Case · Presentation

Managing BK Viremia and Graft Function in a Dual-Organ Recipient.

Tina D. is 60, African American, with type 1 diabetes, hypothyroidism and end‑stage kidney disease secondary to diabetes. Four years ago she had a simultaneous pancreas–kidney transplant. Around two years later the kidney graft failed to BK virus nephropathy, confirmed on biopsy, and she returned to haemodialysis. The pancreas graft kept working despite significant reductions in immunosuppression.

Just over a year ago she received a second kidney, from her sister. No donor‑specific antibodies were detected before transplant. Her panel reactive antibody is 80%.

At routine follow‑up, PCR found BK viremia again. She is asymptomatic — afebrile, anicteric, no pallor or lymphadenopathy, examination unremarkable, BP 118/72, HR 74 — and graft function is stable.

Transplants

dual organ

Panel reactive antibody

80 %

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Case · Workup

The biopsy is unremarkable. The urine is not.

Blood BK virus PCR is 10 000 copies/mL against a normal of undetectable. Urine BK PCR is beyond the detection limit at >100 000 000 IU/mL, consistent with high‑grade viruria — normal is under 125. Kidney biopsy shows no rejection, no inflammation, no pathological abnormality.

The Tutivia™ score is 3. Above 50 is high risk for acute rejection; 50 or below is low risk (Bestard O, et al. 2024). Tacrolimus trough is 5.4 ng/mL (5–8) and sirolimus 6.3 ng/mL (4–12) — both therapeutic.

The post‑transplant panel is normal throughout: creatinine 1.2 mg/dL, HbA_1c 5.1%, amylase 76 U/L, lipase 100 U/L, urine protein trace, LDL 90 mg/dL, and a pancreas biopsy is not needed — that graft is functional with no indicator of dysfunction.

Go to the decision

Case · Decision

What happens to her immunosuppression?

She is on Envarsus XR 4 mg daily and sirolimus 1 mg daily. Viremia is persistent; the rejection score is very low; she has lost a graft to this virus before. Choose one.

• AEnvarsus XR 3 mg daily and sirolimus 0.5 mg daily
• BBelatacept and sirolimus 0.5 mg daily
• CEnvarsus XR 4 mg daily and sirolimus 1 mg daily
• DEnvarsus XR 5 mg daily and sirolimus 2 mg daily

Lock in my answer Select a regimen to continue

Case · Verdict

Management Strategies: Immunosuppression Adjustment and Antiviral Considerations.

• AEnvarsus XR 3 mg daily and sirolimus 0.5 mg dailyCorrectReduce. With persistent BK viremia and the known risk of replication under excessive immunosuppression, cautiously lowering therapy may mitigate progression while maintaining graft function (Brennan DC, et al, 2005). Reduction raises rejection risk, so it requires close monitoring with Tutivia™, kidney function tests, pancreas allograft monitoring and BK viral load.
• BBelatacept and sirolimus 0.5 mg dailyNot recommendedEliminating a calcineurin inhibitor may theoretically reduce replication, but no guidelines or clinical data support initiating belatacept during active viral infection, and conversion carries a 100–150% higher incidence of acute rejection (Lombardi et al., 2022).
• CEnvarsus XR 4 mg daily and sirolimus 1 mg dailyPartially trueMaintain. Kidney function is stable and the Tutivia™ score is very low, but reducing immunosuppression is key to controlling BK viremia, so holding the current dose may not be the most optimal approach (Brennan DC, et al, 2005).
• DEnvarsus XR 5 mg daily and sirolimus 2 mg dailyNot recommendedIncrease. Generally not recommended in the presence of persistent BK viremia, as it could exacerbate viral replication and increase the risk of BKVN (Brennan DC, et al, 2005).

• ThenTutivia™ monitoring, alongside BK virus PCR and kidney function tests, to detect graft dysfunction without invasive testing.
• AndFollow‑up with transplant nephrology and endocrinology.

See what settles it

Case · Evidence

One test she could not use. One she could.

There are no FDA‑approved antiviral therapies for BK virus, so the primary strategy is immunosuppression modulation (Imlay H, et al, 2022). That makes the rejection risk estimate the number the whole decision turns on.

• 01dd‑cfDNA is limited here. She has no detectable donor‑specific antibodies, indicating low risk of antibody‑mediated rejection, and in a multiorgan recipient the signal may reflect injury or turnover from either organ, making it hard to say which graft is affected.
• 02Tutivia™ is non‑invasive. It analyses immune activity at the molecular level to give a quantitative score, separating low from high rejection risk without a biopsy — particularly valuable in multiorgan recipients (Bestard O, et al, 2024).
• 03The gap between the two ends of that score is large. A high‑risk Tutivia™ result carries an odds ratio of 5.74 for acute rejection compared with a low‑risk result — a nearly sixfold increase (Bestard O, et al. 2024).
• 04She is inside the window. Up to 30% of kidney transplant recipients develop BK viremia and 1–10% progress to BKVN (Kant S, et al, 2022); 95% of BKVN occurs in the first two years after transplantation (KDIGO, 2009). She is 389 days out.

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