Blood Group Antigen A Carriers Exhibit an Extended Progression-Free Survival with no more Immune-Related Adverse Events.

Extensive investigations have been conducted regarding the potential correlation between blood type and the immune system, as well as cancer risk in the Southern Chinese population. However, the prognostic value of the blood group and its genetic determinants in the context of immune checkpoint inhibitor (ICI) treatment remains unclear. Therefore, the associations between the ABO blood group and its single nucleotide polymorphisms (SNPs) were examined in relation to ICI treatment outcomes in 370 eligible patients with cancer. This approach allowed us to derive the blood group from the SNPs responsible for blood group determination. In the discovery cohort (N = 168), antigen A carriers (blood types A and AB) exhibited an extended progression-free survival (PFS; hazard ratio (HR) = 0.58, 95% confidence interval (CI) = 0.34-0.98). The association results from the SNP-derived blood were consistent with those from the measured blood group. In the validation cohort (N = 202), Cox regression analysis revealed that the antigen A carriers (rs507666 AA+GA genotype carriers) experienced significantly extended PFS compared with the non-antigen A carriers (HR = 0.61, 95% CI = 0.40-0.93). Therefore, a longer PFS was observed in antigen A carriers (P value = 0.003, HR = 0.60, 95% CI = 0.44-0.84). Furthermore, haplotype 2 carriers (rs507666 GA and rs659104 GG) demonstrated both extended PFS and improved overall survival. Notably, the presence of antigen A was not associated with the occurrence of overall immune-related adverse events (irAEs) or organ-specific toxicity. In summary, our findings revealed that antigen A carriers did not experience a higher incidence of irAEs while exhibiting better immunotherapy efficacy.