Sources/Clones
Axcel/Accurate (polyclonal), Biodesign (1101, 1103), Biogenesis (polyclonal), Biogenex, Biomeda (polyclonal), Chemicon (monoclonal), Calbiochem/Novocastra, Dako (polyclonal), Fitzgerald (polyclonal), Sanbio (F50.4.1, F43.8.1), Sera Lab (polyclonal), Serotec (polyclonal) and Zymed
(ZMAAT3).
Fixation/Preparation
The antigen is preserved in formalin-fixed, paraffin-embedded tissue. Proteolytic digestion increases immunoreactivity but HIER appears unhelpful.
Background
a-1-Antitrypsin (AAT), a 51 kD glycoprotein, is mainly synthesized in the liver, where a pair of at least 24 possible codominant alleles, which belong to the protease inhibitor (Pi) locus on chromosome 2, determine production. It functions as an inhibitor of proteases, especially elastase, collagenase and chymotrypsin. Individual homozygotes of Pi M produce normal quantities of functionally normal AAT whereas, individuals with abnormal Pi genes, such as those designated ZZ, SZ, and PS, have serum concentrations of AAT that are, 40% of normal. Such individuals are at risk for hepatic cirrhosis in childhood or pulmonary emphysema as young adults. Interest in AAT as an immunohistochemical marker arose in the early 1980s because of the search for a marker of histiocytes (monocytes/macrophages). AAT, a-1-antichymotrypsin (AACT) and muramidase (lysozyme) were touted as specific markers of histiocytes (Isaacson et al, 1981), launching their use as a marker of such cells and malignant tumors derived from them. Monocytes have recently been shown to be another site of synthesis of AAT, short-term cultures of plasticadherent peripheral blood cells releasing isotopically labeled AAT into the supernatant. AAT was used to distinguish histiocytic from lymphoid neoplasms (Isaacson and James, 1983). In particular, this enzyme was used to characterize a large pleomorphic lymphoma of the intestine as "malignant histiocytosis" (Isaacson et al, 1982). Many studies employed AAT to support the histiocytic differentiation of malignant fibrous histiocytoma and other so-called "fibrohistiocytic" tumors (Meister & Nathrath, 1981; Du Boulay 1982; Kindblom et al, 1982; Roholl et al, 1985).As with many previous claims in immunohistochemistry for ''specific markers", the initial enthusiasm was soon tempered by caution when it was shown that AAT, AACT and lysozyme immunoreactivity can be commonly found in a large variety of tumors of both epithelial and mesenchymal differentiation. These included carcinoid tumors, malignant melanomas, schwannomas (Permanetter & Meister, 1984; Soini & Miettinen, 1989), islet cell tumors of the pancreas (Ordonez et al, 1983), mixed mesodermal tumor of the ovary (Dictor 1981), uterine sarcomas (Marshall & Braye 1985) and ameloblastoma (Takahashi et al, 1995). The enthusiasm for AAT, AACT and lysozyme as immunohistochemical markers fell off rapidly as this information became more widely known (Dar et al, 1992). Interestingly, the entity of so-called "malignant histiocytosis" in the intestine was soon shown to be of T-cell lineage (Isaacson et al, 1985). Immunoreactivity for this group of proteolytic enzymes may well be a reflection of the intracytoplasmic accumulation of phagolysosomes and to imply histiocytic differentiation.
Applications
AAT, AACT and lysozyme can still provide useful diagnostic information but they have to be used in the context of a panel of antibodies directed to the diagnostic entities considered in differential diagnosis. For example, in pleomorphic tumors of the skin, these markers are useful for the separation of atypical fibroxanthoma from its mimics (Leong & Milios, 1987), although other markers can provide more relevant information to separate such entities (Appendix 1.22), and in identifying tumors rich in phagolysosomes such as granular cell tumors. Immunolabeling for AAT remains an important way of demonstrating the presence of accumulated enzyme within hepatocytes in AAT deficiency (Palmer et al, 1978). Recently, it was suggested that this protease inhibitor is found in thyroid papillary carcinoma but not in normal thyroid tissue, a finding confirmed by Western blotting and immunoprinting (Poblete et al, 1996).
