Monoclonal gammopathy of clinical significance: a novel concept with therapeutic implications

Plasma cell-directed therapies induce profound clinical and durable responses in patients with severe or relapsed/refractory scleromyxedema

BACKGROUND

Scleromyxedema (SM) is a rare skin disorder related to monoclonal gammopathy. High dose intravenous immunoglobulins (HDIVIg) are usually used as a frontline therapy with initial efficacy. However, some patients evolve with relapse, refractory state or severe extra-cutaneous complications such as dermato-neuro syndrome (DNS) or cardiac involvement. The objective of the study is to evaluate the use of anti-plasma cell treatment in these patients in order to obtain a deep and durable dermatological and haematological response.

METHODS

We report here eight patients treated with HDIVIg together with anti-plasma cell therapy including: lenalidomide and dexamethasone (n = 5); bortezomib, cyclophosphamide and dexamethasone (n = 1); daratumumab, lenalidomide and dexamethasone (n = 2).

RESULTS

Combination of HDIVIg with a treatment targeting the monoclonal component led to a high level of haematological remission and drastically improved skin response with an acceptable safety profile in all patients. Moreover, HDIVIg was reduced and stopped in 4 of the 7 patients who achieved complete remission.

CONCLUSIONS

The association of lenalidomide and dexamethasone with HDIVIg could improve the treatment of relapsed or severe SM.

Monoclonal gammopathy of renal significance (MGRS): retrospective monocentric analysis of clinical outcomes and treatment strategies

Monoclonal Gammopathy of Renal Significance (MGRS) is a group of rare disorders in which monoclonal proteins cause kidney damage. Due to its rarity, ongoing research is vital to refine diagnostics, enhance treatment, and improve outcomes. This retrospective study analyzed 34 patients with renal biopsy-proven MGRS-defining lesions. Patients were divided into two subgroups: kidney-limited AL amyloidosis (MGRS-A, 44%, n = 15) and other MGRS (MGRS-NA, 56%, n = 19). Key outcomes included progression-free survival and overall survival. Baseline characteristics such as histopathology, plasma cell percentage, kidney function, and proteinuria were documented alongside initial treatments, and hematologic and renal response. Distinct differences were observed between the two groups: MGRS-NA was primarily associated with glomerular lesions, while MGRS-A exhibited broader kidney involvement. Treatment varied: bortezomib for plasma cell-driven cases and rituximab for B-cell-related conditions. Anemia was the most common side effect (71%), associated with treatment intensity. Despite similar overall survival outcomes, MGRS-A followed a more aggressive course, with a shorter time from diagnosis to death (206 vs. 728 days). Renal and hematologic responses were comparable between the groups, although baseline factors such as hemoglobin and CRP levels were predictive of mortality. These findings underscore the need for more precise characterization and standardized criteria to optimize the management of MGRS.

Diagnosis and Management of Monoclonal Gammopathy of Undetermined Significance: A Review

Importance

Nearly 5% of adults have the precursor malignant condition monoclonal gammopathy of unknown significance (MGUS). Management centers on differentiating MGUS from more serious conditions to determine additional diagnostic testing, monitoring, and potential therapy.

Observations

MGUS is defined by the absence of end-organ damage or symptoms, a small amount of monoclonal immunoglobulin (M protein), and low volume of plasma cells. MGUS must be distinguished from overt malignant diseases like multiple myeloma (MM), immunoglobulin light-chain (AL) amyloidosis, and monoclonal gammopathy of clinical significance (MGCS), all of which cause organ damage or symptoms. Although testing for M proteins is often prompted by clinical findings (eg, osteoporosis or autoimmune disease), recent evidence from screened populations suggests that previous MGUS disease associations were likely overestimated and that testing for M proteins should be reserved for when malignant disease or MGCS is suspected. Risk of progression to malignant disease ranges from 0.5% to 1%, meaning most patients have indolent disease. Guideline-concordant management of MGUS is determined by predicted risk of progression to malignant disease, which depends on subtype of immunoglobulin, M protein concentration, and free light chain ratio. Patients with low-risk MGUS can safely defer bone marrow biopsy and advanced imaging, and should undergo periodic laboratory monitoring. Intermediate- and high-risk MGUS should trigger bone marrow biopsy and bone imaging to detect overt MM and shorter monitoring intervals. Advanced molecular testing may improve on current risk stratification to target monitoring and treatment to those with highest risk of malignant progression and avoid overtreatment of those with low-risk disease. Management will also be informed by results of several clinical trials to clarify the risks and benefits of screening, optimal monitoring strategy, predictors of progression, and potential preventive or curative therapies.

Conclusions and Relevance

Evidence-based management of MGUS currently rests on separating clinically indolent from high-risk precursor disease. Research using novel detection methods, incorporating molecular testing into risk stratification, and evaluating screening, monitoring, and therapeutic or lifestyle interventions has the potential to improve outcomes.

Kidney disease in multiple myeloma

Renal disease is a frequent complication of symptomatic multiple myeloma, that increases morbidity and reduces quality of life and overall survival. It may result from various lesions, the most frequent being light chain cast nephropathy (LCCN), related to precipitation of monoclonal free light chains (FLC) with uromodulin in distal tubules. Rapid identification of the type of kidney disease with appropriate management is key. LCCN typically reveals the underlying myeloma and manifests with severe acute kidney injury, high serum FLC level (>500 mg/l) and predominant light chain proteinuria (urine albumin/creatinine ratio <10 %). Urgent therapy is required, based on vigorous fluid expansion, correction of precipitating factors and introduction of efficient anti-myeloma therapy which choice should consider renal elimination of each agent and patient frailty. Early and deep reduction in serum FLC level conditions renal recovery, warranting assessment of efficacy by serial serum FLC level monitoring. In newly diagnosed patients, the combination of bortezomib, high-dose dexamethasone and an anti-CD38 monoclonal antibody is commonly used. The benefit to risk balance of quadruplets incorporating cyclophosphamide or an immunodulatory agent requires to be evaluated in prospective studies. In patients with severe acute kidney injury, reinforcing chemotherapy with FLC removal through plasma exchange or high-cutoff hemodialysis may increase the probability of renal response, despite controversial data from randomized trials. Histological assessment of the extent of cast formation and interstitial fibrosis/tubular atrophy may help evaluating renal prognosis and refining therapy. Thanks to improved overall survival, renal transplantation may be considered in selected candidates with end-stage kidney disease.

Successful treatment of type I cryoglobulinemia with a combination of carfilzomib, cyclophosphamide, and dexamethasone: a case report and literature review

Type I cryoglobulinemia is typically associated with hematological malignancies such as B-cell lymphomas and plasma cell neoplasms. Its treatment basically targets underlying hematological malignancies, and the prognosis remains unsatisfactory. Despite several reports of type I cryoglobulinemia treated with bortezomib-based regimens, little is available on the treatment of bortezomib-resistant cases. We report a case of severe type I cryoglobulinemia associated with plasma cell neoplasm, refractory to bortezomib and daratumumab, which was successfully managed with a combination of carfilzomib, cyclophosphamide, and dexamethasone (KCd therapy). No sign of relapse has been seen for more than 3 years with maintenance therapy with ongoing carfilzomib. This case highlights the potential efficacy of carfilzomib-based regimens in bortezomib-resistant type I cryoglobulinemia, offering a promising option for cases refractory to conventional treatments.

Monoclonal Insulin Autoimmune Syndrome Successfully Treated With Plasma Cell Directed Therapy

BACKGROUND

Monoclonal insulin autoimmune syndrome (IAS) is a very rare disease characterized by severe attacks of hypoglycemia caused by circulating anti-insulin antibodies produced by a B-cell clone, usually clonal plasma cells.

