Diagnostic differentiation of chronic B‐cell malignancies using monoclonal antibody L161 (CD1c)

Abstract

The expression of membrane CD1c, as defined by monoclonal antibody L161, was examined on malignant lymphoid cells from 191 cases of chronic lymphoproliferative disease and on eight 'normal' enriched tonsil B-cell extracts. Of 79 cases of chronic lymphocytic leukaemia (CLL) studied, 77 showed low (less than 20% positive cells) CD1c expression whereas 63/71 (89%) cases of B-PLL, HCL and B-NHL showed increased CD1c+ (but not CD1a or CD1b) components. In contrast, malignancies corresponding to terminal stages of B-cell differentiation (immunocytoma and myeloma) generally showed low CD1c expression as did lymphoid cells from 10 cases of post-thymic malignancy. Although there was some correlation between the expression of membrane CD1c and immunoglobulin (SIg) light chain densities (P less than 0.001), it is relevant in diagnostic terms that seven cases of B-NHL with low SIg staining intensities more typically associated with CLL were CD1c+. CD1c expression was not, however, correlated with the presence of CD23 or FMC7 determinants but did show a similar pattern of expression to that previously reported for beta-2 microglobulin. Determination of cellular CD1c by APAAP immunocytochemistry confirmed the presence of higher antigen densities in malignant B-cells at intermediate/late stages of differentiation and this interpretation was further supported by the finding that the majority of phenotypically mature tonsil B-cells were also CD1c+. The determination of CD1c expression by malignant B-cells may therefore be of particular value in the diagnostic differentiation of chronic lymphoproliferative disorders.

The MHC Class I Associated Beta2‐microglobulin (β2m) Light Chain is Expressed in a Molar Excess Over HLA‐ABC and CD1 on the Membrane of Leukaemic B Cells but not Leukaemic T Cells: Evidence for Further β2m‐Associated Molecules

“…we investigated the expression of this determinant on leukaemic B eells. and reported maximal expression on B-NHL cells [22]. This was independently confirmed by a separate study, which identified a eorrelation between immunophenotypically defined difTerentiation stage and anatomical location in B-cell subpopulations [26].…”

“…Further potential candidates for the tnantle of Qa-like antigens arc the HLA-linked TCA [19] and HT [20,21] moiccuics. Having previously reported the expression of CD I c on malignant B cells at defined stages of differentiation [22]. this study was undertaken to quantify the level of CDlc expression and lo further explore the possibility that additional /iim-associated non-HLA class I molecules arc expressed on leukaemic B cells.…”

Interferon‐α‐induced changes in surface antigens in a hairy‐cell leukemia (JOK‐1)‘ and a Burkitt's lymphoma cell line (Daudi) during in vitro culture

“…The immunological phenotypes ofJOK-1 and Daudi, compared with those of HC phenotyped in our and other laboratories (15,16,17,18,19,20,21,22), are shown in Table 1. Whereas the surface antigens on Daudi and JOK-1 were very similar, except that Daudi is MHC class I-negative, several differences were observed between the cell lines and HC.…”

Distinct morphophenotypic features of chronic B‐cell leukaemias identified with CDlc and CD23 antibodies

“…SLVL: (a) moderate-to-large sized cells with unevenly distributed, short cytoplasmic projections -(b) intense CD lc staining of the cell membrane and projection (peripheral blood -x800). LPC NHL: (c) 2 large-sized plasmacytoid cells with basophilic cytoplasm -(d) cytoplasmic positivity CD25 (peripheral blood -x800).invariably low expression of CDlc by B-CLL cells, were recently obtained by Jones et al(18) who studied a large number of cases diagnosed on the basis of well-defined morphophenotypic features. Some other minor discrepancies, however, concern the expression of CD 1 lc and CD25 on B-CLLs: Erber et al(16) and Inghirami et al(19) recently reported, respectively, 21 % and 47 % of B-CLL to be CD 1 lc-positive.…”