin and yang of interferons: lessons from the coronavirus disease 2019 (COVID-19) pandemic

The host immune response against severe acute respiratory syndrome coronavirus 2 includes the induction of a group of natural antiviral cytokines called interferons (IFNs). Although originally recognized for their ability to potently counteract infections, the mechanistic functions of IFNs in patients with varying severities of coronavirus disease 2019 (COVID-19) have highlighted a more complex scenario. Cellular and molecular analyses have revealed that timing, location, and subtypes of IFNs produced during severe acute respiratory syndrome coronavirus 2 infection play a major role in determining disease progression and severity. In this review, we summarize what the COVID-19 pandemic has taught us about the protective and detrimental roles of IFNs during the inflammatory response elicited against a new respiratory virus across different ages and its longitudinal consequences in driving the development of long COVID-19.

Human autoantibodies neutralizing type I IFNs: From 1981 to 2023

Human autoantibodies (auto-Abs) neutralizing type I IFNs were first discovered in a woman with disseminated shingles and were described by Ion Gresser from 1981 to 1984. They have since been found in patients with diverse conditions and are even used as a diagnostic criterion in patients with autoimmune polyendocrinopathy syndrome type 1 (APS-1). However, their apparent lack of association with viral diseases, including shingles, led to wide acceptance of the conclusion that they had no pathological consequences. This perception began to change in 2020, when they were found to underlie about 15% of cases of critical COVID-19 pneumonia. They have since been shown to underlie other severe viral diseases, including 5%, 20%, and 40% of cases of critical influenza pneumonia, critical MERS pneumonia, and West Nile virus encephalitis, respectively. They also seem to be associated with shingles in various settings. These auto-Abs are present in all age groups of the general population, but their frequency increases with age to reach at least 5% in the elderly. We estimate that at least 100 million people worldwide carry auto-Abs neutralizing type I IFNs. Here, we briefly review the history of the study of these auto-Abs, focusing particularly on their known causes and consequences.

No link between type I interferon autoantibody positivity and adverse reactions to COVID-19 vaccines

Type I interferons act as gatekeepers against viral infection, and autoantibodies that neutralize these signaling molecules have been associated with COVID-19 severity and adverse reactions to the live-attenuated yellow fever vaccine. On this background, we sought to examine whether autoantibodies against type I interferons were associated with adverse events following COVID-19 vaccination. Our nationwide analysis suggests that type I interferon autoantibodies were not associated with adverse events after mRNA or viral-vector COVID-19 vaccines.

Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-ω auto-Abs in children

We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-α2 in 10 patients: IFN-α2 only in three, IFN-α2 plus IFN-ω in five, and IFN-α2, IFN-ω plus IFN-β in two; IFN-ω only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-α2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-ω in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-α2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-ω only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-ω and/or IFN-α2.

Chest Computed Tomography Characteristics of Critically Ill COVID-19 Patients with Auto-antibodies Against Type I Interferons

PURPOSE

Patients with auto-antibodies neutralizing type I interferons (anti-IFN auto-Abs) are at risk of severe forms of coronavirus disease 19 (COVID-19). The chest computed tomography (CT) scan characteristics of critically ill COVID-19 patients harboring these auto-Abs have never been reported.

METHODS

Bicentric ancillary study of the ANTICOV study (observational prospective cohort of severe COVID-19 patients admitted to the intensive care unit (ICU) for hypoxemic acute respiratory failure between March 2020 and May 2021) on chest CT scan characteristics (severity score, parenchymal, pleural, vascular patterns). Anti-IFN auto-Abs were detected using a luciferase neutralization reporting assay. Imaging data were collected through independent blinded reading of two thoracic radiologists of chest CT studies performed at ICU admission (± 72 h). The primary outcome measure was the evaluation of severity by the total severity score (TSS) and the CT severity score (CTSS) according to the presence or absence of anti-IFN auto-Abs.

RESULTS

Two hundred thirty-one critically ill COVID-19 patients were included in the study (mean age 59.5 ± 12.7 years; males 74.6%). Day 90 mortality was 29.5% (n = 72/244). There was a trend towards more severe radiological lesions in patients with anti-IFN auto-Abs than in others, not reaching statistical significance (median CTSS 27.5 (21.0-34.8) versus 24.0 (19.0-30.0), p = 0.052; median TSS 14.5 (10.2-17.0) versus 12.0 (9.0-15.0), p = 0.070). The extra-parenchymal evaluation found no difference in the proportion of patients with pleural effusion, mediastinal lymphadenopathy, or thymal abnormalities in the two populations. The prevalence of pulmonary embolism was not significantly different between groups (8.7% versus 5.3%, p = 0.623, n = 175).