METHOD

We present 2 female Norwegian patients with monoclonal IAS. The anti-insulin antibodies were quantified by immune precipitation and characterized using a 3-step manual in-house assay. Both patients received plasma cell directed therapy.

RESULT

The first patient received plasma cell directed therapy for a time-limited period and achieved a sustained clinical remission without detectable anti-insulin antibodies. The second patient receives continuous plasma cell directed therapy and is in clinical remission with low values of detectable anti-insulin antibodies.

CONCLUSION

Plasma cell directed therapy was effective and safe in our 2 cases of monoclonal IAS. We recommend considering plasma cell directed therapy for these patients.

POEMS Syndrome

POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Protein, Skin changes) is a syndrome that involves a monoclonal B-cell proliferation, most often plasmacytic, and a variable number of manifestations listed or not in the acronym. These manifestations include sclerotic bone lesions, plasmacytic Castleman disease, papillary edema, peripheral edema, ascites, thrombocytosis and/or polycythemia, venous and/or arterial thrombosis, and renal, pulmonary, and cardiac impairments [1]. Diagnosis is often delayed due to the rarity of this entity and its clinical polymorphism, which can mimic other neurological disorders. First-line treatment for patients without bone marrow involvement and with a limited number of bone lesions is radiation. Patients with diffuse bone lesions or bone marrow involvement should receive systemic treatment, ideally intensive treatment with autologous stem cell transplantation (ASCT) when possible. Lenalidomide and bortezomib (Bortezomib) appear to be very promising, showing very rapid efficacy on neuropathy. Early initiation of treatment, before the development of severe neurological damage, along with supportive care, especially physiotherapy, is crucial for optimal neurological recovery.

Quantitative abnormalities in the β-region of the electrophoretic profile of serum proteins as predictive markers of monoclonality: Machine learning for monoclonality prediction

OBJECTIVE OF THE STUDY

To develop a machine learning algorithm aimed at predicting the presence of a monoclonal (M-) protein when the β-globulin fraction is elevated.

MATERIALS AND METHOD

Patients were selected as part of the University Hospital Laboratory of Brussels routine diagnostic procedures from October 2021 to April 2022. Adult patients with serum protein electrophoresis showing elevated β1 and/or β2 fractions were included. The selection was done following strict exclusion criteria such as acute inflammation, iron deficiency anemia signs or supposed liver disease. To construct a predictive model for prediction of positive immunofixation (IFE) for monoclonality, the following factors were used: age, sex, β1 and β2 concentration (g/L), total proteins (g/L), IgA, IgM, IgG values (g/L) and hypogammaglobulinemia. The dataset underwent a random split, divided into a foundational training set (80%, 247 samples) and a foundational test set (20%, 62 samples). The training sets were subjected to five different algorithms: logistic regression, decision tree, random forest, gradient boosting, and support vector.

RESULTS

309 patients were selected; 149 exhibited a negative IFE and 160 a positive IFE for monoclonality. The evaluation of the five tested models demonstrated very good performance, the chosen model was Random Forest for its high sensitivity (85%) and area under the receiver operating characteristic curve (91%).

CONCLUSION

An accurate algorithm was achieved for predicting the presence of M protein when the β-globulin fraction is elevated which enables early and improved diagnosis of monoclonal gammopathy.

Case report: Therapeutic use of bortezomib in a patient with Schnitzler syndrome

Schnitzler syndrome (SchS) is a rare acquired systemic autoinflammatory disorder, characterized by chronic urticarial rash and immunoglobulin M (IgM) monoclonal gammopathy. Anti-interleukin-1 (IL-1) therapies have been shown to be more effective in managing the clinical symptoms of SchS compared to anti-IL-6 therapies. In this case report, we present a male patient with urticarial rash, fever, and arthralgia. Laboratory tests identified the presence of IgMκ monoclonal protein, and the absence of IL-1β in serum. Whole exome sequencing (WES) did not reveal any pathological variants associated with monogenic autoinflammatory diseases or the MYD88 L265P mutation. He met the diagnostic criteria for SchS and was treated with bortezomib, leading to a significant improvement in clinical symptoms and a decline in IgMκ monoclonal protein levels. The patient tolerated the treatment well. This case suggests that bortezomib may be considered as a potential treatment option for SchS, in addition to anti-IL-1 therapies and bruton tyrosine kinase (BTK) inhibitors.

Monoclonal Gammopathy-Associated Neuropathy

PURPOSE OF REVIEW

Peripheral neuropathy (PN) is more commonly seen in individuals with monoclonal gammopathies, especially in patients with an IgM monoclonal gammopathy or Waldenström macroglobulinemia.

RECENT FINDINGS

There are multiple potential ways that the paraprotein may result in peripheral neuropathy. The diagnosis and management of monoclonal gammopathy-associated PN are challenging and necessitate a concerted effort between the hematologist/oncologist and the neurologist. This review describes the most common PN syndromes associated with monoclonal gammopathy, such as anti-myelin-associated glycoprotein neuropathy, light chain amyloidosis, cryoglobulinemia, POEMS, CANOMAD, and others. We also review the therapies used to treat these conditions.

Renal manifestations of MGUS

Kidney disease is a common complication of monoclonal immunoglobulin (MIg)-secreting B-cell disorders and predominantly occurs in patients who do not meet the criteria for an overt hematological disease. To distinguish this situation from monoclonal gammopathy of undetermined significance, which lacks organ damage, the term monoclonal gammopathy of renal significance (MGRS) was introduced to depict the association of a small, otherwise indolent B-cell clone, with renal disease induced by the secreted MIg. The spectrum of renal disorders in MGRS is wide, encompassing both tubular and glomerular disorders, classified according to the composition of deposits and their ultrastructural pattern of organization. Renal lesions, independent of the tumor burden, are mostly governed by the molecular characteristics of the MIg variable domain and involve either direct (deposition or precipitation) or indirect (autoantibody activity, complement activation) mechanisms. The diagnosis, often suggested by careful analysis of renal and extrarenal symptoms, almost always requires histological confirmation by a kidney biopsy with light, immunofluorescence, and electron microscopy studies. Most patients do not have a known monoclonal gammopathy at presentation. Hematologic investigations should include serum and urine protein electrophoresis and immunofixation, serum-free light chain measurements, and bone marrow studies with flow cytometry and cytogenetics to determine the nature of the pathogenic clone (most commonly plasmocytic). Early diagnosis before the development of severe chronic kidney disease and rapid achievement of deep hematological response through clone-targeted chemotherapy (currently based on proteasome inhibitor and monoclonal anti-CD38 antibody-based combinations for plasma cell clones) are the main factors influencing long-term renal and patient outcomes.

MGCS: where do we stand today?

Monoclonal gammopathies of clinical significance (MGCS) are a heterogeneous group of disorders characterized by the presence of an indolent B-cell or plasma-cell clone producing a toxic monoclonal immunoglobulin resulting in end-organ dysfunction. MGCS is a clinicopathologic diagnosis that requires the demonstration of a monoclonal immunoglobulin in the correct clinical setting. The most common MGCS syndromes are renal, neurologic, and cutaneous, although hematologic and multi-organ MGCS syndromes are also increasingly recognized. Therapy most commonly targets the underlying clonal population; immunoglobulin-targeting therapies as well as complement and cytokine antagonists have emerged for selected MGCS syndromes and may be temporizing in a subset of patients. Other chapters review renal and neurologic MGCS; this chapter focuses on hematologic and multi-organ MGCS syndromes.

