SARS-CoV-2 Vaccine Responses in Individuals with Antibody Deficiency: Findings From The COV-AD Study

Background Vaccination prevents severe morbidity and mortality from COVID-19 in the general population. The immunogenicity and efficacy of SARS-CoV-2 vaccines in patients with antibody deficiency is poorly understood. Objectives COVID in patients with antibody deficiency (COV-AD) is a multi-site United Kingdom study that aims to determine the immune response to SARS-CoV-2 infection and vaccination in patients with primary or secondary antibody deficiency, a population that suffers from severe and recurrent infection and does not respond well to vaccination. Methods Individuals on immunoglobulin replacement therapy or with an IgG less than 4g/L receiving antibiotic prophylaxis were recruited from April 2021. Serological and cellular responses were determined using ELISA, live-virus neutralisation and interferon gamma release assays. SARS-CoV-2 infection and clearance were determined by PCR from serial nasopharyngeal swabs. Results 5.6% (n=320) of the cohort reported prior SARS-CoV-2 infection, but only 0.3% remained PCR positive on study entry. Seropositivity, following two doses of SARS-CoV-2 vaccination, was 54.8% (n=168) compared with 100% of healthy controls (n=205). The magnitude of the antibody response and its neutralising capacity were both significantly reduced compared to controls. Participants vaccinated with the Pfizer/BioNTech vaccine were more likely to be seropositive (65.7% vs 48.0%, p=0.03) and have higher antibody levels compared with the AstraZeneca vaccine (IgGAM ratio 3.73 vs 2.39, p=0.0003). T cell responses post vaccination were demonstrable in 46.2% of participants, were associated with better antibody responses but there was no difference between the two vaccines. Eleven vaccine-breakthrough infections have occurred to date, 10 of them in recipients of the AstraZeneca vaccine. Conclusion SARS-CoV-2 vaccines demonstrate reduced immunogenicity in patients with antibody deficiency with evidence of vaccine breakthrough infection.

The pediatric common variable immunodeficiency — from genetics to therapy: a review

Common variable immunodeficiency (CVID) is the most prevalent antibody deficiency, characterized by remarkable genetic, immunological, and clinical heterogeneity. The diagnosis of pediatric CVID is challenging due to the immaturity of the immune response and sustained actively developing antibody affinity to antigens and immunological memory that may overlap with the inborn error of immunity. Significant progress has been recently done in the field of immunogenetics, yet a paucity of experimental and clinical studies on different systemic manifestations and immunological features of CVID in children may contribute to a delayed diagnosis and therapy. In this review, we aimed at defining the variable epidemiological, etiological, and clinical aspects of pediatric CVID with special emphasis on predominating infectious and non-infectious phenotypes in affected children.Conclusion: While pediatric CVID is a multifaceted and notorious disease, increasing the pediatricians’ awareness of this disease entity and preventing the diagnostic and therapeutic delay are needed, thereby improving the prognosis and survival of pediatric CVID patients. What is Known:• CVID is an umbrella diagnosis characterized by complex pathophysiology with an antibody deficiency as a common denominator.• It is a multifaceted disease characterized by marked genetic, immunological, and clinical heterogeneity.. What is New:• The diagnosis of pediatric CVID is challenging due to the immaturity of innate and adaptive immune response.• Increasing the pediatricians’ awareness of CVID for the early disease recognition, timely therapeutic intervention, and improving the prognosis is needed.

Case Report: Meningoencephalitis With Thrombotic Occlusive Vasculopathy in a Young EBV-Naïve Boy Is Associated With a Novel SH2D1A Mutation

