Design and Rationale of Prolonged Nightly Fasting for Multiple Myeloma Prevention (PROFAST): Protocol for a Randomized Controlled Pilot Trial

BACKGROUND

Obesity is an established, modifiable risk factor of multiple myeloma (MM); yet, no lifestyle interventions are routinely recommended for patients with overweight or obesity with MM precursor conditions. Prolonged nightly fasting is a simple, practical dietary regimen supported by research, suggesting that the synchronization of feeding-fasting timing with sleep-wake cycles favorably affects metabolic pathways implicated in MM. We describe the design and rationale of a randomized controlled pilot trial evaluating the efficacy of a regular, prolonged nighttime fasting schedule among individuals with overweight or obesity at high risk for developing MM or a related lymphoid malignancy.

OBJECTIVE

We aim to investigate the effects of 4-month prolonged nightly fasting on body composition and tumor biomarkers among individuals with overweight or obesity with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), or smoldering Waldenström macroglobulinemia (SWM).

METHODS

Individuals with MGUS, SMM, or SWM aged ≥18 years and a BMI of ≥25 kg/m2 are randomized to either a 14-hour nighttime fasting intervention or a healthy lifestyle education control group. Participants' baseline diet and lifestyle patterns are characterized through two 24-hour dietary recalls: questionnaires querying demographic, comorbidity, lifestyle, and quality-of-life information; and wrist actigraphy measurements for 7 days. Fasting intervention participants are supported through one-on-one telephone counseling by a health coach and automated SMS text messaging to support fasting goals. Primary end points of body composition, including visceral and subcutaneous fat (by dual-energy x-ray absorptiometry); bone marrow adiposity (by bone marrow histology); and tumor biomarkers, specifically M-proteins and serum free light-chain concentrations (by gel-based and serum free light-chain assays), are assessed at baseline and after the 4-month study period; changes therein from baseline are evaluated using a repeated measures mixed-effects model that accounts for the correlation between baseline and follow-up measures and is generally robust to missing data. Feasibility is assessed as participant retention (percent dropout in each arm) and percentage of days participants achieved a ≥14-hour fast.

RESULTS

The PROlonged nightly FASTing (PROFAST) study was funded in June 2022. Participant recruitment commenced in April 2023. As of July 2023, six participants consented to the study. The study is expected to be completed by April 2024, and data analysis and results are expected to be published in the first quarter of 2025.

CONCLUSIONS

PROFAST serves as an important first step in exploring the premise that prolonged nightly fasting is a strategy to control obesity and obesity-related mechanisms of myelomagenesis. In evaluating the feasibility and impact of prolonged nightly fasting on body composition, bone marrow adipose tissue, and biomarkers of tumor burden, this pilot study may generate hypotheses regarding metabolic mechanisms underlying MM development and ultimately inform clinical and public health strategies for MM prevention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05565638; http://clinicaltrials.gov/ct2/show/NCT05565638.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/51368.

Establishment of reference intervals for free light chains and immunoglobulins in Saudi population

OBJECTIVES

Testing of serum-free light chains kappa (κ) and lambda (λ), along with ratio (FLCR) is essential for the diagnosis and management of monoclonal gammopathies. Accurate clinical diagnosis depends upon appropriate local population reference intervals (RIs). This study examined the Saudi population for serum-free light chains and other immunoglobulins to establish RIs and to explore variations in the test results by using the International Federation for Clinical Chemistry and Laboratory Medicine's global protocol for harmonized implementation of RI study.

METHODS

A total of 180 healthy Saudi adults were recruited. All serum samples were assayed using the Freelite reagents from the Binding Site. The variation in reference values attributable to sex, age, BMI, and region was calculated by ANOVA as a standard deviation ratio (SDR). The RIs for the FLCR were derived by the parametric method and validated by using samples from patients with hypo- and hypergammaglobulinemia.

RESULTS

The new RIs for free κ and FLCR were shifted to a higher side from the manufacturer-adapted RIs. Based on the SDR cutoff value (>0.4), between-sex partition RIs were not required for all analytes except IgM. Validation using patients with hypo- or hypergammaglobulinemia and without multiple myeloma, was all within the new RI. BMI, smoking, and exercise were not relevant sources of variation for any analyte.

