Asymptomatic immunodeficiency-associated vaccine-derived poliovirus infections in two UK children.

Increasing detections of vaccine-derived poliovirus (VDPV) globally, including in countries previously declared polio free, is a public health emergency of international concern. Individuals with primary immunodeficiency (PID) can excrete polioviruses for prolonged periods, which could act as a source of cryptic transmission of viruses with potential to cause neurological disease. Here, we report on the detection of immunodeficiency-associated VDPVs (iVDPV) from two asymptomatic male PID children in the UK in 2019. The first child cleared poliovirus with increased doses of intravenous immunoglobulin, the second child following haematopoetic stem cell transplantation. We perform genetic and phenotypic characterisation of the infecting strains, demonstrating intra-host evolution and a neurovirulent phenotype in transgenic mice. Our findings highlight a pressing need to strengthen polio surveillance. Systematic collection of stool from asymptomatic PID patients who are at high risk for poliovirus excretion could improve the ability to detect and contain iVDPVs.

Haploidentical CD3+ TCR αß/CD19+-depleted HSCT for MHC class II deficiency and persistent SARS-CoV-2 pneumonitis.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to coronavirus disease 2019 (COVID-19), which can range from a mild illness to a severe phenotype characterized by acute respiratory distress needing mechanical ventilation. Children with combined immunodeficiencies might be unable to mount a sufficient cellular and humoral immune response against COVID-19 and have persistent disease. Objective: Our aim was to describe a child with combined immunodeficiency and a favorable post-hematopoietic stem cell transplant (HSCT) course following a haploidentical HSCT in the presence of persistent SARS-CoV-2 infection. Methods: A 13-month-old girl with MHC class II deficiency developed persistent pre-HSCT SARS-CoV-2 infection. Faced with a significant challenge of balancing the risk of progressive infection due to an incompetent immune system with the danger of inflammatory pneumonitis peri-immune reconstitution after HSCT, the patient's physicians performed a maternal (with a recent history of COVID-19 infection) haploidentical HSCT. The patient received regdanvimab (after stem cell infusion) and remdesivir (before and after stem cell infusion). Results: The patient exhibited a gradual increase in her cycle threshold values, implying a reduction in viral RNA with concomitant expansion in the CD3 lymphocyte subset and clinical and radiologic improvement. Conclusions: Combination of adoptive transfer of maternal CD45RO+ memory addback T lymphocytes after haploidentical HSCT and use of regdanvimab (a SARS-CoV-2-neutralizing mAb) and remdesivir may have led to the successful outcome in our patient with severe immunodeficiency after she had undergone HSCT. This case highlights the role of novel antiviral strategies (mAbs and CD45RO+ memory T lymphocytes) in contributing to viral clearance in a challenging clinical scenario.

T-replete HLA-matched grafts vs T-depleted HLA-mismatched grafts in inborn errors of immunity.

Hematopoietic cell transplantation (HCT) has become standard-of-care for an increasing number of inborn errors of immunity (IEI). This report is the first to compare transplant outcomes according to T-cell-replete (ie, T-replete) HLA-matched grafts using alemtuzumab (n = 117) and T-cell-depleted (ie, T-depleted) HLA-mismatched grafts using T-cell receptor-αß (TCRαß)/CD19 depletion (n = 47) in children with IEI who underwent first HCT between 2014 and 2019. All patients received treosulfan-based conditioning except patients with DNA repair disorders. For T-replete grafts, the stem cell source was marrow in 25 (21%) patients, peripheral blood stem cell (PBSC) in 85 (73%), and cord blood in 7 (6%). TCRαß/CD19 depletion was performed on PBSCs from 45 haploidentical parental donors and 2 mismatched unrelated donors. The 3-year overall survival (OS) and event-free survival for the entire cohort were 85% (77%-90%) and 79% (69%-86%), respectively. Analysis according to age at transplant revealed a comparable 3-year OS between T-replete grafts (88%; 76%-94%) and T-depleted grafts (87%; 64%-96%) in younger patients (aged <5 years at HCT). For older patients (aged >5 years), the OS was significantly lower in T-depleted grafts (55%; 23%-78%) compared with T-replete grafts (87%; 68%-95%) (P = .03). Grade III to IV acute graft-versus-host disease was observed in 8% of T-replete marrow, 7% of T-replete PBSC, 14% of T-replete cord blood, and 2% of T-depleted PBSC (P = .73). Higher incidence of viremia (P < .001) and delayed CD3 reconstitution (P = .003) were observed after T-depleted graft HCT. These data indicate that mismatched donor transplant after TCRαß/CD19 depletion represents an excellent alternative for younger children with IEI in need of an allograft.

