Discrepancy of B cell frequency between periphery and spleen after rituximab treatment in ABO-incompatible liver transplantation.

ABO-incompatible living-donor liver transplantation (ABO-LDLT) is generally more difficult to perform than ABO-incompatible kidney transplantation. Despite introduction of rituximab, ABO-LDLT in non-responders is a still difficult issue. A 23-year-old woman with primary sclerosing cholangitis underwent LDLT. The recipient's blood type was 0(+) and the donor's was B(+). Rituximab was infused twice on preoperative day (POD) 14 and 7. Plasma exchange (PE) was performed on PODs 5, 3, 2, and 1. However, repeated PE failed to decrease the anti-B antibody titer. On the other hand, preoperative esophagogastroscopy revealed esophageal varices with red color sign. Therefore, simultaneous liver transplantation and Hassab operation were performed. The donor left lobe of the liver was orthotopically transplanted into the recipient following Hassab operation. Flow cytometry on the day of surgery showed that the frequencies of B cells (CD20+) and memory B cells (CD20+/CD27+) in the peripheral blood were 0.9% and 0.3%, respectively; flow cytometry of cells recovered from the spleen revealed that the frequencies of B cells and memory B cells were 2.5% and 2.4%, respectively. Acute cellular rejection occurred on POD 15, and was treated by steroid pulse therapy, leading to a decrease in the anti-B antibody titer. The liver was functioning well on POD 390 (AST 19, ALT 34). In non-responders to ABO-LDLT, anti-donor blood type antibody-producing cells remains in the spleen after the conventional preoperative regimen. Splenectomy is an option for ABO-LDLT non-responders.