X-linked lymphoproliferative disease (XLP1) is a combined immunodeficiency characterized by severe immune dysregulation caused by mutations in the SH2D1A/SAP gene. Loss or dysfunction of SH2D1A is associated with the inability in clearing Epstein-Barr-Virus (EBV) infections. Clinical manifestation is diverse and ranges from life-threatening hemophagocytic lymphohistiocytosis (HLH) and fulminant infectious mononucleosis (FIM) to lymphoma and antibody deficiency. Rare manifestations include aplastic anemia, chronic gastritis and vasculitis. Herein, we describe the case of a previously healthy eight-year old boy diagnosed with XLP1 presenting with acute non-EBV acute meningoencephalitis with thrombotic occlusive vasculopathy. The patient developed multiple cerebral aneurysms leading to repeated intracerebral hemorrhage and severe cerebral damage. Immunological examination was initiated after development of a susceptibility to infections with recurrent bronchitis and one episode of severe pneumonia and showed antibody deficiency with pronounced IgG1-3-4 subclass deficiency. We could identify a novel hemizygous SH2D1A point mutation affecting the start codon. Basal levels of SAP protein seemed to be detectable in CD8+ and CD4+ T- and CD56+ NK-cells of the patient what indicated an incomplete absence of SAP. In conclusion, we could demonstrate a novel SH2D1A mutation leading to deficient SAP protein expression and a rare clinical phenotype of non-EBV associated acute meningoencephalitis with thrombotic occlusive vasculopathy.

Case Series: Convalescent Plasma Therapy for Patients with COVID-19 and Primary Antibody Deficiency

Patients with primary antibody deficiency are at risk for severe and in many cases for prolonged COVID-19. Convalescent plasma treatment of immunocompromised individuals could be an option especially in countries with limited access to monoclonal antibody therapies. While studies in immunocompetent COVID19 patients have demonstrated only a limited benefit, evidence for the safety, timing, and effectiveness of this treatment in antibody-deficient patients is lacking. Here, we describe 16 cases with primary antibody deficiency treated with convalescent plasma in four medical centers. In our cohort, treatment was associated with a reduction in viral load and improvement of clinical symptoms, even when applied over a week after onset of infection. There were no relevant side effects besides a short-term fever reaction in one patient. Longitudinal full-genome sequencing revealed the emergence of mutations in the viral genome, potentially conferring an antibody escape in one patient with persistent viral RNA shedding upon plasma treatment. However, he resolved the infection after a second course of plasma treatment. Thus, our data suggest a therapeutic benefit of convalescent plasma treatment in patients with primary antibody deficiency even months after infection. While it appears to be safe, PCR follow-up for SARS-CoV-2 is advisable and early re-treatment might be considered in patients with persistent viral shedding.

Persistent SARS-CoV-2 infection in patients with secondary antibody deficiency: successful clearance following combination casirivimab and imdevimab (REGN-COV2) monoclonal antibody therapy

Background There is growing evidence that antibody responses play a role in the resolution of SARS-CoV-2 infection. Patients with primary or secondary antibody deficiency are at increased risk of persistent infection. This challenging clinical scenario is associated with adverse patient outcome and potentially creates an ecological niche for the evolution of novel SARS-CoV-2 variants with immune evasion capacity. Case reports and/or series have implied a therapeutic role for convalescent plasma (CP) to secure virological clearance, although concerns have been raised about the effectiveness of CP and its potential to drive viral evolution, and it has largely been withdrawn from clinical use in the UK. Case presentation We report two cases in which persistent SARS-CoV-2 infection was cleared following administration of the monoclonal antibody combination casirivimab and imdevimab (REGN-COV2, Ronapreve). A 55-year-old male with follicular lymphoma, treated with B cell depleting therapy, developed SARS-CoV-2 infection in September 2020 which then persisted for over 200 days. He was hospitalised on four occasions with COVID-19 and suffered debilitating fatigue and malaise throughout. There was no clinical response to antiviral therapy with remdesivir or CP, and SARS-CoV-2 was consistently detected in nasopharyngeal swabs. Intrahost evolution of several spike variants of uncertain significance was identified by viral sequence analysis. Delivery of REGN-COV2, in combination with remdesivir, was associated with clinical improvement and viral clearance within 6 days, which was sustained for over 150 days despite immunotherapy for relapsed follicular lymphoma. The second case, a 68-year-old female with chronic lymphocytic leukaemia on ibrutinib, also developed persistent SARS-CoV-2 infection. Despite a lack of response to remdesivir, infection promptly cleared following REGN-COV2 in combination with remdesivir, accompanied by resolution of inflammation and full clinical recovery that has been maintained for over 290 days. Conclusions These cases highlight the potential benefit of REGN-COV2 as therapy for persistent SARS-CoV-2 infection in antibody deficient individuals, including after failure of CP treatment. Formal clinical studies are warranted to assess the effectiveness of REGN-COV2 in antibody-deficient patients, especially in light of the emergence of variants of concern, such as Omicron, that appear to evade REGN-COV2 neutralisation.

