Objectives We aimed to evaluate rates of antibody response to mRNA SARS-CoV-2 vaccine among kidney transplant recipients, and to identify factors associated with reduced immunogenicity. Methods A prospective cohort study including consecutive kidney transplant recipients in a single referral transplant center. Participants were tested for anti-spike (anti-S) antibodies 2-4 weeks following second vaccine dose. Primary outcome was rate of seropositivity. Univariate and multivariate analyses were conducted to identify factors associated with seropositivity. Results Of 308 kidney transplant recipients included, only 112 (36.4%) tested positive for anti-S antibodies 2-4 weeks after receiving the second dose of BNT162b2 vaccine. Median antibody titer was 15.5 AU/mL (interquartile range [IQR] 3.5-163.6). Factors associated with antibody response were higher estimated glomerular filtration rate (eGFR) (odds ratio [OR] 1.025 per ml/min/1.73m 2 , 95% confidence interval [CI] 1.014 - 1.037, p<0.001), lower mycophenolic acid dose (OR 2.347 per 360 mg decrease, 95% CI 1.782 - 3.089, p<0.001), younger age (OR 1.032 per year decrease, 95% CI 1.015 - 1.05, p<0.001) and lower calcineurin inhibitors (CNI) blood level (OR 1.987, 95% CI 1.146 - 3.443, p=0.014). No serious adverse events to the vaccine were reported. Conclusions Kidney transplant recipients demonstrated inadequate antibody response to mRNA SARS-CoV-2 vaccination. Immunosuppression level was a significant factor in this response. Strategies to improve immunogenicity should be examined in future studies.

No abstract

Background: This study aimed to characterize features present at the time of diagnosis and describe outcomes in patients with post-transplant lymphoproliferative disorder (PTLD) following pediatric solid organ transplantation. Methods:We performed a retrospective review of solid organ transplant patients who developed pathologically confirmed PTLD at our center from 2006 to 2016. Results:Of 594 patients included in this study, 41(6.9%) were diagnosed with PTLD.Median age at transplant was 5.6(IQR 1.7-16.1) years. Proportion of PTLD cases by organ transplanted and median time (IQR) to disease onset were: heart 11/144(7.6%) at 13.6(8.5-55.6) months, lung 7/52(13.5%) at 9.1(4.9-35) months, kidney 8/255(3.1%) at 39.5(13.9-57.1) months, liver 12/125(9.6%) at 7.7(5.5-22) months, intestine 0/4(0%), and multi-visceral 3/14(21.4%) at 5.4(5.4-5.6) months. No significant correlation was seen between recipient EBV status at transplant and timing of development of PTLD.There were six early lesions, 15 polymorphic, 19 monomorphic, and one uncharacterizable PTLD. Following immunosuppression reduction, 30 patients received rituximab, and 14 required chemotherapy. At median 25(IQR 12-53) months follow-up from the onset of PTLD, eight patients died secondary to transplant related complications, three are alive with active disease, and 30 have no evidence of disease. Conclusion:PTLD is a significant complication following pediatric solid organ transplantation. EBV levels in conjunction with symptomatic presentation following transplant may assist in detection of PTLD. Most patients can achieve long-term disease-free survival through immunosuppression reduction, anti-CD20 treatment, and chemotherapy in refractory cases.