ABO‐incompatible kidney transplantation can be successfully conducted by monitoring IgM isoagglutinin titers during desensitization

Abstract

BACKGROUND Recent advances in desensitization techniques and immunosuppressive therapy have led to improved outcomes after ABO‐incompatible (ABO‐i) kidney transplantation (KT). However, questions remain unanswered, particularly regarding which type of ABO isoagglutinin—immunoglobulin M (IgM) or immunoglobulin M (IgG)—is significantly involved in antibody‐mediated rejection (AMR). STUDY DESIGN AND METHODS We retrospectively analyzed data from 120 patients who underwent ABO‐i KT between 2012 and 2014. Preoperative plasma exchange was performed until the IgM isoagglutinin titer was 4 or less, regardless of the IgG titer. Clinical data were compared between patient groups with pre‐KT IgG isoagglutinin titer 16 or greater (high IgG; titer range, 16‐256; n = 39) and 8 or less (low IgG; titer range, −8; n = 81). RESULTS The median follow‐up periods were 59 (high IgG) and 55 (low IgG) months. Patient survival at 5 years (p = 0.314) was 100% (high IgG) and 97.4% (low IgG). Graft survival at 5 years (p = 0.480) was 100% (high IgG) and 98.7% (low IgG). AMR by anti‐ABO antibody occurred in only one patient in the low‐IgG group. CONCLUSION Patients with high pre‐KT IgG isoagglutinin titers had equally successful outcomes as those with low IgG titers. ABO‐i KT can be successfully performed by reducing the pre‐KT IgM isoagglutinin titer to 4 or less, as determined by the immediate spin tube method.

Evaluation of safety of using incompatible plasma for therapeutic plasma exchange during shortage of AB plasma

“…The clinical efficacy of incompatible FFP use based on reduction in the isoagglutinin titer was within our expectations; target isoagglutinin titers were achieved in all cases. The rate of reduction in the isoagglutinin titer was comparable to a previously reported range using AB plasma (1‐3 titers vs 1.55‐1.66 per session) 10 . Regarding the removal of anti‐HLA antibodies, incompatible FFP exhibited reduction rates (25.3%‐35.3% per session) similar to those mentioned in a previous report 14 .…”

“…Test sera were incubated at ambient temperature with either 3% Affirmagen A1 or B cells (Ortho Clinical Diagnostics, Raritan, The United States). The dilution in the last tube with an agglutination score of greater than 1+ was interpreted as the IgM isoagglutinin titer, while the IgG titer was determined by the addition of 0.1 mL polyspecific AHG (Millipore, Livingston, The United Kingdom) to each test tube 10,11 . HLA crossmatching (complement dependent cytotoxicity crossmatch and flow cytometry crossmatch) was performed using isolated lymphocytes.…”

ABO‐incompatible living kidney transplantation

“…The correlation of IgG with a low graft survival rate and AMR was reported 23 . However, Kim et al 24 revealed no difference in prognosis between an IgG titer of ≥16 and ≤8 when the pretransplant IgM titer was decreased to ≤4. Accordingly, the authors confirmed that ABO‐ILKT can be conducted by monitoring the IgM anti‐A/B titer during desensitization.…”

Characteristics of Immunoglobulin M Type Antibodies of Different Origins from the Immunologic and Clinical Viewpoints and Their Application in Controlling Antibody-Mediated Allograft Rejection

“…It has been reported that the IgM antibody is involved in ABO-incompatible transplantation, and desensitization therapy using the IgM-type ABO antibody titer as an index is useful for preventing AMR development [127]. Contrarily, other reports stated that IgG-type ABO antibodies are risk factors for the development of AMR [128].…”