Neurological manifestations of MGUS

Monoclonal gammopathy of undetermined significance (MGUS) is a highly prevalent disorder characterized by a small bone marrow plasma cell or lymphoplasmacytic clone (less than 10%) that produces a small amount of monoclonal paraprotein without associated organ damage. Most patients with MGUS display benign behavior indefinitely, but some progress to an overt malignancy, and others develop organ damage despite no increase in monoclonal protein, resulting in the so-called MG of clinical significance (MGCS). This concept includes different disorders depending on the organ involved, and among them, MG of neurological significance (MGNS) constitutes a real challenge from both a diagnostic and therapeutic point of view. Diagnosis is particularly difficult due to MGNS's heterogeneous clinical presentation and common lack of a diagnostic biopsy. On the other hand, the complexity of treatment lies in the lack of standardized regimens and the common irreversibility of neurological damage. Focusing on the neurological manifestations of MGUS affecting the peripheral nervous system, we describe 3 illustrative cases from daily practice and discuss different aspects of diagnosis to treatment, emphasizing the need for multidisciplinary management based on the close collaboration of neurologists and hematologists.

Clinicopathologic Characteristics of Crystalglobulin-Induced Nephropathy: A Case Series

RATIONALE & OBJECTIVE

Crystalglobulinemia is a rare syndrome characterized by intravascular crystallization of monoclonal immunoglobulins (MIg). Data on kidney involvement are limited to case reports. This series characterizes the clinicopathologic spectrum of crystalglobulin-induced nephropathy (CIN).

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

Nineteen CIN cases identified from the nephropathology archives of Mayo Clinic and Columbia University. CIN was defined by intravascular (extracellular) MIg crystals visible by light microscopy (LM) and electron microscopy (EM).

RESULTS

Among the cases, 68% were male, and 65% were Caucasian (median age, 56 years). Most patients presented with severe acute kidney injury (AKI) (median creatinine, 3.5mg/dL), hematuria, and mild proteinuria (median, 1.1g/day). Common extrarenal manifestations were constitutional (67%), cutaneous (56%), and rheumatologic (50%). Fifty percent of cases had hypocomplementemia. The hematologic disorders were monoclonal gammopathy of renal significance (MGRS) (72%), lymphoma (17%), or myeloma (11%), with 65% of these disorders discovered concomitantly with CIN. All patients had MIg identified on serum protein electrophoresis/immunofixation (IgGκ in 65%). The serum free light chain ratio was outside the renal range in 40%, and bone marrow biopsy detected the responsible clone in 67%. On LM, crystals involved glomeruli (100%) and vessels (47%), often with an inflammatory reaction (89%) and fibrin (58%). All cases exhibited crystal substructures (mostly paracrystalline) by EM. Immunofluorescence on paraffin-embedded tissue was more sensitive than frozen tissue (92% vs 47%) for demonstrating the crystal composition (IgGκ in 63%). Follow-up observation (median, 20 months) was available in 16 patients. Eighty-one percent received steroids, 44% plasmapheresis, 38% hemodialysis, and 69% chemotherapy. Ninety-percent of patients who received clone-directed therapy achieved kidney recovery versus 20% of those who did not (P=0.02).

LIMITATIONS

Retrospective design, small sample size.

CONCLUSIONS

CIN is a rare cause of nephropathy associated with lymphoplasmacytic disorders (mostly MGRS) and typically presents with severe AKI and extrarenal manifestations. Diagnosis often requires immunofluorescence performed on paraffin-embedded kidney tissue. Prompt initiation of clone-directed therapy, coupled with corticosteroids and plasmapheresis, may lead to recovery of kidney function.

Chemotherapy plus therapeutic plasmapheresis with 4% human albumin solution in multiple myeloma patients with acute kidney injury: a prospective, open-label, proof-of-concept study

As no unified treatment protocol or evidence yet exists for plasmapheresis without plasma, this study explored the outcomes of using 4% human albumin (ALB) solution as a replacement solution in patients undergoing plasma exchange for multiple myeloma (MM) patients with acute kidney injury (AKI). This study was prospectively registered (ChiCTR2000030640 and NCT05251896). Bortezomib-based chemotherapy plus therapeutic plasmapheresis (TPP) with 4% human ALB solution was assessed for three years in patients with MM aged >18 years, with AKI according to the Kidney Disease Improving Global Outcomes criteria, and without previous renal impairment from other causes. The primary endpoints were changes in renal function over 18 weeks and survival outcomes at 36 months. The secondary endpoints were the incidence of adverse reactions and symptom improvement. Among the 119 patients included in the analysis, 108 experienced renal reactions. The M protein (absolute changes: median -12.12%, interquartile ranges (IQRs) -18.62 to -5.626) and creatine (median -46.91 μmol/L, IQR -64.70 to -29.12) levels decreased, whereas the estimated glomerular filtration rate (eGFR) increased (median 20.66 mL/(min·1.73 m2), IQR 16.03-25.29). Regarding patient survival, 68.1% and 35.3% of patients survived for >12 and >36 months, respectively. The three symptoms with the greatest relief were urine foam, poor appetite, and blurred vision. All 11 patients (7.6%) who experienced mild adverse reactions achieved remission. In conclusion, in MM patients with AKI, plasma-free plasmapheresis with 4% human ALB solution and bortezomib-based chemotherapy effectively alleviated light chain damage to kidney function while improving patient quality of life.

Non-infectious mixed cryoglobulinemia as a new clinical presentation of mutation in the gene encoding coatomer subunit alpha: a case report of two adult sisters

Cryoglobulinemia is a rare disease characterized by the presence of cryoglobulins in the blood serum. It is usually caused by autoimmune, lymphoproliferative, or infectious factors. The pathogenesis of cryoglobulinemia is not well understood, therefore, genetic testing is very important. We present the case of two adult sisters with different clinical phenotypes of non-infectious cryoglobulinemic vasculitis associated with a rare genetic variant [(Hg38) 1:160323529 C>G, NP_004362.2:p.(Gly203Ala)]. One of the sisters suffered from essential mixed cryoglobulinemia, while the other suffered from cryoglobulinemia associated with systemic connective tissue disease. In both cases, genetic tests revealed a variant in the COPA gene, encoding coatomer subunit alpha. Mutations in the COPA gene are associated with COPA syndrome, an autoimmune interstitial lung, joint, and kidney monogenic disease, found mainly in children. Only 15 pathogenic COPA variants have been reported thus far which suggests that the full spectrum of disease manifestations remains unknown. Ours is the first report of the association of the COPA gene with non-infectious cryoglobulinemic vasculitis in adults. This unexpected finding may direct research into the pathogenesis of cryoglobulinemia and new treatment strategies for this rare disease.

Clinical Spectrum of Monoclonal Protein and the Factors Associated with Lymphoplasmacytic Malignancies

Background: Monoclonal protein (MP) presents in various monoclonal gammopathies, ranging from benign conditions such as monoclonal gammopathy of undetermined significance (MGUS) to life-threatening conditions such as lymphoplasmacytic malignancies (LPMs), which include multiple myeloma (MM) and Waldenström macroglobulinemia (WM). Few studies have comprehensively assessed the clinical spectrum of MP and its factors associated with LPMs. This study aimed to determine the clinical spectrum of MP and identify factors associated with LPMs. Methods: This retrospective study included patients who were first tested for capillary electrophoresis (CEP) and identified as having MP between 2014 and 2023 at two university hospitals. Univariate (crude) and multivariate (adjusted) logistic regression analyses were performed to identify factors associated with LPMs. Results: Among the 1135 included patients with MP, 744 (65.6%) were diagnosed with LPMs and 391 (34.4%) with MGUS. Among the 391 patients with MGUS, 310 (79.3%) had at least 1 clinical association, including 204 with renal diseases, 35 with autoimmune diseases, 33 with chronic liver diseases, 22 with hematologic diseases, and 96 with other conditions. Multivariate analyses indicated that LPMs were associated with female sex (OR = 2.08), lower age (OR = 0.95), higher MP level (OR = 3.53), an abnormal FLC ratio (OR = 6.15), lower hemoglobin level (OR = 0.82), and higher total calcium level (OR = 1.81) (all p < 0.05). Conclusions: This study provides insight into the distribution of MPs and their clinical association with MGUS and identifies factors related to LPM. These can help clinicians manage patients more effectively in the early stages of these conditions.

