Idiotype-bearing peripheral blood lymphocytes in human multiple myeloma and Waldenström's macroglobulinaemia

Infections in patients with leukemia and lymphoma

Infectious complications remain a significant issue in the care of patients with hematologic malignancies. Inherent immune defects related to the primary disease process are present in patients with disorders such as chronic lymphocytic leukemia, multiple myeloma, hairy cell leukemia, and Hodgkin lymphoma. Therapy-related immunosuppression is also commonplace in these patients. This includes not only treatment-related neutropenia, but also defects in cell-mediated immunity, such as those that occur with purine analog therapy. In this chapter, we will review the pathogenesis of infection in these disorders, as well as the spectrum of infectious complications seen and suggested strategies for the prevention of infection.

Immunoregulatory mechanisms in multiple myeloma

This review presents current experimental data regarding immunologic changes associated with multiple myeloma (Table 1). It is becoming increasingly clear that some of the immunologic changes are host responses to the malignant plasma cell clone and monoclonal immunoglobulin. In the last 2 to 3 years an anti-idiotypic response has been clearly documented, and cells expressing CD16 and soluble CD16 have been identified as modulators of myeloma cell growth and differentiation. Abnormalities in B- and T-cell differentiation have been observed, most consistently the deficiency of T4 helper cells. Differences in the immunologic changes point to the provocative hypothesis that, in MGUS and the initial stages of myeloma, immunologic responses play an important role in controlling proliferation of the malignant clone, and at some point the system is overwhelmed or fails, leading to an overt or more aggressive disease. The quest is to understand the genesis of the autoregulatory circuits operative in myeloma. Novel strategies for immunotherapy in management of myeloma will arise through improved understanding of host immune response and its cause-and-effect relationship with myeloma cell growth.

No detectable malignant B cells in the peripheral blood of patients with multiple myeloma

Previous studies have reported the presence of idiotypic B lymphocytes in the peripheral blood of patients with multiple myeloma (MM), suggesting that they may belong to the malignant clone. This led us to investigate by Southern blot analyses the presence of tumour-specific immunoglobulin-gene (Ig-gene) rearrangements in the peripheral-blood mononuclear cells of 21 MM patients. This method was shown to detect clonal cells when they represent as little as 2% of the cell population. B-cell-enriched fractions were also studied in nine cases. An occasional contamination by circulating malignant plasma cells was carefully evaluated using immunofluorescence. Clonal rearrangements were observed in only two cases, in which a contamination by myeloma cells was evident. In these cases the use of different endonucleases clearly demonstrated that these Ig-clonal rearrangements involved post-switched cells. No clonal rearrangement was found when contamination by myeloma cells was absent. Our results demonstrate the absence of detectable B cells involved in the myeloma clone in the peripheral blood of patients with MM.

Abnormalities in lymphocyte profile and specificity repertoire of patients with Waldenstrom's macroglobulinemia, multiple myeloma, and IgM monoclonal gammopathy of undetermined significance

The characteristics of T and B lymphocyte profile and B lymphocyte specificity repertoire were compared in patients with Waldenstrom's macroglobulinemia (WM), IgM monoclonal gammopathy of undetermined significance (IgM MGUS), multiple myeloma (MM), and age-matched normal subjects. Patients with MM had both significantly reduced frequency and number of sIg+ (surface Ig) B cells, whereas patients with WM and IgM MGUS had a reduced frequency but normal numbers of sIg+ B cells in circulation as detected in a capping assay. WM was distinguished by the large numbers of cells in the peripheral blood lymphocyte (PBL) pool that expressed CD9 (BA-2) and CD24 (BA-1) and were monoclonal, based on light chain analysis using flow cytometry. The profile of T lineage cells showed that the ratio of CD4:CD8 was significantly reduced in both MM and WM due to a reduction in the CD4 set. The CD4+ cells were qualitatively abnormal as well, with an enriched proportion of the 4B4+ (CDw29) subset and decreased proportion of the Lp220+ (CD45R) subset. This appeared to be an effect of the disease process on the relatively immature Lp220+ set. From clonal analysis, those patients with WM or IgM MGUS (unlike MM patients) did not exhibit enhanced reactivity with auto-Ig determinants, and most WM patients (7/8) and half of the IgM MGUS patients (3/6) did not have enriched proportions of B cells reactive to tetanus toxoid (TT). The TT-specific B cells in both WM and IgM MGUS, in contrast to MM, appeared fully functional in secretion of anti-TT IgM in vivo. We speculate that the more severe immunodeficiency in MM may be controlled or exacerbated by the presence of an anti-Ig network. The absence of this network in WM allows a relatively more effective immune response, but the immunodeficiency that is observed in these patients involves some abnormality in normal lymphocyte differentiation (is also present in MM).

