Novel T cell interferon gamma release assay (IGRA) using spike recombinant protein for COVID19 vaccine response and Nucleocapsid for SARS-Cov2 response.

We explored the performance of a whole blood interferon gamma release assay (IGRA) based on the stimulation of SARS-Cov2-specific T cells by purified recombinant proteins. Twenty volunteers vaccinated with BNT162b2 were selected first for T cell response evaluation using an in-house IGRA, a commercial IGRA, and ELISpot showing a S2 > S1 poly-epitopic response. Next, 64 vaccinated and 103 non-vaccinated individuals were tested for humoral and T cell response (IGRA-Spike/-nucleocapsid recombinant proteins). Following the second vaccine injection, humoral (100%) and IGRA-Spike T cell (95.3%) responses took place irrespective of sex, age, and vaccine type. The humoral response declined first, followed by IGRA-Spike T cell response after the second vaccine injection. Altogether, this study confirms the utility of the IGRA-Spike/-nucleocapsid assay to complement serology in COVID19 vaccinated individuals and those who have recovered from SARS-Cov2.

Outcomes of kidney transplant recipients admitted to the intensive care unit: a retrospective study of 200 patients.

BACKGROUND: Risk of over-immunosuppression or immunization may mitigate the overall and long-term renal outcomes of kidney transplant recipients (KTR) admitted to the ICU in the modern era but remain poorly described. Thus, there is an unmet need to better characterize the survival of KTR admitted to the ICU, but also the renal and immunological outcomes of survivors. METHODS: Retrospective observational study that included 200 KTR admitted between 2010 and 2016 to the ICU of a teaching hospital (median age 61 years [IQR 50.7-68]; time from transplantation 41 months [IQR 5-119]). Survival curves were compared using the Log-rank test. RESULTS: Mortality rates following admission to the ICU was low (26.5% at month-6), mainly related to early mortality (20% in-hospital), and predicted by the severity of the acute condition (SAPS2 score) but also by Epstein Barr Virus proliferation in the weeks preceding the admission to the ICU. Acute kidney injury (AKI) was highly prevalent (85.1%). Progression toward chronic kidney disease (CKD) was observed in 45.1% of survivors. 15.1% of survivors developed new anti-HLA antibodies (donor-specific antibodies 9.2% of cases) that may impact the long-term renal transplantation function. CONCLUSIONS: Notwithstanding the potential biases related to the retrospective and monocentric nature of this study, our findings obtained in a large cohort of KTR suggest that survival of KTR admitted in ICU is good but in-ICU management of these patients may alter both survival and AKI to CKD transition, as well as HLA immunization. Further interventional studies, including systematic characterization of the Epstein Barr virus proliferation at the admission (i.e., a potential surrogate marker of an underlying immune paralysis and frailty) will need to address the optimal management of immunosuppressive regimen in ICU to improve survival but also renal and immunological outcomes.

Glucocorticoids selectively affect the memory T cell response to SARS-Cov2 spike in vaccinated and post-infected patients with systemic lupus erythematosus.

Immune response to vaccines and pathogens remains unclear in patients with systemic lupus erythematosus (SLE). To investigate this, a single-center retrospective study was conducted with 47 SLE patients vaccinated against COVID-19, including 13 who subsequently developed an asymptomatic/mild disease. As compared to controls, post-vaccine response against Spike was reduced in SLE patients when considering both memory T-cells in a whole blood interferon gamma release assay (IGRA-S) and IgG anti-Spike antibody (Ab) responses. The SLE-associated defective IGRA-S response was associated with a serum albumin level below 40 g/L and with the use of glucocorticoids, while a defective IgG anti-Spike Ab response was associated with lower levels of anti-dsDNA and anti-SSA/Ro 52 kDa Abs. IGRA-S and IgG anti-Spike responses were independent from SLE activity and clinical phenotype, low complement, hypergammaglobulinemia, and lymphopenia. As compared to controls, SLE patients showed a rapid decay of anti-Spike T-cell memory and stable IgG anti-Spike Ab responses. In conclusion, both T cell and humoral anti-Spike responses were independently affected in our SLE patients cohort, which supports the exploration of both responses in the follow-up of SLE patients and especially in those receiving glucocorticoids.

A Randomized Prospective Study Comparing Anti-T-Lymphocyte Igs to Basiliximab in Highly Sensitized Kidney Transplant Patients.

