Alpha-1-antitrypsin and alpha-1-antichymotrypsin

Immunohistochemical expression

Histiocytes and reticulum cells.  Many other cells types.

Diagnostic utility

Its diagnostic value is very limited.  It was at one time used as a marker for malignant fibrous histiocytoma.

Identification of atypical fibroxanthoma of the skin

Identification of granular cell tumours

Differentiation of papillary carcinoma of the thyroid (AAT positive) from normal thyroid tissue (AAT negative).

Identification of accumulated AAT in hepatocytes in AAT deficiency.

References

Isaacson P, Jones DB,Judd MA. Alpha 1-antitrypsin in human macrophages. Lancet 1979; 2:964-5

Palmer PE, DeLellis RA,Wolfe HJ. Immunohistochemistry of liver in alpha1-antitrypsin deficiency. A comparative study. Am J Clin Pathol 1974; 62:350-4

Palmer PE, Ucci AA,Wolfe HJ. Expression of protein markers in malignant hepatoma: evidence for genetic and epigenetic mechanisms. Cancer 1980; 45:1424-31

Kindblom LG, Jacobsen GK,Jacobsen M. Immunohistochemical investigations of tumors of supposed fibroblastic-histiocytic origin. Hum Pathol 1982; 13:834-40

Reintoft I,Hagerstrand IE. Does the Z gene variant of alpha-1-antitrypsin predispose to hepatic carcinoma? Hum Pathol 1979; 10:419-24

©SMUHT/PW Bishop