Very Low Frequency of Pathological Findings in One-Year Protocol Biopsies of Low-Risk Kidney Transplant Recipients - Results from the Nordic Protocol Biopsy Study

Very Low Frequency of Pathological Findings in One-Year Protocol Biopsies of Low-Risk Kidney Transplant Recipients – Results from the Nordic Protocol Biopsy Study

I. Helanterä¹, C. Dörje², F. Ortiz³, A. Varberg Reisæter², C. Hammarstrøm², J. Lauronen⁴, A. Räisänen-Sokolowski⁵, A. J. Haugen⁶, M. Lempinen¹, A. Åsberg², G. Mjøen²

¹Transplantation and Liver Surgery, Helsinki University Hospital, Helsinki, Finland, ²Department of Transplant Medicine, Oslo University Hospital, Oslo, Norway, ³Nephrology, Helsinki University Hospital, Helsinki, Finland, ⁴Histocompatibility Laboratory, Finnish Red Cross Blood Service, Helsinki, Finland, ⁵Department of Pathology, Helsinki University Hospital, Helsinki, Finland, ⁶Medical Department, Bærum Hospital, Bærum, Norway

Meeting: 2022 American Transplant Congress

Abstract number: 210

Keywords: Kidney transplantation, Protocol biopsy, Rejection

Topic: Clinical Science » Kidney » 34 - Kidney: Acute Cellular Rejection

Session Information

Session Name: Kidney: Acute Cellular Rejection

Session Type: Rapid Fire Oral Abstract

Date: Monday, June 6, 2022

Session Time: 3:30pm-5:00pm

Presentation Time: 4:00pm-4:10pm

Location: Hynes Ballroom A

*Purpose: The clinical usefulness of kidney graft protocol biopsies have been debated. We studied the frequency of borderline and T-cell-mediated rejection (TCMR) in one-year protocol biopsies in low-risk kidney transplant recipients.

*Methods: All non-HLA-sensitized recipients of kidney transplants between 2004-2017 with a protocol biopsy at one year in the national transplant centers of Finland (Helsinki) or Norway (Oslo) were studied (N=1601). Donor-specific HLA antibodies (DSA), graft function (plasma creatinine), and proteinuria were measured at the time of one year protocol biopsy. Previous acute rejections within the first year were recorded. Biopsy lesions were categorized according to Banff 2019 classification. The occurrence of subclinical acute TCMR (i2t2v0 or higher) or borderline TCMR (i1t1 or higher) in the protocol biopsy was studied.

*Results: Subclinical acute TCMR was detected in 32/1601 (2.0%) of the protocol biopsies. Borderline TCMR or higher was detected in 196/1601 (12%). Among patients with de novo DSA detected at one year, subclinical TCMR was seen in 11/116 (9.5%), and borderline TCMR or higher in 40/116 (34%). Among patients with a history of previous acute rejection within the first year, TCMR was detected at one year in 28/355 (7.9%) and borderline TCMR or higher in 113/355 (32%). Of the patients with de novo DSA detected at one year, 60/116 (52%) had a previous acute rejection during the first year. On the contrary, among patients with no history of acute rejection, no proteinuria or DSA, and adequate graft function at one year (defined as creatinine <150 µmol/ or <1.7 mg/dL), TCMR was detected in only 1/1018 (0.1%) and subclinical TCMR or higher in only 52/1018 (5.1%) patients at one year (table).

*Conclusions: In conclusion, the likelihood of TCMR or borderline TCMR in one-year protocol biopsies in clinically stable low-risk patients without proteinuria or the presence of DSA, and with no history of acute rejection is very low. The clinical usefulness of protocol biopsies in these patients may be questionable.

Findings in one year protocol biopsies
	TCMR at one year protocol biopsy	Borderline TCMR or higher at one year protocol biopsy
Whole cohort (N=1601)	32 (2.0%)	196 (12%)
Patients with de novo DSA at one year (N=116)	11 (9.5%)	40 (34%)
Patients with any proteinuria (urine protein-to-creatinine >10mg/dl) (N=116)	5 (4.3%)	26 (22%)
Patients with suboptimal graft function (creatinine >1.7 mg/dL) (N=248)	9 (3.6%)	49 (20%)
Patients with a history of acute rejection before the protocol biopsy (N=355)	28 (7.9%)	113 (32%)
Patients with none of the abovementioned risk factors (N=1018)	1 (0.1%)	52 (5.1%)

To cite this abstract in AMA style:

Helanterä I, Dörje C, Ortiz F, Reisæter AVarberg, Hammarstrøm C, Lauronen J, Räisänen-Sokolowski A, Haugen AJ, Lempinen M, Åsberg A, Mjøen G. Very Low Frequency of Pathological Findings in One-Year Protocol Biopsies of Low-Risk Kidney Transplant Recipients – Results from the Nordic Protocol Biopsy Study [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/very-low-frequency-of-pathological-findings-in-one-year-protocol-biopsies-of-low-risk-kidney-transplant-recipients-results-from-the-nordic-protocol-biopsy-study/. Accessed May 18, 2025.

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