Light chain isotype-associated suppression of normal plasma cell numbers in patients with multiple myeloma: Medical Research Council's Working Party for Leukaemia in Adults and the Oxford Lymphoma Group

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.

Fluorescence in situ hybridization analysis of aneuploidization patterns in monoclonal gammopathy of undetermined significance versus multiple myeloma and plasma cell leukemia

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) is a clonal plasma cell (PC) disorder usually characterized by a benign clinical course. However, in approximately 25% of patients, the disorder has been found to evolve into a multiple myeloma (MM). The mechanism leading to the evolution of MGUS remains unknown. The aim of the current study was, first, to assess by interphase fluorescence in situ hybridization (FISH) the incidence of numerical abnormalities of chromosomes 6, 9, 13, and 17 in MGUS patients and to compare it with that found in MM and PC leukemia (PCL) patients and, second, to explore the potential heterogeneity of the pathologic PC in MGUS as a way to identify unique cytogenetic patterns different from those frequently observed in MM and PCL.

METHODS

Numerical abnormalities of chromosomes 6, 9, 13, and 17 were investigated by dual- and triple-color FISH in bone marrow PC from 208 patients corresponding to MGUS (n = 30), MM (n = 158), and PCL (n = 20) cases. In MGUS and MM patients with < 10% PC, both normal and phenotypically aberrant PC were discriminated by multiparameter flow cytometry, the latter subset being specifically sorted for FISH analysis with a purity of 93% +/- 6%.

RESULTS

Overall, 57% of the MGUS patients displayed abnormalities for at least 1 of the 4 chromosomes analyzed compared with 75% of both MM and PCL cases. The most common single chromosome abnormalities detected in MGUS were gains of chromosomes 9 (23%) and/or 6 (21%) and loss of chromosomes 13 (21%) and/or 17 (17%). Compared with MM patients, MGUS patients were found to have both a lower incidence of gains of chromosome 9 (23% vs. 54%, P = 0.002) and monosomy 13/13q(-) deletions (21% vs. 38%, P = 0.07); with respect to PCL cases, MGUS patients were found to have a lower incidence of monosomy 13/13q(-) deletions (21% vs. 75%, P < 0.001) together with a slightly higher frequency of gains of both chromosomes 6 (21% vs. 0%, P = 0.05) and 9 (23% vs. 7%, P = 0.1). The simultaneous use of two or three different chromosome probes showed that within the purified compartment of phenotypically aberrant PC from most MGUS patients (67%), more than 1 PC clone could be identified. In contrast, the incidence of 2 or more PC clones was much lower in MM (19%, P < 0.001) and PCL (15%, P = 0.003). Interestingly, although some FISH patterns were shared by both groups of diseases (i.e., monosomy 13/13q(-) deletions alone, gains of chromosome 9 alone or together with trisomy 6), others were found almost exclusively in either MGUS (i.e., a clone with monosomy 6 and/or 17 together with nuclei displaying a normal chromosome number) or in MM (i.e., monosomy 13/13q(-) deletions together with gains of chromosome 6 and/or 9).

CONCLUSIONS

In summary, the results of the current study showed that MGUS patients displayed a high incidence of numerical alterations, which are usually associated with the presence of more than one tumor cell clone. It is interesting to note that the cytogenetic patterns observed in the aneuploid PC clones from MGUS patients were frequently different from those observed in both MM and PCL.

Quantitation of circulating peripheral blood plasma cells and their relationship to disease activity in patients with multiple myeloma

BACKGROUND

The analysis of peripheral blood mononuclear cells for plasma cells and B-cell surface light chain ratios may provide additional insight on the pathogenesis of multiple myeloma and predict disease activity. The goals of this study were to correlate these parameters with clinically determined disease activity and establish a cutoff value of circulating plasma cells that could be used in future clinical trials.

METHODS

Peripheral blood samples from 84 patients with monoclonal gammopathies were analyzed by an immunofluorescence, slide-based, labeling index (LI) technique for detection of plasma cells, the LI, and light chain ratios. These parameters were compared with disease activity.

