Beta-2 microglobulin as a significant prognostic factor and a new risk model for patients with diffuse large B-cell lymphoma.

Previous reports have evaluated the prognostic value of serum beta-2 microglobulin (B2MG) level in patients with non-Hodgkin lymphoma. However, its role in predicting clinical outcome of patients with diffuse large B-cell lymphoma (DLBCL) in the rituximab era has not been extensively investigated. Here, we evaluated the prognostic value of B2MG and proposed a new prognostic model including B2MG for patients with DLBCL. A total of 274 patients with newly diagnosed de novo DLBCL were retrospectively analyzed. We defined the best cutoff value as 3.2 mg/L by using a receiver operating characteristic curve. Patients with a B2MG level ≥3.2 mg/L had significantly lower overall survival (OS) and progression-free survival than those with a B2MG level <3.2 mg/L (3-year OS, 50.9% vs. 89.4%, p < 0.001; 3-year progression-free survival, 45.3% vs. 79.7%, p < 0.001). Multivariate analysis showed that B2MG, age, performance status, and Ann Arbor stage were independent prognostic factors for OS. We developed a new prognostic model consisting of these four significant factors. We stratified patients into four-risk groups: low (L, 0 factor), low-intermediate (LI, 1-2 factors), high-intermediate (HI, 3 factors), high (H, 4 factors). This new prognostic model showed better risk discrimination compared with the National Comprehensive Cancer Network-International Prognostic Index (5-year OS: 100% and 23.4% vs. 100% and 27.1%, in L and H risk groups, respectively). Our study suggested that B2MG level is a significant prognostic factor in patients with DLBCL. A new prognostic index composed of age, performance status, stage, and B2MG could stratify the outcomes of patients with DLBCL effectively and appears to be a valuable risk model for these patients. Copyright © 2016 John Wiley & Sons, Ltd.

Effectiveness of ß(2)-microglobulin adsorption column in treating dialysis-related amyloidosis: a multicenter study.

BACKGROUND/AIMS: The aim of this study was to determine whether treatment with ß(2)-microglobulin adsorption column (Lixelle) affects bone cysts and clinical symptoms in patients with dialysis-related amyloidosis (DRA). METHODS: Radiographic changes in the number and area of bone cysts of the wrist and the hip joint were compared between 39 hemodialysis (HD) patients treated with Lixelle (Lixelle group) and 28 HD patients treated with conventional therapy as retrospective control (HD group). Clinical symptoms of DRA were also evaluated. RESULTS: In the Lixelle group, the number of bone cysts and the cystic area in wrist joints were significantly decreased, although the changes in these parameters in hip joints were not significant. In the HD group, the corresponding parameters in the hip joints even significantly increased. Clinical symptoms notably improved after Lixelle treatment. CONCLUSION: Treatment with Lixelle reduces the radiolucency of bone cysts in the wrist joints, and improves clinical symptoms associated with DRA.

Resistance to intercompartmental mass transfer limits beta2-microglobulin removal by post-dilution hemodiafiltration.

Although clearance of beta(2)-microglobulin is greater with hemodiafiltration than with high-flux hemodialysis, beta(2)-microglobulin concentrations after long-term hemodiafiltration are only slightly less than those obtained with high-flux hemodialysis. Resistance to beta(2)-microglobulin transfer between body compartments could explain this observation. beta(2)-Microglobulin kinetics were determined in patients receiving on-line post-dilution hemodiafiltration for 4 h with 18 l of filtration. Plasma beta(2)-microglobulin concentrations were measured during and for 2 h following hemodiafiltration and immediately before the next treatment. The filter clearance of beta(2)-microglobulin was determined from arterial and venous concentrations. The beta(2)-microglobulin generation rate was calculated from the change in the plasma concentration between treatments. The intercompartmental clearance was obtained by fitting the observed concentrations to a two-compartment, variable volume model. The plasma clearance of beta(2)-microglobulin by the filter was 73 +/- 2 ml/min. Plasma beta(2)-microglobulin concentrations decreased by 68 +/- 2% from pre- to post-treatment (27.1 +/- 2.2-8.5 +/- 0.7 mg/l), but rebounded by 32+/-3% over the next 90 min. The generation rate of beta(2)-microglobulin was 0.136 +/- 0.008 mg/min. The model fit yielded an intercompartmental clearance of 82 +/- 7 ml/min and a volume of distribution of 10.2 +/- 0.6 l, corresponding to 14.3 +/- 0.7% of body weight. Hemodiafiltration provides a beta(2)-microglobulin clearance of similar magnitude to the intercompartmental clearance within the body. As a result, intercompartmental mass transfer limits beta(2)-microglobulin removal by hemodiafiltration. This finding suggests that alternative strategies, such as increased treatment times or frequency of treatment, are needed to further reduce plasma beta(2)-microglobulin concentrations.

Kinetics of beta2-microglobulin and phosphate during hemodialysis: effects of treatment frequency and duration.