CONCLUSIONS

Locally derived RIs for free light chains and immunoglobulins analytes specific for Saudis were established after careful consideration of various factors. These RIs were more reliable than those provided as guidance by the manufacturer, or from other countries, for appropriate classification and prediction of disease progression for Saudi patients.

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.

A Complex Case of Extensive Systemic Amyloidosis With Underlying Monoclonal Gammopathy

Systemic amyloid light chain, or primary amyloidosis (AL amyloidosis), is a serious medical condition that leads to the deposition of abnormal proteins called amyloid fibrils in various organs of the body. AL amyloidosis can present with different symptoms, which can make diagnosis challenging. This case report presents a clinical scenario of a 53-year-old female patient who had come in for shortness of breath and lower extremity swelling and was found to have acute on chronic pulmonary embolism. The patient had a history of systemic amyloidosis diagnosed with a kidney and duodenal biopsy. She also had a bone marrow biopsy done and was found to have IgG monoclonal gammopathy. Throughout the hospital course, patients required cautious diuretic use given the worsening kidney function. She was given intravenous anticoagulation initially and later switched to oral medication on discharge. Due to the aggressive nature of amyloidosis, a decision was made to start the patient on chemotherapy in an outpatient setting. This case presents an interesting scenario of systemic amyloidosis with concomitant monoclonal gammopathy that was complicated by acute pulmonary embolism. The case is important as it shows the different levels of amyloidosis and teaches us the benefit of taking a multidisciplinary approach to making a concrete plan for patients with advanced amyloidosis disease.

A Case of Light Chain Deposition Disease Leading to Acute Liver Failure and Review of Literature

Light chain deposition disease (LCDD) is a monoclonal immunoglobulin deposition disease characterized by light chain deposition in soft tissues and viscera, causing systemic organ dysfunction with an underlying lymphoproliferative disorder. While the kidney is the most affected organ, cardiac and hepatic involvement is also seen with LCDD. Hepatic manifestation can range from mild hepatic injury to fulminant liver failure. Herein, we are presenting a case of an 83-year-old woman with a monoclonal gammopathy of undetermined significance (MGUS), who presented to our institution with acute liver failure progressing to circulatory shock and multiorgan failure. After an extensive workup, a diagnosis of hepatic LCDD was determined. In conjunction with the hematology and oncology department, chemotherapy options were discussed, but given her poor prognosis, the family decided to pursue a palliative route. Though establishing a prompt diagnosis is important for any acute condition, the rarity of this condition, along with paucity of data, makes timely diagnosis and treatment challenging. The available literature shows variable rates of success with chemotherapy for systemic LCDD. Despite chemotherapeutic advances, liver failure in LCDD indicates a dismal prognosis, where further clinical trials are difficult owing to the low prevalence of the condition. In our article, we will also be reviewing previous case reports on this disease.

Detection and Characterization of Paraproteinemia in Canine Chronic B-cell Lymphocytic Leukemia Using Routine and Free Light Chain Immunofixation

BACKGROUND

Hyperglobulinemia is reported in 26% of canine chronic B-cell lymphocytic leukemia (B-CLL) cases. However, few cases have been characterized by protein electrophoresis and immunofixation (IF), and the incidence of a monoclonal protein (M-protein) is unknown using these techniques.

OBJECTIVE

To characterize and determine the proportion of canine B-CLL cases with an M-protein using plasma protein electrophoresis (PPE), routine and free light chain (fLC) IF, and to assess if productive B-CLL cases express MUM1/IRF4 by cell tube block (CTB).

METHODS

PPE, routine (targeting IgG, IgA, IgM, IgG4, and light chain) and fLC IF were performed using 48 dog B-CLL plasma samples from patients diagnosed via peripheral blood flow cytometry. CTB was performed on a separate cohort of 15 patients.