Monoclonal B-cells in blood in non-Hodgkin lymphoma. Correlation with clinical features and prognoses

Presence of monoclonal B-cells in peripheral blood (MBCB) was studied in 132 previously untreated patients with non-Hodgkin lymphoma classified according to the Kiel classification. Detection of B-cells was performed by immunofluorescence microscopy, using antibodies against immunoglobulin light chains. Thirty-six patients (27%) were found to have MBCB. In the subgroup of low grade lymphomas 25/75 (33%) and in high grade lymphomas, 11/57 (19%) had MBCB. Presence of MBCB was correlated to clinical stage and 81% of the patients with MBCB were in stage IV. Twenty-two out of 36 (61%) patients with MBCB had normal lymphocyte counts (less than 5.0 X 10(9]. MBCB indicated a less favourable prognosis, mainly due to the close association with stage IV. It was concluded that studies of MBCB by this simple method are useful in detecting 'subclinical' blood involvement and valuable in the initial staging procedure as well as in the follow-up of the patients.

Impaired immunoglobulin synthesis in multiple myeloma: a B-cell dysfunction

Peripheral blood samples collected from normal individuals and patients with benign monoclonal gammopathy and multiple myeloma were separated and assayed for their T- and B-cell subpopulations as well as immunoglobulin (IgG, IgM) synthesis in vitro. To rule out any functional or quantitative alterations related to therapy, only newly diagnosed multiple myeloma patients and subjects with benign monoclonal gammopathy were included in our study. Multiple myeloma patients were further subdivided into two groups. Group A consisted of patients with low and intermediate tumor burdens, while group B included patients with high tumor mass. B- and T-cell subset analysis revealed an abnormal ratio between B/T and OKT4+/OKT8+ lymphocytes compared to healthy controls. These alterations were especially prominent in group B multiple myeloma. Immunoglobulin synthesis was studied in pokeweed-mitogen-stimulated lymphocyte cultures. The results indicate that the failure to synthesize and secrete immunoglobulin resides within the B-cell lineage and is probably due to a functional B-cell defect. T-cell immunoregulatory functions seem to be unaffected in both multiple myleoma and benign monoclonal gammopathy patients.

Cytogenetic evidence that the malignant event in multiple myeloma occurs in a precursor lymphocyte

Multiple myeloma is traditionally thought of as a disease of plasma cells. Evidence from studies using antiodiotype antibodies, however, suggests that malignant events may take place in a precursor lymphocyte perhaps as early as the pre-B cell. In this study, we present cytogenetic evidence to support the latter view. Peripheral blood was obtained from a patient with plasma cell leukemia and light chain disease. Karyotypic analysis, using Giemsa banding techniques, showed an abnormal karyotype: 44,XY,-6,-8,-13,-16,-22,+mar1,+ mar2,+mar3,del(1)(p22,p32),11p+,13q+,14q+. A suspension culture was established and a plasma cell line was grown. It was characterized by transmission electron microscopy as having an eccentric nucleus, abundant cytoplasm, and extensive endoplasmic reticulum. A subculture of this line was subsequently grown that was characterized by transmission electron microscopy as a lymphoid cell with diminished quantity of cytoplasm without extensive endoplasmic reticulum. Karyotypic analysis of the smaller cell demonstrated a modal number of 88 chromosomes and was a tetraploid derivative of the first. Our study provides cytogenetic evidence that cells with a lymphocytic phenotype show karyotypic abnormalities seen in the malignant plasma cell of the same patient, and thus, can be considered as evidence favoring the initiating cell of plasma cell myeloma as being an early B lymphocyte.

Severe deficiency of B lymphocytes in peripheral blood from multiple myeloma patients

A major problem in the assessment of circulating B lymphocytes in multiple myeloma is the extent to which cells with passively absorbed Ig contribute to the assay. We have analyzed peripheral blood B cell numbers in 51 patients in various treatment categories by using an assay that is not subject to artifacts involving cytophilic Ig. We have defined a B lymphocyte by three different criteria (a) expression of a high surface density of Ig (b) expression of a high density of HLA.DR and (c) expression of a marker exclusive to surface Ig+ B cells. By these criteria, normal individuals have an average of 6% B cells. In multiple myeloma patients, B cell levels in purified mononuclear cell preparations are severely reduced. Untreated patients and the majority of patients on intermittent chemotherapy have 20-600-fold fewer B cells than do normal donors (average = 0.3%). This decrease was even greater in whole blood of patients as compared with normal donors (100-1,000-fold fewer B cells). The number of B cells did not correlate with disease status or paraprotein concentration. We found no evidence to support the idea that B lymphocytes in patients include a substantial monoclonal subset.

In vitro immunoglobulin production by peripheral blood mononuclear cells from multiple myeloma patients and patients with benign monoclonal gammopathy. Regulation by cell subsets

Peripheral blood mononuclear cells (PBM) from four patients with IgG myeloma and four patients with benign monoclonal gammopathy (BMG) were stimulated with pokeweed mitogen (PWM), and the in vitro immunoglobulin production over 7 days was measured with an enzyme-linked immunosorbent assay. All myeloma patients were sufficiently treated with cytostatic drugs. Their PBM did not produce monoclonal Ig in vitro, as opposed to PBM from two patients with BMG. Unseparated PBM from myeloma patients produced smaller amounts of polyclonal Ig than unseparated cells from normal donors. However, macrophage-depleted PBM from myeloma patients produced amounts of Ig comparable to those of normal donors when autologous or allogeneic adherent cells were returned in defined numbers. T cells from three of the four myeloma patients could provide help for the Ig production by B cells from healthy donors. These results indicate that functionally normal polyclonal B cells circulate in the blood of myeloma patients. The circulating T-cell population also has no obvious defect. In contrast, blood macrophages seemed to be altered with respect to their regulating function for polyclonal Ig production. The results obtained by using cell populations from patients with BMG did not differ from those of healthy people.

