Prevalence of monoclonal gammopathy of undetermined significance in Thailand

Prevalence of monoclonal gammopathy of undetermined significance in Shenzhen, China

BACKGROUND

Data on the prevalence of monoclonal gammopathy of undetermined significance (MGUS) in China are very limited. Our aim was to determine the prevalence and clinical characteristics of MGUS in a large Chinese population.

METHODS

This study included 49,220 healthy people who received serum immunofixation electrophoresis (sIFE) and serum protein electrophoresis (SPE) tests. Serum free light chain ratio, immunoglobulin quantification, and other clinically correlates of MGUS were performed for all patients with M-protein.

RESULTS

A total of 576 MGUS patients were identified by sIFE, with a median age of 58 years and an overall prevalence of 1.17% (95% CI, 1.08-1.27). Among those aged 50 years and older, the prevalence of MGUS was 2.26% (95% CI, 2.04-2.50). The prevalence of MGUS was significantly higher in males than in females (P < 0.05). The median concentration of M-protein was 3.1 g/L, ranging from 0.5 g/L to 25.1 g/L. The M-protein type was IgG in 55.4% of MGUS patients, followed by IgA (31.1%), IgM (9.5%), IgD (0.5%), biclonal (2.3%), and light chain (1.2%). Abnormalities in SPE, FLC ratios, and immunoglobulin levels were observed in 78.3%, 31.1%, and 38.4% of MGUS patients, respectively.

CONCLUSIONS

The prevalence of MGUS is substantially lower in southern China than in whites and blacks.

The epidemiology of Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a rare subtype of non-Hodgkin lymphoma characterized by the presence of lymphoplasmacytic lymphoma (LPL) in the bone marrow accompanied by a monoclonal immunoglobulin type M (IgM) in the serum. WM was first described only 80 years ago and became reportable in the US as a malignancy in 1988. Very little systematic research was conducted prior to 2000 to characterize incidence, clinical characteristics, risk factors or diagnostic and prognostic criteria, and there were essentially no WM-specific clinical interventional trials. Since the inaugural meeting of the International Workshop in Waldenström's Macroglobulinemia (IWWM) in 2000, WM has become the focus of a steadily increasing and productive body of research, engaging a growing number of investigators throughout the world. This introductory overview provides summary of the current understanding of the epidemiology of WM/LPL as a backdrop for a series of consensus panel recommendations arising from research presented at the 11th IWWM.

Monoclonal Gammopathy of Undetermined Significance: A Comprehensive Review

Monoclonal Gammopathy of Undetermined Significance (MGUS) is an asymptomatic premalignant plasma cell dyscrasia with a predominate rise of the IgG immunoglobulin fraction without end-organ damage, often diagnosed incidentally. Despite its progression into various subsequent forms of hematological malignancies, MGUS remains underdiagnosed. A literature search was conducted using the Medline, Cochrane, Embase, and Google Scholar databases, including articles published until December 2022. Keywords used encompassed "Monoclonal Gammopathy of Undetermined Significance," "Plasma Cell dyscrasia," "Monoclonal gammopathy of renal significance," and "IgM Monoclonal gammopathy of Undetermined Significance," This study aimed to conduct a critical review to update knowledge regarding the pathophysiology, risk factors, clinical features, diagnostic protocols, complications, and current and novel treatments for MGUS. We recommend a multidisciplinary approach to manage MGUS due to the complexity of the illness's etiology, diagnosis, and therapy. This comprehensive review also highlights future prospects, such as developing screening protocols for at-risk populations, prevention of disease progression by early diagnosis through genome-wide association studies, and management using Daratumumab and NSAIDs.

Monoclonal gammopathy of undetermined significance: evaluation, risk assessment, management, and beyond

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant state for a spectrum of lymphoplasmacytic malignancies. The risk of progression of MGUS to a symptomatic therapy requiring plasma cell dyscrasia is about 1% per year. Studies carried out over the previous 10 years have improved risk stratification of MGUS based on serologic and genomic evaluations, which has led to better management of patients. In this review, we address the epidemiology, diagnosis, and pathogenesis of MGUS and discuss risk-adapted best practice approaches to monitor patients.