BACKGROUND: Two prospective studies that were performed before the era of highly sensitive solid-phase assays have shown a lower incidence of acute rejection in highly sensitized kidney-transplant patients given polyclonal antibodies compared with those given anti-CD25 monoclonal antibodies. METHODS: This prospective pilot randomized French multicenter study aimed to compare anti-T-lymphocyte Ig (ATLG) (n = 32) and basiliximab (n = 27) in highly sensitized kidney-transplant patients without preformed donor-specific antibodies (pDSAs) as assessed by a Luminex Single-Antigen flow bead assay. Only patients with a calculated panel reactive antibody ≥50%, with at least 1 antibody with a mean fluorescence intensity ≥5000 and without a historical pDSA and without a pDSA on the day of transplantation were included. RESULTS: Treatment failure as defined by biopsy-proven acute rejection, patient lost to follow-up, graft loss, and death was observed in 18.8% (95% confidence interval [CI], 8.9%-37.1%) and 18.8% (95% CI, 8.9%-37.1%) in patients who received ATLG and 14.8% (95% CI, 5.8%-34.8%) and 28.2% (95% CI, 14.2%-51.2%) of patients who received basiliximab, respectively at 6 (P = 0.66) and 12 (P = 0.62) months post-transplantation. One T cell-mediated rejection was observed in ATLG-treated patients (3.1%). One antibody-mediated rejection due to a de novo donor-specific antibody (DSA) occurred in basiliximab-treated patients (3.7%). Patient survival, graft survival, kidney parameters, and infection rate were similar in the 2 groups. CONCLUSION: This pilot study indicates that in highly sensitized kidney-transplant patients without pDSAs, both ATLG and basiliximab can be used efficiently and safely. However, because of the lack of power, these results should be interpreted with caution.

Efficacy of immunoadsorption to reduce donor-specific alloantibodies in kidney-transplant candidates.

OBJECTIVES: We implemented a desensitization program at our center to enable transplant in kidney-transplant candidates who have a living human-leukocyte antigen-incompatible (HLAi) donor. We report on the efficacy of semispecific immunoadsorption to allow HLAi kidney transplant in 6 highly sensitized patients. MATERIALS AND METHODS: We chose immunoadsorption as the apheresis technique coupled to hemodialysis as a means to decrease donor-specific alloantibodies in kidney transplant candidates submitted to a pretransplant desensitization program to remove detrimental antibodies. RESULTS: Six highly sensitized kidney-transplant patients (5 females), awaiting their first (n = 1) or second (n = 5) kidney transplant from a living donor, were enrolled in this desensitization program. They had 1 (n = 2), 2 (n = 1), 3 (n = 2), or 4 (n = 1) donor-specific alloantibodies; their mean fluorescent intensities at predesensitization ranged from 1200 to 19 000. Each patient underwent between 10 and 16 immunoadsorption sessions. At the time of transplant, donor-specific alloantibodies were undetectable in 2 patients (A24, DR3); donorspecific alloantibodies decreased by > 50% in 8 patients (A11, B44, DR3, DR11, DQ3 thrice, DQ5); donor-specific alloantibodies remained unchanged in 2 patients (B50, DR13); and mean fluorescent intensities were slightly increased in 2 patients (Cw6, DQ8). In the analysis of final outcomes, 2 patients experienced no rejection (1 experienced donor-specific alloantibody elimination, and 1 experienced a > 50% decrease in donor-specific alloantibodies). One patient presented with acute antibody-mediated rejection, which required immunoadsorption sessions and eculizumab therapy (donor-specific alloantibodies between 5000 and 19 000). Two patients presented with subacute antibody-mediated rejection; 1 was treated by plasmapheresis/rituximab therapy, and the other was treated with plasmapheresis/ methylprednisolone pulses. Another patient presented with chronic antibody-mediated rejection, which was treated unsuccessfully with plasmapheresis/rituximab; a tentative of rescue therapy with eculizumab was attempted without success. CONCLUSIONS: Desensitization of the humanleukocyte antigen using this immunoadsorption procedure effectively reduced or eliminated donorspecific alloantibodies in 71% of patients undergoing kidney transplant, at the time of transplant.

Long term outcomes of transplantation using kidneys from expanded criteria donors: prospective, population based cohort study.

