TIA-1, T-cell intracellular antigen-1, granule membrane protein 17

TIA-1 is a 15 kD cytotoxic granule-associated protein. expressed by cytotoxic T-cells1. Perforin punctures a hole in the membrane of a target cell. TIA-1 and granzyme enter through the hole and activate proteins which induce apoptosis2. Perforin and granzyme are only expressed upon activation of cytotoxic cells; TIA-1 is expressed irrespective of the activation state of cytotoxic T-cells and myeloid cells2. This is in contrast to perforin and granzyme B, the expression of which increases in activated cells.

Immunohistochemical expression

It is expressed by:

• both activated and non-activated cytotoxic T-cells.

• A wide range of T-cell lymphomas

• Nasal type NK cell lymphomas usually express TIA-1, perforin and granzyme B. Hepatosplenic gd peripheral T-cell lymphomas usually express TIA-1 alone.

• 75% of anaplastic large cell lymphomas

• Gastric T-cell lymphomas which are not associated with integrated proviral HTLV-1, but not those that are1.

• Some cases of hairy cell leukaemia.

• Some cases of classical Hodgkin lymphoma but not lymphocyte predominance Hodgkin lymphoma

Diagnostic utility

• Diagnosis of cytotoxic T-cell and NK cell lymphoma.

• Possibly in the diagnosis of hairy cell leukaemia among low-grade B-cell lymphomas.

References

1 Hatano, B., K. Ohshima, et al. (2002). "Non-HTLV-1-associated primary gastric T-cell lymphomas show cytotoxic activity: clinicopathological, immunohistochemical characteristics and TIA-1 expression in 31 cases." Histopathology 41(5): 421-36.

2 Mori, N., Y. I. Murakami, et al. (2004). "TIA-1 expression in hairy cell leukemia." Mod Pathol 17(7): 840-6.

This page last revised 1.9.2004.

©SMUHT/PW Bishop