CONCLUSION

There was no significant difference in disease severity as evaluated by chest CT in severe COVID-19 patients admitted to the ICU for hypoxemic acute respiratory failure with or without anti-IFN auto-Abs.

High Anti-Interferon-Alpha Autoantibody Levels in Severe/Critical COVID-19 Patients from Peru

Innate immune responses through the production of type I interferon-α (anti-IFN-α) play an essential role in the defense against viruses. The autoantibodies (auto-Abs) anti-IFN-α are implicated in COVID-19 pathogenesis with higher levels among patients with worse prognoses. The study aimed to assess the levels of anti-IFN-α auto-Abs in Peruvian patients with severe/critical hospitalized COVID-19 compared to asymptomatic/mild COVID-19 outpatients and healthy controls. We analyzed 101 serum samples, including 56 (55.5%) severe/critical, 13 (12.3%) asymptomatic/mild COVID-19 patients, and 32 (32.2%) healthy controls, which we tested using a commercial ELISA anti-IFN-α-auto-Abs kit. We observed seropositivity of 48.2% (26/54) to anti-IFN-α auto-Abs among the severe/critical COVID-19 group, but 0% (0/13) and 3.1% (1/32) among the asymptomatic/mild COVID-19 and healthy groups (P = 0.021), respectively. Furthermore, we observed a significant association between the log10 of anti-IFN-α auto-Abs and the COVID-19 status, with the log10 of anti-IFN-α auto-Abs levels being significantly higher among the severe/critical COVID-19 group compared to the healthy controls (β = 1.20; confidence interval [95% CI]: 0.72-1.67; P < 0.001). Such association remains significant either when adjusted by age and gender (adjusted β = 1.16; 95% CI: 0.62-1.70; P < 0.001) and when adjusted by the subjects' age, gender, and obesity (adjusted β = 1.16; 95% CI: 0.62-1.70; P < 0.001). Despite not measuring neutralizing activity, this study highlights the high frequency of these auto-Abs in the Peruvian population with a worse prognosis of COVID-19.

Role of autoantibodies targeting interferon type 1 in COVID-19 severity: A systematic review and meta-analysis

Introduction

Impairment of the type I interferon (IFN-I) signaling pathway is associated with increased severity of COVID-19 disease. Here we have undertaken a systematic review and meta = analysis on the association between the severity of COVID-19 and IFN-1 autoantibodies (AAbs; aIFN-1, aIFN-α, aIFN-ω, and aIFN-β).

Methods

Four databases, including Medline [PubMed], Embase, Web of Science, and Scopus, were systematically searched to find papers on the role of aIFN-1 and its subtype AAbs in the severity of COVID-19 infection. Data on the prevalence of aIFN-1, aIFN-α, aIFN-ω, and aIFN-β were pooled using random- or fixed-effects models. Subgroup analysis was performed based on disease severity. Odds ratios (OR) for COVID-19 disease outcome, including length of hospital stay, ICU admission and death, were calculated in relation to positive or negative plasma IFN-1 AAbs.

Results

A total of 33 studies with 13023 patients were included. The overall prevalence of circulating aIFN-1, aIFN-α, and aIFN-ω AAbs was 17.8 % [13.8, 22.8], 7.2 % [4.7, 10.9], and 4.4 % [2.1, 8.6], respectively, and the overall prevalence of neutralizing aIFN-1, aIFN-α, aIFN-ω, and aIFN-β AAbs was 7.1 % [4.9, 10.1], 7.5 % [5.9, 9.5], 8.0 % [5.7, 11.1] and 1.2 % [0.4, 3.5], respectively. Circulating aIFN-α (OR = 4.537 [2.247, 9.158]), neutralizing aIFN-α (O = 17.482 [8.899, 34.342]), and neutralizing aIFN-ω (OR = 12.529 [7.397, 21.222]) were significantly more frequent in critical/severe patients than in moderate/mild patients (p < 0.001 for all). Anti-IFN-1 was more common in male subjects (OR = 2.248 [1.366, 3.699], p = 0.001) and two COVID-19 outcomes including ICU admission (OR = 2.485 [1.409, 4.385], p = 0.002) and death (OR = 2.593 [1.199, 5.604], p = 0.015) occurred more frequently in patients with positive anti-IFN-1.Conclusion: aIFN-1 and its subtypes AAbs are associated with severe and critical COVID-19 disease and may be a predictive marker for a poor prognosis, particularly in men.