RESULTS

Of the 84 patients studied, 27% had inactive and 73% had active disease. The mean number of plasma cells for patients with inactive disease was 0.61 x 10(6)/l, compared with 139.6 x 10(6)/l for patients with active disease (P < 0.001). The mean ratios of involved to uninvolved light chain percentages for patients with inactive and active disease were 1.6 and 9.2, respectively (P = 0.002). The absolute number of plasma cells better predicted disease activity than the light chain ratio. By use of a cutoff value of 3 x 10(6)/l, 67% of patients with active disease were determined to have 3 x 10(6)/l or more plasma cells, and 96% of those with inactive disease had less than 3 x 10(6)/l plasma cells.

CONCLUSIONS

These results suggest that detection of circulating plasma cells is a marker of disease activity in patients with plasma cell disorders and that an appropriate cutoff value is 3 x 10(6)/l or more circulating plasma cells.

Measurement of free kappa and lambda chains in serum and the significance of their ratio in patients with multiple myeloma

An inhibition enzyme-linked immunoassay technique using commercially available antibodies has been developed for the quantitation of both kappa and lambda light chains in the serum of patients with B-cell malignancies. Assay conditions were selected to enable measurement of free light chains in the concentration range between 0.1 and 20 mg/l. The normal range for free lambda chains in serum was found to be 0.4-4.2 mg/l and for free kappa chains it was 1.6-15.2 mg/l. At diagnosis the serum of most patients with multiple myeloma contained increased levels of the malignant free light chain and in some cases there was also elevation of the non-malignant light chain. The absolute level of the malignant light chain at diagnosis did not correlate with survival nor with laboratory parameters such as IgM or creatinine. A correlation with beta 2 M and serum paraprotein levels was evident only in cases of IgA myeloma. Although the absolute level of free serum light chain had no value as a prognostic indicator, the ratio of kappa:lambda chains closely followed the clinical assessment of disease status, being near the normal range (1.2-9.1) in plateau phase or stable disease. During periods of progressive disease this ratio ranged from 19 to 460 (n = 14) in patients with kappa myeloma, and 0.0013-0.14 (n = 9) in patients with lambda myeloma. Determination of the ratio of free light chains in the serum may allow effective monitoring and earlier warning of disease progression in patients with multiple myeloma.

Aberrant expression of immunoglobulin light chain isotype in B lymphocytes from patients with monoclonal gammopathies: isotypic discordance and clonal B-cell excess

A study was made of 29 patients with monoclonal gammopathies to detect aberrations in immunoglobulin (Ig) light chain isotype expression in lymphocytes at various levels of B-cell differentiation, namely, circulating surface Ig positive (SIg+) cells, Ig-secreting cells (plaque forming cells, PFC) and mitogen-induced PFC. By using kappa-lambda analysis, two major phenotypes of aberrant Ig light chain isotype expression were found in circulating B cells at these three levels of differentiation: an absolute increase in B cells bearing the same Ig light chain isotype as that of monoclonal protein (clonal B-cell excess), and a relative decrease in those B cells (isotypic discordance). Isotypic discordance (ID) was found to be essentially negative in patients with monoclonal gammopathy of undetermined significance (MGUS) provided that they were in a stable condition. In myeloma patients, ID was found only in stage I, except for a remission case of stage III (4/7 in stage I, 0/8 in stage II, and 1/6 in stage III). ID was not restricted to a circulating SIg+ cell level but was also demonstrable at a spontaneous or pokeweed mitogen-induced PFC level. However, ID was negative at a PFC level induced by Staphylococcus aureus Cowan I. Clonal B-cell excess (CE) was frequently found in patients with active myeloma but not in stable patients (0/8 in MGUS, 1/7 in stage I, 8/8 in stage II, and 4/6 in stage III). CE was positive not only at a circulating SIg+ cell level but also at a circulating PFC level. Furthermore, patients with CE at a PFC level were found to have a higher proliferating capacity, defined as a percentage labelling index of marrow myeloma cells, than those without CE at a PFC level (P less than 0.02). ID and CE can therefore be considered as useful markers for discriminating between MGUS and myeloma, evaluating the clinical stability and predicting the clinical course.

