Lai K N, Ho R T, Tam J S, Lai F M
Department of Medicine, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, Hong Kong.
Kidney Int. 1996 Dec;50(6):1965-77. doi: 10.1038/ki.1996.519.
Glomerular deposition of hepatitis B virus (HBV) antigens are observed in chronic HBsAg carriers with different glomerulonephritides yet the etiologic role of HBV remains uncertain. We examined the paraffin section of kidney biopsies from 40 chronic HBsAg carriers with membranous nephropathy (MGN), mesangiocapillary glomerulonephritis (MCGN) or IgA nephropathy (IgAN) for HBV DNA and HBV RNA using in situ hybridization (ISH). Glomerular HBV antigens were present in all biopsies by immunofluorescence. HBsAg or HBcAg mRNA was also studied in RNA extracted from frozen renal tissue using a two-step polymerase chain reaction (PCR) following reverse transcription (RT). HBcAg DNA was not easily detected with ISH alone, but was readily found in 31 biopsies (78%) following PCR. HBV DNA was detected mainly in the cytoplasm of proximal tubular epithelia but not in glomerular cells. HBsAg and/or HBcAg mRNA were detected by RT-PCR in extracted RNA from 13 biopsies (33%). The PCR findings were further confirmed by (a) Southern blot hybridization using a cloned HBV probe and (b) absence of PCR product following treating RNA with RNase or omitting the RT. It is plausible that HBV DNA in renal tubules represents endocytosis of HBV DNA in the urinary filtrate and the HBV RNA extracted from kidney biopsies could derive from infiltrating cells bearing HBV RNA. Hence, ISH with specific HBV core gene RNA probe was performed subsequently. HBcAg RNA, localized in the nuclei and cytoplasm of glomerular and tubular cells, was detected in 56%, 20%, and 36% of renal biopsies in chronic HBsAg carriers with MGN, MCGN, and IgAN, respectively. Our findings indicate the presence of viral transcription in glomerular cells and renal tubular epithelia, supporting an etiological role of HBV in some chronic HBsAg carriers who develop coexisting glomerulonephritides.
在患有不同类型肾小球肾炎的慢性乙肝表面抗原（HBsAg）携带者中，可观察到乙肝病毒（HBV）抗原在肾小球的沉积，但HBV的病因学作用仍不明确。我们采用原位杂交（ISH）技术，检测了40例患有膜性肾病（MGN）、系膜毛细血管性肾小球肾炎（MCGN）或IgA肾病（IgAN）的慢性HBsAg携带者肾活检组织石蜡切片中的HBV DNA和HBV RNA。通过免疫荧光法检测，所有活检组织中均存在肾小球HBV抗原。还使用逆转录（RT）后的两步聚合酶链反应（PCR），对从冷冻肾组织中提取的RNA进行了HBsAg或HBcAg mRNA研究。单独使用ISH不易检测到HBcAg DNA，但在PCR后，31例活检组织（78%）中很容易检测到。HBV DNA主要在近端肾小管上皮细胞的细胞质中检测到，而在肾小球细胞中未检测到。通过RT-PCR在13例活检组织（33%）提取的RNA中检测到了HBsAg和/或HBcAg mRNA。PCR结果通过以下方式进一步得到证实：（a）使用克隆的HBV探针进行Southern印迹杂交；（b）用核糖核酸酶处理RNA或省略RT后未出现PCR产物。肾小管中的HBV DNA可能代表尿滤液中HBV DNA的内吞作用，从肾活检组织中提取的HBV RNA可能来源于携带HBV RNA的浸润细胞。因此，随后进行了特异性HBV核心基因RNA探针的ISH检测。在患有MGN、MCGN和IgAN的慢性HBsAg携带者的肾活检组织中，分别有56%、20%和36%检测到了定位于肾小球和肾小管细胞核及细胞质中的HBcAg RNA。我们的研究结果表明肾小球细胞和肾小管上皮细胞中存在病毒转录，支持HBV在一些并发肾小球肾炎的慢性HBsAg携带者中的病因学作用。