High frequency of type I interferon auto-antibodies in a group of middle-aged HIV-infected patients: A cross-sectional exploratory study

BACKGROUND

Auto-antibodies neutralizing the activity of type I interferons have been recently described in patients infected by SARS-CoV-2. They can be present even before the onset of the infection. Since type I interferons exert a dichotomous role in the pathogenesis of acute versus chronic HIV infection and auto-antibodies are often found in untreated and anti-retroviral treated HIV+ patients, we investigated whether auto-antibodies anti-type I interferons are present at high prevalence in those HIV+ patients with concomitant opportunistic infections (OIs).

METHODS

The analysis of auto-antibodies against two types of type I interferons (IFN-α2 and IFN-ω) was performed using the ELISA test in 60 patients chronically infected by HIV who showed concomitant infections caused by mycobacterium tuberculosis or nontuberculosis mycobacterium or with active cytomegalovirus infections. Results were compared with those of 283 SARS-CoV-2 swab positive patients showing mild to severe pneumonia. A chi-square (χ2 ) test or the Wilcoxon-Mann-Whitney test were used to compare the HIV+ patient categorical or continuous variables, respectively.

RESULTS

A high prevalence of auto-antibodies to type I interferons was found in middle-aged HIV-infected patients with concomitant OIs (11.6% vs. 5.3% in COVID-19 subjects; p < .05). No statistically differences were found for viro/immunological characteristics (CD4 and CD8 cell counts and viral load) between patients with and without type I interferons auto-antibodies.

CONCLUSIONS

This study, which is the first searching auto-antibodies against type I interferons in HIV-infected patients, demonstrated that their prevalence was higher than that expected by the age of these patients. Furthermore, it indicated that these auto-antibodies are nonspecifically increased in critical SARS-CoV-2 infection but can be found also in other infections.

High-Dose Steroids for Nonresolving Acute Respiratory Distress Syndrome in Critically Ill COVID-19 Patients Treated With Dexamethasone: A Multicenter Cohort Study

OBJECTIVES

To determine the impact of high doses of corticosteroids (HDCT) in critically ill COVID-19 patients with nonresolving acute respiratory distress syndrome (ARDS) who had been previously treated with dexamethasone as a standard of care.

DESIGN

Prospective observational cohort study. Eligible patients presented nonresolving ARDS related to severe acute respiratory syndrome coronavirus 2 infection and had received initial treatment with dexamethasone. We compared patients who had received or not HDCT during ICU stay, consisting of greater than or equal to 1 mg/kg of methylprednisolone or equivalent for treatment of nonresolving ARDS. The primary outcome was 90-day mortality. We assessed the impact of HDCT on 90-day mortality using univariable and multivariable Cox regression analysis. Further adjustment for confounding variables was performed using overlap weighting propensity score. The association between HDCT and the risk of ventilator-associated pneumonia was estimated using multivariable cause-specific Cox proportional hazard model adjusting for pre-specified confounders.

SETTING

We included consecutive patients admitted in 11 ICUs of Great Paris area from September 2020 to February 2021.

PATIENTS

Three hundred eighty-three patients were included (59 in the HDCT group, 324 in the no HDCT group).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

At day 90, 30 of 59 patients (51%) in the HDCT group and 116 of 324 patients (35.8%) in the no HDCT group had died. HDCT was significantly associated with 90-day mortality in unadjusted (hazard ratio [HR], 1.60; 95% CI, 1.04-2.47; p = 0.033) and adjusted analysis with overlap weighting (adjusted HR, 1.65; 95% CI, 1.03-2.63; p = 0.036). HDCT was not associated with an increased risk of ventilator-associated pneumonia (adjusted cause-specific HR, 0.42; 95% CI, 0.15-1.16; p = 0.09).

CONCLUSIONS

In critically ill COVID-19 patients with nonresolving ARDS, HDCT result in a higher 90-day mortality.

Does SARS-CoV-2 Induce IgG4 Synthesis to Evade the Immune System?