Daratumumab-based treatment of monoclonal gammopathy-associated angioedema due to acquired C1-inhibitor deficiency

Daratumumab-based treatment could control severe, treatment-refractory, life-threatening angioedema due to acquired C1-inhibitor deficiency associated with monoclonal gammopathy.

The identification and correction of pseudohypercalcemia

Background

We found that a subset of patients with monoclonal gammopathy exhibited hypercalcemia without apparent causes or clinical manifestations In a cohort of 289 monoclonal gammopathy patients, 2.4% presented with such atypical hypercalcemia, with one notable case exhibiting normal ionized calcium levels, suggesting the presence of pseudohypercalcemia.

Objective

The aim of this study is to elucidate the factors contributing to pseudohypercalcemia in monoclonal gammopathy and to develop a novel globulin-corrected calcium formula for clinical application.

Methods

This observational study enrolled 110 monoclonal gammopathy patients from our center. An additional 33 patients were recruited to validate the newly proposed formula. Univariate analysis identified potential risk factors. And multivariate logistic regression identified definitive influential factors. The determined influential factors were utilized to develop a formula by multiple linear regression, which was validated by a paired t-test and the Youden index.

Results

This study found that globulin was a risk factor for pseudohypercalcemia. It revealed that pseudohypercalcemia should be considered in patients with globulin levels ≥61 g/L (P=0.014). Both albumin and globulin were confirmed as independent factors associated with bound calcium. Given that, we developed a formula to correct ionized calcium levels, which was consistent with ionized calcium tested by blood gas analysis. The diagnostic accuracy of the new formula (Youden index is 0.906) is better than the traditional formula (Youden index is 0.906). Interestingly, all monoclonal immunoglobulin types, except for light chains, showed an equal propensity to develop pseudohypercalcemia (P=0.306). It also showed a linear correlation between IgA, IgG, and IgM and bound calcium.

Conclusion

This study confirmed that elevated globulin affects serum total calcium and offered the threshold of globulin ≥ 61 g/L in the differential diagnosis of peudohypercalcemia from hypercalcemia. The new formula based on albumin and globulin was developed, which was verified to be better than the traditional formula for correctly diagnosing hypercalcemia. In addition, we found that neither light chains nor heavy chains of monoclonal immunoglobulin alone can result in pseudohypercalcemia.

Clinical Reasoning: A 49-Year-Old Man With Progressive Numbness, Gait Instability, and Tremors

Approaching patients with paraproteinemic neuropathies can be challenging for the practicing neurologist, and a well-defined strategy considering specific etiologies is necessary to arrive at the correct diagnosis. In this case, a 49-year-old man presented with a 2-year history of progressive upper then lower extremity numbness, weakness, gait instability, and tremors. His examination was marked by proximal and distal symmetric upper and lower extremity weakness, large more than small-fiber sensory loss, prominent sensory ataxia, action and postural tremors, and globally absent deep tendon reflexes. His workup was notable for a chronic demyelinating sensorimotor polyradiculoneuropathy and a monoclonal immunoglobulin (Ig) M kappa gammopathy. This case highlights the approach to a patient with a rare subtype of IgM paraproteinemic neuropathy with a review of the differential diagnoses, red flag features of co-occurring hematologic disorders, and guided workup. We further discuss typical features of this rare diagnosis and therapeutic options.

SOHO State of the Art Updates and Next Questions: Diagnosis and Management of Monoclonal Gammopathy of Undetermined Significance and Smoldering Multiple Myeloma

Monoclonal proteins are common, with a prevalence in the United States around 5% and the incidence increases with age. Although most patients are asymptomatic, the vast majority of cases are caused by a clonal plasma cell disorder. Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions with variable risk of progression to multiple myeloma (MM). In recent years, significant progress has been made to better understand the factors that lead to the development of symptoms and progression to myeloma. In this review, we summarize the current diagnosis treatment guidelines for MGUS and SMM and highlight recent advances that underscore a shifting paradigm in the evaluation and management of plasma cell precursor conditions.

Unraveling monoclonal gammopathy of renal significance: a mini review on kidney complications and clinical insights

Monoclonal gammopathy of renal significance (MGRS) is where kidney injury occurs due to the accumulation or effects of abnormal monoclonal proteins. These proteins, originating from non-cancerous or pre-cancerous plasma cells or B cells, deposit in specific areas of the kidney. Mechanisms contributing to MGRS include high levels of vascular endothelial growth factor secretion, autoantibodies targeting complement components, and targeting specific receptors leading to nephropathy. Kidney lesions in monoclonal gammopathy of renal significance (MGRS) are classified based on the presence of organized or nonorganized deposits, including fibrillar, microtubular, or crystal inclusions. Kidney biopsy is essential for confirming the diagnosis of MGRS by identifying monoclonal immunoglobulin deposits. Immunofluorescence helps determine the class of light and/or heavy chain involved in MGRS. The treatment approach is clone-directed and hence it depends on the presence of B cell clone or plasma cell clone or any detectable monoclonal protein. Chemotherapy targeting plasma cell or B cell malignancies and autologous hematopoietic cell transplantation may be used to manage MGRS. Kidney outcomes in MGRS patients strongly correlate with the hematologic response to chemotherapy.

Monoclonal Gammopathy of Clinical Significance (MGCS) and Related Disorders: A Review and the Role of Imaging

The term monoclonal gammopathy of clinical significance (MGCS) refers to a group of symptomatic monoclonal gammopathies that do not meet the diagnostic criteria for malignant plasma cell disorders, such as multiple myeloma or Waldenström macroglobulinemia. These symptoms are attributable to the paraneoplastic effects of monoclonal immunoglobulins that occur through diverse mechanisms. The presence of symptoms distinguishes MGCS from monoclonal gammopathy of undetermined significance, which lacks significant symptomatic presentation. The presentations of MGCS are manifold, adding to the diagnostic challenge. Clinical suspicion is key for accurate and timely diagnosis. Radiologic imaging can provide pivotal information to guide the diagnosis. In this review, we discuss MGCS from a radiology perspective and highlight pertinent imaging features associated with the disorders.

Monoclonal gammopathy of renal significance from the perspective of nephrologists

Kidney disease is a frequent complication of multiple myeloma and other malignancies associated with monoclonal gammopathies. Additionally, dysproteinemia-related kidney disease can occur independently of overt multiple myeloma or hematologic malignancies. Monoclonal gammopathy of renal significance (MGRS) is a spectrum of disorders in which a monoclonal immunoglobulin produced by a benign or premalignant B-cell or plasma cell clone causes kidney damage. MGRS-associated renal disease manifests in various forms, including immunoglobulin-associated amyloidosis, monoclonal immunoglobulin deposition diseases (light chain, heavy chain, and combined light and heavy chain deposition diseases), proliferative glomerulonephritis with monoclonal immunoglobulin deposits, C3 glomerulopathy with monoclonal gammopathy, and light chain proximal tubulopathy. Although MGRS is a nonmalignant or premalignant hematologic condition, it has significant renal implications that often lead to progressive kidney damage and, eventually, end-stage kidney disease. This review discusses the epidemiology, pathogenesis, and management of MGRS and focuses on the perspective of nephrologists.

