Kidney transplant recipients are at increased risk of severe outcomes during COVID-19. Antibodies against the virus are thought to offer protection, but a thorough characterization of anti–SARS-CoV-2 immune globulin isotypes in kidney transplant recipients following SARS-CoV-2 infection has not been reported.

We performed a cross-sectional study of 49 kidney transplant recipients and 42 immunocompetent controls at early (≤14 days) or late (>14 days) time points after documented SARS-CoV-2 infection. Using a validated semiquantitative Luminex-based multiplex assay, we determined the abundances of IgM, IgG, IgG1–4, and IgA antibodies against five distinct viral epitopes.

Kidney transplant recipients showed lower levels of total IgG antitrimeric spike (S), S1, S2, and receptor binding domain (RBD) but not nucleocapsid (NC) at early versus late time points after SARS-CoV-2 infection. Early levels of IgG antispike protein epitopes were also lower than in immunocompetent controls. Anti–SARS-CoV-2 antibodies were predominantly IgG1 and IgG3, with modest class switching to IgG2 or IgG4 in either cohort. Later levels of IgG antispike, S1, S2, RBD, and NC did not significantly differ between cohorts. There was no significant difference in the kinetics of either IgM or IgA antispike, S1, RBD, or S2 on the basis of timing after diagnosis or transplant status.

Kidney transplant recipients mount early anti–SARS-CoV-2 IgA and IgM responses, whereas IgG responses are delayed compared with immunocompetent individuals. These findings might explain the poor outcomes in transplant recipients with COVID-19.

This article contains a podcast athttps://www.asn-online.org/media/podcast/JASN/2021_11_23_briggsgriffin112321.mp3

在 COVID-19 期间，肾移植受者出现严重后果的风险增加。人们认为针对该病毒的抗体可以提供保护，但尚未报道 SARS-CoV-2 感染后肾移植受者体内抗 SARS-CoV-2 免疫球蛋白同种型的全面特征。

我们在记录的 SARS-CoV-2 感染后的早期（≤14 天）或晚期（>14 天）时间点对 49 名肾移植受者和 42 名免疫功能正常的对照者进行了横断面研究。使用经过验证的基于 Luminex 的半定量多重检测，我们确定了针对 5 个不同病毒表位的 IgM、IgG、IgG1-4 和 IgA 抗体的丰度。

肾移植受者在 SARS-CoV-2 感染后的早期时间点与晚期时间点相比，总 IgG 抗三聚体刺突 (S)、S1、S2 和受体结合域 (RBD) 水平较低，但核衣壳 (NC) 水平较低。 IgG 抗刺突蛋白表位的早期水平也低于免疫活性对照。抗 SARS-CoV-2 抗体主要是 IgG1 和 IgG3，在任一队列中都有少量类别转换为 IgG2 或 IgG4。随后的 IgG 抗尖峰、S1、S2、RBD 和 NC 水平在各队列之间没有显着差异。根据诊断后的时间或移植状态，IgM 或 IgA 抗尖峰、S1、RBD 或 S2 的动力学没有显着差异。

肾移植受者会出现早期的抗 SARS-CoV-2 IgA 和 IgM 反应，而 IgG 反应与免疫功能正常的个体相比会延迟。这些发现可能可以解释患有 COVID-19 的移植受者的不良结局。

本文包含播客https://www.asn-online.org/media/podcast/JASN/2021_11_23_briggsgriffin112321.mp3