CD 23

Accurate, Biodesign (BB-10, BU38, 9P.25), Biotest (TU1), Cymbus Bioscience, Dako (MHM6), Gen Trak, Immunotech (9P25), Pharmingen (B3B4), RDI (TU1), Sanbio (BL-C/B8) and Serotec (B-G6, BSL-23).

Current available antibodies are immunoreactive only in fresh-frozen sections and fresh cytologic preparations.

The CD 23 antigen is an integral membrane glycoprotein of molecular weight 45-60 kD. It has been identified as a low-affinity receptor for IgE and may be involved in the regulation of IgE production as well as also being a receptor for lymphocyte growth factor. Following crosslinkage of antigen and Ig, CD 23 becomes expressed and serves as an autocrine stimulus driving B-cell proliferation. CD 23 appears on B cells within 24 h following a variety of stimuli. Surface CD 23 has a half-life of only 1-2 h and is shed in the form of soluble fragments of varying molecular weight which display the autocrine-promoting activity. Two species of CD 23 have been described FceRIIa and FceRIIb, differing in the N-terminal cytoplasmic region and sharing the same C-terminal extracellular region. FceRIIa is strongly expressed on IL-4-activated B cells and weakly on mature B cells; it also stains some dendritic reticulum cells which probably acquire the antigen from neighboring B cells (Kikutani et al, 1986). FceRIIa is not found on circulating B cells and its expression can only be induced on surface IgMD+ cells and not on those B cells that have lost IgD, undergone isotype switch and express IgG, IgA or IgE. FceRIIb is expressed weakly on a range of cell types including monocytes, eosinophils, platelets, some T cells and NK cells. IL-4-treated monocytes show stronger staining (Zola, 1987; Armitage & Goff, 1988).

CD 23 is found in most low-grade B-cell lymphomas and in Reed-Sternberg cells in Hodgkin's disease (Rowlands et al, 1990). Activated B cells within germinal centers express CD 23 in high density but mantle zone (resting) B cells are negative or stain only weakly. The majority of B-cell CLLs and a variable proportion of B-cell non-Hodgkin's lymphoma are CD 23+, whereas mantle cell lymphomas are generally negative, so that this marker is useful when applied with other markers to separate the small cell lymphomas. Precursor B-cell and T-cell ALL/LBL, acute myeloid leukemia, chronic myeloid leukemia and post-thymic T cell neoplasms are CD 23- (Raghoebier et al, 1991). The marker is upregulated by EBV infection (Thorley Lawson et al, 1985).

Anti-CD 23 (clone BU38, Biodesign) which is reactive to a variable extent in paraffin-embedded sections following treatment with protease-1 (Kumar et al, 1996), is no longer available.

•Armitage RJ, Goff LK 1988. Functional interaction between B cell subpopulation defined by CD23 expression. European Journal of Immunology 18: 1753-1760.

•Kikutani H, Suemura M, Owaki H et al 1986. Fce receptor, a specific differentiation marker transiently expressed on mature B cells before e receptor, a specific differentiation marker transiently expressed on mature B cells before isotype switching. Journal of Experimental Medicine 164: 1455-1469.

•Kumar S, Green GA, Teruya-Feldstein J et al 1996. Use of CD23 (BU38) on paraffin sections in the diagnosis of small lymphocytic lymphoma and mantle cell lymphoma. Modern Pathology 9: 925-929.

•Raghoebier S, Kramer MHH, Vankrieken JHJM et al 1991. Essential differences in oncogene involvement between primary nodal and extranodal large cell lymphoma. Blood 78: 2680-2685.

•Rowlands DC, Hansel TT, Crocker J 1990. Immunohistochemical determination of CD 23 expresssion in Hodgkin's disease using paraffin sections. Journal of Pathology 160: 239-243.

•Thorley-Lawson DA, Nadler LM. Bhan AK, Schooley RT 1985. BLAST-2 (EBVCS), an early cell surface marker of human B cell activation, is superinduced by Epstein-Barr virus. Journal of Immunology 134: 3007-3012.

•Zola H 1987. The surface antigens of human B lymphocytes. Immunology Today 8: 303-315.

Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.