Persistent SARS-CoV-2 Infection in Patients With Secondary Antibody Deficiency: Successful Clearance Following Combination Casirivimab and Imdevimab (REGN-COV2) Monoclonal Antibody Therapy

Background There is growing evidence that antibody responses play a role in the resolution of SARS-CoV-2 infection. Patients with primary or secondary antibody deficiency are at increased risk of persistent infection. This challenging clinical scenario is associated with adverse patient outcome and potentially creates an ecological niche for the evolution of novel SARS-CoV-2 variants with immune evasion capacity. Case reports and/or series have implied a therapeutic role for passive immunisation with convalescent plasma (CP) to secure virological clearance, although concerns have been raised about the effectiveness of CP and its potential to drive viral evolution, and it has largely been withdrawn from clinical use in the UK. Case presentation: We report two cases in which persistent SARS-CoV-2 infection was cleared following administration of the monoclonal antibody combination casirivimab and imdevimab (REGN-COV2, Ronapreve). A 55-year-old male with follicular lymphoma, treated with B cell depleting therapy, developed SARS-CoV-2 infection in September 2020 which then persisted for over 200 days. He was hospitalised on four occasions with COVID-19 and suffered debilitating fatigue and malaise throughout. There was no clinical response to antiviral therapy with remdesivir or CP, and SARS-CoV-2 was consistently detected in nasopharyngeal swabs. Intrahost evolution of several spike variants of uncertain significance was identified by viral sequence analysis. Delivery of REGN-COV2, in combination with remdesivir, was associated with clinical improvement and viral clearance within 6 days, which was sustained for over 150 days despite immunotherapy for relapsed follicular lymphoma. The second case, a 68-year-old female with chronic lymphocytic leukaemia on ibrutinib, also developed persistent SARS-CoV-2 infection. Despite a lack of response to remdesivir, infection promptly cleared following REGN-COV2 in combination with remdesivir, accompanied by resolution of inflammation and full clinical recovery that has been maintained for over 290 days. Conclusions These cases highlight the potential benefit of REGN-COV2 as therapy for persistent SARS-CoV-2 infection in antibody deficient individuals, including after failure of CP treatment. Formal clinical studies are warranted to assess the effectiveness of REGN-COV2 in antibody-deficient patients.

Efficacy of Intravenous Immunoglobulin Replacement Therapy in Patients with Predominantly Antibody Deficiency

Background Intravenous immunoglobulin G (IVIG) has been used as an antibody replacement therapy in primary immunodeficiency (PID) for more than 50 years. Most routinely, IVIG is used in patients with predominantly antibody deficiency such as: X-linked Agammaglobulinemia, common variable immunodeficiency and combined immunodeficiency such as: severe combined immunodeficiency. Aim To evaluate the efficacy and safety of regular IVIG therapy among patients with predominantly antibody deficiency in terms of frequency of infection and adverse effects. Methods Thirty patients diagnosed with predominantly antibody deficiency were recruited from the Pediatric Allergy and Immunology Unit, Children’s Hospital, Ain Shams University. These patients were followed up for one year in order to evaluate the frequency of infection and and adverse reactions of regular monthly IVIG therapy. The adequacy of IVIG dose was evaluated by the trough level of serum immunoglobulin G (IgG). Results Of the 30 patients, 21 (70%) were males and 9 (30%) were females. They had a median age of 87 months (range:15-294). Their median age at presentation and at diagnosis were 36 months (range :3-168) and 87 months (range:15-204) respectively. The mean ± SD of serum IgG before commencement of IVIG and after were 265.10 ± 108.39mg/dl and 572.04 ± 186.72 respectively. The rate of major infection dropped after starting replacement therapy with a median of 2 (1-2) before and 0 (0-1) after treatment. In spite of the reduction in the rate of pneumonia occurrence in patients with IgG trough level >500 mg/dl, it had no statistical significance. This could be attributable to small sample size. One patient developed anaphylaxis and was shifted to another brand. Conclusion IVIG is a safe and effective drug for patients with predominantly antibody deficiency. Compliance, adherence to therapy and appropriate dosage is needed to achieve better infection control.