title: Flow cytometry crossmatch before kidney transplantation in contemporary practice: target cell utilization, results patterns, and associated long-term graft survival.
abstract: The flow cytometry crossmatch (FXCM) is an increasingly common method for pre-transplant crossmatching. We examined FCXM use in a national sample of kidney transplants, characterizing target cell utilization, results patterns, and associated graft outcomes. We queried Organ Procurement and Transplant Network Registry to identify kidney transplants performed in 1995-2007 with prospective FCXM testing for IgG antibodies against T-cells, B-cells or undifferentiated lymphocytes. FCXM was categorized according to target utilization and target-specific results. We modeled associations of FCXM testing-results patterns with risk of five-year graft loss and with projected graft survival by multivariable survival analysis. Sixty-five percent of the deceased donor transplants were performed with negative T-cell and B-cell FCXM, 16% with negative T-cell/unmeasured B-cell FCXM, 9% with negative undifferentiated lymphocyte FCXM, and < 0.5% with negative B-cell/unmeasured T-cell FCXM. Test results for at least one target were positive in 7.6% of transplants, most commonly in the form of B-cell positive/T-cell negative. Allograft survival was most favorable when both T-cell and B-cell FCXM targets were included and yielded negative results. Notably, B-cell positive/T-cell negative FCXM predicted elevated graft loss risk, with approximately 16% and 32% relative risk increases for deceased and living donor grafts, respectively, compared to negative T-cell and B-cell FCXM. Negative FCXM results with undifferentiated targets alone also predicted inferior graft survival. These data support the importance of using differentiated B-cell and T-cell targets for FCXM. Transplants that proceeded with positive FCXM experienced decrements in long-term graft survival - the decision to accept such risk must be individualized.
authors.affiliation: Center for Outcomes Research, Saint Louis University School of Medicine, St. Louis, MO, USA.
authors.forename: Krista L
authors.initials: KL
authors.lastname: Lentine
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: Graff
authors.forename: Huiling
authors.initials: H
authors.lastname: Xiao
authors.forename: Kian A
authors.initials: KA
authors.lastname: Modanlou
authors.forename: Paolo R
authors.initials: PR
authors.lastname: Salvalaggio
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Brennan
authors.forename: Brett W
authors.initials: BW
authors.lastname: Pinsky
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Burroughs
authors.forename: Mark A
authors.initials: MA
authors.lastname: Schnitzler
mesh_terms: D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000097:blood*; D002454:Cell Differentiation; D002648:Child; D002675:Child, Preschool; D019992:Databases as Topic; D005260:Female; D005434:Flow Cytometry; D006084:Graft Rejection / Q000276:immunology / Q000401:mortality / Q000517:prevention & control*; D006085:Graft Survival / Q000276:immunology*; D006648:Histocompatibility; D006650:Histocompatibility Testing / Q000379:methods*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016030:Kidney Transplantation / Q000276:immunology* / Q000401:mortality; D019520:Living Donors; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D009927:Tissue and Organ Procurement; D023001:Transplantation Tolerance; D014184:Transplantation, Homologous; D016896:Treatment Outcome; D014481:United States; D055815:Young Adult
chemical_list: D000906:Antibodies