Monoclonal immunoglobulin crystalline nephropathies

Monoclonal Ig crystalline nephropathies are rare lesions resulting from precipitation of monoclonal Igs in the kidney as crystalline inclusions. They can be categorized into lesions with predominant intracellular crystals (light chain [LC] proximal tubulopathy, LC crystal-storing histiocytosis, and LC crystalline podocytopathy) and lesions with predominant extracellular crystals (crystalglobulin-induced nephropathy and crystalline variant of LC cast nephropathy). The majority of these lesions are associated with low tumor burden lymphoproliferative disorders, with the exception of crystalline variant of LC cast nephropathy. Extrarenal involvement (e.g., skin and cornea) is frequent. Kidney biopsy is the cornerstone for diagnosis, which often requires electron microscopy and antigen retrieval. A thorough hematologic workup and evaluation of extrarenal involvement is mandatory for management. Treatment of these lesions is with clone-directed therapy, with the goal of achieving hematologic very good partial response or complete response, which preserves or improves kidney function. In vitro and in vivo studies, animal models, and novel sequencing techniques have been invaluable tools to understand the pathogenesis of LC proximal tubulopathy and can be used to increase our limited knowledge of the pathogenesis of the other monoclonal Ig crystalline nephropathies. This review provides an update on the pathology, renal and hematologic characteristics, extrarenal manifestations, prognosis, treatment, and pathogenesis of monoclonal Ig crystalline nephropathies.

Effective treatment of refractory monoclonal gammopathy-associated pure red cell aplasia with isatuximab, pomalidomide and dexamethasone

Monoclonal gammopathy-associated pure red cell aplasia (MG-PRCA) is characterized by the absence or pronounced hypoplasia of erythroid precursors in the bone marrow, causing reticulocytopenia and a normocytic, normochromic anaemia in a patient with a monoclonal plasma cell dyscrasia. We report here on the successful treatment of MG-PRCA with isatuximab, pomalidomide, and dexamethasone after multiple lines of immunosuppressive and anti-plasma cell-directed treatments.

N-linked glycosylation of the M-protein variable region: glycoproteogenomics reveals a new layer of personalized complexity in multiple myeloma

OBJECTIVES

Multiple myeloma (MM) is a plasma cell malignancy characterized by a monoclonal expansion of plasma cells that secrete a characteristic M-protein. This M-protein is crucial for diagnosis and monitoring of MM in the blood of patients. Recent evidence has emerged suggesting that N-glycosylation of the M-protein variable (Fab) region contributes to M-protein pathogenicity, and that it is a risk factor for disease progression of plasma cell disorders. Current methodologies lack the specificity to provide a site-specific glycoprofile of the Fab regions of M-proteins. Here, we introduce a novel glycoproteogenomics method that allows detailed M-protein glycoprofiling by integrating patient specific Fab region sequences (genomics) with glycoprofiling by glycoproteomics.

METHODS

Glycoproteogenomics was used for the detailed analysis of de novo N-glycosylation sites of M-proteins. First, Genomic analysis of the M-protein variable region was used to identify de novo N-glycosylation sites. Subsequently glycopeptide analysis with LC-MS/MS was used for detailed analysis of the M-protein glycan sites.

RESULTS

Genomic analysis uncovered a more than two-fold increase in the Fab Light Chain N-glycosylation of M-proteins of patients with Multiple Myeloma compared to Fab Light Chain N-glycosylation of polyclonal antibodies from healthy individuals. Subsequent glycoproteogenomics analysis of 41 patients enrolled in the IFM 2009 clinical trial revealed that the majority of the Fab N-glycosylation sites were fully occupied with complex type glycans, distinguishable from Fc region glycans due to high levels of sialylation, fucosylation and bisecting structures.

CONCLUSIONS

Together, glycoproteogenomics is a powerful tool to study de novo Fab N-glycosylation in plasma cell dyscrasias.

Gammopathic dermopathy: characterization of cutaneous MGUS

Monoclonal Gammopathy of Undetermined Significance (MGUS) is a clonal plasma cell disorder that is considered preneoplastic, asymptomatic, and only requiring observation. However, MGUS may result in cutaneous complications, which are poorly understood, causing treatment delays and patient suffering. We present 30 patients with cutaneous findings associated with MGUS, characterizing clinical presentations, isoforms, treatments, and outcomes. These included: MGUS-associated 'rashes' (pruritic eczematous rashes), reactive and mucin-depositional conditions (pyoderma gangrenosum, scleromyxedema), M-protein-related deposition disorders (POEMS syndrome, Waldenstrom macroglobulinemia), and cutaneous lymphomas. Twelve of 30 (40%) patients received multiple myeloma drugs (MMDs). Eleven (92%) patients improved, and those not receiving MMDs rarely improved, suggesting that MMDs have efficacy for cutaneous manifestations of MGUS. Therefore, trialing MMDs may be warranted for patients with MGUS not responding to other therapies. Moreover, evaluation for monoclonal gammopathy in elderly patients with intractable pruritus or other chronic skin conditions that are non-responsive to skin-directed therapies should be considered.

Multiple myeloma

Multiple myeloma (MM) is a haematological lymphoid malignancy involving tumoural plasma cells and is usually characterized by the presence of a monoclonal immunoglobulin protein. MM is the second most common haematological malignancy, with an increasing global incidence. It remains incurable because most patients relapse or become refractory to treatments. MM is a genetically complex disease with high heterogeneity that develops as a multistep process, involving acquisition of genetic alterations in the tumour cells and changes in the bone marrow microenvironment. Symptomatic MM is diagnosed using the International Myeloma Working Group criteria as a bone marrow infiltration of ≥10% clonal plasma cells, and the presence of at least one myeloma-defining event, either standard CRAB features (hypercalcaemia, renal failure, anaemia and/or lytic bone lesions) or biomarkers of imminent organ damage. Younger and fit patients are considered eligible for transplant. They receive an induction, followed by consolidation with high-dose melphalan and autologous haematopoietic cell transplantation, and maintenance therapy. In older adults (ineligible for transplant), the combination of daratumumab, lenalidomide and dexamethasone is the preferred option. If relapse occurs and requires further therapy, the choice of therapy will be based on previous treatment and response and now includes immunotherapies, such as bi-specific monoclonal antibodies and chimeric antigen receptor T cell therapy.

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.

Monoclonal gammopathy of clinical significance in a young patient treated with melphalan-thalidomide-prednisone

Key Clinical Message

We report an observation of a young patient presenting with severe type 1 cryoglobulinemic vasculitis revealing a monoclonal gammopathy of clinical significant. Treatment with Melphalan-Thalidomide Prednisone improved the symptoms. Early diagnosis would prevent serious tissue damage.

Abstract

Monoclonal gammopathy encompass diverse clinical forms. Only the cancerous form, multiple myeloma (MM), is treated based on specific diagnostic criteria. A new clinical entity, monoclonal gammopathy of clinical significance (MGCS), warrants special attention due to its need for specific treatment. It involves patients with signs of potentially severe organ involvement that do not meet MM criteria. We present the case of a 34-year-old Malagasy woman with severe type I cryoglobulinemic vasculitis associated with noncancerous monoclonal gammopathy, showing a favorable outcome after treatment with Thalidomide. Symptoms included toe necrosis, a severe ulcer on the left calf evolving for 3 months, and stocking-like dysesthesias. Investigations revealed monoclonal gammopathy at 30.1 g/L, proteinuria at 1 g/24 h, medullary plasma cell at 6%, and circulating cryoglobulin of Ig kappa type. CRAB criteria (anemia, hypercalcemia, renal insufficiency, and osteolysis) were absent. Treatment with Thalidomide, combined with corticosteroids and local care for 4 months, resulted in ulcer healing, disappearance of dysesthesias, and persistent normalization of gammaglobulin. Our case underscores the importance of specific treatment for MGCS.

Phenotypes and outcome of diffuse pulmonary non-amyloid light chain deposition disease

BACKGROUND

Light chain deposition disease (LCDD) is a very rare entity. Clinical manifestations of LCDD vary according to the organs involved. Data on pulmonary LCDD are scarce and limited to small series or case reports. This study aimed to describe the characteristics and outcome of diffuse pulmonary non-amyloid LCDD localized to the lungs.

