Expression pattern of the human FcRH/IRTA receptors in normal tissue and in B-chronic lymphocytic leukemia

• Published in: International immunology Vol. 18; no. 9; pp. 1363 - 1373
• Main Authors: Polson, Andrew G., Zheng, Bing, Elkins, Kristi, Chang, Wesley, Du, Changchun, Dowd, Patrick, Yen, Lulu, Tan, Christine, Hongo, Jo-Anne, Koeppen, Hartmut, Ebens, Allen
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.09.2006; Oxford Publishing Limited (England)
• Subjects: Animals; B-Lymphocytes - metabolism; chronic lymphocytic leukemia; Fc receptor homologs; Fc receptor-like; FcRL; Flow Cytometry; Humans; Immunohistochemistry; immunoreceptor translocation associated; Killer Cells, Natural - metabolism; Leukemia, Lymphocytic, Chronic, B-Cell - metabolism; memory B cells; Mice; NK cells; Polymerase Chain Reaction; Receptors, Cell Surface - biosynthesis; Receptors, Immunologic - biosynthesis
• ISSN: 0953-8178; 1460-2377
• DOI: 10.1093/intimm/dxl069

A new family of Ig domain receptors referred to as the immune receptor translocation-associated (IRTA) proteins, FcR homologs (FcRHs) or FcR-like that are expressed in lymphoid cells has been recently described. RNA expression analysis suggests that FcRH1–5/IRTA1–5 are expressed exclusively in subsets of the B-cell compartment. We generated mAbs to FcRH1–5/IRTA1–5 and examined their protein expression pattern in normal tissue and in chronic lymphocytic leukemia (CLL) cells. Our data indicated that FcRH1–5/IRTA1–5 were expressed in B-cell sub-populations; however, in some cases, the protein was not expressed in the same B-cell populations as suggested by the RNA expression analysis. FcRH1/IRTA5 was expressed throughout the B-cell lineage starting at the pro-B-cell stage but was down-regulated in plasma cells. FcRH2/IRTA4 was expressed preferentially in memory B cells. FcRH3/IRTA3 was expressed at low levels in naive, germinal center (GC) and memory B cells but was also expressed in NK cells. FcRH4/IRTA1 was expressed in a sub-population of memory B cells associated with mucosal tissue. FcRH5/IRTA2 was expressed in mature B cells and memory B cells and down-regulated in GC cells and, unlike all other B-cell-specific markers, maintained its expression in plasma cells from tonsil, spleen and bone marrow. We examined the expression of FcRH1–5/IRTA1–5 on the surface of CLL cells and found a similar pattern of expression on CLL cells as in the normal mature B cells, except for FcRH3/IRTA3 which was up-regulated in CLL.