Persistence of low levels of alloantibody after desensitization in crossmatch-positive living-donor kidney transplantation.
BACKGROUND
: Desensitization protocols have been developed to allow successful kidney transplantation in sensitized recipients. However, a detailed analysis of the impact of these protocols on alloantibody has not been performed.


METHODS
: We studied 12 living-donor kidney-transplant recipients with positive antihuman globulin-enhanced complement dependent cytotoxicity (AHG-CDC) crossmatches against their donors. Using a variety of crossmatch techniques and single-antigen flowbeads (SAFBs), we characterized the specificity and amount of alloantibody at baseline before desensitization, after desensitization (using plasmapheresis followed by 100 mg/kg intravenous immunoglobulin, and anti-CD20 antibody), and 4 months after transplantation (after splenectomy and on maintenance immunosuppression).


RESULTS
: All 12 patients with a positive baseline AHG-CDC crossmatch were AHG-CDC crossmatch negative at the time of transplant (after desensitization). However, despite desensitization, the majority of patients had low-level donor-specific alloantibodies demonstrable on the day of transplantation by both flow crossmatch (FXM 8/12) and SAFBs (10/11). Four months after transplantation, no patient had a positive AHG-CDC crossmatch, but again the majority had persistent low levels of donor-specific alloantibodies by FXM (6/12) and SAFBs (9/11). No patient experienced hyperacute rejection, and the persistence of low levels of donor-specific alloantibodies did not correlate with the development of humoral rejection in the early posttransplant period.


CONCLUSIONS
: Despite desensitization, a majority of positive crossmatch transplant recipients demonstrate low levels of donor-specific alloantibodies both on the day of transplant and 4 months after transplantation. The impact of these antibodies appears to be minimal early after transplant, but their long-term significance bears further study.
Department of Nephrology and Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
James M
JM
Gloor
Steven
S
DeGoey
Nancy
N
Ploeger
Howard
H
Gebel
Robert
R
Bray
S Breanndan
SB
Moore
Patrick G
PG
Dean
Mark D
MD
Stegall
D001402:B-Lymphocytes / Q000276:immunology; D003404:Creatinine / Q000097:blood; D005434:Flow Cytometry / Q000379:methods; D005500:Follow-Up Studies; D006680:HLA Antigens / Q000276:immunology*; D006650:Histocompatibility Testing / Q000379:methods*; D006801:Humans; D007114:Immunization; D007165:Immunosuppression Therapy / Q000379:methods; D007518:Isoantibodies / Q000097:blood*; D007519:Isoantigens / Q000276:immunology; D016030:Kidney Transplantation / Q000276:immunology*; D019520:Living Donors; D012086:Reoperation; D013601:T-Lymphocytes / Q000276:immunology; D013997:Time Factors
D006680:HLA Antigens; D007518:Isoantibodies; D007519:Isoantigens; D003404:Creatinine