Faculty Bibliography

Transplanting hepatitis C viremic donor organs into hepatitis C virus (HCV)-negative recipients is becoming increasingly common; however, practices for posttransplant direct-acting antiviral (DAA) treatment vary widely. Protracted insurance authorization processes for DAA therapy often lead to treatment delays.

Antibody responses among immunocompromised solid organ transplant recipients (SOT) infected with Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) may be diminished compared to the general population and have not been fully characterized. We conducted a cohort study at our transplant center to investigate the rate of seroconversion for SARS-CoV-2 IgG antibodies among SOT recipients who were diagnosed with Coronavirus disease 2019 (COVID-19) and underwent serum SARS-CoV-2 IgG enzyme-linked immunosorbent assay (ELISA) testing. The 61 patients who were included in the final analysis underwent initial SARS-CoV-2 IgG testing at a median of 62 days (Interquartile range 55.0-75.0) from symptom onset. Note that, 51 of 61 patients (83.6%) had positive SARS-CoV-2 IgG results, whereas 10 (16.4%) had negative IgG results. Six (60%) out of 10 seronegative patients underwent serial IgG testing and remained seronegative up to 17 weeks post-diagnosis. Use of belatacept in maintenance immunosuppression was significantly associated with negative IgG antibodies to SARS-CoV-2 both in univariate and multivariate analyses (Odds ratio 0.04, p = .01). In conclusion, the majority of organ transplant recipients with COVID-19 in our study developed SARS-CoV-2 antibodies. Further longitudinal studies of the durability and immunologic role of these IgG responses and the factors associated with lack of seroconversion are needed.

The current kidney allocation system (KAS) preferentially allocates kidneys from blood type A2 or A2B (A/A2B) donors to blood type B candidates. We used national data to evaluate center-level performance of A2/A2B to B transplants, and organ procurement organization (OPO) reporting of type A or AB donor subtyping, in 5-year time periods prior to (2009-2014) and following (2015-2019) KAS implementation. The number of centers performing A2/A2B to B transplants increased from 17 pre-KAS to 76 post-KAS, though this still represents only a minority of centers (7.3% pre-KAS and 32.6% post-KAS). For high-performing centers, the median net increase in A2/A2B to B transplants was 19 cases (range -2-72) per center in the 5 years post-KAS. The median net increase in total B recipient transplants was 21 cases (range -17-119) per center. Despite requirements for performance of subtyping, in 2019 subtyping was reported on only 56.4% of A/AB donors. This translates into potential missed opportunities for B recipients, and even post-KAS up to 2322 A2/A2B donor kidneys may have been allocated for transplantation as A/AB. Further progress must be made both at center and OPO levels to broaden implementation of A2/A2B to B transplants for the benefit of underserved recipients.

Purpose: Blood type B candidates on the deceased donor kidney waitlist have a lower transplantation rate and longer wait time than candidates of other blood types. The new national kidney allocation system (KAS), implemented in December 2014, prioritizes the allocation of kidneys from blood type A2 and A2B deceased donors to blood type B candidates to mitigate this disparity in access to transplantation. We analyzed our center's data to determine whether blood type A2/A2B to B transplantation is clinically feasible without the need for additional immunosuppression.
Method(s): We conducted a single-center retrospective cohort study to analyze the utilization and outcomes in A2/A2B to B deceased donor renal transplants. Data on adult, kidney-only recipients were extracted with custom reports from the United Network for Organ transplantation (UNOS) portal. We used multivariable Coxproportional hazards models to compare graft and patient survival in blood type A2/A2B to B deceased donor renal transplants to survival in blood type B to B transplants. We estimated Kaplan-Meier (KM) graft and patient survival functions.
Result(s): Since 2015, our center has performed 44 A2/A2B to B and 65 B to B kidney transplants. We followed the patients for a median of 712 days (IQR 343-1143). Recipients of A2/A2B to B and B to B kidney transplants were similar with respect to age, gender, estimated post-transplant survival (EPTS), calculated panel reactive antibody (CPRA), HLA ABDR mismatch, kidney donor profile index (KDPI), and the incidence of delayed graft function (DGF). A higher percentage of A2/A2B to B transplant recipients were Black/African American (22/44, 50%) than B to B transplant recipients (14/65, 21.5%). Blood type A2/A2B to B and B to B transplant recipients had similar 1-year graft (97.7% vs. 93.8%, p=0.34) and 1-year patient survival (97.7% vs. 98.5%, p=0.78) rates. Multivariable models adjusted for race/ ethnicity showed that death censored graft survival (adjusted HR=1.45, p=0.70, 95% CI=0.21 to 9.82) and patient survival (4.22, p=0.14, 95% CI=0.64 to 27.92) in A2/A2B to B transplant recipients were similar to the traditionally ABO blood type compatible B to B transplants.
Conclusion(s): The NYU Langone blood type A2/A2B to B transplantation adds to the body of evidence suggesting that blood type A2/A2B to B transplantation is clinically feasible. This provision of the KAS appears to be having its intended effect of increasing access to transplantation in blood type B candidates with no attendant compromise in overall patient or death censored graft survival