肾移植术后多瘤病毒相关肾病的临床病理特点

目的 探讨肾移植术后多瘤病毒感染相关肾病的病理诊断要点及临床病理特点。 方法 回顾性分析我院2008至2011年间确诊的13例多瘤病毒相关肾病，其中3例进行了重复肾活检，对患者的临床特点和病理组织学改变进行回顾性分析，并结合多瘤病毒抗原SV40-T免疫组化结果，分析移植后多瘤病毒感染的临床病理特点。 结果 多瘤病毒肾病多发生在移植后12~18个月，临床均表现为血肌酐升高。病理组织学改变依病程早晚可有3种形式：早期病变仅局限在集合管，间质炎性细胞浸润轻微，可不出现病毒包涵体，仅出现细胞核增大，细胞排列不整齐；中期表现为显著的小管间质炎，受累小管可扩散至肾小管各段甚至壁层上皮细胞，出现上皮细胞脱落、基底膜裸露，并出现典型的核内包涵体及多种细胞核的改变；晚期患者呈显著慢性肾小管间质病变，出现弥漫性小管萎缩和间质大片纤维化。此期虽典型的病毒包涵体少见，但免疫组化仍显示明显的SV40-T阳性。13例患者经免疫抑制剂减量或调整治疗后，2例患者进入肾衰竭，4例患者肌酐持续升高，7例患者血肌酐保持稳定。 结论 多瘤病毒肾病的病理组织学改变轻重不一，病毒感染后肾小管上皮细胞的形态学改变多样，早期患者免疫抑制剂减量治疗有较好疗效，晚期预后差。对移植后血肌酐升高的患者应及早行肾活检穿刺检查，并常规行多瘤病毒免疫组化染色以防漏诊。

Clinicopathological features of polyomavirus-associated nephropathy

Objective To interpret the clinicopathological features and the key factors for diagnosis of polyomavirus-associated nephropathy (PVAN). Methods Clinicopathological data of 13 cases of polyomavirus-associated nephropathy during 2008-2011 in our hospital were retrospectively analyzed.Three cases received repeat biopsy.The clinicopathological features were analyzed according to the light microscopic scene and SV40-T immunochemical expression.Results Recipients had a peak incidence of PVAN in 12 to 18 months period after renal transplantation,accompanied by elevated serum creatinine.Due to the progression of the disease,3patterns of histological findings could be identified.The early lesion was confined to the collected ducts,with slightly inflammatory infiltration in medullary interstitium,viral inclusions were not necessarily seen.The only findings could be enlarged nuclear and irregular arrangement of the tubular epithelial cells.At the developing stage,prominent tubulointerstitial nephritis was detected,and the involved tubules extended to other segments of renal tubule,even the parietal epithelial cells of Bowman's capsule could be compromised.The epithelial cells shed off,leading the tubular basement membrane exposed.Typical intra-nuclear inclusions as well as variable nuclear changes were found.At the end stage,the allograft showed notable chronic tubulointersititial change,with diffuse tubular atrophy and interstitial fibrosis.Although in this period,typical viral inclusions were rare, still IHC showed positive expression of SV40-T. After immunosuppressant reduction or exchange,2 cases developed renal failure,4 cases showed sustained increment in serum creatinine,while 7 cases had a stabilized serum creatinine level. Conclusions Polyomavirus-associated nephropathy can display uneven pathological changes,as well as the morphology of the infected epithelial cells.Segments of the involved tubule are associated with the course of disease.Reduction of immunosuppressant at the early stage has a favorable effect.A prompt renal biopsy should be done in renal transplant recipient if who shows increased serum creatinine,and a routine polyomavirus immunohistochemical staining should be applied as well.