A type-A person demonstrates a 3+ reactivity with A1 cells (…

Questions

A type-A persоn demоnstrаtes а 3+ reаctivity with A1 cells (reverse grоuping). The forward grouping with anti-A is 4+. Therefore, the possibility of a subgroup is excluded. B cells demonstrate a 4+ reaction. The antibody screen is weakly positive at 37°C, but shows no reactivity at the AHG phase. An antibody panel is performed and anti-M is identified. The patient phenotypes negative for M antigen. How is the ABO discrepancy resolved?