Callea F, Fevery J, De Groote J, Desmet V J
J Hepatol. 1986;2(3):389-401. doi: 10.1016/s0168-8278(86)80050-2.
Immunostaining for alpha-1-antitrypsin (AAT) was applied on paraffin-embedded liver specimens from 38 Pi Z phenotype (27 Pi MZ; 9 Pi ZZ; 2 Pi SZ) individuals (33 adults, 5 newborns). Histological diagnoses included normal liver, various forms of chronic hepatitis, cirrhosis. A positive hepatocytic staining for AAT was revealed in all cases, whereas on PAS-D staining 5 cases were negative. Immunostaining revealed different patterns: type I: fine solid granules or coarse laminated globules filling the whole liver cell cytoplasm; type II: positive granules marginated towards the cell's periphery; type III: positive granules restricted to focal areas in the cytoplasm. Type I and III patterns were observed in all specimens. Association of type I and III with type II was seen in all Pi MZ and Pi SZ cases, but only in 3 of the 9 Pi ZZ specimens. To check the specificity of these staining patterns for the Z allele of AAT in adults and newborns, 180 further cases were investigated blindly by immunohistochemistry. Recognition of hepatocytic staining patterns type I, II and III allowed to reliably diagnose the Pi Z phenotype in 6 cases, whose heterozygous state was confirmed by independent serum phenotyping (5 Pi MZ, 1 Pi SZ). These results allow to conclude that: (1) immunohistochemistry is a reliable technique (superior to PAS-D staining) to identify Pi Z individuals (homo- and heterozygotes) on paraffin-embedded liver sections; (2) heterozygotes Pi MZ and Pi SZ cannot be differentiated without serum phenotyping; (3) immunohistochemistry is helpful in distinguishing between Z homozygotes from heterozygotes, but determination of AAT serum concentration is required to allow confident distinction without phenotyping. AAT immunohistochemistry thus allows to diagnose the Z allele of AAT when phenotyping procedures are not available or in retrospective studies on biopsy and autopsy material.
对38例Pi Z表型个体（27例Pi MZ；9例Pi ZZ；2例Pi SZ）（33例成人，5例新生儿）的石蜡包埋肝标本进行α-1抗胰蛋白酶（AAT）免疫染色。组织学诊断包括正常肝脏、各种形式的慢性肝炎、肝硬化。所有病例均显示肝细胞AAT染色阳性，而在PAS-D染色中5例为阴性。免疫染色显示不同模式：I型：细小的实心颗粒或粗大的层状小球充满整个肝细胞胞质；II型：阳性颗粒沿细胞周边排列；III型：阳性颗粒局限于胞质内的局灶区域。所有标本均观察到I型和III型模式。在所有Pi MZ和Pi SZ病例中均可见I型和III型与II型的关联，但在9例Pi ZZ标本中仅3例出现这种情况。为了检验这些染色模式对成人和新生儿AAT Z等位基因的特异性，另外180例病例通过免疫组织化学进行盲法研究。识别肝细胞染色模式I型、II型和III型能够在6例病例中可靠地诊断Pi Z表型，其杂合状态通过独立的血清表型分析得到证实（5例Pi MZ，1例Pi SZ）。这些结果可以得出以下结论：（1）免疫组织化学是在石蜡包埋肝切片上识别Pi Z个体（纯合子和杂合子）的可靠技术（优于PAS-D染色）；（2）若无血清表型分析，无法区分杂合子Pi MZ和Pi SZ；（3）免疫组织化学有助于区分Z纯合子和杂合子，但需要测定AAT血清浓度才能在无表型分析的情况下进行可靠区分。因此，当无法进行表型分析程序或对活检和尸检材料进行回顾性研究时，AAT免疫组织化学可用于诊断AAT的Z等位基因。
