ABSTRACT
Purpose: Kidney transplant recipients (KTRs) have poor outcomes compared to non-KTRs with acute COVID-19. To provide insight into management of immunosuppression (IS) during COVID-19, we studied immune signatures from the peripheral blood during and after COVID-19 infection from a multicenter KTR cohort. Method(s): Clinical data were collected by chart review. Paxgene blood RNA was polyA-selected and sequenced at enrollment Results: A total of 64 KTRs affected with COVID-19 were enrolled (31 Early cases (<4weeks from a positive SARS-CoV-2 PCR test) and 33 late cases). Out of the 64 patients, eight died and three encountered graft losses during follow-up. Among 31 early cases, we detected differentially expressed genes (nominal p-value < 0.01) in the blood transcriptome that were positively or negatively associated with the COVID-19 severity score (scale of 1 to 7 with increasing severity;Fig 1A). Enrichment analyses showed upregulation of neutrophil and innate immune pathways and downregulation of adaptive immune activation pathways with increasing severity score (Fig 1B). This observation was independent of lymphocyte count, despite reduction in immunosuppression (IS) in 75% of KTRs. Interestingly, compared with early cases, the blood transcriptome in late cases showed "normalization" of these enriched pathways after 4 weeks, suggesting return of adaptive immune system activation despite re-initiation of immunosuppression (Fig 1C). The latter analyses were adjusted for the severity score. Interestingly, similar pathway enrichment with worsening severity of COVID-19 was identifiable from a public dataset of non-KTRs (GSE152418), showing overlapped signatures for acute COVID-19 between KTRs and non-KTRs (overlap P<0.05) (Fig 1D). Conclusion(s): Blood transcriptome of COVID-KTRs shows marked decrease in adaptive immune system activation during acute COVID-19, even during IS reduction, which show recovery after acute illness. (Figure Presented).
ABSTRACT
Purpose: To determine if HLA allo-antibody levels are affected by COVID-19 in renal transplanted patients and to compare the immunoglobulin class and subclass profiles as well as the epitope binding patterns of anti-HLA and anti-SARS-CoV-2 antibodies. Method(s): A cross-sectional study of 46 kidney transplant recipients diagnosed with PCR+ SARS-CoV-2 infection was conducted. Serum samples were collected at the time of infection. For 21 patients, we obtained historical anti-HLA antibody information before COVID-19. Using a single-antigen bead Luminex assay, we determined IgG, IgG1/2/3/4, IgM, and IgA antibodies against Class I and Class II HLA, as well as against five SARS-CoV-2 (Wuhan strain) protein fragments: nucleocapsid, whole spike (S), spike S1, spike S2 and spike receptor binding domain (RBD). Result(s): 26/46 subjects had anti-HLA antibodies of which fourteen had donorspecific anti-HLA antibodies (DSA) compared with 45/46 had anti-SARS-CoV2 antibodies. The majority of DSA were specific to HLA-DQ (10/14), with a dominant IgG/IgG1/IgG3 subclass prevalence. Anti-SARS-CoV-2 antibodies exhibited stronger reactivity towards S and RBD and had increased IgM (38/43, 79%) and IgA (41/42, 85%) prevalence when compared to DSAs (5/14, 35% and 2/14, 14%, p<0.001).Out of 21 patients with pre-COVID-19 data available, calculated panel antibody reactivity (cPRA) levels did not change after COVID-19 in 14 cases (67%);cPRA increased in two cases (10%), both of them with allograft nephrectomy and immunosuppression discontinuation, and decreased in five patients (20%) (from 65.4+/-12.6% before COVID-19, to 29.4+/-33.6% after COVID-19) (Figure 1). Patients with DSA exhibited significantly lower anti-S IgG (9453+/-9945 vs 17975+/-12792;P=0.001), anti-RBD IgM (4464+/-3693 vs 8751+/-6468;P=0.03) and anti-nucleoprotein IgA (998+/-835 vs 5476+/-6895;P=0.001) anti-SARS-CoV2 antibody MFI values than patients without DSA. Conclusion(s): cPRA values did not increase following PCR confirmed COVID-19 diagnosis in renal transplant recipients and those subjects with pre-existing DSA had lower antibody strength directed at SARS-CoV-2 antigens. The lack of increase in alloantibody response is quite remarkable, since over 80% of the patients underwent either significant reduction or withdrawal of mycophenolate mofetil after COVID-19 diagnosis. (Figure Presented).
