Hemolytic anemia after kidney transplantation: a prospective analysis.

BACKGROUND: Hemolysis may occur in 9% to 40% of patients after solid organ transplantation and be caused by the passenger lymphocyte syndrome (PLS). STUDY DESIGN AND METHODS: We have prospectively examined 217 kidney transplant recipients before (Day −1) and after (up to Days +10, +20, and +30) surgery. ABO-identical transplant was performed in 180 (82.9%) patients, while 37 (17.1%) individuals received ABO-compatible nonidentical grafts. Direct antiglobulin tests (DATs) were performed by tube technique (polyspecific anti-human globulin [IgG + C3d]), positive DAT samples were further tested by gel agglutination (monospecific anti-IgG, -IgM, -IgA, or -C3), and eluates were prepared from DAT-positive red blood cells (RBCs) by the dichloromethane elution test. RESULTS: We observed that 34 of 217 (15.7%) patients developed a positive DAT up to Day +30. The percentage of patients with positive DATs was significantly higher in those having ABO-compatible nonidentical transplants compared to those that received ABO-identical grafts (10/37 = 27.0% vs. 24/180 = 13.3%; p = 0.037). Specific RBC antibodies (anti-A or anti-B) were found in only 5 of 37 (13.5%) patients having ABO-compatible nonidentical transplants who presented with clinical hemolysis. We found only three reactive eluates from 24 patients with positive DATs who received ABO-identical transplants but had no hemolysis. CONCLUSIONS: Our data collected prospectively demonstrated that: 1) positive DATs occurred in 15.7% of all patients up to Day +30 after a kidney transplant; 2) the DAT positivity occurred up to Day +10 in 9.7% of all transplanted patients; 3) the majority of the transplant recipients with a positive DAT had a nonreactive RBC eluate; and 4) PLS was the cause of a positive DAT in 13.5% of patients submitted to ABO-compatible nonidentical kidney transplants. [ABSTRACT FROM AUTHOR]