Higher pro‐inflammatory cytokines IL‐6 and IFN‐γ are associated with anti‐SARS‐CoV‐2 spike protein‐specific seroconversion in renal allograft recipients.

Background: Maintenance immunosuppressive regimens are speculated to hamper immunogenic response against severe acute respiratory syndrome‐coronavirus‐2 (SARS‐CoV‐2) in renal transplant recipients (RTRs) compared to the healthy population. Healthy people with SARS‐CoV‐2 infection often develop neutralizing antibodies and secret copious quantities of cytokines, leading to virus clearance and sometimes more severe immune‐related complications. Methods: RTRs, either acquired SARS‐CoV‐2 infection (infection group, n = 132) or were vaccinated with two vaccine doses (vaccination group, n = 78) against SARS‐CoV‐2, were recruited in the study. Thirty‐five unvaccinated RTRs, without anti‐SARS‐CoV‐2 spike protein‐specific antibodies, were also included as control. Cytokines interleukine‐6 (IL‐6), interferon‐γ (IFN‐γ), TGF‐β, and IL‐10 were measured using ELISA. The SARS‐CoV‐2 spike protein‐specific IgG‐titer was measured by chemiluminescent microparticle immunoassay methods. Results: The seroconversion rate in the infection group was 115/132 (87.12%), with a median antibody titer 706.40 au/mL (IQR, 215.45–1844.42), and in the vaccination group was 63/78 (80.76%) with antibody titer 1454.20 au/mL (IQR, 80.52–3838.75). The IL‐6, IFN‐γ, TGF‐β, and IL‐10 levels were significantly higher in both the infection and vaccination group compared to healthy control. In the infection group, pro‐inflammatory cytokines IL‐6 (55.41 ± 24.30 vs. 31.64 ± 16.98 pg/mL, p <.001) and IFN‐γ (91.21 ± 33.09 vs. 61.69 ± 33.28 pg/mL, p =.001) were significantly higher in the seroconverter group as compared to non‐seroconverter. Similarly, in the vaccination group, pro‐inflammatory cytokines IL‐6 (50.31 ± 25.67 vs. 30.00 ± 11.19 pg/mL; p =.002) and IFN‐γ (65.70 ± 39.78 vs. 32.14 ± 17.48 pg/mL; p =.001) were significantly higher in the seroconverter group compared to non‐seroconverter. In contrast, TGF‐β (820.96 ± 415.78 vs. 1045.57 ± 204.66; p =.046) was higher in non‐seroconverter. Conclusions: Pro‐inflammatory cytokines IL‐6 and IFN‐γ were significantly associated with seroconversion after SARS‐CoV‐2 infection and vaccination in RTRs. [ABSTRACT FROM AUTHOR]