Objective:To investigate the role of TcpC, a virulence factor of uropathogenic Escherichia coli (UPEC), in immune evasion, and analyze its related pathogenic mechanism. Methods:C57BL/6 mice were injected with 10 9 colony-forming unit of wild-type (CFT073 wt) or tcpc gene-knockout (CFT073 Δ tcpc) UPEC CFT073 strains from urethra into bladder to construct a mouse model of pyelonephritis. These mice were sacrificed 5 d after infection and their kidneys were taken to observe the gross pathological changes. Hematoxylin-eosin staining was used to observe histopathological changes in kidney tissues and immunohistochemistry was performed to locate TcpC in kidney tissues. The bacterial loads in urine samples of UPEC infected-mice were counted by ten-fold dilution method, and the presence of tcpc gene in the genomic DNA of bacteria from CFT073-infected mouse kidney or urine samples was measured by PCR. The expression of TcpC at mRNA level was detected by qRT-PCR after infecting dendritic cells with CFT073 wt strains. The influences of UPEC infection on the activation of NF-κB signaling pathway and the secretion of proinflammatory factors by dendritic cells were analyzed by Western blot and ELISA, respectively. The viability of UPEC strains in dendritic cells were observed by laser confocal microscope. Results:Compared with the CFT073 Δ tcpc group, the mice in the CFT073 wt group had obvious abscess in the kidneys as well as massive neutrophil infiltration and abundant TcpC in kidney tissues. The bacterial loads in the urine of CFT073 wt-infected mice were significantly higher than those in the urine of CFT073 Δ tcpc mice. PCR results showed that tcpc gene was successfully amplified from mouse kidney and urine samples. Increased expression of TcpC at both mRNA and protein levels was detected in CFT073 wt-infected dendritic cells. CFT073 wt infection inhibited the phosphorylation of NF-κB p50 and the production of proinflammatory factors in dendritic cells. TcpC promoted the survival of CFT073 wt in dendritic cells. Conclusions:TcpC expression increases significantly during CFT073 wt infection or in mice with CFT073 wt-induced pyelonephritis. It promotes the survival of CFT073 wt in dendritic cells by inhibiting the activation of NF-κB signaling pathway and reducing the secretion of pro-inflammatory cytokines. TcpC is involved in the pathogenesis of UPEC and immune evasion.

Objective: To analyze the changes in homologous immunity after RhCE-matched transfusion in positive patients with RhCE blood group antibodies, and to provide precise transfusion strategies for chronic anemia patients. Methods: Patients with chronic anemia in our hospital from January 2020 to March 2024 (continuously receiving blood transfusions for more than 6 months) were enrolled, and 63 cases of unexpected antibody screening positive and identified as RhCE blood group antibodies were selected as the research subjects. The changes in unexpected antibody yield rate after ABO and RhCcDEe isotype blood transfusion were observed. Patients with MNS, Kidd, or Lewis blood group antibodies were screened for corresponding negative donors using monoclonal antibodies for extended typing transfusion based on RhCcEe typing, and the changes in unexpected antibody yield rate after transfusion were observed. Blood group genotyping was performed when serological techniques failed to resolve discrepancies or detect abnormal antigen expression. Results: After RhCcDEe-matched transfusions, RhCE antibodies disappeared in 62 patients, while 1 patient developed anti-Ce. The latter did not develop blood type isotype immunity after receiving RhccEE donor blood. Among the 62 patients, 9 developed unexpected antibodies against other systems: anti-M (4 cases), anti-Mur (2), anti-S (1), anti-Jka (1), and anti-Lea (1). No additional alloimmunization occurred after extended antigen-matched transfusions. A patient with serologically weak e phenotype was genotyped as DCe/DcE, with gene sequencing revealing an 827C>A mutation in exon 6 of the RHCE gene, forming the RHCE 01.31 allele. Conclusion: Precise transfusion strategies incorporating RhCE, MNS, Kidd, and Lewis blood group antigen typing can reduce the probability of blood group homologous immunity. RhCE complex antibodies and RhCE variants pose difficulties for clinical RhCE typing transfusion, which can be addressed through cross-matching and genetic analysis.