ESPN 54th Annual Meeting

ESPN 2022


 
Humoral response to COVID-19 mRNA vaccines in a cohort of young kidney transplant recipients from a single Center in Northern Italy
MARTA BRAMBILLA 1 SARA TESTA 1 MARCO CAZZANIGA 2 JESSICA SERAFINELLI 1 CHIARA TAMBURELLO 1 VIGANONI MARIA 2 MASSIMO OGGIONI 3 FERRUCCIO CERIOTTI 3 GIOVANNI MONTINI 4

1- FONDAZIONE IRCCS CA GRANDA OSPEDALE MAGGIORE POLICLINICO, PEDIATRIC NEPHROLOGY, DIALYSIS AND TRANSPLANT UNIT, MILAN, ITALY
2- UNIVERSITY OF MILAN, MILAN, ITALY
3- FONDAZIONE IRCCS CA GRANDA OSPEDALE MAGGIORE POLICLINICO, CLINICAL LABORATORY, MILAN, ITALY
4- FONDAZIONE IRCCS CA GRANDA OSPEDALE MAGGIORE POLICLINICO, PEDIATRIC NEPHROLOGY, DIALYSIS AND TRANSPLANT UNIT; UNIVERSITY OF MILAN, DEPARTMENT OF CLINICAL SCIENCES AND COMMUNITY HEALTH, UNIVERSITY OF MILAN, MILAN, ITALY
 
Introduction:

 To investigate immune-response to COVID-19 vaccines in young kidney transplant (KT) recipients from Northern Italy. 

Material and methods:

We prospectively studied KT patients aged 12 to 25 years, managed in our Center on maintenance IS therapy (corticosteroids, CNI and anti-proliferative agents), who received a complete primary antiSARS-CoV2 vaccination course and an additional dose one month later according to Italian Medicines Agency. From 1st July 2021 to 31st January 2022 we evaluated antiSpike-protein antibody response at T0 (before vaccine), at T1 and T2 (14±3 days after 2nd and 3rd doses respectively) of BNT162b2 (Pfizer/BioNTech) or mRNA-1273 (Moderna)Exclusion criteria were: KT or other IS within 6 months; relapse of primary kidney disease; vaccine before KT; ongoing COVID-19.

Results:

87 patients were eligible; 68 (45M) patients were enrolled. Median age was 19.5 (IQR: 16.3–21.9) years; median time from KT was 61.4 (IQR: 36.7-111.7) months. Anti-spike total Ig titer was considered undetectable if <0.8 U/ml, (Roche® Elecsys Anti-SARS-CoV-2 S).

At T14 pts (21.5%; data in 65 pts) had a positive titer (median: 211.5 U/mL IQR:147-829); among them five had a history of SARS-Cov2. Five patients dropped out of study after enrollment.

At T1 35 pts (63.6%; data in 55 pts) and at T2 44 pts (90.0%; data in 49 pts) seroconverted or enhanced titer, if previously immunized (median:1256 U/mL; IQR:308.00-13000 and 3662 U/mL; IQR: 193–13000, respectively). 55% of non-responders at T1 seroconverted after the third dose. Patients that experienced COVID-19 before vaccination developed significantly higher antibody titer (median 13000 vs 3.7 p<0.05). No patient had side effects, including acute rejection or DSAs. 

Conclusions:

KT pediatric recipients exhibit a satisfactory response after 2 doses of vaccine, that become comparable to that of immunocompetent population after the third. Furthermore, the response after two doses is better if compared with adult KT population (63.6% vs 4-48%).