ABSTRACT
Purpose: Kidney transplant recipients (KTRs) have poor outcomes vs non-KTRs with acute COVID-19. To provide insight into management of immunosuppression during acute COVID-19, we studied peripheral blood transcriptomes during and after COVID-19 from a multicenter KTR cohort. Method(s): Clinical data were collected by chart review. Paxgene blood RNA was polyA-selected and sequenced at enrollment. Result(s): A total of 64 KTRs with COVID-19 were enrolled (31 Early cases (<4weeks from a positive SARS-CoV-2 PCR test) and 33 late cases). Out of the 64 patients, eight died and three encountered graft losses during follow-up. Due to presence of mRNA reads in the blood transcriptome unmapped to the human genome, we aligned the mRNA short reads to the SARS-CoV-2 genome. Surprisingly, our strategy detected the SARS-Cov2 mRNA, especially Spike mRNA in 27 (87%) early cases, and 18 (54%) of late cases (Fig 1A and B). We then analyzed the raw reads from a public dataset of non-KTRs with Paxgene RNA (GSE172114). The SARS-CoV-2 Spike mRNA was detected in 2/47 (4.2%) critically ill COVID-19 cases and 0/25 noncritically ill cases in this non-KTR dataset (compared to KTRs, Chi-square P<0.001;Fig 1B). Among our KTRs, the amount of Spike mRNA was associated positively with the COVID-19 severity score (scale of 1 to 7 of increasing severity;Fig 1C) and inversely with time from initial positive PCR (Fig 1D). More interestingly, 7/64 patients had detectable Spike RNA-emia beyond 60 days after COVID-19 diagnosis. Of the 3 graft losses in our cohort, 2 occurred among these 7 patients. Conclusion(s): Blood transcriptome of KTRs with COVID-19 demonstrated a risk for persistent viremia with implications for pathogenesis of COVID-19 disease. This finding also supports using passive immune strategies in COVID-KTRs. (Figure Presented).
ABSTRACT
Purpose: Solid organ transplant recipients are at increased risk of severe outcomes with infection by SARS-CoV-2, the etiologic agent of COVID-19. Antibodies directed against the virus are thought to offer protection and monoclonal antibodies directed against the virus have been used therapeutically. However, a thorough characterization of anti-SARS-CoV2 immune globulin isotypes in organ transplant recipients has not been reported. Methods: Using a semi-quantitative Luminex-based multiplex assay, we determined antibody levels from 48 SARS-CoV-2 PCR+ hospitalized kidney transplant recipients. We measured total IgG, IgM, IgA and IgG subtypes of antibodies directed against 5 distinct viral epitopes including the nucleocapsid protein as well as multiple regions of the spike protein including the receptor binding domain. Results: We identified multiple patterns of antibody responses. Specifically, 5 subjects were seronegative and 29 subjects had IgM, IgG and IgA antibodies specific for multiple epitopes of SARS-CoV-2. The 14 remaining subjects displayed a mixture of immunoglobulin isotypes. Of three subjects indeterminant for IgG antibodies, two had developed IgM, suggesting that they were early in the course of their immune response. Longitudinal samples from one subject demonstrated dynamic changes from IgM+IgG+ -> IgM-IgG+. Utilizing the semi-quantitative aspect of the assay, we found that IgG antibodies to the full Spike and Spike S1 domains were present at a statistically reduced level compared to immunocompetent controls while those directed against the Spike S2 domain were statistically higher. Interestingly, 77% of these subjects had detectable IgA directed against combinations of spike and/ or nucleocapsid specificity. IgG subtype analysis and correlation between antibody expression patterns with clinical severity is under investigation. Conclusions: Overall, these studies indicate that solid organ transplant recipients have the capacity to mount a dynamic antibody response to SARS-CoV-2 infection and that this response differs from immunocompetent individuals.
ABSTRACT
Purpose: Both anti-HLA and anti-SARS-CoV-2 antibodies target protein antigens. The aim of the present study was to compare the class and subclass profile of such antibodies in a cohort of kidney transplant patients. Methods: We detected and identified anti-HLA and anti-SARS-CoV-2 antibody in 48 kidney transplant recipients who were hospitalized for SARS-CoV-2 PCR+ infection. Anti-HLA antibodies were detected by single-antigen bead Luminex assay, with IgG class, and IgG1-2-3-4 subclass secondary antibody. Anti-SARSCoV- 2 antibodies were also detected by Luminex assay directed against 5 distinct viral epitopes including the nucleocapsid protein as well as multiple regions of the spike protein. The secondary antibodies addressed total IgG, IgG1-2-3-4, IgM and IgA class/subclasses. Results: The antibody profile (Table 1) included 12/48 cases of donor-specific anti- HLA antibodies, and 43/48 cases with anti-SARS-CoV2 antibodies. The majority of HLA-specific antibodies targeted HLA-DQ, with a dominant IgG class and an IgG1+IgG2+IgG3 subclass prevalence. However, anti-SARS-CoV2 antibody profile was characterized by increased prevalence of IgM (38/43, 79%) and IgA (41/42, 85%), and a lower prevalence of IgG2. Conclusions: Overall, these data suggests that kidney transplant recipients with Covid-19 exhibit a humoral immune response both to donor-HLA and SARS-CoV-2. Although both are protein antigens, the allo-immune response has a high-IgG/low IgA pattern, while the Covid-19 antibody profile includes high IgA. Additional follow-up is needed to determine if the increased IgA is a consistent marker of anti-SARS-CoV-2 antibody response. (Table Presented).