References
•Dar AU, Hird PM, Wagner BE, Underwood JC 1992. Relative usefulness of electron microscopy and immunocytochemistry in tumour diagnosis: 10 years of retrospective analysis. Journal of Clinical Pathology 45:693-696.
•Dictor M 1981. Alpha-1-antitrypsin in a malignant mixed mesodermal tumor of the ovary. American Journal of Surgical Pathology 5: 543-550.
•Du Boulay 1982. Demonstration of alpha-1-antitrypsin and alpha-1-antichymotrypsin in fibrous
histiocytomas using the immunoperoxidase technique. American Journal of Surgical Pathology 6:559-564.
•Isaacson PG, Jones DB, Millward-Sadler GH et al 1981. Alpha-1-antitrypsin in human macrophages.
•Journal of Clinical Pathology 34: 982-990.
•Isaacson PG, Jones DB, Sworn MJ, Wright DH 1982. Malignant histiocytosis of the intestine: report of three cases with immunological and cytochemical analysis. Journal of Clinical Pathology 35:510-516.
•Isaacson PG, Jones DB 1983. Immunohistochemical differentiation between histiocytic and lymphoid neoplasms. Histochemical Journal 15: 621-635.
•Isaacson PG, Spencer J, Connolly CH, et al 1985. Malignant histiocytosis of the intestine: a T cell
lymphoma. Lancet 1:688-691.
•Kindblom LG, Jacobsen GK, Jacobsen M 1982. Immunohistochemical investigations of tumors of supposed fibroblastic-histiocytic origin. Human Pathology 13: 834-840.
•Leong AS-Y, Milios J 1987. Atypical fibroxanthoma of the skin: a clinicopathological and immunohistochemical study and a discussion of its histogenesis. Histopathology 11:463-475.
•Marshall RJ, Braye SG 1985. Alpha-1-antitrypsin, alpha-1-antichymotrypsin, actin and myosin in uterine sarcomas. International Journal of Gynecological Pathology 4: 346-354.
•Meister P, Nathrath W 1981. Immunohistochemical characterization of histiocytic tumors. Diagnostic Histopathology 4:79-87.
•Ordonez NG, Manning JT Jr, Hanssen G 1983. Alpha-1-antitrypsin in islet cell tumors of the pancreas.
•American Journal of Clinical Pathology 80:277-282.
•Palmer PE, Wolfe HJ, Dayal Y, Gang DL 1978. Immunocytochemical diagnosis of alpha-1-antitrypsin deficiency. American Journal of Surgical Pathology 2:275-281.
•Permanetter W, Meister P 1984. Distribution of lysozyme (muramidase) and alpha-1-antichymotrypsin in normal and neoplastic epithelial tissues: a survey. Acta Histochemia 74: 173-179.
•Poblete MT, Nualart F, Del Pozo M, et al 1996. Alpha-1-antitrypsin expression in human thyroid papillary carcinoma. American Journal of Surgical Pathology 20: 956-963.
•Roholl PJ, Kleyne J, Pijpers HW, Van Unnik JA 1985. Comparative immunohistochemical investigation of markers for malignant histiocytes. Human Pathology 16:763-771.
•Soini Y, Miettinen M 1989. Alpha-1-antitrypsin and lysozyme. Their limited significance in
fibrohistiocytic tumors. American Journal of Clinical Pathology 91: 515-521.
•Takahashi H, Tsuda N, Yamabe S, et al 1995. Immunohistochemical detection of alpha 1-antitrypsin, alpha 1-antichymotrypsin, transferrin and ferritin in ameloblastoma.
•Annals of Cellular Pathology 9:135-150.
