Failure to remove de novo donor-specific HLA antibodies is influenced by antibody properties and identifies kidney recipients with late antibody-mediated rejection destined to graft loss - a retrospective study.

Current research is focusing on identifying bioclinical parameters for risk stratification of renal allograft loss, largely due to antibody-mediated rejection (AMR). We retrospectively investigated graft outcome predictors in 24 unsensitized pediatric kidney recipients developing HLA de novo donor-specific antibodies (dnDSAs), and treated for late AMR with plasmapheresis + low-dose IVIG + Rituximab or high-dose IVIG + Rituximab. Renal function and DSA properties were assessed before and longitudinally post treatment. The estimated GFR (eGFR) decline after treatment was dependent on a negative % eGFR variation in the year preceding treatment (P = 0.021) but not on eGFR at treatment (P = 0.74). At a median follow-up of 36 months from AMR diagnosis, 10 patients lost their graft. Altered eGFR (P < 0.001) and presence of C3d-binding DSAs (P = 0.005) at treatment, and failure to remove DSAs (P = 0.01) were negatively associated with graft survival in the univariable analysis. Given the relevance of DSA removal for therapeutic success, we analyzed antibody properties dictating resistance to anti-humoral treatment. In the multivariable analysis, C3d-binding ability (P < 0.05), but not C1q-binding, and high mean fluorescence intensity (P < 0.05) were independent factors characterizing DSAs scarcely susceptible to removal. The poor prognosis of late AMR is related to deterioration of graft function prior to treatment and failure to remove C3d binding and/or high-MFI DSAs.

Interferon-ribavirin therapy induces serum antibodies determining 'rods and rings' pattern in hepatitis C patients.

A cytoplasmic antigen associated to inosine-5'-monophosphatedehydrogenase 2 eliciting specific antibodies (antirods and rings, RR) has been identified in patients with chronic hepatitis C who were exposed to pegylated interferon (PI) and ribavirin (RBV). The significance of anti-RR in these patients merits to be investigated. Sera from 88 chronic hepatitis C virus (HCV)-infected patients undergoing PI-RBV therapy were analysed for the presence of RR pattern by indirect immunofluorescence on HEp-2 substrate (Inova Diagnostics, San Diego, CA, USA). Anti-RR antibodies developed de novo in 32 patients independently of any demographic and virological feature, but with a significant association with cumulative exposure to PI-RBV (P = 0.0089; chi-square test). RR pattern was significantly more frequent in relapsers than in patients achieving sustained virological response (56% vs 30%; P = 0.0282, chi-square test). Anti-RR titre ranged from 1:80 to 1:1280, but significantly declined following treatment cessation. Anti-RR develop de novo in a substantial proportion of patients exposed to PI-RBV in relation to the duration of treatment exposure. Further investigations are necessary to unravel the mechanisms leading to the formation of these autoantibodies.

DQ molecules are the principal stimulators of de novo donor-specific antibodies in nonsensitized pediatric recipients receiving a first kidney transplant.

Data on the different HLA-antibody (Ab) categories in pediatric kidney recipients developing de novo donor-specific Abs (DSA) after transplantation are scarce. We retrospectively evaluated 82 consecutive nonsensitized pediatric recipients of a first kidney graft for de novo HLA Ab occurrence and antigen specificity. At a median follow-up of 6 years, 29% of patients developed de novo DSA, while 45% had de novo non-DSA. DSA appeared at 25-month median time post-transplant and were mostly directed toward HLA-DQ antigens. Considering each HLA antigen, the estimated rate of DQ DSA (7.55 per 100 person-years) was much higher than the rates observed for non-DQ DSA. The HLA-DQ Ab recognized determinants of the DQß chain in 70% of cases, α chain in 25% of cases, and both chains in one patient. Non-DSA peaked earlier than DSA, and were largely directed against HLA class I specificities that belonged to HLA-A- and HLA-B-related cross-reacting epitope groups (CREG) in 56% of cases. Our results indicate a need for evaluating HLA-DQ compatibilities in kidney allocation, in order to minimize post-transplant development of de novo DSA, known to be responsible for antibody-mediated rejection and graft loss.

Photopheresis Abates the Anti-HLA Antibody Titer and Renal Failure Progression in Chronic Antibody-Mediated Rejection.

OBJECTIVE: Chronic renal antibody-mediated rejection (ABMR) is a common cause of allograft failure, but an effective therapy is not available. Extracorporeal photopheresis (ECP) has been proven successful in chronic lung and heart rejection, and graft versus host disease. The aim of this study was to evaluate the effectiveness of ECP in chronic ABMR patients. PATIENTS AND METHODS: We investigated ECP treatment in 14 patients with biopsy-proven chronic ABMR and stage 2-3 chronic renal failure. The primary aim was to e valuate the eGFR lowering after 1 year of ECP therapy. The ECP responders (R) showed eGFR reduction greater than 20% vs the basal levels. We also evaluated the effectiveness of ECP on proteinuria, anti-HLA antibodies (HLAab), interleukin 6 (IL-6) serum levels, and CD3, CD4, CD8, CD19, NK, Treg and T helper 17 (Th17) circulating cells. RESULTS: Three patients dropped out of the study. The R patients were eight (72.7%) out of the 11 remaining patients. Because ECP was not associated with any adverse reaction, the R patients continued such treatment for up to 3 years, showing a persisting eGFR stabilization. Twenty four hour proteinuria did not increase in the R patients over the follow-up when compared to the non-responder patients (NR). In the R patients, the HLAab levels were reduced and completely cleared in six out of eight patients when compared with the NR patients. The NR HLAab levels also increased after the discontinuation of the ECP. The ECP in the R patients showed a decrease in CD3, CD4, CD8, CD19, and NK circulating cells. The ECP treatment in the R patients also induced Tregs and Th17 cell increases, and a decrease of the IL-6 serum levels. CONCLUSIONS: ECP abates the HLAab titer and renal failure progression in patients with chronic renal ABMR, modulating the immune cellular and humoral responses.

Early acute rejection after lung transplantation mimicking viral pneumonia in the middle of COVID-19 pandemic: A case report.

INTRODUCTION: In addition to morbidity and mortality rate per se, COVID-19 outbreak leads to potential 'side effects', which are difficult to evaluate and predict. Lung transplantation is a consolidated treatment for end-stage chronic lung disease requiring significantly demanding management. Deciding whether to keep transplant programmes open during an epidemic of this size is not easy, as immunosuppressed subjects face the risk of infection and related mortality. Additionally, there is a chance for the patient's standard care process to be compromised. PRESENTATION OF CASE: We report the case of a patient undergoing bilateral lung transplantation during the explosion of COVID-19 epidemic in Lombardy; he died from definite early acute antibody-mediated rejection, clinically (persistent high fever, unresponsive to treatment) and radiologically mimicking viral pneumonia but persistently negative for SARS-CoV-2. DISCUSSION: The diagnosis was difficult given this atypical presentation, confounded by global scenario. Grafts were procured from a donation after circulatory death donor in an uncontrolled setting and a donor-recipient transmission was possible. Our institute became a COVID-Hospital right during the first post-transplantation days. Radiological imaging had the same features of SARS-CoV-2 pneumonia. CONCLUSIONS: This is the first report of lung transplantation of the COVID-19 era in Europe. Our extremely fragile patient was COVID-19 free up to the end. Donor-recipient transmission is conceivable, but the risk should be assessed with respect to waiting list mortality. Ultimately, treating COVID-19 patients can be a resource-consuming activity but we decided to keep our centre open.