A Safe Anti-A2 Titer for a Successful A2 Incompatible Kidney Transplantation: A Single-center Experience and Review of the Literature.

BACKGROUND: Kidney allocation system allows blood type B candidates accept kidneys from A2/A2B donors. There is no mandate by UNOS on which the anti-A2 level is acceptable. We aimed to investigate the safety of kidney transplant in blood group B patients with anti-A2 titers ≤16. METHODS: We performed 41 A2-incompatible kidney transplants in blood group B recipients between May 2015 and September 2019. Clinical outcomes were compared with a control group of 75 blood group B recipients who received blood group compatible kidney transplantation at the same period. RESULTS: Of the 41 recipients, 85% were male, 48% African American, with a median age of 53 (20-73) y. Thirty-eight (93%) were deceased-donor and 3 (7%) were living-donor kidney transplant recipients. Pretransplant anti-A2 IgG titers were 2 in 16, 4 in 9, 8 in 6, and 16 in 5 and too weak to titer in 5 recipients. Eight patients had pretransplant donor-specific antibodies. During a median follow-up of 32.6 mo (6-57.3) patient and graft survival were 100% and 92% in the A2-incompatible kidney transplant group, and 91% and 92% in the blood group compatible group, respectively. Twelve A2-incompatible recipients underwent a 21 clinically indicated kidney biopsies at a median 28 d (6-390) after transplantation. None of the patients developed acute antibody-mediated rejection and 2 patients (5%) had acute T-cell-mediated rejection. Interestingly, peritubular capillary C4d positivity was seen in 7 biopsies which did not have any findings of acute rejection or microvascular inflammation but not in any of the rejection-free biopsies in the control group. C4d positivity was persistent in 5 of those patients who had follow-up biopsies. CONCLUSIONS: A2-incompatible transplantation is safe in patients with anti-A2 titers ≤16 with excellent short-term kidney allograft outcomes. C4d positivity is frequent in allograft biopsies without acute rejection.

COVID-19 and Solid Organ Transplantation: A Review Article.

The coronavirus pandemic has significantly impacted solid organ transplantation (SOT). Early in the outbreak period, transplant societies recommended suspending living kidney transplant programs in communities with widespread transmission to avoid exposing recipients to increased risk of immunosuppression, while recommendations were made to reserve deceased-donor kidney transplantation for likely life-saving indications. SOT recipients may be at high risk from COVID-19 disease due to chronic immunosuppressive treatment and other medical comorbidities. Mortality rates reported between 13 to over 30% in SOT recipients. In addition to high rates of complications and mortality attributable to COVID-19 infections, the pandemic has also led to additional complexities in transplantation including new questions regarding screening of donors and recipients, decision making to accept a patient for kidney transplant or wait after pandemic. The clinical implications of COVID-19 infection may also differ depending on the type of the transplanted organ and recipient comorbidities which further impacts decisions on continuing transplantation during the pandemic. Transplant activity during a pandemic should be tailored with careful selection of both donors and recipients. Furthermore, while tremendous strides have been made in treatment strategies and vaccinations, the impact of these in transplant recipients may be attenuated in the setting of their immunosuppression. In this review, we aim to summarize several aspects of COVID-19 in transplantation, including the immune response to SARS-CoV-2, SARS-CoV-2 diagnostics, clinical outcomes in SOT recipients, and end-stage kidney disease patients, transplant activity during the pandemic, and treatment options for COVID-19 disease.

COVID-19 infection in kidney transplant recipients at the epicenter of pandemics.

We investigated the prevalence and clinical outcomes of COVID-19 in recipients of kidney transplants in the Bronx, New York, one of the epicenters of the pandemic. Between March 16 and June 2, 2020, 132 kidney transplant recipients tested positive by SARS-CoV-2 RT-PCR. From May 3 to July 29, 2020, 912 kidney transplant recipients were screened for SARS-CoV-2 IgG antibodies during routine clinic visits, of which 16.6% tested positive. Fifty-five of the 152 patients had previously tested positive by RT-PCR, while the remaining 97 did not have significant symptoms and had not been previously tested by RT-PCR. The prevalence of SARS-CoV-2 infection was 23.4% in the 975 patients tested by either RT-PCR or SARS-CoV-2 IgG. Older patients and patients with higher serum creatinine levels were more likely diagnosed by RT-PCR compared to SARS-CoV-2 IgG. Sixty-nine RT-PCR positive patients were screened for SARS-CoV-2 IgG antibodies at a median of 44 days post-diagnosis (Inter Quartile Range 31-58) and 80% were positive. Overall mortality was 20.5% but significantly higher (37.8%) in the patients who required hospitalization. Twenty-three percent of the hospitalized patients required kidney replacement therapy and 6.3% lost their allografts. In multivariable analysis, older age, receipt of deceased-donor transplantation, lack of influenza vaccination in the previous year and higher serum interleukine-6 levels were associated with mortality. Thus, 42% of patients with a kidney transplant and with COVID-19 were diagnosed on antibody testing without significant clinical symptoms; 80% of patients with positive RT-PCR developed SARS-CoV-2 IgG and mortality was high among patients requiring hospitalization.