The International Scoring System (ISS) for multiple myeloma remains a robust prognostic tool independently of patients' renal function

BACKGROUND

The International Staging System (ISS) is the most widely used staging system for patients with multiple myeloma (MM). However, serum β2-microglobulin increases in renal impairment (RI) and there have been concerns that ISS-3 stage may include 'up-staged' MM patients in whom elevated β2-microglobulin reflects the degree of renal dysfunction rather than tumor load.

PATIENTS AND METHODS

In order to assess the impact of RI on the prognostic value of ISS, we analyzed 1516 patients with symptomatic MM and the degree of RI was classified according to the Kidney Disease Outcomes Quality Initiative-Chronic Kidney Disease (CKD) criteria.

RESULTS

Forty-eight percent patients had stages 3-5 CKD while 29% of patients had ISS-1, 38% had ISS-2 and 33% ISS-3. The frequency and severity of RI were more common in ISS-3 patients. RI was associated with inferior survival in univariate but not in multivariate analysis. When analyzed separately, ISS-1 and ISS-2 patients with RI had inferior survival in univariate but not in multivariate analysis. In ISS-3 MM patients, RI had no prognostic impact either in univariate or multivariate analysis. Results were similar, when we analyzed only patients with Bence-Jones >200 mg/day.

CONCLUSIONS

ISS remains unaffected by the degree of RI, even in patients with ISS-3, which includes most patients with renal dysfunction.

Extensive apoptosis of bone marrow cells as evaluated by the in situ end-labelling (ISEL) technique may be the basis for ineffective haematopoiesis in patients with myelodysplastic syndromes

Apoptosis is a gene-directed cellular self-destruction which begins with internucleosomal cleavage of DNA and ends eventually with fragmentation of the nucleus. We have shown that the technique of ISEL of fragmented DNA appears to be an accurate and reliable measurement of the early stages of apoptosis. The present study was undertaken in order to define the incidence of programmed cell death in bone marrow (BM) haematopoietic and stromal cells of myelodysplastic syndromes (MDS). The ISEL technique was employed in 21 BM biopsies of MDS patients. The analysis showed that in 11/21 patients, >70% cells (high score) were undergoing programmed cell death while 5 patients showed up to 1/3 of the biopsy containing apoptotic cells and 2 patients had only few occasional ISEL positive cells. Stromal cells including fat cells, endothelial cells and fibroblasts were frequently in apoptosis in large clusters. Our results indicate that extensive apoptosis of haematopoietic cells documented in BM biopsies of MDS patients may be the explanation for the ineffective haematopoiesis which is the hallmark of these disorders.

Excessive proliferation matched by excessive apoptosis in myelodysplastic syndromes: the cause-effect relationship

The paradox of pancytopenia despite cellular bone marrows (BM) was investigated in 120 patients with myelodysplastic syndromes (MDS). Detailed cell cycle kinetics were examined following in vivo infusions of iodo--and/or bromodeoxyuridine (IUdR/BrdU), while the incidence of apoptosis was measured by in situ end labeling (ISEL) of fragmented DNA. Results showed that MDS are highly proliferative disorders with an equally high incidence of apoptotic intramedullary cell death accounting for the paradox of cellularity/cytopenia. By double-labeling BM biopsy sections for ISEL/BrdU we found the peculiar situation of "signal antonymy" where S-phase cells were frequently apoptotic, a phenomenon so far only seen in MDS biopsies. The cause-effect relationship of this excessive proliferation/apoptosis is discussed at length.

Cell cycle kinetic studies in 68 patients with myelodysplastic syndromes following intravenous iodo- and/or bromodeoxyuridine

Sixty-eight patients with myelodysplastic syndromes (MDS) received sequential infusions of iodo- and/or bromodeoxyuridine for cell kinetic analysis. Bone marrow biopsy sections were treated by appropriate antibodies and a labeling index (LI), duration of S-phase (Ts), and total cell cycle time (Tc) of myeloid cells were determined. The mean LI was 28.4%, Ts was 11.8 hours and Tc was 40.7 hours. The %LI decreased as the disease evolved from refractory anemia toward transformation to acute leukemia (p = 0.04). Double-labeling of biopsy sections for apoptosis and proliferation showed that 30-90% of S-phase cells in MDS patients were simultaneously apoptotic or "antonymous." We conclude that MDS are highly proliferative disorders in which the ineffective hematopoiesis is probably the result of excessive apoptosis rather than slow proliferation.