RESULTS

Hyperproteinemia (>7.5 g/dL) was present in 17/48 cases (35%). An M-protein was detected in 32/48 cases (67%). Of these, 19/32 cases (59%) had only complete (monoclonal heavy and light chain) M-proteins detected, 10/32 cases (31%) had both complete and fLC M-proteins detected, and 3/32 cases (9%) had only an fLC M-protein detected. IgM was the most common clonal immunoglobulin isotype detected (23 cases). CD21⁺ cell counts were higher in cases with detectable M-protein. Plasma fLC IF suggested β-γ region interference, likely caused by clotting proteins. All B-CLL cases consistently expressed PAX5 and did not express MUM1/IRF4.

CONCLUSIONS

Most B-CLL cases had an M-protein and were not hyperproteinemic. Most cases with paraproteins had a complete IgM monoclonal gammopathy; a subset had documented fLCs. The prognostic significance of heavy and fLC presence should be evaluated.

Differential Progression of Lymphoma in Two Captive Steller's Eiders (Polysticta stelleri)

This report details 2 different presentations of lymphoma in captive Steller's eiders (Polysticta stelleri). A female Steller's eider, at least 10 years old, developed lameness and lethargy. A complete blood cell count (CBC) revealed a severely elevated total white blood cell (WBC) count with a lymphocytosis. A subsequent liver biopsy confirmed a diagnosis of lymphoma and lymphocytic leukemia. The female Steller's eider was euthanatized 11 days after presentation. On necropsy, neoplastic lymphoid infiltrates were present in multiple tissues, primarily in the skin and subcutis. The results of a CBC from an apparently healthy male Steller's eider, at least 14 years old, also indicated this bird had an increased WBC count with a lymphocytosis. Serum submitted for protein electrophoresis indicated that this bird had a monoclonal gammopathy. Lymphocytes isolated from the male Steller's eider had low levels of proliferation in response to mitogens. The bird survived nearly 2 years without treatment, and the WBC count continued to increase during this time. The male Steller's eider maintained good body condition and exhibited normal behavior throughout the course of the disease until a sudden decline just prior to death. Lymphoma was diagnosed based on histopathology results. Infiltrates of atypical lymphocytes were observed in the bone marrow, proventriculus, ventriculus, heart, and eyes.

Chemotherapy-based approach is the preferred treatment for sporadic late-onset nemaline myopathy with a monoclonal protein

Sporadic late-onset nemaline myopathy (SLONM) associated with monoclonal protein (MP) is a rare disease with an aggressive, and often fatal course. Whether SLONM + MP represents a malignancy or dysimmune disease remains unclear. Currently, two main approaches are used to treat SLONM + MP: nonchemotherapy-based treatment (immunosuppression, intravenous immunoglobulins, plasmapheresis and plasma exchange) or chemotherapy with or without autologous stem cell transplantation. Due to the rare occurrence of the disease, the best treatment modality is unknown. We analyzed treatment and outcomes in a large cohort of 53 patients with SLONM + MP: four our own patients and 49 cases from published literature. Neurological improvement in the nonchemotherapy group (N = 25) was observed in 52% of patients: 8% reached marked improvement, 8% moderate response, 36% mild response; none reached complete remission (CR). In the chemotherapy group (N = 28), neurological improvement was seen in 86% of patients: 46% reached CR, 25% marked response, 11% moderate response and 4% mild response. The best neurological improvement correlated with deep hematological remission. Mean time to best response in the chemotherapy group was 8 months versus 21 months in the nonchemotherapy group (P < .001). Overall survival was higher in patients in the chemotherapy group. A chemotherapy approach should be the preferred treatment for patients with SLOMN + MP with the goal to reach complete hematologic remission. Based on the clinical, morphological peculiarities, aggressive disease course and superior clinical benefits of chemotherapy over nonchemotherapy, SLONM + MP should be considered as a hematological malignancy with the presence of MP of clinical rather than undetermined significance.

