Impact of donor-specific antibody with low mean fluorescence intensity on allograft outcomes in kidney transplant.

BACKGROUND: Immune-mediated rejection is the most common cause of allograft failure in kidney transplant (KT) patients. Exposure to alloantigen, including human leukocyte antigen (HLA), results in the production of donor-specific antibodies (DSA). There are limited data about low levels of mean fluorescence intensity (MFI) DSA, especially post-transplantation. This study evaluated allograft outcomes in KT patients with low MFI DSA. METHODS: From January 2007 to December 2021, KT patients who were tested for post-transplant DSA at Ramathibodi Hospital, Bangkok, Thailand, with the DSA MFI ≤ 1000 were evaluated. These KT patients were categorized into two groups: very low DSA (VLL; MFI = 1-500) and low DSA (LL; MFI = 501-1000). All KT patients were evaluated for the primary outcomes, such as the incidence of acute rejection, serum creatinine levels at one and five years after transplantation as well as allograft and patient survivals. RESULTS: Among 36 KT patients 25 were included as those with VLL and 11 as those with LL. The LL group had significantly higher T-cell mediated allograft rejection (TCMR) than the VLL group (45% vs. 12%, P = 0.04). In addition, 10 patients, 5 in the VLL group and 5 in the LL group developed antibody-mediated allograft rejection (ABMR). Both TCMR and ABMR were confirmed by biopsy results. There was a trend toward higher MFI in KT patients with ABMR than without ABMR (P = 0.22). At 5 post-transplant years, serum creatinine, allograft and patient survivals were comparable between these two groups. Furthermore, the univariate and multivariate analyzes revealed that the LL group was a high risk for rejection. CONCLUSION: Low MFI DSA values after transplantation may be associated with a higher incidence of rejection, but this finding did not show differences in allograft and patient survival in this study's analysis.

A 46-Year-Old Thai Woman with Secondary Acquired Pure Red Cell Aplasia Due to Treatment with Recombinant Erythropoietin While on Dialysis for End-Stage Renal Disease Who Recovered Following ABO-Incompatible Kidney Transplantation.

BACKGROUND Pure red cell aplasia (PRCA) is an uncommon cause of anemia in end-stage kidney disease (ESKD). It is attributed to recombinant human erythropoietin (rHuEPO) administration. Although immunosuppression is the mainstay therapy, its effectiveness varies from 30% to 70%. PRCA in ESKD has been reported to improve following kidney transplantation. CASE REPORT A 46-year-old woman with ESKD secondary to lupus nephritis was treated for uremia at our center. She developed severe anemia. Bone marrow aspiration and biopsy revealed a reduction of erythroid precursors, consistent with PRCA. Because she had no sibling's blood group matched with her, ABO-incompatible kidney transplantation was an option for treatment. She underwent a desensitization protocol consisting of rituximab 375 mg/m2, tacrolimus, mycophenolate mofetil, and prednisolone 4 weeks before surgery, in addition to 3 sessions of double-filtration plasmapheresis (DFPP) every other day followed by intravenous immunoglobulin (IVIG) and 1 session of specific immunoadsorption (Glycosorb® B column) at pre-transplant day -1. She also received low-dose rabbit anti-thymocyte globulin (rATG) (Thymoglobulin®) (total 2.0 mg/kg). Maintenance therapy included tacrolimus, mycophenolate mofetil, and prednisolone. Allograft function normalized a few days after transplantation and her Hb gradually increased. CONCLUSIONS We report a rare case of PRCA in a patient with ESKD undergoing ABO-incompatible kidney transplantation. The outcome was satisfactory, with complete correction of anemia and kidney function.

Durability of Humoral and Cellular Immunity after an Extended Primary Series with Heterologous Inactivated SARS-CoV-2 Prime-Boost and ChAdOx1 nCoV-19 in Dialysis Patients (ICON3).