ABSTRACT
Background: Human kidney organoids have been utilized as a model to study genetic kidney diseases and kidney development. Innate or adaptive immune responses in organoids are currently poorly defined. Kidney transplant rejection and activation of complement pathways are two common renal immune phenomena. SARS-CoV-2 virus, the pathogen of the recent pandemic, leads to complement pathway activation in human kidneys and can infect kidney organoids. Here, we investigated (i) the alloimmunogenicity of kidney organoids in a humanized mice model, and (ii) the responses to exogenous complement C5a and spike protein (S1) of SARS-CoV-2 in kidney organoids. Methods: Kidney organoids were generated from human embryonic stem cells using protocols developed in our laboratory, and transplanted under the kidney capsule in humanized (BLT) mice. Immunophenotype, mixed lymphocyte reaction, and intracellular cytokine staining were analyzed from grafts and mouse splenocytes collected after 30 days of transplantation. In other experiments organoids were treated with S1 protein and human recombinant C5a for 24 hours or 3 days respectively, followed by qPCR and immunofluorescence analysis. Results: Transplanted organoids were extensively infiltrated by lymphocytes. Graft CD8+ T cells demonstrated a switch from naïve to memory T cells. Splenocytes isolated from transplanted BLT mice showed increased IFN-γ and TNF-α. Splenocytes proliferated after exposure to 2D kidney organoids (MLR) for 72 hours ex vivo, and organoids were markedly injured as reflected by DNA damage (γ-H2AX) and cleaved caspase 3. Reflecting innate responses, robust interstitial fibrosis was found in nontransplanted organoids after direct activation of C5aR by exogenous C5a. We confirmed ACE2 expression on proximal tubules and parietal epithelium of glomeruli, consistent with human autopsy results. Non-transplanted organoids treated with S1 protein showed transcriptionally upregulated C5a1 receptors. Conclusions: Our results indicate the alloimmunogenicity of kidney organoids and the deleterious effects of C5a in kidney organoids. Human kidney organoids represent a novel platform to study renal immunology including adaptive and innate immunity and the inflammatory responses to coronavirus disease (COVID-19).
ABSTRACT
Background: Chronic immunosuppression and comorbidities may expose kidney transplant recipients to an increased risk of developing critical coronavirus disease 2019 (COVID-19), but data in transplantation have been limited so far to single centers. To determine the clinical presentation, outcomes, and mortality risk factors in transplant patients with COVID-19, we analyzed retrospective data from a large international transplant consortium (TANGO Study). Methods: Retrospective cohort study included kidney transplant recipients admitted with COVID-19 in 11 centers participating in the international TANGO consortium. We included all adult (≥18 yeas) kidney transplant recipients with a functioning kidney allograft who were admitted to a hospital between March-April, 2020. Epidemiological, demographic, clinical, laboratory, treatment, and outcome data were extracted from electronic medical records using an ad hoc designed data collection form. Results: Among 9,697 kidney transplant recipients followed at 11 transplant centers, 145 (1.5%) were hospitalized due to COVID-19. 65% were male and more than half were over 60 years old (55%). Median time since transplant was 5 years (2-10) and only 16% were transplanted less than one year from the presentation. Prevalent comorbidities included hypertension (95%), obesity (41%), heart disease (25%) and lung disease (19%). Common symptoms at the onset of illness were fever and dyspnea (71%), followed by myalgia (54%) and diarrhea (35%). Management of anti-rejection therapy varied across centers: antimetabolites were withdrawn in 69% of patients and calcineurin inhibitor in 26%. Other treatments used during hospitalization included hydroxychloroquine (83%), antibiotics (76%), tocilizumab (13%) and antivirals (10%). During a median follow-up of 13 days (IQR: 7 - 21) after diagnosis of COVID-19, mortality was 30% and occurred at a median 10 (5-16) days after admission. Acute kidney injury (AKI) occurred in 46% and respiratory failure requiring intubation in 29% of cases. No rejection events were observed. Conclusions: Our large international consortium indicates that kidney transplant recipients with COVID-19 have increased mortality (30%) upon hospitalization compared to the general population with a high rate of AKI (46%) and significant respiratory failure (29%).