The reactions with anti-B are weaker than expected (e.g., 1+ or 2+) and often show MFA microscopically. The patient's autocontrol is negative even though anti-B is present (patient is group A). The patient's own anti-B will not recognize and agglutinate the B-like antigen, but everyone else's anti-B (including the typing sera) will. It is hypothesized that the patient's anti-B molecules that could react with the pseudo-B antigen on the patient's own red cells are neutralized by soluble pseudo-B antigen in the patient's plasma.