Bibliografia
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
Axcel/Accurate (polyclonal), Biodesign (1101, 1103), Biogenesis (polyclonal), Biogenex, Biomeda (polyclonal), Chemicon (monoclonal), Calbiochem/Novocastra, Dako (polyclonal), Fitzgerald (polyclonal), Sanbio (F50.4.1, F43.8.1), Sera Lab (polyclonal), Serotec (polyclonal) and Zymed
(ZMAAT3).
Fixation/Preparation
The antigen is preserved in formalin-fixed, paraffin-embedded tissue. Proteolytic digestion increases immunoreactivity but HIER appears unhelpful.
Background
a-1-Antitrypsin (AAT), a 51 kD glycoprotein, is mainly synthesized in the liver, where a pair of at least 24 possible codominant alleles, which belong to the protease inhibitor (Pi) locus on chromosome 2, determine production. It functions as an inhibitor of proteases, especially elastase, collagenase and chymotrypsin. Individual homozygotes of Pi M produce normal quantities of functionally normal AAT whereas, individuals with abnormal Pi genes, such as those designated ZZ, SZ, and PS, have serum concentrations of AAT that are, 40% of normal. Such individuals are at risk for hepatic cirrhosis in childhood or pulmonary emphysema as young adults. Interest in AAT as an immunohistochemical marker arose in the early 1980s because of the search for a marker of histiocytes (monocytes/macrophages). AAT, a-1-antichymotrypsin (AACT) and muramidase (lysozyme) were touted as specific markers of histiocytes (Isaacson et al, 1981), launching their use as a marker of such cells and malignant tumors derived from them. Monocytes have recently been shown to be another site of synthesis of AAT, short-term cultures of plasticadherent peripheral blood cells releasing isotopically labeled AAT into the supernatant. AAT was used to distinguish histiocytic from lymphoid neoplasms (Isaacson and James, 1983). In particular, this enzyme was used to characterize a large pleomorphic lymphoma of the intestine as "malignant histiocytosis" (Isaacson et al, 1982). Many studies employed AAT to support the histiocytic differentiation of malignant fibrous histiocytoma and other so-called "fibrohistiocytic" tumors (Meister & Nathrath, 1981; Du Boulay 1982; Kindblom et al, 1982; Roholl et al, 1985).As with many previous claims in immunohistochemistry for ''specific markers", the initial enthusiasm was soon tempered by caution when it was shown that AAT, AACT and lysozyme immunoreactivity can be commonly found in a large variety of tumors of both epithelial and mesenchymal differentiation. These included carcinoid tumors, malignant melanomas, schwannomas (Permanetter & Meister, 1984; Soini & Miettinen, 1989), islet cell tumors of the pancreas (Ordonez et al, 1983), mixed mesodermal tumor of the ovary (Dictor 1981), uterine sarcomas (Marshall & Braye 1985) and ameloblastoma (Takahashi et al, 1995). The enthusiasm for AAT, AACT and lysozyme as immunohistochemical markers fell off rapidly as this information became more widely known (Dar et al, 1992). Interestingly, the entity of so-called "malignant histiocytosis" in the intestine was soon shown to be of T-cell lineage (Isaacson et al, 1985). Immunoreactivity for this group of proteolytic enzymes may well be a reflection of the intracytoplasmic accumulation of phagolysosomes and to imply histiocytic differentiation.
Applications
AAT, AACT and lysozyme can still provide useful diagnostic information but they have to be used in the context of a panel of antibodies directed to the diagnostic entities considered in differential diagnosis. For example, in pleomorphic tumors of the skin, these markers are useful for the separation of atypical fibroxanthoma from its mimics (Leong & Milios, 1987), although other markers can provide more relevant information to separate such entities (Appendix 1.22), and in identifying tumors rich in phagolysosomes such as granular cell tumors. Immunolabeling for AAT remains an important way of demonstrating the presence of accumulated enzyme within hepatocytes in AAT deficiency (Palmer et al, 1978). Recently, it was suggested that this protease inhibitor is found in thyroid papillary carcinoma but not in normal thyroid tissue, a finding confirmed by Western blotting and immunoprinting (Poblete et al, 1996).
