Pediatric autoimmune hepatitis (AIH) is relatively common and has a characteristic but relatively nonspecific histopathology with a usually prominent lymphoplasmacytic infiltrate. Herein, we describe for the first time the presence of characteristic hyaline droplets in the cytoplasm of Kupffer cells on routine hematoxylin and eosin (H&E) sections in AIH. The medical records and pathologic material over a 20-year period (1992 to 2012) were reviewed from children with AIH (n=30), hepatitis B virus (n=30), and hepatitis C virus (n=30) from the pathology files at Boston Children's Hospital. All children had percutaneous needle liver biopsies. We reviewed sections stained with H&E, PAS, and PAS with diastase for the presence of hyaline droplets in all 90 biopsies. We also performed immunohistochemical analysis for IgG, IgA, and IgD in 6 biopsies with AIH. Hyaline droplets were identified in Kupffer cells throughout the lobules in 15 of 30 biopsies (easily found in 13 and rare in 2); conversely, no droplets were identified in 15. Droplets were identified in 10 AIH type 1 biopsies, 1 in AIH type 2, 3 in overlap syndrome, and 1 in unclassified. Serum IgG levels, when available, were correlated with biopsy findings. Seventeen patients had serum IgG levels available for review. The average IgG level in patients without droplets in their biopsies was 1364 mg/dL, in contrast to 3424 mg/dL in patients with droplets (P=0.021). Immunohistochemical analysis performed in 6 biopsies revealed that droplets were nearly always positive for IgG, occasionally for IgA, and rarely for IgD. None of the biopsies in patients with hepatitis C contained hyaline droplets. One biopsy of a patient with hepatitis B revealed hyaline droplets; this biopsy had an unusually prominent plasmacytic infiltrate, and the patient was found to have an elevated IgG serum level and antibodies to smooth muscle actin. As far as we are aware, hyaline droplets in Kupffer cells on routine H&E sections have never been described. They should be distinguished from the nonspecific granular lysosomal structures frequently found in Kupffer cells in a variety of chronic liver diseases and from erythrophagocytosis. Hyaline droplets may occur in AIH regardless of the type and correlate with a >2-fold increase in serum level of IgG as compared with patients without droplets in their biopsies. Identification of hyaline droplets in Kupffer cells provides a useful diagnostic clue to distinguish AIH from other forms of chronic hepatitis.
本文复习了波士顿儿童医院20年间（1992-2012年）30例AIH、30例乙型病毒性肝炎和30例丙型病毒性肝炎的儿童患者医疗记录和病理资料。所有患者均做过经皮肝穿刺活检，复习HE切片、PAS染色切片和经淀粉酶消化后PAS染色切片，90例肝穿刺活检均存在透明小滴。我们还对其中6例AIH肝穿刺活检进行了IgG、IgA和IgD免疫组化检测。30例AIH中有15例整个小叶内的Kupffer细胞内见透明小滴（13例透明小滴明显，2例透明小滴较少），与此相反，另外15例AIH不见透明小滴。见透明小滴的15例AIH分别为：I型AIH10例、II型AIH1例、AIH重叠综合征3例及未分类AIH1例。检测到的血清IgG水平，与患者活检结果有关。共有17例患者检测了血清IgG水平，活检中无透明小滴的患者平均血清IgG水平为1364 mg/dL，而有透明小滴的患者为3424 mg/dL（P=0.021）。6例免疫组化检测显示透明小滴几乎总是IgG阳性，IgA偶尔阳性，IgD很少阳性。丙型肝炎患者活检中均无透明小滴。1例乙型肝炎患者活检显示透明小滴，并见显著淋巴浆细胞浸润，该患血清IgG水平升高，血清SMA抗体阳性。