SARS-CoV-2, the virus that causes the COVID-19 disease, has been shown to cause immune suppression in certain individuals. This can manifest as a reduced ability of the host's immune system to effectively control the infection. Studies have reported that patients with COVID-19 can exhibit a decline in white blood cell counts, including natural killer cells and T cells, which are integral components of the immune system's response to viral pathogens. These cells play critical roles in the immune response to viral infections, and their depletion can make it harder for the body to mount an effective defense against the virus. Additionally, the virus can also directly infect immune cells, further compromising their ability to function. Some individuals with severe COVID-19 pneumonia may develop a "cytokine storm", an overactive immune response that may result in tissue damage and organ malfunction. The underlying mechanisms of immune suppression in SARS-CoV-2 are not entirely understood at this time, and research is being conducted to gain a more comprehensive understanding. Research has shown that severe SARS-CoV-2 infection promotes the synthesis of IgG4 antibodies. In this study, we propose the hypothesis that IgG4 antibodies produced by B cells in response to infection by SARS-CoV-2 generate immunological tolerance, which prevents its elimination and leads to persistent and chronic infection. In summary, we believe that this constitutes another immune evasion mechanism that bears striking similarities to that developed by cancer cells to evade immune surveillance.

Autoantibodies Neutralizing Type III Interferons Are Uncommon in Patients with Severe Coronavirus Disease 2019 Pneumonia

Autoantibodies (AABs) neutralizing type I interferons (IFN) underlie about 15% of cases of critical coronavirus disease 2019 (COVID-19) pneumonia. The impact of autoimmunity toward type III IFNs remains unexplored. We included samples from 1,002 patients with COVID-19 (50% with severe disease) and 1,489 SARS-CoV-2-naive individuals. We studied the prevalence and neutralizing capacity of AABs toward IFNλ and IFNα. Luciferase-based immunoprecipitation method was applied using pooled IFNα (subtypes 1, 2, 8, and 21) or pooled IFNλ1-IFNλ3 as antigens, followed by reporter cell-based neutralization assay. In the SARS-CoV-2-naive cohort, IFNλ AABs were more common (8.5%) than those targeting IFNα2 (2.9%) and were related with older age. In the COVID-19 cohort the presence of autoreactivity to IFNλ did not associate with severe disease [odds ratio (OR) 0.84; 95% confidence interval (CI) 0.40-1.73], unlike to IFNα (OR 4.88; 95% CI 2.40-11.06; P < 0.001). Most IFNλ AAB-positive COVID-19 samples (67%) did not neutralize any of the 3 IFNλ subtypes. Pan-IFNλ neutralization occurred in 5 patients (0.50%), who all suffered from severe COVID-19 pneumonia, and 4 of them neutralized IFNα2 in addition to IFNλ. Overall, AABs to type III IFNs are rarely neutralizing, and do not seem to predispose to severe COVID-19 pneumonia on their own.

Loss of STAT2 may be dangerous in a world filled with viruses

Type I IFNs, a family of cytokines that signal through a single receptor and signaling mechanism, were originally named for their ability to interfere with viral replication. While type II IFN (IFN-γ) largely protects against intracellular bacteria and protozoa, type I IFNs largely protect from viral infections. Inborn errors of immunity in humans have demonstrated this point and its clinical relevance with increasing clarity. In this issue of the JCI, Bucciol, Moens, et al. report the largest series of patients to date with deficiency of STAT2, an important protein for type I IFN signaling. Individuals with STAT2 loss demonstrated a clinical phenotype of viral susceptibility and inflammatory complications, many of which remain poorly understood. These findings further illustrate the very specific and critical role that type I IFNs play in host defense against viruses.

Chest computed tomography characteristics of critically ill COVID-19 patients with auto-antibodies against type I interferons

Purpose

patients with auto-antibodies neutralizing type I interferons (anti-IFN auto-Abs) are at risk of severe forms of coronavirus disease 19 (COVID-19). The chest computed tomography (CT) scan characteristics of critically ill COVID-19 patients harboring these auto-Abs have never been reported.

Methods

Bicentric ancillary study of the ANTICOV study (observational prospective cohort of severe COVID-19 patients admitted to the intensive care unit (ICU) for hypoxemic acute respiratory failure) on chest CT scan characteristics (severity score, parenchymal, pleural, vascular patterns). Anti-IFN auto-Abs were detected using a luciferase neutralization reporting assay. Imaging data were collected through independent blinded reading of two thoracic radiologists of chest CT studies performed at ICU admission (±72h). The primary outcome measure was the evaluation of severity by the total severity score (TSS) and the CT severity score (CTSS) according to the presence or absence of anti-IFN auto-Abs.