OBJECTIVES: To assess the long term outcomes of transplantation using expanded criteria donors (ECD; donors aged ≥ 60 years or aged 50-59 years with vascular comorbidities) and assess the main determinants of its prognosis. DESIGN: Prospective, population based cohort study. SETTING: Four French referral centres. PARTICIPANTS: Consecutive patients who underwent kidney transplantation between January 2004 and January 2011, and were followed up to May 2014. A validation cohort included patients from another four referral centres in France who underwent kidney transplantation between January 2002 and December 2011. MAIN OUTCOME MEASURES: Long term kidney allograft survival, based on systematic assessment of donor, recipient, and transplant clinical characteristics; preimplantation biopsy; and circulating levels of donor specific anti-HLA (human leucocyte antigen) antibody (DSA) at baseline. RESULTS: The study included 6891 patients (2763 in the principal cohort, 4128 in the validation cohort). Of 2763 transplantations performed, 916 (33.2%) used ECD kidneys. Overall, patients receiving ECD transplants had lower allograft survival after seven years than patients receiving transplants from standard criteria donors (SCD; 80% v 88%, P<0.001). Patients receiving ECD transplants who presented with circulating DSA at the time of transplantation had worse allograft survival after seven years than patients receiving ECD kidneys without circulating DSA at transplantation (44% v 85%, P < 0.001). After adjusting for donor, recipient, and transplant characteristics, as well as preimplantation biopsy findings and baseline immunological parameters, the main independent determinants of long term allograft loss were identified as allocation of ECDs (hazard ratio 1.84 (95% confidence interval 1.5 to 2.3); P < 0.001), presence of circulating DSA on the day of transplantation (3.00 (2.3 to 3.9); P < 0.001), and longer cold ischaemia time (> 12 h; 1.53 (1.1 to 2.1); P = 0.011). Recipients of ECD kidneys with circulating DSA showed a 5.6-fold increased risk of graft loss compared with all other transplant therapies (P < 0.001). ECD allograft survival at seven years significantly improved with screening and transplantation in the absence of circulating DSA (P < 0.001) and with shorter (<12 h) cold ischaemia time (P=0.030), respectively. This strategy achieved ECD graft survival comparable to that of patients receiving an SCD transplant overall, translating to a 544.6 allograft life years saved during the nine years of study inclusion time. CONCLUSIONS: Circulating DSA and cold ischaemia time are the main independent determinants of outcome from ECD transplantation. Allocation policies to avoid DSA and reduction of cold ischaemia time to increase efficacy could promote wider implement of ECD transplantation in the context of organ shortage and improve its prognosis.

Anti-human leukocyte antigen immunization after early allograft nephrectomy.

INTRODUCTION: The occurrence of de novo anti-human leukocyte antigen (HLA) antibodies and donor-specific antibodies (DSAs) after early graft loss is not well known. The aims of this single-center study were to evaluate the incidence of de novo DSAs and non-DSA anti-HLA antibodies after allograft nephrectomy for early graft loss and to seek the predictive factors for the development of DSAs. MATERIALS AND METHODS: Thirty-two patients, who experienced an early graft loss (<3 months after transplantation) and required an allograft nephrectomy, and who were considered for retransplantation, were included in the study. Anti-HLA antibodies were assessed, using the Luminex assay, before transplantation, on day 15 and at months 1, 3, 6, and 9 after the nephrectomy, and then every 3 to 6 months until the last follow-up. RESULTS: The median time between transplantation and allograft nephrectomy was 2.5 (0-81) days. The median follow-up was 335 (30-1441) days. At month 9, postallograft nephrectomy, the incidence of DSAs was 56.6% (17/30). Anti-HLA class I and class II DSAs were detected, respectively, in 33.3% (10/30) and 30% (9/30) of patients. The incidence of de novo non-DSA anti-HLA antibodies was 64% (19/30): of these, 83.3% reacted to the donors' epitopes. Induction therapy (type and dose) and the time between transplantation and allograft nephrectomy did not influence the incidence of DSAs. No independent predictive factor for the development of DSAs was identified. CONCLUSION: Even after a short transplantation period, DSAs and non-DSA anti-HLA antibodies may develop in more than 50% of patients whose immunosuppression has been stopped after an allograft nephrectomy.