Flow cross-matching identifies patients at risk for postoperative elaboration of cytotoxic antibodies.
BACKGROUND
Cytotoxic IgG against class I antigens can contribute to renal dysfunction or failure after transplantation. However, the clinical relevance of IgG measured by flow cytometric cross-matching is controversial. This study correlated pre- and postoperative flow reactivity with clinical outcome among renal transplant patients with negative preoperative cytotoxic cross-matches.


METHODS
Nonsensitized primary renal allograft patients (n = 157) with negative preoperative cytotoxic cross-matches (complement-dependent lymphocytotoxicity assays) were stratified on the basis of IgG reactivity measured by flow cytometric cross-matching (FCXM) as FCXM negative (Neg) or positive against class I (T-pos FCXM) or class II (B-pos FCXM) antigens. The groups were compared in terms of frequency of early rejection and 1-year graft survival.


RESULTS
Patient distribution was 67% Neg, 14% T-pos FCXM, 14% B-pos FCXM, and 5% IgM FCXM. The incidence of early rejection was 25+/-3% for Neg and 51+/-3% for T- and B-pos FCXM (P < 0.05). One-year graft survival for Neg versus T-pos and B-pos FCXM was 97+/-3% versus 44+/-10% (P < 0.05) and 77+/-5% (P = 0.06), respectively. Rejections requiring plasmapheresis were found only among patients with T-pos FCXM. Among 29 patients, FCXM and complement-dependent lymphocytotoxicity assays were performed 10+/-2 and 28+/-4 days after transplantation. Pre- and posttransplant antibody levels were relatively unchanged among Neg and B-pos FCXM patient groups. In contrast, patients with T-pos FCXM produced cytotoxic IgG against class I after transplantation, which may have contributed to the severe graft dysfunction experienced by this group.


CONCLUSIONS
FCXM is a useful tool to stratify primary renal transplant candidates in terms of potential risk for severe rejection. Furthermore, demonstration of preoperative flow reactivity against class I may identify a subgroup of patients at risk for early elaboration of cytotoxic alloantibody.
Kimball
P
P
Department of Surgery, Medical College of Virignia, Richmond 23298, USA.
Rhodes
C
C
King
A
A
Fisher
R
R
Ham
J
J
Posner
M
M
D000920:Antibody-Dependent Cell Cytotoxicity; D001402:B-Lymphocytes / Q000276:immunology; D006084:Graft Rejection / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D006650:Histocompatibility Testing / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007518:Isoantibodies / Q000096:biosynthesis*; D016030:Kidney Transplantation / Q000276:immunology*; D018570:Risk Assessment; D013601:T-Lymphocytes / Q000276:immunology
D007074:Immunoglobulin G; D007518:Isoantibodies