Current understanding of beta2-microglobulin (beta2M) and phosphate (or inorganic phosphorus) kinetics during hemodialysis is reviewed. The postdialysis:predialysis concentration ratio for beta2M is determined by dialyzer clearance for beta2M, treatment time, patient body size (specifically, extracellular fluid volume), and total ultrafiltration volume during the treatment. Evaluation of these treatment parameters can be used to calculate dialyzer clearance for beta2M; however, such calculated values are only approximations, since they neglect intradialytic generation, nonrenal (nondialyzer) clearance, and postdialysis rebound of beta2M. The detailed kinetics of beta2M during hemodialysis are best described using a two-compartment model. Theoretical predictions from such two-compartment models suggest that the product of dialyzer clearance for beta2M and weekly treatment duration, independent of treatment frequency, is the main determinant of plasma beta2M concentrations. The kinetics of phosphate removal during hemodialysis are incompletely understood. Phosphate is removed from both extracellular and intracellular compartments during hemodialysis; the plasma phosphate concentration levels off after the first 1 or 2 hours of treatment and plasma concentrations can rebound even before therapy is complete. Increases in dialyzer clearance of phosphate have been previously achieved only by increasing dialysis membrane surface area or by the use of hemodiafiltration. A four-compartment model of phosphate kinetics proposed recently by Spalding et al. suggests that the major barrier to phosphate removal is limited transfer of phosphate between the intracellular and extracellular compartments, although other complex factors also play important roles. Theoretical predictions using the model of Spalding et al. suggest that increasing either treatment frequency or treatment duration can increase phosphate removal. The kinetics of beta2M are representative of middle molecules whose removal during hemodialysis is governed predominantly by clearance at the dialyzer. In contrast, phosphate removal is limited primarily by its sequestration in the intracellular compartment (and possibly other compartments), not by its clearance at the dialyzer. The kinetics of phosphate may therefore be representative of uremic toxins whose removal is limited by sequestration into compartments or by protein binding. Enhanced removal of both of these uremic toxins using a given therapy will require treatments of increased frequency and longer duration.

The role of MHC class I heterodimer expression in mouse ankylosing enthesopathy.

Ankylosing enthesopathy (ANKENT) is a spontaneous mouse joint disease with strikingly similar pathology to human HLA-B27-associated enthesopathies such as ankylosing spondylitis. In C57Bl/10 mice, transgenic HLA-B*2702 as well as H2 genes have been shown to be relative risk factors for ANKENT. To investigate the role of major histocompatibility complex (MHC) class I expression in disease pathogenesis, ANKENT occurrence was compared among beta2-microglobulin (beta2m) knockout littermates with or without transgenes for HLA-B*2702 and human beta2m. In the knockout phenotype lacking beta2m, ANKENT occurrence is significantly reduced (P = 0.016). In the absence of beta2m, B*2702 is not detected on the cell membrane, nor does it increase the risk for ANKENT. This means that the previous finding that HLA-B*2702 increases susceptibility to ANKENT in C57Bl/10 mice cannot be ascribed to a transgene insertion effect. Rather, in order to increase disease susceptibility, B*2702 must be coexpressed with mouse beta2m (mo-beta2m). In contrast, when HLA-B*2702 is expressed with beta2m of human origin, disease susceptibility is not affected. Thus, both H2(b)-derived class I heterodimers and HLA-B*2702/mo-beta2m heterodimers contribute to ANKENT susceptibility.

Prognostic value of pretreatment serum beta 2 microglobulin in myeloma: a Southwest Oncology Group Study.

Six hundred twelve eligible, previously untreated patients with active multiple myeloma and at least some data available for analysis were entered into a randomized trial (Southwest Oncology Group [SWOG] Phase III myeloma study 8229/30), in which the prognostic significance of pretreatment serum beta 2 microglobulin levels was evaluated. Because there was no statistically significant survival difference between the alternating and syncopating VMCP/VBAP regimens, it was possible to evaluate serum beta 2 microglobulin for the total population all together. The serum beta 2 microglobulin measurements showed the highest significance of any prognostic factor, both in the bivariate and multivariate regression analyses. The median survival was 36 months for the 322 patients with pretreatment serum beta 2 microglobulin values of less than 6 micrograms/mL, as compared with a median survival of 23 months for the 225 patients with a beta 2 level of greater than or equal to 6 mcg/mL (P less than .0001). The stepwise multiple regression model first contained serum beta 2 microglobulin, followed by serum albumin, serum calcium, age, and serum creatinine. Serum beta 2 microglobulin was highly correlated with stage: median values ranged from 3.7 micrograms/mL for stage IA, to 10.1 for stage IIIB. It was possible to stratify myeloma patients based on combinations of serum beta 2 microglobulin with both albumin and age, producing excellent separation of patients into low-, intermediate-, and high-risk categories. It is concluded that serum beta 2 microglobulin is the most powerful prognostic factor currently available for multiple myeloma and that it can be used alone or in combination with other variables for pretreatment stratification.