STUDY DESIGN AND METHODS

A multicenter retrospective cohort study was conducted. Clinical characteristics were collected, and chest CTs were centrally reviewed. The diagnosis of pulmonary non-amyloid LCDD was confirmed by immunohistochemistry.

RESULTS

Thirty-one cases were identified (68% female), with a median age at diagnosis of 50 years (IQR 20). Baseline FEV1/FVC was < 0.70 in 45% of patients. Mean (± SD) FEV1 and DLCO were 86% ± 26.2 and 52% ± 23.9, respectively. CT revealed peculiar patterns of thin-walled cysts (58%) and thin-walled cystic bronchiectases (27%). Increased serum kappa light chain was found in 87% of patients. Histological analysis showed kappa light chain deposits in all patients, except one with lambda chain deposits. Median annual FEV1 decline was 127 ml (IQR 178) and median DLCO decline was 4.3% (IQR 4.3). Sixteen patients received immunomodulatory treatment or chemotherapy; serum light chain levels decreased in 9 cases (75%), without significant improvement in FEV1 (p = 0.173). Overall, 48% of patients underwent bilateral lung transplantation. Transplant-free survival at 5 and 10 years were 70% and 30%, respectively. An annual FEV1 decline greater than 127 ml/year was associated with increased risk of death or transplantation (p = 0.005).

CONCLUSIONS

Diffuse pulmonary LCDD is characterised by female predominance, a peculiar imaging pattern with bronchiectasis and/or cysts, progressive airway obstruction and severe DLCO impairment, and poor outcome. Lung transplantation is a treatment of choice.

Monoclonal Gammopathy and Its Association with Progression to Kidney Failure and Mortality in Patients with CKD

BACKGROUND

Little is known about the prognostic significance of monoclonal gammopathy of undetermined and renal significance (MGUS and MGRS) in patients with CKD. The objective of this study was to determine the clinical and kidney outcomes of patients with CKD with either MGUS or MGRS compared with those with CKD without MGUS or MGRS.

METHODS

We conducted a retrospective cohort study from 2013 to 2018. Patients who had both CKD diagnosis and monoclonal testing were identified. Patients were divided into MGRS, MGUS, and no monoclonal gammopathy groups. Cumulative incidence functions and Cox proportional hazards regression were used to model time to event data and to evaluate the association between monoclonal gammopathy status and risk of kidney failure, with death treated as a competing risk.

RESULTS

Among 1535 patients, 59 (4%) had MGRS, 648 (42%) had MGUS, and 828 (54%) had no monoclonal gammopathy. Unadjusted analysis showed that compared with no monoclonal gammopathy patients, patients with MGRS were at higher risk of kidney failure (hazard ratio [HR] [95% confidence interval]: 2.5 [1.5 to 4.2] but not patients with MGUS (HR [95% confidence interval]: 1.3 [0.97 to 1.6]), after taking death into account as a competing risk. However, in the multivariable analysis, after adjusting for age, sex, eGFR, proteinuria, and Charlson Comorbidity Index, the risk of progression to kidney failure (with death as competing risk) in the MGRS group was no longer statistically significant (HR: 0.9 [0.5 to 1.8]). The same was also true for the MGUS group compared with the group with no monoclonal gammopathy (HR: 1.3 [0.95 to 1.6]). When evaluating the association between MGUS/MGRS status and overall survival, MGRS was significantly associated with mortality in fully adjusted models compared with the group with no monoclonal gammopathy, while MGUS was not.

CONCLUSIONS

After adjusting for traditional risk factors, MGUS/MGRS status was not associated with a greater risk of kidney failure, but MGRS was associated with a higher risk of mortality compared with patients with no monoclonal gammopathy.

Type 1 Cryoglobulinemic Vasculitis Due to Monoclonal Gammopathy of Undetermined Significance Successfully Treated by Bortezomib Plus Dexamethasone

Cryoglobulins are immunoglobulins that precipitate in cold conditions. Type I cryoglobulinemic vasculitis is associated with hematological malignancies. We herein report a case of steroid-resistant type 1 cryoglobulinemic vasculitis associated with monoclonal gammopathy of undetermined significance (MGUS) in a 47-year-old woman. By immunofixation of cryoglobulin, we found that the main component of cryoglobulin was the M protein due to MGUS, so treatment of MGUS was needed. Bortezomib+dexamethasone therapy resulted in a rapid decrease in cryoglobulin and improvement in the symptoms of cryoglobulinemic vasculitis. In refractory type I cryoglobulinemic vasculitis, treatment of the underlying gammaglobulinopathy should be considered.

Laboratory practice is central to earlier myeloma diagnosis: Utilizing a primary care diagnostic tool and laboratory guidelines integrated into haematology services

Treatment advances have greatly improved survival, but myeloma is among the worst of all cancers for delayed diagnosis, causing serious morbidities and early deaths. This delay is largely because the symptom profile of myeloma has very low specificity, and in primary care, myeloma is rare. However, initiating the journey to diagnosis simply requires considering myeloma and sending blood to test for monoclonal immunoglobulin. Laboratory tests reliably detect monoclonal immunoglobulin, which is present in 99% of myeloma cases, so why do health care systems have such a problem with delayed diagnosis? The Myeloma UK early diagnosis programme has brought together diverse expertise to investigate this problem, and this article was prepared by the programme's working group for laboratory best practice. It reviews evidence for test requesting, analysis and reporting, for which there is large variation in practice across the United Kingdom. It presents a 'GP Myeloma diagnostic tool' and how it can be integrated into laboratory practice alongside a laboratory best practice tool. It proposes improved requesting and integration with haematology services for reporting and interpretation. Here the laboratory has a central role in creating efficient and cost-effective pathways for appropriate and timely bone marrow examination for myeloma diagnosis.

Systematic review and meta-analysis of the clinical features of MGRS

BACKGROUND

It is crucial to identify patients with monoclonal gammopathy of renal significance (MGRS) from those without MGRS but with monoclonal gammopathy and concomitant kidney diseases. However, there have been few studies with large sample sizes, and their findings were inconsistent. This study aimed to conduct a meta-analysis of MGRS to describe the general characteristics of MGRS and its predictive factors.

METHODS

Cohort or case-control studies published through December 2022 and related to clinicopathological features of MGRS were retrieved from the PubMed, Cochrane Library, Web of Science, Scopus, and Embase databases. Two researchers searched for studies that met the inclusion criteria. In the univariate analysis, fixed- or random- effects models were used to obtain pooled estimates of the weighted mean difference (WMD) and odds ratio (OR) for risk factors. In the multivariate analysis, the ORs of the independent risk factors from each study were pooled after transforming the original estimates.

RESULTS

The meta-analysis included six studies. Univariate analysis showed that the following variables were statistically significant in MGRS: age (WMD = 1.78, 95%CI 0.21-3.35), hypertension (OR = 0.54, 95%CI 0.4-0.73), diabetes (OR = 0.42, 95%CI 0.29-0.59), albumin (WMD = - 0.26, 95%CI - 0.38--0.14), urinary protein level (WMD = 0.76, 95%CI 0.31-1.2), urinary protein ≥ 1.5 g/d (OR = 1.98, 95%CI 1.46-2.68), lambda-chain value (WMD = 29.02, 95%CI 16.55-41.49), abnormal free light-chain ratio (OR = 4.16, 95%CI 1.65-10.47), bone marrow puncture rate (OR = 5.11, 95% CI 1.31-19.95), and abnormal bone marrow outcome rate (OR = 9.63, 95%CI 1.98-46.88). Multivariate analysis showed urinary protein ≥ 1.5 g/d (OR = 2.80, 95%CI 1.53-5.15) and an abnormal free light-chain ratio (OR = 6.98, 95%CI 4.10-11.91) were associated with predictors of MGRS.