Serum thymidine kinase as a marker of disease activity in patients with multiple myeloma

Serum thymidine kinase (STK) levels have recently been used to detect tumour regression and progression in a number of hematological malignancies. In this study, patients with myeloma were monitored longitudinally for STK and several other potentially useful tumour markers to determine which laboratory parameters are the most useful for differentiating between stable and progressive disease. STK was determined by radioenzyme assay, lymphocyte surface markers were analysed by flowcytometry, plasma cell labelling index (LI) by immunofluorescence with anti BU-1, serum B2-microglobulin (SB2M) by radioimmunoassay and M proteins by radial immunodiffusion. Detailed multiparameter longitudinal investigations of 5 patients and ongoing studies of 70 other patients suggest that STK is a more reliable marker of progressive disease than either SB2M, LI, M-protein or CD10 positive lymphocytes. A rise in STK during the emergence of progressive disease at least paralleled and usually preceded any change in the other parameters which often did not change at all. All samples from patients with progressive disease (n = 29) had a STK above the normal range (0-5U/l) whereas 76% of patients in clear stable disease had a STK within the normal range. All samples (n = 34) from patients with light chain isotype suppression (LCIS) had STK values of less than 12 U/L and 82% of samples (n = 33) from patients without LCIS had a STK above the normal range (0-5U/L). The correlation between STK and LI was r = 0.65; p less than 0.001 (n = 21). The radioenzyme assay for STK is simple, reproducible and a valuable tool for monitoring patients with myeloma and when used in conjunction with other clinical and laboratory investigations, aids in the separation of patients with stable myeloma from patients whose disease is progressive.

Immunogold-silver technique applied to showing malignant B cell infiltration of gastrointestinal tract in patients with chronic lymphocytic leukaemia and non-Hodgkin's lymphoma

Gastric, duodenal, and rectal biopsy specimens from 20 patients with chronic lymphocytic leukaemia (CLL) and non-Hodgkin's lymphoma (NHL), not primarily of gastrointestinal origin, were examined using the immunogold-silver staining (IGSS) technique. In paraffin sections the presence of kappa and lambda surface immunoglobulin in lymphoid infiltrates was shown. Using this technique, nine patients were shown to have infiltration of the gastrointestinal mucosa by monoclonal B cells at one or more sites. In a further case a lymphoid aggregate was shown to express both kappa and lambda surface light chains, suggesting that it had a benign nature.

Multiple myeloma: light chain isotype suppression--a marker of stable disease at presentation

Prognosis in multiple myeloma (MM) is related to the establishment of an immunologically and kinetically characteristic plateau phase. Patients who present with this state may not benefit from immediate chemotherapy. We assessed 20 patients with MM who were staged according to the Salmon and Durie classification at diagnosis and monitored throughout the course of their disease. Patients with a lambda paraprotein and a kappa/lambda lymphocyte ratio in the blood greater than 4.0 were considered to demonstrate light chain isotype suppression (LCIS). Similarly, patients with a kappa paraprotein and a kappa/lambda ratio of less than 0.55 were also considered to have LCIS (1). 14 patients had LCIS; of these, 6 were classified as stage IA, 2 as stage IB, 3 as stage IIA, and 3 as stage IIIA. 6 patients did not have LCIS; 3 were classified as stage IIA, 1 as stage IIIA and 2 as stage IIIB. 10 patients with LCIS were assessed for treatment benefit following administration of melphalan and prednisone, as defined by a fall in the serum paraprotein level of greater than 50% over 6 months. In 8 patients the serum paraprotein levels did not fall, and the patients remained in good health without clinical deterioration. Thus LCIS at presentation may indicate patients in whom treatment can be safely deferred or in whom aggressive therapy is not indicated.

Quantitation of the monoclonal plasma cell component in bone marrow from patients with serum paraproteinemia and nondiagnostic marrow morphology

Twenty-one patients with serum monoclonal gammopathy but lacking acceptable morphological evidence of myelomatosis were studied with reference to the degree, if any, of monoclonal plasma cell expansion in aspirated marrow samples, enriched for plasma cells and analysed with respect to light chain distribution. Four of these patients had a biopsy-proven plasmacytoma of bone. Bone marrow aspirated from sites distant to the tumor showed clear evidence of infiltration by monoclonal plasma cells in two of the cases studied; the other two patients had normal results. Of the 17 other cases, 14 showed evidence of a monoclonal plasma cell component qualitatively concordant with the serum paraprotein as one would expect. These cases could be subdivided into those with myeloma (six cases) and those with monoclonal gammopathy of undetermined significance (eight cases) on the basis of conventional biochemical and radiological criteria. Three of the 17 patients, however, did not show evidence of monoclonal plasma cell infiltration, despite the presence of lytic lesions. It is important to recognize this minority group that simulates myeloma but that may well reflect alternative pathology that has not been identified.

