Cell surface expression of beta 2-microglobulin (beta 2m) correlates with stages of differentiation in B cell tumours.

Abstract

SUMMARY Cell surface 32-microglobulin (f2m) densities of malignant B cells were determined by enzyme immunoassay in 97 cases of immunologically defined lymphoproliferative disease. Absolute f2m densities were found to depend on disease category with the lowest levels found on cells from chronic lymphocytic leukaemia (mean = 5-6 ng/106 cells, n = 27); atypical chronic lymphocytic leukaemia (mean = 5.9 ng/106 cells, n = 8); and prolymphocytoid chronic lymphocytic leukaemia variant (mean = 6 0 ng/106 cells, n = 16). fi2m densities for B non-Hodgkin's lymphoma (n = 14) and B prolymphocytic leukaemia (n = 17) cases were 8 1 and 10-0 ng/106 cells, respectively, and the highest densities were found on cells from "late-B cell" tumours (mean = 14 3 ng/106 cells). Plasma cells from cases of Ig secreting tumours expressed unexpectedly low fJ2m densities (mean = 9.3 ng/106 cells; n = 6).f12-microglobulin (fl2m) forms the invariant light chain of the HLA class I molecule' and is expressed, in non-covalent association with the 43000 dalton heavy chain,2 on the surface of cells from many tissues.34 HLA antigens seem to play a part in regulating the immune response by major histocompatibility complex restriction of T cell mediated cytotoxicity,5 and f2m is required for the structural integrity of the HLA molecule.6`8 Defective expression of HLA has been reported in a variety of tumours,49 and it is possible that this impairs T cell mediated responses to tumour cells.'0 fi #2m is shed into plasma as a result of normal membrane turnover'2 and is raised in many pathological conditions."3 Correlations between serum 152m and estimated tumour mass have been noted in chronic lymphocytic leukaemia"4 and myeloma,'5 and serum #2m is also closely correlated with prognosis in myeloma.'6 The underlying importance of these observations has yet to be determined. Further insights may be gained by examining relations between serum concentration and cell surface expression. We present the findings of a vertical study into surface 132m expression in malignant lymphoid cells from patients with morphologically and immunologically classified B cell disorders.

Serum β2-Microglobulin for Staging and Monitoring of Multiple Myelomas and Other Non-Hodgkin Lymphomas

“…This indicates the independence of immunoglobulin and (32m synthesis in spite of their homology, which corresponds to in vitro experiments [24], The origin of increasing (32m production in malignant disease progression has not been established, but it was specu lated that the rise in serum (32m seen in the progression of some B-cell tumors to more clinically aggressive forms may be accom panied by a reduction in surface p2m expression [25], Higher p2m levels in IgD and light-chain myeloma could be re lated to their general poor prognosis. These patients often de velop renal complications because of Bence-Jones proteinuria.…”

Prognostic factors in the non-Hodgkin's lymphomas--a time for consensus?

“…It has been demonstrated that cell surface expression of P2m shows broadly considerable variation in patients with nonHodgkin's lymphomas, presumably reflecting the heterogeneity of these disorders (Jones et al, 1987). Of all the biochemical indicators investigated in the lymphomas, serum lactic dehydrogenase (LDH) has enjoyed the most universal acceptance.…”