title: Hyperacute renal allograft rejection from anti-HLA class 1 antibody to B cells--antibody detection by two color FCXM was possible only after using pronase-digested donor lymphocytes.
abstract: We present a report of a transplant recipient who lost her renal allograft from hyperacute rejection. This was secondary to a weak IgG anti-HLA class I antibody that was only reactive to donor B lymphocytes. This antibody was not detected in her pretransplant serum by the conventional complement-dependent cytotoxicity assays using donor blood lymphocytes. Pretransplant sera were analyzed retrospectively by two-color flow cytometric crossmatching (FCXM). It was difficult to determine if the recipient's serum contained an IgG antibody specific for HLA on donor B cells since IgG from control AB sera and pretransplant sera bound equally well to CD19 B cells. However, when donor lymphocytes were pretreated with pronase to digest the membrane receptor for Fc domain of IgG (Fc gamma R) on non-T-cells, control IgG in AB serum did not bind to B cells and, hence, it was easy to detect binding of IgG (in pretransplant sera) to HLA on B cells. This case underscores the importance of identifying weak anti-HLA class I antibodies reactive only to B cells. Moreover, it shows that the currently used two-color FCXM lacks the specificity to detect such antibodies.
authors.affiliation: Department of Internal Medicine, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
authors.forename: P I
authors.initials: PI
authors.lastname: Lobo
authors.forename: C E
authors.initials: CE
authors.lastname: Spencer
authors.forename: R B
authors.initials: RB
authors.lastname: Isaacs
authors.forename: C
authors.initials: C
authors.lastname: McCullough
mesh_terms: D000328:Adult; D000906:Antibodies / Q000032:analysis / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006084:Graft Rejection / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D016030:Kidney Transplantation / Q000276:immunology*; D011402:Pronase
chemical_list: D000906:Antibodies; D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G; D011402:Pronase