TARC, a CC chemokine, is frequently expressed in classic Hodgkin's lymphoma but not in NLP Hodgkin's lymphoma, T-cell-rich B-cell lymphoma, and most cases of anaplastic large cell lymphoma.
Thymus and activation-regulated chemokine (TARC) has been identified as a lymphocyte-directed CC chemokine that attracts activated T-helper type 2 (Th2) cells in humans. Recent studies showed that the T cells surrounding Reed-Sternberg cells in Hodgkin's lymphomas (HL) are Th2 type. Anaplastic large cell lymphomas (ALCL), T-cell-rich B-cell lymphoma (TCRBCL) can mimic HL in some instances. This study aimed to establish the pattern of TARC expression in these diseases. Immunohistochemical stain using a polyclonal goat anti-human antibody to TARC was performed on 119 cases of confirmed HL; 99 were classical type (43 mixed cellularity, 43 nodular sclerosis, 5 lymphocyte depleted, 4 lymphocyte rich, 4 unclassifiable) and 20 lymphocyte predominant HL. Additional 27 ALCL (9 T-, 18 null-cell phenotype), 16 T-cell and 8 B-cell non-Hodgkin's lymphoma (NHL) were studied. A total of 85.8% of the classical HL, one case of ALCL, and one case of large cell B-cell lymphoma with anaplastic morphology showed positive TARC expression in the tumor cells. The expression was paranuclear and/or diffuse in the cell cytoplasm. The tumor cells in all cases of lymphocyte predominant HL, TCRBCL, null ALCL, and T-NHL did not express TARC. The high frequency of TARC expression in the Reed-Sternberg cells of classical HL may explain the characteristic T-cell infiltrate in this disease. The absence in other types that may be morphologically similar indicates that staining for TARC may aid in differential diagnosis.
Peh
S C
SC
Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia. pehsc@medicine.med.um.edu.my
Kim
L H
LH
Poppema
S
S
D054414:Chemokine CCL17; D019742:Chemokines, CC / Q000378:metabolism*; D003937:Diagnosis, Differential; D004854:Herpesvirus 4, Human / Q000302:isolation & purification; D006689:Hodgkin Disease / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D016393:Lymphoma, B-Cell / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D016539:Reed-Sternberg Cells / Q000378:metabolism; D013601:T-Lymphocytes / Q000473:pathology*
C106230:CCL17 protein, human; D054414:Chemokine CCL17; D019742:Chemokines, CC