Abstract: PO2400
Impact of Body Mass Index on Baseline Donor-Derived Cell-Free DNA in Kidney Transplant Recipients
Session Information
- Clinical and Immunologic Predictors of Post-Transplant Outcomes
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Transplantation
- 1902 Transplantation: Clinical
Authors
- Aramada, Harsha, Allegheny Health Network, Pittsburgh, Pennsylvania, United States
- Chopra, Bhavna, Allegheny Health Network, Pittsburgh, Pennsylvania, United States
- Sureshkumar, Kalathil K., Allegheny Health Network, Pittsburgh, Pennsylvania, United States
Background
Donor derived cell free DNA (dd-cfDNA) is useful in predicting acute rejection in renal allografts. The technology uses next generation sequencing and does not require donor genotyping. dd-cfDNA is expressed as a percentage of the total (including self and non-self) circulating DNA fragments. Since self-portion of cell free DNA can vary according to body size, we aimed to test the hypothesis that expressed percent of baseline dd-cfDNA can vary by the recipient's body mass index (BMI).
Methods
Our center has been doing for-cause as well as surveillance (for high immunologic risk) dd-cfDNA in kidney transplant recipients (KTRs) using AlloSure (CareDx, Brisbane, CA). We identified patients who underwent kidney transplantation between September 2017 and June 2019 and had serial dd-cfDNA levels. A dd-cfDNA value ≥ 1% prompted allograft biopsy. KTR with biopsy evidence for rejection or other injuries were excluded from the analysis. Study subjects were divided into BMI (kg/m2) groups as follow: <25, 25-29.9, ≥30.Baseline dd-cfDNA values were compared between BMI groups.
Results
There were 88 (81 first-time and 7 repeat) KTRs during the study period who had dd-cfDNA measurements and available BMI. We excluded 16 first-time and 3 repeat KTRs from the analysis due to biopsy evidence of rejection. The remaining 69 patients had 227 dd-cfDNA levels available for analysis. Patients were divided based on BMI categories with stratification of baseline dd-cfDNA values as shown in table 1. There were no significant differences in baseline dd-cfDNA values for BMI groups <25 vs. 25-29.9 (0.63 ± 0.63% vs. 0.41±0.27%, p=0.16) and BMI groups 25-29.9 vs. ≥30 (0.41±0.27% vs. 0.33±0.16%, p= 0.22). However, there was a trend towards significantly higher baseline dd-cfDNA values in BMI group <25 vs. ≥30 (0.63±0.63% vs. 0.33±0.16%, p=0.06).
Conclusion
Our study showed a trend towards significant differences in dd-cfDNA values between extremes of BMI groups. These differences could become significant with larger study subjects. Our findings point towards the need for normalization of dd-cfDNA values with respect to body size for reporting purposes.
Table 1. BMI and dd-cfDNA
| BMI (kg/m2) categories | <25 | 25 -29.9 | ≥30 |
| Number of patients | 19 | 29 | 21 |
| Number of dd-cfDNA tests | 67 | 96 | 64 |
| dd-cfDNA % mean± SD | 0.63±0.63 | 0.41±0.27 | 0.33±0.16 |