CONCLUSIONS

Compared with non-MGRS patients with monoclonal gammopathy and concomitant kidney diseases, patients with MGRS were older, had fewer underlying diseases, more urinary protein, more abnormal free light-chain ratio, and more abnormal bone marrow results. Urinary protein ≥ 1.5 g/d and an abnormal free light-chain ratio were independent risk factors for MGRS.

Monoclonal Gammopathy of Undetermined Cardiovascular Significance; Current Evidence and Novel Insights

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant condition characterized by the presence of low levels of a monoclonal protein in the serum and a low percentage of clonal plasma cells in the bone marrow. MGUS may progress to multiple myeloma or other plasma cell disorders at a rate of 1% annually. However, MGUS may also have adverse effects on the cardiovascular system independent of its malignant potential. Emerging data have shown that MGUS is associated with cardiovascular disease. The mechanisms underlying this association are not fully understood but may involve genetic abnormalities, vascular calcification, cryoglobulinemia, cold agglutinin disease, autoantibodies and the direct or indirect effects of the monoclonal protein on the vascular endothelium. Herein, we review current evidence in this field and we suggest that patients with MGUS may benefit from regular cardiovascular risk assessment to prevent severe cardiovascular complications, in parallel with close hematological follow-up to monitor potential disease progression.

POEMS syndrome: Update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

POEMS syndrome is a life-threatening condition due to an underlying plasma cell neoplasm. The major criteria for the syndrome are polyradiculoneuropathy, clonal plasma cell disorder, sclerotic bone lesions, elevated vascular endothelial growth factor, and the presence of Castleman disease. Minor features include organomegaly, endocrinopathy, characteristic skin changes, papilledema, extravascular volume overload, and thrombocytosis.

DIAGNOSIS

The diagnosis of POEMS syndrome is made with three of the major criteria, two of which must include polyradiculoneuropathy and clonal plasma cell disorder, and at least one of the minor criteria.

RISK STRATIFICATION

Because the pathogenesis of the syndrome is not well understood, risk stratification is limited to clinical phenotype rather than specific molecular markers. Risk factors include low serum albumin, age, pleural effusion, pulmonary hypertension, and reduced estimated glomerular filtration rate.

RISK-ADAPTED THERAPY

For those patients with a dominant plasmacytoma, first-line therapy is irradiation. Patients with diffuse sclerotic lesions or disseminated bone marrow involvement should receive systemic therapy. Corticosteroids are temporizing, but alkylators and lenalidomide are the mainstays of treatment, the former either in the form of low-dose conventional therapy or as high-dose conditioning for stem cell transplantation. Thalidomide and bortezomib also have activity, but their benefit needs to be weighed against their risk of exacerbating the peripheral neuropathy. Daratumumab combinations also appear promising based on case series. Prompt recognition and institution of both supportive care measures and therapy directed against the plasma cell result in the best outcomes.

POEMS syndrome: origination from clonal plasma cells or B cells?

OBJECTIVES

POEMS syndrome is a rare disorder which has been increasingly recognized. The clonal origin is controversial. Some people argue that POEMS syndrome originates from abnormal plasma cell clones. So, treatment frequently targets the plasma cell clone. Nevertheless, others believe that both plasma cells and B cells can be the potential culprit in POEMS syndrome.

METHODS

A 65-year-old male came to the emergency department of our hospital with the complaints of bilateral soles numbness and weight loss for half a year, abdominal distension for half a month, and chest tightness and shortness of breath for one day. He was then diagnosed as POEMS syndrome complicated with monoclonal B-cell lymphocytosis (non-CLL type). A standard bendamustine plus rituximab (BR) regimen combined with low dose of lenalidomide was administered.

RESULTS

After four cycles of treatment, the ascites of the patient was absent and the neurological symptom disappeared. The renal function, the IgA level, and the VEGF level all returned to normal.

DISCUSSION

POEMS syndrome, a multi-system disorder, is easily misdiagnosed. The clonal origin of POEMS syndrome is controversial and needs further study. For now, there are no approved treatment regimens. Treatments mainly target the plasma cell clone. This case suggested that other therapy besides anti-plasma cell treatment may also be effective in POEMS syndrome.

CONCLUSION

We report a patient with POEMS syndrome who achieved complete response after treatment with the combination of a standard BR regimen and low dose of lenalidomide. POEMS syndrome's pathological mechanisms and therapies warrant further studies.

Recommendations for the study of monoclonal gammopathies in the clinical laboratory. A consensus of the Spanish Society of Laboratory Medicine and the Spanish Society of Hematology and Hemotherapy. Part I: Update on laboratory tests for the study of monoclonal gammopathies

Monoclonal gammopathies (MG) are characterized by the proliferation of plasma cells that produce identical abnormal immunoglobulins (intact or some of their subunits). This abnormal immunoglobulin component is called monoclonal protein (M-protein), and is considered a biomarker of proliferative activity. The identification, characterization and measurement of M-protein is essential for the management of MG. We conducted a systematic review of the different tests and measurement methods used in the clinical laboratory for the study of M-protein in serum and urine, the biochemistry and hematology tests necessary for clinical evaluation, and studies in bone marrow, peripheral blood and other tissues. This review included literature published between 2009 and 2022. The paper discusses the main methodological characteristics and limitations, as well as the purpose and clinical value of the different tests used in the diagnosis, prognosis, monitoring and assessment of treatment response in MG. Included are methods for the study of M-protein, namely electrophoresis, measurement of immunoglobulin levels, serum free light chains, immunoglobulin heavy chain/light chain pairs, and mass spectrometry, and for the bone marrow examination, morphological analysis, cytogenetics, molecular techniques, and multiparameter flow cytometry.

Determination of the target of monoclonal immunoglobulins: a novel diagnostic tool for individualized MGUS therapy, and prevention and therapy of smoldering and multiple myeloma

Subsets of patients diagnosed with a monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM) or multiple myeloma (MM), present with a monoclonal immunoglobulin (Ig) specific for an infectious pathogen, including hepatitis C and B viruses (HCV, HBV), Helicobacter pylori and several Herpesviruses. Such cases are likely initiated by infection, since in the context of HCV- or HBV-infected patients, antiviral therapy can lead to the disappearance of antigenic stimulation, control of clonal plasma cells, and reduced or suppressed monoclonal Ig production. Complete remission has been obtained with anti-HCV therapy in refractory MM with a HCV-specific monoclonal Ig, and antiviral treatments significantly improved the probability of survival of MM patients infected with HCV or HBV prior to the diagnosis of MM. Monoclonal Igs may also target glucolipids, particularly glucosylsphingosine (GlcSph), and GlcSph-reducing therapy can lead to complete remission in SMM and MM patients presenting with a GlcSph-specific monoclonal Ig. The present review describes the importance of determining the target of the monoclonal Ig of MGUS, SMM and MM patients, and discusses the efficacy of target-reducing treatments in the management of MGUS, SMM and MM cases who present with a monoclonal Ig reactive against a treatable infectious pathogen or GlcSph.