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.

SARS-CoV-2 Testing of 11,884 Healthcare Workers at an Acute NHS Hospital Trust in England: A Retrospective Analysis.

Healthcare workers (HCWs) are known to be at increased risk of infection with SARS-CoV-2, although whether these risks are equal across all roles is uncertain. Here we report a retrospective analysis of a large real-world dataset obtained from 10 March to 6 July 2020 in an NHS Foundation Trust in England with 17,126 employees. 3,338 HCWs underwent symptomatic PCR testing (14.4% positive, 2.8% of all staff) and 11,103 HCWs underwent serological testing for SARS-CoV-2 IgG (8.4% positive, 5.5% of all staff). Seropositivity was lower than other hospital settings in England but higher than community estimates. Increased test positivity rates were observed in HCWs from BAME backgrounds and residents in areas of higher social deprivation. A multiple logistic regression model adjusting for ethnicity and social deprivation confirmed statistically significant increases in the odds of testing positive in certain occupational groups, most notably domestic services staff, nurses, and health-care assistants. PCR testing of symptomatic HCWs appeared to underestimate overall infection levels, probably due to asymptomatic seroconversion. Clinical outcomes were reassuring, with only a small minority of HCWs with COVID-19 requiring hospitalization (2.3%) or ICU management (0.7%) and with no deaths. Despite a relatively low level of HCW infection compared to other UK cohorts, there were nevertheless important differences in test positivity rates between occupational groups, robust to adjustment for demographic factors such as ethnic background and social deprivation. Quantitative and qualitative studies are needed to better understand the factors contributing to this risk. Robust informatics solutions for HCW exposure data are essential to inform occupational monitoring.

Outcome of autoimmune cytopenia after hematopoietic cell transplantation in primary immunodeficiency.

BACKGROUND: Post hematopoietic cell transplantation (HCT) autoimmune cytopenia (AIC) is a potentially life-threatening complication, but studies focusing on large cohorts of patients transplanted for primary immunodeficiency are lacking. OBJECTIVES: This study sought to determine the incidence, risk factors, and outcomes of post-HCT AIC and B-lymphocyte function following rituximab. METHODS: We retrospectively studied 502 children with primary immunodeficiency who were transplanted at our center between 1987 and 2018. RESULTS: Thirty-six patients (9%) developed post-HCT AIC, with a median onset of 6.5 months post-HCT. On univariate analysis, pre-HCT AIC, mismatched donor, alemtuzumab, anti-thymocyte antiglobulin, and acute and chronic graft versus host disease were significantly associated with post-HCT AIC. After multivariate analysis, alemtuzumab (subdistribution hazard ratio, 9.0; 95% CI, 1.50-54.0; P = .02) was independently associated with post-HCT AIC. Corticosteroid and high-dose intravenous immunoglobulin achieved remission in 50% (n = 18), additional rituximab led to remission in 25% (n = 9), and the remaining 25% were treated with a combination of various modalities including sirolimus (n = 5), bortezomib (n = 3), mycophenolate mofetil (n = 2), splenectomy (n = 2), and second HCT (n = 3). The mortality of post-HCT AIC reduced from 25% (4 of 16) prior to 2011 to 5% (1 of 20) after 2011. The median follow-up of 5.8 years (range, 0.4 to 29.1 years) showed that 26 of 30 survivors (87%) were in complete remission, and 4 were in remission with ongoing sirolimus and low-dose steroids. Of the 17 who received rituximab, 7 had B-lymphocyte recovery, 5 had persistent low B-lymphocyte count and remained on intravenous immunoglobulin replacement, 2 had second HCT, and 3 died. CONCLUSIONS: The frequency of post HCT AIC in our cohort was 9%, and the most significant risk factors for its occurrence were the presence of graft versus host disease and the use of alemtuzumab.