Kidney Week

Abstract: PO2190

Regulatory T Cells, BK Virus Infection, and Long-Term Outcomes in Kidney Transplant Recipients

Session Information

• Transplantation: Clinical - Noninvasive Biomarkers, Immune Regulation, and Fascinomas
  November 04, 2021 | Location: On-Demand, Virtual Only
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 1902 Transplantation: Clinical

Authors

• Caliskan, Yasar, Saint Louis University School of Medicine, Saint Louis, Missouri, United States

Yasar Caliskan, MD

• Kiran, Bayram, Kastamonu Universitesi, Kastamonu, Kastamonu, Turkey

Bayram Kiran,

• Kekik, Cigdem, Istanbul Universitesi Istanbul Tip Fakultesi, Istanbul, Istanbul, Turkey

Cigdem Kekik,

• Yazici, Halil, Istanbul Universitesi Istanbul Tip Fakultesi, Istanbul, Istanbul, Turkey

Halil Yazici,

• Senturk Ciftci, Hayriye, Istanbul Universitesi Istanbul Tip Fakultesi, Istanbul, Istanbul, Turkey

Hayriye Senturk Ciftci,

• Dirim, Ahmet Burak, Istanbul Universitesi Istanbul Tip Fakultesi, Istanbul, Istanbul, Turkey

Ahmet Burak Dirim,

• Mirioglu, Safak, Istanbul Universitesi Istanbul Tip Fakultesi, Istanbul, Istanbul, Turkey

Safak Mirioglu,

• Oto, Ozgur Akin, Istanbul Universitesi Istanbul Tip Fakultesi, Istanbul, Istanbul, Turkey

Ozgur Akin Oto,

• Randall, Henry B., Saint Louis University School of Medicine, Saint Louis, Missouri, United States

Henry B. Randall,

• Savran Oguz, Fatma, Istanbul Universitesi Istanbul Tip Fakultesi, Istanbul, Istanbul, Turkey

Fatma Savran Oguz,

• Turkmen, Aydin, Istanbul Universitesi Istanbul Tip Fakultesi, Istanbul, Istanbul, Turkey

Aydin Turkmen,

• Lentine, Krista L., Saint Louis University School of Medicine, Saint Louis, Missouri, United States

Krista L. Lentine,

Background

Regulatory T cells (Tregs) may inhibit pathogen-specific immunity in infectious disorders. We monitored Treg levels during BK virus (BKV) viremia/viruria, examined pattern of Tregs that might contribute BKV infection, and assessed their prognostic value for the KTx outcomes.

Methods

We evaluated 20 KTx recipients (male:13, mean age:41±12 years, living donor 15) in whom BKV viremia/viruria was detected at a median 12.6 (IQR, 4.6-31.2) months after KTx. Serum and urine BKV DNA were measured by real-time PCR at baseline, 1 and 3 months after detection of BKV viremia/viruria. Lymphocyte profile and CD4(+)CD25(+)FoxP3(+) Tregs were measured by flow cytometry concurrently at these time points. Graft outcomes over 8 years were examined in relation to BK viremia, viruria levels, and lymphocyte profiles.

Results

At the time of diagnosis of BKV viremia/viruria, 17 (85%) patients were on calcineurin inhibitor (CNI)-based triple immunosuppression. CNI was discontinued in 9 patients, sirolimus was started in 3 of them. Mycophenolic acid was switched to azathioprine or the dose was decreased in all patients. Reduction in overall immunosuppression was associated with a decrease in serum and urine BKV DNA levels. Tregs and CD8(+) T lymphocytes were significantly decreased and CD4(+) T lymphocytes were increased during this period (Figure 1). After a median follow-up of 8.1 years (IQR, 3.3-8.5), 6 (30%) patients lost their allografts. There were no significant differences in mean Tregs levels between patients with and without graft failure (p=0.63). Serum and urine mean BKV DNA levels were similar between patients with and without graft failure (p=0.38 and p=0.20, respectively).

Conclusion

Tregs may play a role in BKV infection, reduction in the overall amount of immunosuppression is associated with improvement of BKV viremia/viruria accompanied by a decrease in Treg levels. Future work is needed to discriminate predictors of allograft failure in patients with BK nephropathy.