The durability of a three-dose extended primary series of COVID-19 vaccine in dialysis patients remains unknown. Here, we assessed dynamic changes in SARS-CoV-2-specific humoral and cell-mediated immunity at baseline, 3 months, and 6 months after the extended primary series in 29 hemodialyzed (HD), 28 peritoneal dialyzed (PD) patients, and 14 healthy controls. Participants received two doses of inactivated SARS-CoV-2 vaccine followed by a dose of ChAdOx1 nCoV-19 vaccine. At 6 months, median anti-RBD IgG titers (IQR) significantly declined from baseline in the HD (1741 (1136−3083) BAU/mL vs. 373 (188−607) BAU/mL) and PD (1093 (617−1911) BAU/mL vs. 180 (126−320) BAU/mL) groups, as did the mean percent inhibition of neutralizing antibodies (HD: 96% vs. 81%; PD: 95% vs. 73%) (all p < 0.01). Age and post-vaccination serological response intensity were predictors of early humoral seroprotection loss. In contrast, cell-mediated immunity remained unchanged. In conclusion, humoral immunity declined substantially in dialysis patients, while cell-mediated immunity remained stable 6 months after the extended heterologous primary series of two inactivated SARS-CoV-2/ChAdOx1 nCoV-19 vaccine. A booster dose could be considered in dialysis patients 3 months after this unique regimen, particularly in the elderly or those with a modest initial humoral response.

Immunogenicity of ChAdOx1 nCoV-19 vaccine after a two-dose inactivated SARS-CoV-2 vaccination of dialysis patients and kidney transplant recipients.

Vaccination with inactivated SARS-CoV-2 virus produces suboptimal immune responses among kidney transplant (KT), peritoneal dialyzed (PD), and hemodialyzed (HD) patients. Participants were vaccinated with two-dose inactivated SARS-CoV-2 vaccine (V2) and a third dose of ChAdOx1 nCoV-19 vaccine (V3) at 1-2 months after V2. We enrolled 106 participants: 31 KT, 28 PD, and 31 HD patients and 16 controls. Among KT, PD, and HD groups, median (IQR) of anti-receptor binding domain antibody levels were 1.0 (0.4-26.8), 1092.5 (606.9-1927.2), and 1740.9 (1106-3762.3) BAU/mL, and percent neutralization was 0.9 (0-9.9), 98.8 (95.9-99.5), and 99.4 (98.8-99.7), respectively, at two weeks after V3. Both parameters were significantly increased from V2 across all groups (p < 0.05). Seroconversion and neutralization positivity rates in PD, HD, and control groups were 100% but were impaired in KT patients (39% and 16%, respectively). S1-specific T-cell counts were increased in PD and HD groups (p < 0.05) but not in KT patients. The positive S1-specific T-cell responder rate was > 90% in PD, HD, and control groups, which was higher than that in KT recipients (74%, p < 0.05). The heterologous inactivated virus/ChAdOx1 nCoV-19 vaccination strategy elicited greater immunogenicity among dialysis patients; however, inadequate responses remained among KT recipients (TCTR20210226002).

Short-Term Immunogenicity Profiles and Predictors for Suboptimal Immune Responses in Patients with End-Stage Kidney Disease Immunized with Inactivated SARS-CoV-2 Vaccine.

INTRODUCTION: Patients with end-stage kidney disease (ESKD) are at risk of severe coronavirus disease and mortality. Immunogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivated whole-virus vaccine in patients with ESKD has never been explored. METHODS: We conducted a prospective cohort study of 60 patients with ESKD and 30 healthy controls. All participants received two doses of an inactivated whole-virus SARS-CoV-2 vaccine (Sinovac Biotech Ltd) 4 weeks apart. SARS-CoV-2-specific humoral and cell-mediated immune responses were investigated and referenced with healthy controls. RESULTS: After two doses, an anti-receptor-binding domain immunoglobulin G of 50 AU/ml or greater was present in 53 of 60 patients (88%) in the ESKD group and all participants (100%) in the control group (P = 0.05). The percentage of patients with ESKD and controls with neutralizing antibodies of 35% threshold or greater was 58% and 88%, respectively (P = 0.01). Furthermore, the proportion of patients with ESKD and S1-specific T cell response was comparable with controls (82% vs. 77%, P = 0.45). Old age, high ferritin level, and low absolute lymphocyte count were independently associated with poor humoral immune responses. CONCLUSIONS: Patients with ESKD could develop similar SARS-CoV-2-specific cell-mediated immune responses compared to healthy controls, although suboptimal humoral immune responses were observed following two doses of SARS-CoV-2 vaccination. Therefore, patients with ESKD and the abovementioned factors are at risk of generating inadequate humoral immune responses, and a vaccine strategy to elicit greater immunogenicity among these relatively immunocompromised patients is warranted. (Thai Clinical Trials Registry, TCTR20210226002).