PD-1, programmed death-1

PD-1 is a member of the CD28 family of receptors

• CD28; a costimulatory activator of T-cells is expressed on all CD4+ T-cells and half of CD8+ T-cells.

• CTLA-4, cytotoxic T-lymphocyte-associated antigen, an inhibitor of T-cell activation

• ICOS, inducible costimulator

• BTLA, B- and T-lymphocyte attenuator

• PD-1, an inhibitor of T-and B-cells, is expressed by activated T-cells, B-cells and myeloid cells.

There are two known ligands for PD-1; PD-L1 and PD-L2.

An antibody against PD-1 has been raised that is immunoreactive in paraffin-embedded tissues¹.

Immunohistochemical expression

• In tonsils, on T-cells and some B-cells of the light zone of germinal centres.

• NOT by fetal or adult thymic cells

• By angioimmunoblastic lymphoma but not by other lymphomas:

	B-lymphoblastic lymphoma/leukaemia	0/31
	CLL	0/41
	Mantle cell lymphoma	0/41
	follicular lymphoma	0/61
	Marginal zone lymphoma	0/31
	Hairy cell leukaemia	0/31
	DLBCL	0/61
	Burkitt lymphoma	0/71
	Lymphoplasmacytic lymphoma	0/31
	Myeloma	0/31
	B-cell lymphoma	0/421
	Classical Hodgkin lymphoma	0/111
	Nodular LP Hodgkin lymphoma	0/14 (the T-cells forming rosettes around L&H cells are positive)1
	T-lymphoblastic lymphoma	0/51
	T-prolymphocytic lymphoma	0/31
	Angioimmunoblastic lymphoma	23/23 (a subset of the positive cells are also positive for CD10 and bcl-6. The follicular dendritic cells adjacent to the PD-1 positive T-cells stain for PD-L1)1
	Peripheral T-cell lymphoma	0/141
	Anaplastic large cell lymphoma	0/121
	Adult T-cell leukaemia/lymphoma	0/31

Diagnostic utility

• Potentially in the diagnosis of Angioimmunoblastic lymphoma.

References

¹ Dorfman DM, Brown JA, Shahsafaei A, et al. Programmed Death-1 (PD-1) is a Marker of Germinal Center-associated T Cells and Angioimmunoblastic T-Cell Lymphoma. Am J Surg Pathol 2006; 30:802-810

This page last revised 12.7.2006.

©SMUHT/PW Bishop