A comparison of antibody response in kidney transplant recipients and healthcare workers who had PCR-confirmed COVID-19 infection

BACKGROUND/AIM: Data on antibody response following COVID-19 in kidney transplant recipients is scarce. This crosssectional study aims to investigate the antibody response to COVID-19 among kidney transplant recipients. MATERIALS AND METHODS: We recruited 46 kidney transplant recipients with RT-PCR-confirmed COVID-19 and 45 recipients without COVID-19 history. We also constructed two control groups (COVID-19 positive and negative) from a historical cohort of healthcare workers. We used age and sex-based propensity score matching to select the eligible subjects to the control groups. We measured the SARS-CoV-2 IgG levels quantitatively using the Abbott ARCHITECT system. An antibody level above 1.4 S/C was defined as positivity. RESULTS: Transplant recipients with COVID-19 had a higher BMI, and COVID-19 history in a household member was more common than that of the transplant recipient without COVID-19. IgG seropositivity rate (69.6% vs. 78.3%, p = 0.238) and the median IgG level (3.28 [IQR: 0.80–5.85] vs. 4.59 [IQR: 1.61–6.06], p = 0.499) were similar in COVID-19-positive transplant recipients and controls. Kidney transplant recipients who had a longer duration between RT-PCR and antibody testing had lower antibody levels (r = −0.532, p < 0.001). CONCLUSION: At the early post-COVID-19 period, kidney transplant recipients have a similar antibody response to controls. However, these patients’ antibody levels and immunity should be closely monitored in the long term.