IgM monoclonal gammopathy of undetermined significance: clinicopathologic features with and without IgM-related disorders

A subset of patients with immunoglobulin M (IgM) monoclonal gammopathy of undetermined significance (MGUS) develop IgM-related disorders (IgM-RD) including peripheral neuropathy, cryoglobulinemia and/or cold agglutinin disease (CAD). We examined the clinical and bone marrow pathologic findings in 191 IgM MGUS patients (2016 World Health Oragnization criteria). Clonal plasma cells were identified in 41 of 171 (24%) cases by immunohistochemistry (IHC) and clonal B cells in 43 of 157 (27%). IgM-RD was identified in 82 (43%) cases, including peripheral neuropathy (n=67, 35%), cryoglobulinemia (n=21, 11%), and CAD (n=10, 5%). Cases of CAD showed distinctive features including lack of MYD88 mutations (P=0.048), supporting the concept of primary CAD as a distinct clinicopathologic disorder. Following exclusion of CAD, comparison of the remaining cases with (n=72) or without (n=109) IgM-RD showed IgM-RD to be more frequent in men than women (P=0.02) and to be more highly associated with MYD88 L265P (P=0.011). Cases with and without IgM-RD otherwise showed similar features including serum IgM concentrations, presence of lymphoid aggregates, clonal B cells by flow cytometry or clonal plasma cells by IHC. No differences were observed in overall survival between cases with and without IgM-RD. No cases in this series met criteria for plasma cell type IgM MGUS as defined in the 2022 International Consensus Classification of lymphoid neoplasms. These results show IgM-RD to be common in patients with IgM MGUS. While CAD shows distinctive features, the remaining cases of IgM-RD largely show pathologic findings similar to IgM MGUS without IgM-RD.

Serum Paraprotein Is Associated with Adverse Prognostic Factors and Outcome, across Different Subtypes of Mature B-Cell Malignancies-A Systematic Review

The presence of a serum paraprotein (PP) is usually associated with plasma-cell dyscrasias, Waldenstrom Macroglobulinemia/lymphoplasmacytic lymphoma, and cryoglobulinemia. However, PP is also often reported in other high- and low-grade B-cell malignancies. As these reports are sparse and heterogeneous, an overall view on this topic is lacking, Therefore, we carried out a complete literature review to detail the characteristics, and highlight differences and similarities among lymphoma entities associated with PP. In these settings, IgM and IgG are the prevalent PP subtypes, and their serum concentration is often low or even undetectable without immunofixation. The relevance of paraproteinemia and its prevalence, as well as the impact of IgG vs. IgM PP, seems to differ within B-NHL subtypes and CLL. Nonetheless, paraproteinemia is almost always associated with advanced disease, as well as with immunophenotypic, genetic, and clinical features, impacting prognosis. In fact, PP is reported as an independent prognostic marker of poor outcome. All the above call for implementing clinical practice, with the assessment of paraproteinemia, in patients' work-up. Indeed, more studies are needed to shed light on the biological mechanism causing more aggressive disease. Furthermore, the significance of paraproteinemia, in the era of targeted therapies, should be assessed in prospective trials.

Diplomate in Medical Laboratory Immunology Certification Examination: A New Chapter for Medical Laboratory Immunology

It is indeed a privilege to be an immunologist in what is arguably the golden age of immunology. From astounding advances in fundamental knowledge to groundbreaking immunotherapeutic offerings, immunology has carved out an enviable niche for itself in basic science and clinical medicine. The need and the vital importance of appropriate education, training, and certification in clinical immunology was recognized by the World Health Organization as far back as 1972. In the United States, Ph.D. scientists with board certification in medical laboratory immunology have served as directors of high-complexity Clinical Laboratory Improvement Amendments- and College of American Pathologists-certified clinical immunology laboratories since 1977. From 1977 to 2017, board certification for medical laboratory immunology was administered by the American Society for Microbiology through the American Board of Medical Laboratory Immunology examination. The American Board of Medical Laboratory Immunology examination was phased out in 2017, and in the fall of 2019, the American Society for Clinical Pathology (ASCP) Board of Certification (BOC) examination committee took on the responsibility of developing a new doctoral-level certification examination for medical laboratory immunology. This transition to the ASCP BOC represents a well-deserved and much-needed recognition of the rapid advances in and the highly specialized nature of medical laboratory immunology and its ever-increasing relevance to patient care. This new ASCP BOC certification is called the Diplomate in Medical Laboratory Immunology, and, as of April 1, 2023, it is now available to potential examinees. In this report, we describe the examination, eligibility routes, and potential career pathways for successful diplomates.

Monoclonal gammopathy of increasing significance: time to screen?

Monoclonal gammopathy (MG) is a frequently detected clonal B-cell or plasma-cell disorder. Importantly, every multiple myeloma (MM) case is preceded by MG. Although clinical algorithms now allow earlier treatment of patients with biomarkers of malignancy before MM-induced tissue damage (CRAB) occurs, most patients are still diagnosed late. It is important to revisit how MG should be managed in clinical practice and whether screening is required. As the prevalence of MG and other medical co-morbidities both rise with increasing age, the degree of contribution of MG to disease states other than malignant progression is often unclear. This can lead to monitoring lapses and under recognition of the organ dysfunction that can occur with monoclonal gammopathy of clinical significance (MGCS). Therefore, models of progression to MM and/or MGCS require further refinement. While MG is currently detected incidentally, a case for screening has been made with ongoing studies in this area. Screening has the potential benefit of earlier detection and prevention of both MGCS and delayed MM presentations, but important drawbacks include the psychosocial impact on individuals and resource burden on healthcare services. MG terminology should transition alongside our increasing understanding of the condition and genomic characterization that have already begun to revise the MG nomenclature. The biology of MG has been poorly understood and is often inferred from the biology of MM, which is unhelpful. We review the literature and case for MG screening in this paper. In particular, we highlight areas that require focus to establish screening for MG.

Hematologic Disorders and the Nervous System

OBJECTIVE

This article discusses the epidemiology, diagnosis, treatment, and prevention of neurologic complications of red blood cell, platelet, and plasma cell disorders.

LATEST DEVELOPMENTS

Cerebrovascular complications can occur in patients with blood cell and platelet disorders. Treatment strategies to prevent stroke are available for patients with sickle cell disease, polycythemia vera, and essential thrombocythemia. A diagnosis of thrombotic thrombocytopenic purpura should be considered in patients with neurologic symptoms, hemolytic anemia, thrombocytopenia, mild renal insufficiency, and fever. Plasma cell disorders can be associated with peripheral neuropathy, and classification of the monoclonal protein type and neuropathy aid in diagnosis. Patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) syndrome can present with arterial and venous neurologic events.

ESSENTIAL POINTS

This article discusses the neurologic complications of blood cell disorders and the most recent advances in prevention and treatment.

Laboratory and Clinical Settings of Heavy/Light Chain (HLC) Assays in the Management of Monoclonal Gammopathies and Multiple Myeloma

The antibody-related immune response is mediated by immunoglobulins (Igs), soluble circulating glycoproteins produced by activated B cells that, upon the recognition of specific epitopes on pathogen surfaces, activate, proliferate, and differentiate into antibody-secreting plasma cells. Although the antibodies are effectors of the humoral immune adaptive response, their overproduction in response to a dysregulated proliferation of clonal plasma cell production in tumoral conditions (i.e., multiple myeloma), enriches the serum and urinary matrices, assuming the crucial role of biomarkers. Multiple myeloma (MM) is a plasma cell dyscrasia characterized by the expansion and accumulation of clonally activated plasma cells in bone marrow, determining the release of high amounts of monoclonal component (MC) that can be detected as intact immunoglobulin (Ig), immunoglobulin fragments, or free light chains (FLCs). The importance of detecting biomarkers for the diagnosis, monitoring, and prognosis of diseases is highlighted by the international guidelines that recommend specific assays for the analysis of intact Igs and FLC. Moreover, a developed assay called Hevylite^® allows for the quantification of immunoglobulins that are both involved (iHLC) and not involved (uHLC) in the tumor process; this is a fundamental aspect of following up the patient's workup and evaluating the progression of disease, together with the treatments response. We here summarize the major points of the complex scenario involving monoclonal gammopathies and MM clinical management in view of advantages derived for the use of Hevylite^®.