A new method for the preparation of anti-idiotypic antibodies against six different human cold agglutinins

A method based on sequential immunoadsorption for the preparation of a highly specific antibody directed against the idiotypic determinant of human cold agglutinins (CA) is described. In the present study, human cold agglutinins (CA) were used as a model, but the method can easily be adapted for the preparation of anti-idiotypic antibodies against other monoclonal human immunoglobulins. Since regenerable immunoadsorbents were used, the isolation can be accomplished even with rather low amounts of the respective immunoglobulin.

Simultaneous occurrence of acute myelogenous leukaemia and multiple myeloma without previous chemotherapy

A patient with simultaneous occurrence of multiple myeloma and acute myelogenous leukaemia without previous chemotherapy was studied. Indirect immunofluorescence and protein A-coupled ox red blood cells rosette technique by use of anti-idiotype (Id) antibody showed some T cells with receptors of idiotypic specificity identical with that of the secreted myeloma protein. Plaque forming cell assay showed the presence of Id producing peripheral blood lymphocytes with EB virus receptor, probably B cells. These observations strongly suggest that multiple myeloma was not the result of a neoplastic transformation of the most differentiated B cells, plasma cell, but of lymphoid stem cells capable of differentiating to either B or T cells. However, there was not a detectable population of myeloblasts that expressed the same idiotype. Chromosomal analysis revealed a deletion of the long arm of chromosome 8 in myeloblasts but not in T or B cells. These results support the hypothesis of separate clonal origins for the leukaemic and myeloma components in this case.

Properties of an anti-idiotype antiserum: demonstration of cross-reacting mitogenic determinants on bone marrow plasmacytoma cells

An antiserum against a monoclonal protein of IgG/kappa type from a patient S. was produced by immunization of guinea pigs. Idiospecificity of the antiserum (anti-Id AS) was tested by immunoprecipitation and hemagglutination inhibition. About 70% mononuclear cells prepared from the bone marrow (BM) aspirate of this patient stained positive when the antiserum was used in an indirect immunofluorescence (IF) procedure detecting surface membrane structures. Commercial antisera specific for gamma, kappa and lambda immunoglobulin (Ig) chains stained only 5-17% of the cells. With mu chain and delta chain specific antisera no reactivity could be observed. The presence of idiotype cross-reacting determinants (Id-CR-D), that is idiotypes not associated with Ig isotypes could be also demonstrated by a significant increase of 3H-thymidine incorporation of the BM cells in the presence of the anti-Id AS. Phytohemagglutinin (PHA), pokeweed mitogen (PWM) and concanavalin A had no effect. In a cell sorting experiment using affinity gel chromatography it could be shown that the anti-Id AS preferentially binds to proplasmacytes. Cells of this type were enriched two-fold over plasma cells in the eluate. The analysis of peripheral blood lymphocytes (PBL) from the patient revealed about 40% positive cells without correlation to a certain subpopulation. Administration of prednisolone to the patient resulted in a significant reduction of the Id positive cells within two days. In conclusion it appears that our antiserum detects cells of an individual tumour clone within PBL and BM-cells. By the stimulating effect of the anti-Id AS a proliferative potential of plasmacytoma cells could be defined which may work also 'in vivo'. Thus, Id-CR-D may operate as a tumour growth receptor.

In vitro production of monoclonal and polyclonal immunoglobulins by peripheral blood mononuclear cells in human plasma cell myeloma

The in vitro monoclonal and polyclonal immunoglobulin (Ig) production of peripheral blood mononuclear cells was studied in human multiple myeloma (four IgG myelomas, one IgA myeloma) and in one patient with benign monoclonal gammopathy. Using an enzyme-linked immunosorbent assay with anti-class-specific antisera and antisera against idiotypic structures on the myeloma protein, it was possible to quantitate separately monoclonal and polyclonal Ig of the same class in cell culture supernatants. After stimulation with pokeweed mitogen (PWM) patients' cells produced lower amounts of polyclonal Ig than cells from healthy adults. In contrast, production of monoclonal Ig could not be enhanced by PWM. Moreover, the kinetics of monoclonal Ig production was different from that of polyclonal Ig. Myeloma cells contained large amounts of monoclonal Ig while their content of polyclonal Ig was low. A rapid release of preformed monoclonal Ig during the first day of culture was not inhibited by puromycin. A later phase of release was partly suppressed by puromycin and was probably caused by active protein synthesis.