JCV viruria associates with suboptimal recovery of kidney function three years after living kidney donation

Abstract Introduction: Few studies have investigated pre-donation factors that could affect renal recovery after living kidney donation (LKD). We retrospectively investigated the role of John Cunningham virus (JCV) infection and other pre-donation factors on the magnitude of kidney function decline after LKD. Methods: Urine JCV viral loads, glomerular filtration rate, and blood pressure were evaluated in 60 consecutive LK donors before donation. Suboptimal compensatory hypertrophy was defined as an eGFR <60% of the pre-donation eGFR. Results: LKD (40% JCV infected) were followed for 3.2±1.6 years. No association was found between age, gender, and baseline hypertension with 1st, 2nd, 3rd, and 4th years post-donation eGFR <60% of the pre-donation eGFR. Mean eGFR recovery at the 3rd year after donation was lower in JCV infected donors vs non-infected donors (61.8% vs 71.0%, p=0.006). Conclusion: We hypothesized that JCV could shift glomeruli into a hyperfiltration state before nephrectomy, modulating the magnitude of compensatory hypertrophy after donation. Conversely, JCV might curtail the ability of the remaining kidney to promote hyperfiltration. Longer follow up is needed to determine whether JCV viruria ultimately leads to lower eGFR over time or if it is a protective factor for the remaining kidney.

摘要与引言：目前鲜有研究探讨可影响活体肾捐献（living kidney donation, LKD）术后肾脏恢复的捐献前相关因素。本研究回顾性分析了约翰·坎宁安病毒（John Cunningham virus, JCV）感染及其他捐献前因素对活体肾捐献术后肾功能下降幅度的影响。
研究方法：本研究对60名连续纳入的活体肾捐献者，在捐献前检测了其尿液JCV病毒载量、肾小球滤过率（glomerular filtration rate, GFR）及血压水平。将术后估算肾小球滤过率（estimated glomerular filtration rate, eGFR）低于捐献前基线水平60%的情况定义为代偿性肥大（compensatory hypertrophy）不佳。
研究结果：本研究对40%存在JCV感染的活体肾捐献者进行了为期3.2±1.6年的随访。未发现年龄、性别及基线高血压与捐献后第1、2、3、4年的eGFR低于捐献前基线eGFR 60%的情况存在关联。与未感染JCV的捐献者相比，JCV感染捐献者在捐献后第3年的平均eGFR恢复水平更低（61.8% vs 71.0%，p=0.006）。
研究结论：本研究推测，JCV可能在肾切除术（nephrectomy）术前即使肾小球处于高滤过状态（hyperfiltration state），进而调控捐献后代偿性肥大的幅度；反之，JCV或会削弱剩余肾脏促进高滤过的能力。尚需更长时间的随访，以明确JCV病毒尿症（viruria）是否会随时间推移最终导致eGFR水平降低，或是其对剩余肾脏具有保护作用。