Differential Clinical Outcomes in Kidney Transplant Recipients With De Novo C1q+ and C1q- Donor Specific Antibodies

M. Ajaimy,¹ A. Colovai,² S. Calp,¹ J. Lindower,¹ M. Melamed,³ E. Akalin.¹

¹Transplantation, Einstein/Montefiore Transplant Center, Bronx
²Tissue Typing Laboratory, Einstein/Montefiore Transplant Center, Bronx
³General Nephrology, Einstein/Montefiore Teaching Hospital, Bronx.

Meeting: 2015 American Transplant Congress

Abstract number: 372

Keywords: Antibodies, Sensitization

Session Information

Session Name: Concurrent Session: Kidney: Antibodies and Allograft Injury

Session Type: Concurrent Session

Date: Tuesday, May 5, 2015

Session Time: 2:15pm-3:45pm

Presentation Time: 2:39pm-2:51pm

Location: Room 118-AB

Background: We investigated the prevalence and clinical significance of C1q binding versus non-C1q binding de novo DSA in kidney transplant recipients.

Methods: The study group included consecutive patients who received kidney transplantation at our center between May 2009 and December 2012, and had no pre-formed DSA. Serum anti-HLA antibodies were monitored after transplantation at 3, 12 months and yearly thereafter, and at the time of clinically indicated biopsies. To characterize DSA specificity and complement binding capacity, conventional and C1q Single Antigen Bead assays were used.

.Results: Out of 284 patients, 31 (11%) developed de novo DSA during a median follow-up of 29 months (17, 50). Of these, 23% had class I, 46% had class II, and 31% showed both class I and II DSA. DSA directed to donor HLA-DQ were most frequently observed (48% of the patients with DSA). C1q+ DSA were identified in 11 out of 31 patients (35%). Overall, mean fluorescence intensity (MFI) values of class I C1q+ DSA were significantly higher compared to those of C1q- DSA (6476±3016 vs. 2471±1546 p=0.01) but not for class II (7198±3496 vs. 4616±3952, p=0.13). Incidence of acute and chronic AMR was significantly higher in the C1q+DSA+ (45% and 36%) group compared to the C1q-DSA (5% and 5%) and DSA- groups (1% and 2%) (p < 0.001).


Variable	No DSA(N=253)	De Novo C1q+ DSA(N=11)	De Novo C1q- DSA(N=20)	P value
Mean age at transplant	53±12.5	45.7±14.1	48.1±11.1	0.02
Gender, % female	39	66	50	0.62
Race, % African American	32	63	50	0.03
Transplant type, % living donor	31	36	20	0.54
Previous Transplant,%	9	0	10	0.56
Mean class I PRA	21±31	37±41	47±36	<0.001
Mean class II PRA	22±32	60±35	64±31	<0.001
Mean serum creatinine, mg/dl	1.4±0.6	2.2±1.2	1.5±0.4	0.001
Acute cellular rejection,%	5	9	5	0.81
Acute AMR, %	1	45	5	<0.001
Chronic AMR,%	2	36	5	<0.001
Graft survival,%	94	73	95	0.01
Patient survival,%	98	100	95	0.66

Furthermore, graft survival was lower in the C1q+DSA group (73%) compared to the C1q-DSA (95%) and DSA- (94%) groups. Patients with C1q+ DSA had higher creatinine levels compared to C1q-DSA and DSA- groups.

Conclusions: The development of C1q+ DSA after renal transplantation is associated with acute and chronic AMR, and lower graft survival and allograft function.

To cite this abstract in AMA style:

Ajaimy M, Colovai A, Calp S, Lindower J, Melamed M, Akalin E. Differential Clinical Outcomes in Kidney Transplant Recipients With De Novo C1q+ and C1q- Donor Specific Antibodies [abstract]. Am J Transplant. 2015; 15 (suppl 3). https://atcmeetingabstracts.com/abstract/differential-clinical-outcomes-in-kidney-transplant-recipients-with-de-novo-c1q-and-c1q-donor-specific-antibodies/. Accessed June 23, 2025.

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