Early renal graft function deterioration in recipients with preformed anti-MICA antibodies: partial contribution of complement-dependent cytotoxicity

• Published in: Nephrology, dialysis, transplantation Vol. 31; no. 1; pp. 150 - 160
• Main Authors: Sánchez-Zapardiel, Elena, Castro-Panete, María José, Mancebo, Esther, Morales, Pablo, Laguna-Goya, Rocío, Morales, José María, Apaza, Jacqueline, de Andrés, Amado, Talayero, Paloma, Paz-Artal, Estela
• Format: Journal Article
• Language: English
• Published: England 01-01-2016
• Subjects: Adult; Aged; Aged, 80 and over; Antibody Specificity; Antibody-Dependent Cell Cytotoxicity; Autoantibodies - blood; Autoantibodies - immunology; Complement Activation; Female; Glomerular Filtration Rate; Graft Rejection - blood; Graft Rejection - epidemiology; Graft Rejection - immunology; HeLa Cells; Histocompatibility Antigens Class I - immunology; Humans; Kidney - immunology; Kidney - physiopathology; Kidney Transplantation; Male; Middle Aged; Proportional Hazards Models; Renal Insufficiency, Chronic - epidemiology; Renal Insufficiency, Chronic - immunology; Renal Insufficiency, Chronic - surgery; Retrospective Studies; Transplantation, Homologous; Treatment Outcome; anti-MICA antibodies; pretransplantation; cytotoxicity; renal transplant
• ISSN: 0931-0509; 1460-2385
• DOI: 10.1093/ndt/gfv308

We previously reported that preformed anti-MHC class I-related chain A (MICA) antibodies increase the risk for renal graft rejection and enhance the deleterious effect of PRA(+) status early after transplantation.
We studied 727 kidney recipients. Days to reach optimal serum creatinine level, estimated glomerular filtration rate (eGFR) at Month 3 and chronic kidney disease (CKD) stages were recorded. Anti-MICA specificities and C1q binding were tested by solid-phase assay. Complement-dependent cytotoxicity (CDC) and flow cytometry (FC) cross-matches with HeLa and PMA/CD28-T-blasts were performed.
PRA(+)MICA(+) recipients exhibited longer time to reach optimal serum creatinine level after transplantation (P = 0.005) and had the lowest eGFR at Month 3 (P = 0.006). PRA(+)MICA(+) status independently increased the risk for CKDT stage 5 at Month 3 [hazard ratio (HR) 4.92, P = 0.030]. Pre-transplant anti-MICA antibodies were polyspecific and showed stronger reactions when coexisting with anti-HLA antibodies (mean standard fluorescent intensity 112 157 ± 44 426 in HLA(+)MICA(+) sera versus 49 680 ± 33 116 in HLA(-)MICA(+) sera, P = 0.0006). Anti-AYVE supereplet reactivity was significantly higher in HLA(+)MICA(+) versus HLA(-)MICA(+) patients (P < 0.001) and significantly superior than anti-CMGWS supereplet within HLA(+)MICA(+) patients (P = 0.001). Three of 13 anti-MICA(+) pre-transplant sera were positive for the C1q binding assay; one of them (serum 3) exclusively recognized AYVE supereplet with a strong reactivity against MICA*027 antigen (same as MICA*008). Anti-MICA antibodies in anti-HLA-absorbed serum 3 bound native MICA molecules in MICA*008(+) HeLa and PMA/CD28-T-blasts and mediated cell death by activating complement.
Preformed anti-MICA antibodies may occasionally be cytotoxic by fixing and activating complement. This way they might contribute to worse early kidney graft function.