Isatuximab plus carfilzomib and dexamethasone in East Asian patients with relapsed multiple myeloma: IKEMA subgroup analysis

In the phase 3 IKEMA study (NCT03275285), isatuximab (Isa) plus carfilzomib (K) and dexamethasone (d) significantly improved progression-free survival (PFS) in relapsed multiple myeloma (MM), compared with Kd. This IKEMA subgroup analysis evaluated efficacy and safety of Isa-Kd versus Kd among East Asian patients. Eligible patients had 1-3 prior lines of therapy and were stratified by number of prior lines and revised International Staging System. The primary endpoint was PFS. Key secondary endpoints included overall response, very good partial response or better (≥VGPR), minimal residual disease (MRD) negativity, and complete response (CR) rate. Forty-six East Asian patients (19 Japanese, 27 South Korean) were randomized to Isa-Kd (n = 25) or Kd (n = 21). Isa-Kd improved PFS (HR 0.64; 95% CI 0.23-1.76), ≥VGPR (80.0% vs 52.4%), MRD negativity rate (44.0% vs 9.5%), and CR (44.0% vs 23.8%). The rate of grade ≥ 3 treatment-emergent adverse events (TEAEs) was 79% for Isa-Kd versus 55% for Kd. The rate of serious TEAEs was 46% versus 50%, and the rate of TEAEs leading to treatment discontinuation was 4% versus 10%. Overall, Isa-Kd improved efficacy and safety versus Kd in East Asian patients with relapsed MM, consistent with the overall IKEMA population.

A nationwide study of patients with monoclonal gammopathy of undetermined significance with a 10-year follow-up in South Korea

In clinical practice, most patients with monoclonal gammopathy of undetermined significance (MGUS) undergo long-term follow-up without disease progression. There is insufficient real-world data about how closely and whether anything other than disease progression should be monitored. Herein, we performed a nationwide study of 470 patients with MGUS with a 10-year follow-up to determine the patterns of disease progression and other comorbidities. During the follow-up period, 158 of 470 patients with MGUS (33.62%) progressed to symptomatic monoclonal gammopathies. Most of these were multiple myeloma (134/470 patients, 28.51%), and those diagnosed within 2 years after diagnosis of MGUS was high. Approximately 30-50% of patients with MGUS had hypertension, diabetes, hyperlipidemia, and osteoarthritis at the time of diagnosis, and these comorbidities were newly developed during the follow-up period in approximately 50% of the remaining patients with MGUS. Approximately 20-40% of patients with MGUS have acute or chronic kidney failure, thyroid disorders, disc disorders, peripheral neuropathy, myocardial infarction, stroke, and heart failure during the follow-up period. Altogether, when MGUS is diagnosed, close follow-up of the possibility of progression to multiple myeloma is required, especially within 2 years after diagnosis; simultaneously, various comorbidities should be considered and monitored during the follow-up of patients with MGUS. Continuous research is needed to establish appropriate follow-up guidelines.

Autoimmune disease is associated with a lower risk of progression in monoclonal gammopathy of undetermined significance

OBJECTIVES AND METHODS

We conducted a population-based study including 19 303 individuals diagnosed with MGUS in Sweden from 1985 to 2013, with the aim to determine whether a prior history of autoimmune disease, a well-described risk factor for MGUS is a risk factor for progression of MGUS to multiple myeloma (MM) or lymphoproliferative diseases (LPs). Using the nationwide Swedish Patient registry, we identified MGUS cases with versus without an autoimmune disease present at the time of MGUS diagnosis and estimated their risk of progression.

RESULTS

A total of 5612 (29.1%) MGUS cases had preceding autoimmune diseases. Using Cox proportional hazards models, we found the risk of progression from MGUS to MM (HR = 0.83, 95% CI 0.73-0.94) and LPs (HR = 0.84, 95% CI 0.75-0.94) to be significantly lower in MGUS cases with prior autoimmune disease (compared to MGUS cases without).

