ABSTRACT
Background. Hematopoietic cell transplant (HCT) recipients who develop coronavirus disease 2019 (COVID-19), have dismal prognosis with approximately 20% mortality. Given the lack of a specific and effective therapy, the availability of various vaccination platforms against SARS-CοV-2 has generated optimism towards the development of a robust herd immunity. Notwithstanding the prioritization of HCT recipients to COVID-19 vaccination, limited information is available on whether and to what extent, they mount an immune response to SARS-CοV-2 vaccination as they were generally excluded from vaccination trials. Aim. To gain insights in the immune responses developed to SARS-CoV-2 vaccines under immunosuppression, we studied the humoral and cellular immune responses to SARS-CoV-2 vaccination in HCT recipients. Methods. We prospectively studied (April-July 2021), adult patients who had undergone HCT in our Unit and received two doses of a SARS-CoV-2 vaccine (as per international guidelines) after providing written informed consent. Responses were studied before each vaccination dose and 12-51 days later after the second dose. Neutralizing antibodies against SARS-CoV-2 (CoV-2-NAbs) were measured using an FDA approved methodology for diagnostic use (ELISA, cPass™ SARS-CoV-2 NAbs Detection Kit;GenScript, Piscataway, NJ, USA;cut-off value for a positive result set at ≥30%) and SARS-CoV-2 spike-specific T cells (spike-STs) by interferon-γ Elispot after pulsing peripheral blood mononuclear cells with spike pepmixes. Results. Humoral responses were studied on 65 patients, (50 allo-HCT/15 auto-HCT, Figure A). T cell responses were measured on 38/65 vaccinated patients (32 allo-HCT/6 auto-HCT) with a median of 3 (0.17-31) and 2 years (1.25-8) post allo- and auto-HCT respectively, and 19 healthy, unexposed vaccinees. One patient with prior COVID-19, was excluded from analysis. All patients were vaccinated with the Pfizer-BioNTech, except for 2 vaccinated with the AstraZeneca vaccine. Both CoV-2-NAbs and spike-STs were barely detectable before vaccination but could be detected in both allo- and auto-HCT patients after the first vaccination dose, reaching statistically significant increase after the second vaccination dose (p<0.001 and p=0.036, respectively). Circulating spike-STs in allo-HCT recipients, although present, were lower over their counterparts in healthy volunteers (p<0.001) and auto-HCT patients (p=0.080). In the latter patient cohort, the rather long period post auto-HCT (≥1.25 years for all patients) might have generated unintended bias towards elevated immune responses. The longer time post HCT in all patients was associated with increased CoV-2-NAbs and spike-STs (p=0.004 and p=0.030). Allo-HCT recipients under immunosuppression had lower levels of CoV-2-NAbs and spike-STs after the booster dose compared to patients off-treatment (Figure B and C, p<0.001 and p=0.021 respectively). In particular, only 50% and 40% of patients on systemic immunosuppression reached adequate CoV-2-Nab and spike-ST levels after the second dose, as compared to 98% and 94% of immunosuppression-free patients. One allo-HCT recipient with failure to mount any immune response post booster vaccination, developed 40 days later COVID-19 infection and succumbed. The one allo-HCT recipient off treatment who did not elicit protective immune response after vaccination, was suffering from metabolic syndrome, a potentially immunosuppressive entity. Overall, there was a good correlation between humoral and T-cellular responses (p=0.013), although few cases were observed with sufficient T-cell response but no humoral reactivity and vice versa. Conclusion. Herein, we report for first time humoral and T cell responses post SARS-CoV-2 vaccination in HCT recipients. Transplant recipients not under active and intense immunosuppression at the time of vaccination may benefit significantly from COVID-19 vaccination even though these responses are blunted compared to healthy individuals. However, for the severely immunocompromised patients it seems high y unlikely that they could be protected by vaccination and for this vulnerable population, different vaccination schemes or therapeutic platforms should be developed along with collateral measures including minimal exposure and immunization of caregivers and health care providers. [Formula presented] Disclosures: Gavriilaki: Alexion, Omeros, Sanofi Corporation: Consultancy;Pfizer Corporation: Research Funding;Gilead Corporation: Honoraria. Yannaki: SANDOZ: Speakers Bureau;Gilead: Speakers Bureau;Novartis: Speakers Bureau;bluebird bio, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding. Anagnostopoulos: Abbvie: Other: clinical trials;Sanofi: Other: clinical trials;Ocopeptides: Other: clinical trials;GSK: Other: clinical trials;Incyte: Other: clinical trials;Takeda: Other: clinical trials;Amgen: Other: clinical trials;Janssen: Other: clinical trials;novartis: Other: clinical trials;Celgene: Other: clinical trials;Roche: Other: clinical trials;Astellas: Other: clinical trials.