Light chain isotype associated suppression of surface immunoglobulin expression on peripheral blood lymphocytes in myeloma during plateau phase

Light chain isotype suppression in multiple myeloma has been reported in the plasma cells of the lamina propria of the gut (Leonard et al, 1979). In this paper we present further evidence of systemic suppression of the light chain isotype of the paraprotein expressed on normal peripheral blood lymphocytes in myeloma. Twenty patients with myeloma in plateau phase were monitored over 6 months for the expression of either kappa or lambda light chains on the surface of peripheral blood lymphocytes using monoclonal antibodies. The surface markers were analysed on an Ortho Spectrum III flow cytometer. Results of these studies indicate a selective suppression of the cells expressing the light chain isotype of the paraprotein in stable myeloma. Thus, in kappa myeloma there is a low kappa/lambda ratio and in lambda myeloma there is a high kappa/lambda ratio, and this suppression is lost with progressive disease.

The incidence of B cell leukaemia and lymphopenia in B cell neoplasia in adults: a study using the Kiel classification of non-Hodgkin's lymphoma

The incidence of B cell leukaemia in 186 consecutive untreated patients with histologically defined B cell neoplasms is described. The lymphomas were classified by the Kiel convention. B cell leukaemia in the context of this paper refers to the situation where a neoplastic clone of B cells in the blood greatly outnumbers normal blood B cells. It is defined as an absolute blood B cell count greater than 0.75 X 10(9)1(-1) where either greater than 90% B cells express kappa immunoglobulin light chains or greater than 80% express lambda light chains. This was found in several patients where the total blood lymphocyte count was within normal limits. All patients with diffuse lymphocytic lymphoma with the histological appearances of B cell chronic lymphocytic leukaemia (ML-BCLL) were found to have B cell leukaemia. However, more than half these patients had blood B cell counts less than 10 X 10(9)1(-1). B cell leukaemia was also a feature in approximately 33% of patients with follicle centre cell tumours and 33% of those with lymphoplasmacytoid tumours. B cell leukaemia was not detected in 34/35 patients with myelomatosis. The 35th patient had plasma cell leukaemia. Only 3/22 patients with high grade lymphoma had B cell leukaemia. In the three principal tumour types associated with B cell leukaemia mu + delta was the most common immunoglobulin heavy chain phenotype. Spontaneous mouse red cell rosette formation also characterised leukaemic B cells in these three groups but high proportions of mouse rosetting cells were seen only in association with ML-BCLL. None of 4 cases of prolymphocytic leukaemia showed mouse red cell rosetting. HLA-DR alpha chain was found on the leukaemic cells of all patients except one with ML-BCLL. B cell lymphopenia was a frequent finding in all histological groups in those patients who did not have B cell leukaemia.

Distribution of plasma cells in normal rectal mucosa

In a survey of 36 histologically normal rectal biopsies, plasma cell counts were recorded at different depths of the lamina propria. The necessity of surveying the lamina propria at every level from the muscularis mucosae to the epithelium, in order to obtain an accurate estimate of plasma cell frequency is demonstrated. The relative accuracy of counting smaller areas of lamina propria is tested and the ratio of epithelium to lamina propria area established.

Prognostic features in the third MRC myelomatosis trial. Medical Research Council's Working Party on Leukaemia in Adults

This paper reports the prognostic significance of clinical and laboratory features recorded at presentation in 485 patients entered into the Medical Research Council's 3rd therapeutic trial in myelomatosis between July 1975 and August 1978. The data were complete up to 1 January 1980, with a median follow-up time of 36 months. The 3 major determinants of prognosis were the blood urea concentration (BUC), the haemoglobin concentration ([Hb]), and the clinical performance status. Three prognostic groups based on these determinants were specified. The groups contained 22%, 56% and 22% of the patients and gave 2-year survival probabilities of 76%, 50% and 9% respectively. Patients in the good-prognosis group had a BUC less than or equal to 8 mM. [Hb] greater than or equal to 100 g/l, and no or minimal symptoms. Those in the poor-prognosis group had either [Hb] less than or equal to 75 g/l or a BUC greater than 10 mM and restricted clinical activity. Patients who had combinations of the 3 determinant features which excluded them from these 2 groups were classified into an intermediate prognosis group.