CONCLUSIONS

In this large population-based study, a history of autoimmune disease was associated with a reduced risk of progression from MGUS to MM/other LPs. Potential underlying reason is that MGUS caused by chronic antigen stimulation is biologically less likely to undergo the genetic events that trigger progression. Our results may have implications in clinical counseling for patients with MGUS and underlying autoimmune disease.

Older Human B Cells and Antibodies

B cells have a number of different roles in the immune response. Their excellent antigen presentation potential can contribute to the activation of other cells of the immune system, and evidence is emerging that specialized subsets of these cells, that may be increased with age, can influence the cell-mediated immune system in antitumor responses. They can also regulate immune responses, to avoid autoreactivity and excessive inflammation. Deficiencies in regulatory B cells may be beneficial in cancer but will only exacerbate the inflammatory environment that is a hallmark of aging. The B cell role as antibody producers is particularly important, since antibodies perform numerous different functions in different environments. Although studying tissue responses in humans is not as easy as in mice, we do know that certain classes of antibodies are more suited to protecting the mucosal tissues (IgA) or responding to T-independent bacterial polysaccharide antigens (IgG₂) so we can make some inference with respect to tissue-specific immunity from a study of peripheral blood. We can also make inferences about changes in B cell development with age by looking at the repertoire of different B cell populations to see how age affects the selection events that would normally occur to avoid autoreactivity, or increase specificity, to antigen.

Monoclonal gammopathy of undetermined significance in Chinese population: A prospective epidemiological study

The aim of this study was to identify the prevalence of monoclonal gammopathy of undetermined significance (MGUS) in different groups of age and the clinical features in China. This multicenter prospective study enrolled 1797 health subjects. The overall prevalence of MGUS was 2.73%. The prevalence of different age groups was 1.19% (41‐50 y), 1.16% (51‐60 y), 2.19% (61‐70 y), 3.66% (71‐80 y), and 7.76% (≥81 y). The prevalence of MGUS in male (n = 843) was 2.97%, while the prevalence of MGUS in female (n = 952) was 2.52%, but this difference of the two groups was not statistically significant. As for subtype of MGUS, IgG subtype was 55.1% (27 cases), IgA subtype was 14.3%, and IgM subtype was 12.2%. The M protein of one case became negative after 3 months, and the others remained positive without obvious disease transformation (follow‐up duration: 3‐7 mo). Thus, the prevalence of MGUS in China was similar to that in Mexican Americans, but lower than that in the other Asian country, American Whites, American Blacks, and Africans, and had a trend of increase with age. Male had higher prevalence of MGUS in China. The most common subtype was IgG.

Clinical profiles of multiple myeloma in Asia-An Asian Myeloma Network study

The incidence of multiple myeloma (MM) is known to be variable according to ethnicity. However, the differences in clinical characteristics between ethnic groups are not well-defined. In Asian countries, although the incidence of MM has been lower than that of Western countries, there is growing evidence that MM is increasing rapidly. The Asian Myeloma Network decided to initiate the first multinational project to describe the clinical characteristics of MM and the clinical practices in Asia. Data were retrospectively collected from 23 centers in 7 countries and regions. The clinical characteristics at diagnosis, survival rates and initial treatment of 3,405 symptomatic MM patients were described. Median age was 62 years (range, 19-106), with 55.6% of being male. Median overall survival (OS) was 47 months (95% CI 44.0-50.0). Stem cell transplantation was performed in 666 patients who showed better survival rates (79 vs. 41 months, P < 0.001). The first-line treatments of 2,970 patients were analyzed. The overall response rate was 71% including very good partial response or better in 31% of the 2,660 patients those were able to be evaluated. New drugs including bortezomib, thalidomide, and lenalidomide were used in 36% of 2,970 patients and affected OS when used as a first-line treatment.