References
•Dar AU, Hird PM, Wagner BE, Underwood JC 1992. Relative usefulness of electron microscopy and immunocytochemistry in tumour diagnosis: 10 years of retrospective analysis. Journal of Clinical Pathology 45:693-696.
•Dictor M 1981. Alpha-1-antitrypsin in a malignant mixed mesodermal tumor of the ovary. American Journal of Surgical Pathology 5: 543-550.
•Du Boulay 1982. Demonstration of alpha-1-antitrypsin and alpha-1-antichymotrypsin in fibrous
histiocytomas using the immunoperoxidase technique. American Journal of Surgical Pathology 6:559-564.
•Isaacson PG, Jones DB, Millward-Sadler GH et al 1981. Alpha-1-antitrypsin in human macrophages.
•Journal of Clinical Pathology 34: 982-990.
•Isaacson PG, Jones DB, Sworn MJ, Wright DH 1982. Malignant histiocytosis of the intestine: report of three cases with immunological and cytochemical analysis. Journal of Clinical Pathology 35:510-516.
•Isaacson PG, Jones DB 1983. Immunohistochemical differentiation between histiocytic and lymphoid neoplasms. Histochemical Journal 15: 621-635.
•Isaacson PG, Spencer J, Connolly CH, et al 1985. Malignant histiocytosis of the intestine: a T cell
lymphoma. Lancet 1:688-691.
•Kindblom LG, Jacobsen GK, Jacobsen M 1982. Immunohistochemical investigations of tumors of supposed fibroblastic-histiocytic origin. Human Pathology 13: 834-840.
•Leong AS-Y, Milios J 1987. Atypical fibroxanthoma of the skin: a clinicopathological and immunohistochemical study and a discussion of its histogenesis. Histopathology 11:463-475.
•Marshall RJ, Braye SG 1985. Alpha-1-antitrypsin, alpha-1-antichymotrypsin, actin and myosin in uterine sarcomas. International Journal of Gynecological Pathology 4: 346-354.
•Meister P, Nathrath W 1981. Immunohistochemical characterization of histiocytic tumors. Diagnostic Histopathology 4:79-87.
•Ordonez NG, Manning JT Jr, Hanssen G 1983. Alpha-1-antitrypsin in islet cell tumors of the pancreas.
•American Journal of Clinical Pathology 80:277-282.
•Palmer PE, Wolfe HJ, Dayal Y, Gang DL 1978. Immunocytochemical diagnosis of alpha-1-antitrypsin deficiency. American Journal of Surgical Pathology 2:275-281.
•Permanetter W, Meister P 1984. Distribution of lysozyme (muramidase) and alpha-1-antichymotrypsin in normal and neoplastic epithelial tissues: a survey. Acta Histochemia 74: 173-179.
•Poblete MT, Nualart F, Del Pozo M, et al 1996. Alpha-1-antitrypsin expression in human thyroid papillary carcinoma. American Journal of Surgical Pathology 20: 956-963.
•Roholl PJ, Kleyne J, Pijpers HW, Van Unnik JA 1985. Comparative immunohistochemical investigation of markers for malignant histiocytes. Human Pathology 16:763-771.
•Soini Y, Miettinen M 1989. Alpha-1-antitrypsin and lysozyme. Their limited significance in
fibrohistiocytic tumors. American Journal of Clinical Pathology 91: 515-521.
•Takahashi H, Tsuda N, Yamabe S, et al 1995. Immunohistochemical detection of alpha 1-antitrypsin, alpha 1-antichymotrypsin, transferrin and ferritin in ameloblastoma.
•Annals of Cellular Pathology 9:135-150.
Bibliografia
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
