Lower CD3 and CD4 counts in kidney transplant recipients who did not respond to COVID-19 vaccination

Background: Kidney transplant recipient's response rate to COVID-19 vaccination is reportedly less than 54% after the 2nd dose, significantly lower than general population and dialysis patients, reported as between 85-90% and 95-100%, respectively. Methods: We studied SARS-CoV-2 anti-spike IgG levels in our kidney transplant recipients after their COVID-19 vaccination using the OrthoV IgG platform. Results: 69 kidney transplant recipients received a SARS-CoV-2 vaccine (47 Pfizer, 20 Moderna and 2 Johnson and Johnson) at a median 36 months after transplantation (range, 3 months to 22 years). 61% were male, 39% Black, 29% Hispanic with a median age of 60 (range 22-82). 72% were deceased-donor kidney transplant recipients. 23 patients had previous history of COVID-19 diagnosed by SARS-CoV-2 PCR and/or antinucleocapsid antibody and 21 of those patients (91%) developed anti-spike IgG after 1st or 2nd dose with a median level of 13.2 (11.2-16.2). 46 patients without history of previous COVID-19, 17 (37%) developed anti-spike IgG at a median of 28 days (range 10-72) after the second vaccine dose with a median level of 5.7 (1.22-15.4). Patients who didn't develop anti-spike IgG tended to be older, of African-American descent, on MMF > 1 g/day, have lower CD3 and CD4 counts. Conclusions: In summary, most kidney transplant recipients without history of COVID-19 did not produce anti-spike IgG after being fully vaccinated and it is associated with augmented immunosuppression, lower T cell counts, African-American race and older age.