Monoclonal gammopathies of clinical significance (MGCS): In pursuit of optimal treatment

Effect of adipose tissue on the development of multiple myeloma

Multiple myeloma (MM), also referred to as Kahler's disease, is a cancer characterized by the uncontrolled growth of abnormal plasma cells and is associated with alterations in the bone tissue microenvironment. Bone marrow adipose tissue (BMAT), which comprises approximately ten percent of total body fat, can influence the progression, survival, and drug resistance of MM cells through paracrine, hormonal, and metabolic pathways. Obesity can lead to an increase in BMAT mass, which not only disrupts bone metabolism but also reduces bone density, potentially progressing from monoclonal gammopathy of undetermined significance, a benign condition, to MM. A range of factors, including impaired fatty acid metabolism, increased production of adipokines that support myeloma, and heightened expression of oncogenic microRNAs in multiple myeloma, contribute to the progression of this incurable blood cancer. To better understand the relationship between excess adipose tissue accumulation and the risk of developing multiple myeloma, a comprehensive review of published data was conducted.

Clonality Determination by Detecting Unmodified Monoclonal Serum Free Light Chains Using On-Probe Extraction Coupled with Liquid Chromatography-High-Resolution Mass Spectrometry

BACKGROUND

Serum free light chains (FLCs) are an essential clinical biomarker for the diagnosis and monitoring of patients with plasma cell neoplasms. The current widely used immunoassay methods quantify total serum FLCs, which include monoclonal FLCs as well as FLCs in the polyclonal background. Patients with chronic diseases, inflammatory disorders, or renal dysfunction can have elevated total FLCs that lead to ambiguous results. These patients may benefit from a direct measurement of monoclonal FLCs. The purpose of this study was to develop a method that couples on-probe extraction (OPEX) with liquid chromatography-high-resolution mass spectrometry (LC-HR-MS), abbreviated to OPEX-MS, to directly determine the clonality of FLCs.

METHODS

OPEX immunocapture was performed using microprobes loaded with anti-kappa or anti-lambda light chain antibodies. Captured proteins were separated by reversed-phase LC and analyzed by HR-MS.

RESULTS

Four cohorts of samples from unique patients were tested based on immunoassay FLC results. The LC-HR-MS analysis in the OPEX-MS method provides both a unique retention time along with deconvoluted masses of FLC monomers and dimers for each clone. The study found that 16 out of 49 (33%) kappa FLC elevated samples as well as 83 out of 100 (83%) dual kappa and lambda FLC elevated samples did not have monoclonal FLCs, which is consistent with the knowledge that there is often no clonal population in samples with mildly elevated FLC immunoassay results.

CONCLUSIONS

The OPEX-MS method can serve as a complementary approach to directly determine clonality in patients with difficult-to-interpret FLC immunoassay results.

Massive arterial and venous thrombosis from smouldering multiple myeloma: further evidence for monoclonal gammopathy of thrombotic significance

A man in his 40s presented to the emergency department after 2 weeks of abdominal pain and bloating. Radiological investigations revealed multiple unusual sites of thrombosis, including large thrombi in his portal and mesenteric veins, and a left ventricular thrombus with resultant embolic infarcts to his spleen, kidneys, coronary arteries and brain. Standard causes of underlying thrombophilia were excluded. A serum protein electrophoresis and serum-free light chains, with subsequent bone marrow biopsy, lead to the diagnosis of smouldering multiple myeloma (sMM), albeit an unusual presentation with severe clinical sequelae. Although sMM is known to be associated with an increased risk of venous thromboembolism, it is not recognised to cause thrombosis in both venous and arterial vascular beds simultaneously. Physicians encountering patients with multiple thrombi in unusual vascular beds without clear aetiology should consider an underlying monoclonal gammopathy in their list of differentials.

Lenalidomide and Dexamethasone in Scleromyxedema: A Case Report of Long-Term Efficacy and Challenges in a 54-Year-Old Patient

Lichen myxedematosus (LM) is characterized by dermal mucin buildup, fibroblast proliferation, and variable presentation. The diffuse variant, known as scleromyxedema, is identified by monoclonal paraprotein presence and lack of thyroid issues, with considerations for infections and underlying conditions. Despite lacking FDA-approved treatment, intravenous immunoglobulin stands as effective, although resource-intensive, while targeting the clonal source of pathogenic immunoglobulin offers an alternate therapeutic route. Our case explores the efficacy of an oral plasma cell-focused lenalidomide regimen, inducing relief and treatment-free periods, while still facing relapses. However, this approach poses risks, necessitating a comparative safety and efficacy assessment. Data remains insufficient to establish the prolonged efficacy of plasma cell-targeted therapy versus alternatives for monoclonal gammopathy of undetermined significance-associated scleromyxedema. We present the case of a 54-year-old male patient diagnosed with LM managed for six years with relapsing and remitting symptoms.