Results

231 critically ill COVID-19 patients were included in the study (mean age 59.5±12.7 years; males 74.6%). Day 90 mortality was 29.5% (n=72/244). There was a trend towards more severe radiological lesions in patients with auto-IFN anti-Abs than in others, not reaching statistical significance (median CTSS 27.5 (21.0-34.8] versus 24.0 (19.0-30.0), p=0.052; median TSS 14.5 (10.2-17.0) versus 12.0 (9.0-15.0), p=0.070). The extra-parenchymal evaluation found no difference in the proportion of patients with pleural effusion, mediastinal lymphadenopathy or thymal abnormalities in the two populations. The prevalence of pulmonary embolism was not significantly different between groups (8.7% versus 5.3%, p=0.623, n=175).

Conclusion

There was no significant difference in disease severity as evaluated by chest CT in severe COVID-19 patients admitted to the ICU for hypoxemic acute respiratory failure with or without anti-IFN auto-Abs.

Autoantibodies to Interferons in Infectious Diseases

Anti-cytokine autoantibodies and, in particular, anti-type I interferons are increasingly described in association with immunodeficient, autoimmune, and immune-dysregulated conditions. Their presence in otherwise healthy individuals may result in a phenotype characterized by a predisposition to infections with several agents. For instance, anti-type I interferon autoantibodies are implicated in Coronavirus Disease 19 (COVID-19) pathogenesis and found preferentially in patients with critical disease. However, autoantibodies were also described in the serum of patients with viral, bacterial, and fungal infections not associated with COVID-19. In this review, we provide an overview of anti-cytokine autoantibodies identified to date and their clinical associations; we also discuss whether they can act as enemies or friends, i.e., are capable of acting in a beneficial or harmful way, and if they may be linked to gender or immunosenescence. Understanding the mechanisms underlying the production of autoantibodies could improve the approach to treating some infections, focusing not only on pathogens, but also on the possibility of a low degree of autoimmunity in patients.

De novo lupus nephritis after SARS-CoV-2 infection

The relationship between viral infection and onset of autoimmune diseases such as systemic lupus erythematosus remains uncertain. During the COVID-19 pandemic, organ-specific and multisystemic autoimmune phenomena temporally related to the viral infection have been described. Immune dysregulation triggered by the SARS-CoV-2 virus leading to hyperactivation of both the innate and adaptive immune systems contributes to the excessive production of pro-inflammatory cytokines, autoantibodies, and subsequent autoimmune manifestations. We report two patients without known autoimmune diseases who developed lupus nephritis shortly after a documented mild SARS-CoV-2 infection. Together with other similar cases in the literature, the observation supports a viral trigger of the development of systemic lupus erythematosus in susceptible individuals.

A natural goldmine of binding proteins and soluble receptors simplified their translation to blockbuster drugs, all in one decade

Human urinary proteins are a goldmine of natural proteins a feature that simplifies their translation to biologics. Combining this goldmine together with the ligand-affinity-chromatography (LAC) purification method, proved a winning formula in their isolation. LAC specificity, efficiency, simplicity and inherent indispensability in the search for predictable and unpredictable proteins, is superior to other separation techniques. Unlimited amounts of recombinant cytokines and monoclonal antibodies (mAb) accelerated the "triumph". My approach concluded 35 years of worldwide pursuit for Type I IFN receptor (IFNAR2) and advanced the understanding of the signal transduction of this Type of IFN. TNF, IFNγ and IL-6 as baits enabled the isolation of their corresponding soluble receptors and N-terminal amino acid sequence of the isolated proteins facilitated the cloning of their cell surface counterparts. IL-18, IL-32, and heparanase as the baits yielded the corresponding unpredictable proteins: the antidote IL-18 Binding Protein (IL-18BP), the enzyme Proteinase 3 (PR3) and the hormone Resistin. IFNβ proved beneficial in Multiple Sclerosis and is a blockbuster drug, Rebif®. TNF mAbs translated into Remicade® to treat Crohn's disease. Enbrel® based on TBPII is for Rheumatoid Arthritis. Both are blockbusters. Tadekinig alfa™, a recombinant IL-18BP, is in phase III clinical study for inflammatory and autoimmune diseases. Seven years of continuous compassionate use of Tadekinig alfa™ in children born with mutations (NLRC4, XIAP) proved life-saving and is an example of tailored made medicine. IL-18 is a checkpoint biomarker in cancer and IL-18BP is planned recently to target cytokine storms resulting from CAR-T treatment and in COVID 19.