Measurement of apoptosis, proliferation and three cytokines in 46 patients with myelodysplastic syndromes

Extensive apoptosis or programmed cell death (PCD) of both hematopoietic (erythroid, myeloid, megakaryocytic) and stromal cells in myelodysplastic syndromes (MDS) cancels the high birth-rate resulting in ineffective hematopoiesis and has been demonstrated as the probable basis for peripheral cytopenias in MDS by our group. It is proposed that factors present in the microenvironment are inducing apoptosis in all the cells whether stromal or parenchymal. To investigate this hypothesis further, bone marrow biopsies from 46 MDS patients and eight normal individuals were examined for the presence of three cytokines, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) and granulocyte macrophage-colony stimulating factor (GM-CSF) and one cellular component, macrophages, by the use of monoclonal antibodies immunohistochemically. Results showed the presence of TNF-alpha and TGF-beta in 41/46 and 40/46 cases of MDS respectively, while only 15 cases showed the presence of GM-CSF. Further a significant direct relationship was found between the degree of TNF-alpha and the incidence of PCD (p= 0.0015). Patients who showed high PCD also had an elevated TNF-alpha level. Thus, the expression of high amounts of TNF-alpha and TGF-beta and low amounts of the viability factor GM-CSF may be responsible for the high incidence of PCD leading to ineffective hematopoiesis in MDS. Future studies will be directed at attempting to reverse the lesion in MDS by using anti-TNF-alpha drugs such as pentoxifylline.

A paradigm shift in myelodysplastic syndromes

A poorly defined transforming event(s) affects the pluripotential bone marrow (BM) stem cell in myelodysplastic syndromes (MDS), conferring a growth advantage upon it which leads eventually to monoclonal hematopoiesis. The progeny of this transformed ancestor undergo recognizable albeit dysplastic maturation. We propose that this picture is further complicated by a variety of cytokines, tumor necrosis factor alpha (TNF-alpha), transforming growth factor beta (TGF-beta) and interleukin 1beta (IL-1beta) which exert a dual effect on the diseased cells. The immature CD34+ cells are stimulated to proliferate, while their later differentiated daughters are induced to undergo apoptosis accounting for the clinical syndrome of pancytopenia despite hypercellular BMs. Studies directed at measuring the rates of proliferation and apoptosis as well as the levels of TNF-alpha, TGF-beta and IL-1beta confirm this hypothesis and are presented in greater detail. A novel approach towards MDS therapy emerges as a result of this paradigm shift based upon the premise that anti-cytokine therapy would prevent excessive intramedullary apoptosis and result in improved cytopenias as well as cause a slowing down of the diseased precursor cell proliferation resulting in resumption of polyclonal hematopoiesis. Because a number of cytokines function through common lipid second messengers, interruption of this pathway should theoretically cause disruption in the signalling of a cascade of cytokines.

Novel insights into the biology of myelodysplastic syndromes: excessive apoptosis and the role of cytokines

The paradox of myelodysplastic syndromes (MDS) which present with pancytopenias despite cellular bone marrows (BM) was investigated by conducting detailed studies of proliferation and apoptosis in 89 MDS patients. Our results demonstrated a rapid rate of both proliferation as well as apoptosis. Levels of three cytokines, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) and interleukin-1 beta (IL-1 beta) were measured in the same patients. High levels of TNF-alpha were found to correlate with high levels of apoptosis in 83 MDS patients (P = 0.0045). We propose a dual role for TNF-alpha (or other cytokines) in the pathogenesis of MDS. On the one hand, TNF-alpha induces apoptosis in the maturing cells causing pancytopenia while on the other, it stimulates the proliferation of the primitive progenitors accounting for the hypercellular BM frequently seen in MDS. A new model for MDS is presented. The initial abnormality probably affects a primitive hemopoietic progenitor which acquires a growth advantage leading to monoclonal hemopoiesis, which in turn makes these cells susceptible towards acquiring additional mutations and appearance of cytogenetically marked (or unmarked) clones. Cytokines such as TNF-alpha whose source is presently unknown, then contribute towards the clinical syndrome of pancytopenia and hypercellularity.

Apoptosis in bone marrow biopsy samples involving stromal and hematopoietic cells in 50 patients with myelodysplastic syndromes

Cell-cycle kinetics were measured in situ after infusions of iododeoxyuridine and/or bormodeoxyuridine in 50 patients with myelodysplastic syndromes (MDS) and the median labeling index in bone marrow (BM) biopsy samples was 28.6%. Unfortunately, 26 of 50 patients showed that > or = 75% of hematopoietic cells of all three lineages were undergoing programmed cell death (PCD) in their biopsy samples as shown by the in situ end labeling (ISEL) technique. Ten patients had 1/3 and eight had 2/3 ISEL+ cells. Stromal cells were frequently ISEL+ and often S-phase cells were also found to be simultaneously ISEL+. Nucleosomal DNA fragments as a ladder in agarose gel were present in BM aspirates of four patients who showed high ISEL and were absent in two who had no ISEL staining in biopsy samples, but only when DNA was extracted after a 4-hour in vitro incubation in complete medium. Therefore, laddering data confirmed the ISEL findings that the majority of hematopoietic cells in MDS are in early stages of PCD. We conclude that extensive intramedullary cell death may explain the paradox of pancytopenia despite hypercellular marrows in MDS patients. Investigating approaches that protect against PCD in some MDS subsets would be of interest.