Light chain deposition disease presenting with gastrointestinal disorder as primary manifestation: report of two cases and literature review

Light chain deposition disease (LCDD) is an under-recognized condition characterized by deposition of abnormal monoclonal light chains in tissues, leading to organ dysfunction. LCDD involving the gastrointestinal tract is very uncommon, and its diagnosis is challenging. We herein report two cases of LCDD that manifested as inflammatory bowel disease-like symptoms and protein-losing gastroenteropathy. Both patients were women in their early 60s. Tissue biopsies from the gastrointestinal mucosa demonstrated extracellular deposits, which were negative by Congo red staining but positive for κ-light chain by immunohistochemistry. The recent literature on LCDD was reviewed. When patients unexpectedly show extracellular deposits in gastrointestinal biopsy specimens, evaluation of immunoglobulin chains is recommended for diagnosis of LCDD after systemic amyloidosis has been excluded.

[Monoclonal gammopathy of uncertain significance]

Monoclonal gammopathy of uncertain significance is a premalignant plasma cell neoplasm with a high prevalence in the population over 50 years of age and an annual risk of progression of 1%. Multiple recent studies have led to advances in understanding both the pathogenesis of these disorders and their risk of progression to other diseases. Patients require lifelong follow-up, and a multidisciplinary and risk-adapted approach is essential. In recent years, an increasing number of entities associated with a paraprotein, known as clinically significant monoclonal gammopathies, have been recognized.

Contemporary Monoclonal Antibody Utilization in Glomerular Diseases

Therapeutic monoclonal antibodies (MAbs) have been one of the fastest growing drug classes in the past 2 decades and are indicated in the treatment of cancer, autoimmune disorders, solid organ transplantation, and glomerular diseases. The Food and Drug Administration has approved 100 MAbs between 1986 and 2021, and MAbs account for 20% of Food and Drug Administration's new drug approval every year. MAbs are preferred over traditional immunosuppressive agents because of their high specificity, reduced number of drug-drug interactions, and low toxicity, which make them a prime example of personalized medicine. In this review article, we provide an overview of the taxonomy, pharmacology, and therapeutic applications of MAbs in glomerular diseases. We searched the literature through PubMed using the following search terms: monoclonal antibodies, glomerular diseases, pharmacokinetics, pharmacodynamics, immunoglobulin, murine, chimeric,humanized, and fully human, and limited our search to years 2018-2023. We selected peer-reviewed journal articles with an evidence-based approach, prioritizing randomized control trials in specific glomerular diseases, if available. Advances in the MAb field have resulted in a significant paradigm shift in targeted treatment of immune-mediated glomerular diseases, and multiple randomized control trials are currently being conducted. Increased recognition is critical to expand their use in experimental research and personalized medicine.

Outcomes of Patients with Monoclonal Gammopathy of Undetermined Significance with and without Atrial Fibrillation: A Retrospective Cohort Analysis of the Nationwide Inpatient Sample Database

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) is a non-malignant precursor of multiple myeloma (MM). MGUS has been suggested to be associated with a higher risk of cardiovascular diseases, including AFIB, but it is still unclear whether this association is real. Studies are lacking on the impact of atrial fibrillation on health outcomes in this population. The association of AFIB in this population is lagging and merits further investigation.

METHODS

The study conducted a retrospective analysis of the Nationwide Inpatient Sample (NIS) for 2018, including adult patients with primary diagnoses of MGUS and AFIB. Patients were divided into two groups based on AFIB presence. Outcomes assessed included complications, length of stay, mortality, hospital charges, and discharge disposition.

RESULTS

The study included 9007 patients with MGUS of whom 2404 had AFIB. Patients with both MGUS and AFIB had higher rates of acute kidney injury [AKI] (31.5% vs. 27.5%; p = 0.002) and pericarditis (2% vs. 1.2%; p = 0.029). They also had longer hospital stays (5 vs. 4 days; p < 0.001) and higher hospitalization costs ($43,729 vs. $41,169; p < 0.001).

CONCLUSIONS

The study showed that the prevalence of AFIB in MGUS patients is high. Patients with AFIB had increased rates of complications (AKI and pericarditis) and higher mortality compared to patients without AFIB. Further studies screening for AFIB in this patient population are warranted.

Anti-HERV-K Drugs and Vaccines, Possible Therapies against Tumors

The footprint of human endogenous retroviruses (HERV), specifically HERV-K, has been found in malignancies, such as melanoma, teratocarcinoma, osteosarcoma, breast cancer, lymphoma, and ovary and prostate cancers. HERV-K is characterized as the most biologically active HERV due to possession of open reading frames (ORF) for all Gag, Pol, and Env genes, which enables it to be more infective and obstructive towards specific cell lines and other exogenous viruses, respectively. Some factors might contribute to carcinogenicity and at least one of them has been recognized in various tumors, including overexpression/methylation of long interspersed nuclear element 1 (LINE-1), HERV-K Gag, and Env genes themselves plus their transcripts and protein products, and HERV-K reverse transcriptase (RT). Therapies effective for HERV-K-associated tumors mostly target invasive autoimmune responses or growth of tumors through suppression of HERV-K Gag or Env protein and RT. To design new therapeutic options, more studies are needed to better understand whether HERV-K and its products (Gag/Env transcripts and HERV-K proteins/RT) are the initiators of tumor formation or just the disorder’s developers. Accordingly, this review aims to present evidence that highlights the association between HERV-K and tumorigenicity and introduces some of the available or potential therapies against HERV-K-induced tumors.