Management of multiple myeloma in Asia: resource-stratified guidelines

Treatment of multiple myeloma has undergone substantial developments in the past 10 years. The introduction of novel drugs has changed the treatment of the disease and substantially improved survival outcomes. Clinical practice guidelines based on evidence have been developed to provide recommendations on standard treatment approaches. However, the guidelines do not take into account resource limitations encountered by developing countries. The huge disparities in economy, health-care infrastructure, and access to novel drugs in Asian countries hinder the delivery of optimum care to every patient with multiple myeloma in Asia. In this Review we outline the guidelines that correspond with different levels of health-care resources and expertise, with the aim to unify diagnostic and therapeutic guidelines and help with the design of future studies in Asia.

Precursors to lymphoproliferative malignancies

We review monoclonal B-cell lymphocytosis (MBL) as a precursor to chronic lymphocytic leukemia and monoclonal gammopathy of undetermined significance (MGUS) as a precursor to plasma cell disorders. These conditions are present in the general population and increase with age. These precursors aggregate with lymphoproliferative malignancies in families suggesting shared inheritance. MBL and MGUS may share some of the same risk factors as their related malignancies but data are limited. Although these conditions are characterized by enhanced risk for the associated malignancy, the majority of individuals with these conditions do not progress to malignancy. A key focus for current work is to identify markers that predict progression to malignancy.

Immunoparesis and monoclonal gammopathy of undetermined significance are disassociated in advanced age

Immunoparesis and a skewed serum free light chain (FLC) ratio are indicators of immune dysfunction predictive of progression from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM). Previous studies have reported increased prevalence of MGUS by age, but no study has examined the relationship between immunoparesis and abnormal FLC ratios in the elderly. We screened 453 older adults (median age, 80 years; range, 65-96) to characterize the patterns of immunoparesis and abnormal FLC ratio in relation to MGUS. We defined MGUS in 4.4% of the subjects; the prevalence was 12.5% among individuals of >90 years. In MGUS (vs. non-MGUS) cases, immunoparesis and abnormal FLC ratios were detected in 70.0% (vs. 49.0%; P = 0.07) and 50.0% (vs. 12.9%; P = 0.0001), respectively. Based on small numbers, MGUS patients with abnormal FLC ratio were borderline (P = 0.07) more likely to have immunoparesis. Overall, the prevalence of immunoparesis varied in a nonlinear fashion, with lowest frequencies in the youngest and oldest groups. Our observed disassociation between MGUS prevalence and impaired immunoglobulin production suggests that separate mechanisms are involved in the development of MGUS and immunoparesis in advanced age. These findings emphasize the need for molecularly defined methods to characterize myeloma precursor states and better predict progression to MM.

Monoclonal gammopathy of undetermined significance and smoldering multiple myeloma: a review of the current understanding of epidemiology, biology, risk stratification, and management of myeloma precursor disease

The term monoclonal gammopathy of undetermined significance (MGUS) was coined in 1978. The recent advances in our knowledge about MGUS and smoldering multiple myeloma (SMM) have helped us better understand the pathogenesis of myeloma. It seems that myeloma evolves from a precursor state in almost all cases. We do not completely understand the multistep process from the precursor state to myeloma, but studies like whole genome sequencing continue to improve our understanding of this process. The process of transformation may not be linear acquisition of changes, but rather a branched heterogeneous process. Clinical features that are prognostic of rapid transformation have been identified, but no specific molecular markers have been identified. Even with recent advances, multiple myeloma remains an incurable disease in the vast majority, and intervening at the precursor state provides a unique opportunity to alter the natural history of the disease. A limitation is that a vast majority of patients with precursor disease, especially low-risk MGUS, will never progress to myeloma in their lifetime, and treating these patients is not only unnecessary but may be potentially harmful. The challenge is to identify a subset of patients with the precursor state that would definitely progress to myeloma and in whom interventions will have a meaningful impact. As our understanding of the molecular and genetic processes improves, these studies will guide the selection of high-risk patients more appropriately and ultimately direct a tailored management strategy to either delay progression to symptomatic myeloma or even "cure" a person at this premalignant stage.