Sialylated immunoglobulin G can neutralize influenza virus infection through receptor mimicry

Differences in Immunoglobulin G Glycosylation Between Influenza and COVID-19 Patients

The essential role of immunoglobulin G (IgG) in immune system regulation and combatting infectious diseases cannot be fully recognized without an understanding of the changes in its N-glycans attached to the asparagine 297 of the Fc domain that occur under such circumstances. These glycans impact the antibody stability, half-life, secretion, immunogenicity, and effector functions. Therefore, in this study, we analyzed and compared the total IgG glycome-at the level of individual glycan structures and derived glycosylation traits (sialylation, galactosylation, fucosylation, and bisecting N-acetylglucosamine (GlcNAc))-of 64 patients with influenza, 77 patients with coronavirus disease 2019 (COVID-19), and 56 healthy controls. Our study revealed a significant decrease in IgG galactosylation, sialylation, and bisecting GlcNAc (where the latter shows the most significant decrease) in deceased COVID-19 patients, whereas IgG fucosylation was increased. On the other hand, IgG galactosylation remained stable in influenza patients and COVID-19 survivors. IgG glycosylation in influenza patients was more time-dependent: In the first seven days of the disease, sialylation increased and fucosylation and bisecting GlcNAc decreased; in the next 21 days, sialylation decreased and fucosylation increased (while bisecting GlcNAc remained stable). The similarity of IgG glycosylation changes in COVID-19 survivors and influenza patients may be the consequence of an adequate immune response to enveloped viruses, while the observed changes in deceased COVID-19 patients may indicate its deviation.

Administration of intravenous immunoglobulin in the treatment of COVID-19: A review of available evidence

Since December 31, 2019, unknown causes of pneumonia have been reported in Wuhan, China. This special pneumonia associated with a novel coronavirus was named 2019-nCoV by the World Health Organization (WHO) in January 2020. From the beginning of this infectious disease, clinicians and researchers have been endeavoring to discover an effective and suitable treatment for affected patients. To date, there is no definitive and specific treatments for coronavirus disease-19 (COVID-19) infection while drugs introduced are still in the clinical trial phase. Intravenous immune globulin (IVIG) is a biological product prepared from the serum and an optional treatment for patients with antibody deficiencies. In many countries, much attention has been paid to the use of IVIG in the treatment of patients with COVID-19. Due to the therapeutic importance of IVIG in virus infections, in the current study, we reviewed the possible effect of IVIG in viral infections and potential evidence of IVIG therapy in patients with COVID-19 virus.

Intravenous Immunoglobulin Protects Against Severe Pandemic Influenza Infection

Influenza is a highly contagious, acute, febrile respiratory infection that can have fatal consequences particularly in individuals with chronic illnesses. Sporadic reports suggest that intravenous immunoglobulin (IVIg) may be efficacious in the influenza setting. We investigated the potential of human IVIg to ameliorate influenza infection in ferrets exposed to either the pandemic H1N1/09 virus (pH1N1) or highly pathogenic avian influenza (H5N1). IVIg administered at the time of influenza virus exposure led to a significant reduction in lung viral load following pH1N1 challenge. In the lethal H5N1 model, the majority of animals given IVIg survived challenge in a dose dependent manner. Protection was also afforded by purified F(ab′)₂ but not Fc fragments derived from IVIg, supporting a specific antibody-mediated mechanism of protection. We conclude that pre-pandemic IVIg can modulate serious influenza infection-associated mortality and morbidity. IVIg could be useful prophylactically in the event of a pandemic to protect vulnerable population groups and in the critical care setting as a first stage intervention.

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Intravenous immunoglobulin (IVIg), prepared prior to a pandemic, prevents pandemic influenza disease in ferrets.

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IVIg effectively reduced viral levels of pandemic H1N1 influenza and prevented disease due to avian influenza H5N1.

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This work has implications for preventing and treating pandemic influenza infections with IVIg before a vaccine is available.

Influenza pandemics cause large numbers of infections and deaths. There is a lag between the identification of a pandemic and the development of vaccines. Future pandemics may be caused by influenza strains resistant to current anti-influenza drugs. New treatments are needed for future pandemic influenza outbreaks. We show that a readily available product (intravenous immunoglobuling – pooled antibodies from human donors) can prevent viral replication and disease caused by 2 strains of pandemic influenza viruses (“swine-flu” and “bird-flu”) in an appropriate animal model of influenza. This could form the basis of future treatments for severe influenza caused by pandemic strains.