激活的滤泡辅助 T (aTfh) 细胞可能在宿主对严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) mRNA 疫苗接种的免疫反应中发挥重要作用。我们在 40 名肾移植受者 (KTR) 和 17 名健康对照志愿者 (HC) 的外周血中表征了 aTfh 细胞对第二剂 (D2) 和第三剂（加强剂；D3）mRNA 疫苗的免疫反应。 D3 后，KTR 中 SARS-CoV-2 特异性 IgG 抗体显着增加；尽管如此，D2 和 D3 后的水平显着低于 HC。 D2 后，与 KTR 中的血清阴性患者相比，在 HC 以及 KTR 中的血清阳性患者中观察到活化的 CD45RA-CXCR5 ICOS PD1 循环 Tfh (acTfh) 细胞显着增加。与 HC 不同，KTR 的免疫反应不太明显，包括产生干扰素 γ、肿瘤坏死因子 α 和白介素 21 的 acTfh 和 T 细胞。此外，acTfh 细胞的增加与 D3 后的抗 IgG 抗体水平显着相关。这些结果表明 KTR 中的 acTfh 细胞对 SARS-CoV-2 的特异性反应受损，并且表明外周血中的 acTfh 细胞可能在 SARS-CoV-2 mRNA 疫苗接种后的抗体维持中发挥重要作用。© 2024。 s）。

Activated T follicular helper (aTfh) cells are likely important in host immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination. We characterized the immune responses of aTfh cells to the second (D2) and third (booster; D3) doses of an mRNA vaccine in the peripheral blood of 40 kidney transplant recipients (KTRs) and 17 healthy control volunteers (HCs). A significant increase in SARS-CoV-2-specific IgG antibody was seen after D3 in the KTRs; nonetheless, the levels after D2 and D3 were significantly lower than in the HCs. After D2, dramatic increases in activated CD45RA-CXCR5+ICOS+PD1+ circulating Tfh (acTfh) cells were observed in the HCs, as well as the seropositive patients among the KTRs, when compared with the seronegative patients among the KTRs. Unlike the HCs, KTRs had less prominent immune responses, including the acTfh and T cells that produce interferon gamma, tumor necrosis factor alpha, and interleukin 21. In addition, the increase in acTfh cells was significantly associated with anti-IgG antibody levels after D3. These results indicate impaired SARS-CoV-2-specific responses via acTfh cells in KTRs, and they suggest that acTfh cells in peripheral blood may play an important role in antibody maintenance following SARS-CoV-2 mRNA vaccination.© 2024. The Author(s).