ABSTRACT
Background: Complement dysregulation has been documented in the molecular pathophysiology of COVID-19 and recently implicated in the relevant pediatric patient inflammatory responses. Aims: Based on our previous data in adults, we hypothesized that signatures of complement genetic variants would also be detectable in pediatric patients exhibiting COVID-19 signs and symptoms. Methods: We prospectively studied consecutive pediatric patients from our COVID-19 Units (November 2020-March 2021). COVID-19 was confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR). Patient data were recorded by treating physicians that followed patients up to discharge. DNA was obtained from peripheral blood samples. Probes were designed using the Design studio (Illumina). Amplicons cover exons of complement-associated genes (C3, C5, CFB, CFD, CFH, CFHR1, CFI, CD46, CD55, MBL2, MASP1, MASP2, COLEC11, FCN1, FCN3 as well as ADAMTS13 and ΤHBD) spanning 15 bases into introns. We used 10ng of initial DNA material. Libraries were quantified using Qubit and sequenced on a MiniSeq System in a 2x150 bp run. Analysis was performed using the TruSeq Amplicon application (BaseSpace). Alignment was based on the banded Smith-Waterman algorithm in the targeted regions (specified in a manifest file). We performed variant calling with the Illumina-developed Somatic Variant Caller in germline mode and variant allele frequency higher than 20%. Both Ensembl and Refseq were used for annotation of the output files. A preliminary analysis (A) for the identification of variants of clinical significance was based on annotated ClinVar data, while a further and more selective analysis (B) was performed to identify missense complement coding variants that may biochemically contribute to the deregulation of innate responses during infection. This analysis was mainly based on the dbSNP and UniProt databases and available literature. Results: We studied 80 children and adolescents, 8 of whom developed inflammatory syndromes (MIS-C group). Among them, 41 were hospitalized and eventually all survived. 1. In our preliminary analysis, patients exhibited heterogeneous variant profiles including pathogenic, benign, likely benign, and variants of unknown significance (median number of variants: 97, range: 61-103). We found a variant of ADAMTS13 (rs2301612, missense) in 39 patients. We also detected two missense risk factor variants, previously detected in complement-related diseases: rs2230199 in C3 (33 patients);and rs800292 in CFH (36 patients). Among them, 40 patients had a combination of these characterized variants. This combination was significantly associated with the presence of dyspnea (p=0.031) and cough (p=0.042). Furthermore, 27 patients had a pathogenic variant in MBL2 (rs1800450), and 7 a pathogenic deletion in FCN3 that have been previously associated with inflammatory syndromes. 2. The results of our further analysis are summarized in Figure. We identified common variants, some well represented by relatively high frequencies (>70%) (rs11098044 in CFI, rs1061170 in CFH and rs12711521 in MASP2) and others less abundant, but varying considerably between the hospitalized group, the non-admitted group and the MIS-C individuals (rs2230199 in C3, rs1065489 in CFH, rs12614 and rs641153 in CFB, rs1800450 in MBL2, rs2273346 and rs72550870 in MASP2, rs72549154 in MASP3 and rs7567833 in COLEC11, all highlighted in Figure in red).). Structurally, the majority of these common variants of interest encode charge reversal mutations. These may influence protein-protein interactions in complex formations that are important for complement activation and/or regulation. Conclusion: In pediatric COVID-19 we have detected a novel set of complement missense coding variants some of which have been implicated earlier in inflammatory syndromes and endothelial stress responses. Certain combinations of mutations of alternative and/or lectin pathway components may increase the threshold dynamics of complement consumption and therefore alter COVID-19 phenotypes. [Formula prese ted] Disclosures: Gavriilaki: Alexion, Omeros, Sanofi Corporation: Consultancy;Gilead Corporation: Honoraria;Pfizer Corporation: Research Funding. Anagnostopoulos: Abbvie: Other: clinical trials;Sanofi: Other: clinical trials;Ocopeptides: Other: clinical trials;GSK: Other: clinical trials;Incyte: Other: clinical trials;Takeda: Other: clinical trials;Amgen: Other: clinical trials;Janssen: Other: clinical trials;novartis: Other: clinical trials;Celgene: Other: clinical trials;Roche: Other: clinical trials;Astellas: Other: clinical trials.