Monoclonal Gammopathy of Renal Significance-A Rare Renal Presentation: A Review of Cases Reported

Monoclonal gammopathy of undetermined significance is a precursor to multiple myeloma characterized by monoclonal gammopathy without evidence of end organ damage. Some patients with clonal plasma cell disorder that do not meet the requirements for multiple myeloma have been seen to develop pathologic renal disease due to direct effects from deposition of monoclonal protein, referred to as monoclonal gammopathy of renal significance. In this article, we present a rare renal manifestation of monoclonal gammopathy of renal significance as focal segmental glomerulosclerosis.

Detection of monoclonal protein by capillary zone electrophoresis can be challenged by iodinated contrast agent interference: a case report

The detection of monoclonal immunoglobulins is a key element in the diagnosis of monoclonal gammopathy. In clinical practice, screening and measurement of monoclonal proteins are commonly performed using capillary zone electrophoresis (CZE). Some exogenous substances, such as iodinated contrast agents, absorb incident UV light at the same wavelengths as the peptide bonds and may therefore interfere with the detection of proteins in CZE. We herein use the description of a case to illustrate that iodinated contrast agents can mask the presence of monoclonal immunoglobulins in CZE and we discuss the strategy needed to confirm this interference. Performing immunofixation, immunosubtraction, or a second CZE at a distance from the first blood sample is not only necessary to confirm the presence of an iodinated contrast media interference but also to ensure the absence of monoclonal proteins.

Cutaneous Plasmacytosis Associated with Ehrlichiosis in an African-American Patient

Cutaneous plasmacytosis is a rare disease that presents clinically with multiple red-brown papules and plaques with minimal to no epidermal change. Histopathologic findings include a perivascular dermal infiltration of polyclonal plasma cells. The etiology of cutaneous plasmacytosis is unknown, but hypothesized to be due to persistent or repeated antigenic stimulation. Ehrlichia represents a family of obligate intracellular bacteria that have been associated with the development of plasma cell dyscrasias in the veterinary literature. We present a case of a 67-year-old male patient with the development of progressively worsening cutaneous plasmacytosis following prolonged hospitalization secondary to ehrlichiosis sepsis. The patient initially presented with isolated cutaneous involvement and normal laboratory findings that eventually progressed to include multiple laboratory abnormalities, including anemia, hyperproteinemia, and elevated serum creatinine. Further diagnostic workup was declined by the patient despite evidence of progression to systemic plasmacytosis or multiple myeloma.

Light chain myeloma and detection of free light chains in serum and urine of dogs and cats

Background

Detection of free light chains (fLC) in animals relies on protein electrophoresis or the Bence‐Jones protein test on urine.

Objective

To describe the detection of both serum fLC (sfLC) and urine fLC (ufLC) in 8 dogs and 2 cats using a commercially available human immunofixation (IF) kit.

Animals

Archived serum or urine samples from 27 dogs and 2 cats submitted to the Colorado State University Veterinary Diagnostic Laboratory for routine diagnostics.

Methods

Retrospective study evaluating the presence of fLC in dogs and cats using agarose gel electrophoresis and routine and fLC IF performed on serum and urine. The performance of the fLC IF reagents was evaluated using samples characterized by routine IF, tandem mass spectrometry, and a combination of fLC IF and western blotting. Free light chains were documented by paired electrophoresis and fLC IF.

Results

The fLC only myeloma case developed end‐stage renal failure 5 months post initial diagnosis. All electrophoresis‐defined urinary Bence‐Jones proteins were labeled by the anti‐free λ light chain (anti‐fλ) reagent; none were labeled by the anti‐free κ light chain (anti‐fκ); 2 of these were identified as fκ by mass spectrometry. An electrophoretically identical protein restriction that was labeled by the anti‐fλ reagent was present in the paired serum from 5/8 of cases, documenting sfLC.

Conclusions and Clinical Importance

Commercially available human IF reagents identified sfLC and ufLC in both dogs and cats. Free light chains may be nephrotoxic in dogs.

Outcomes of screening for gammopathies in children and adults with Gaucher disease type 1 in a cohort from Brazil and the United States

Multiple myeloma is the most common hematological malignancy in Gaucher disease type 1 (GD1). There is a lack of outcome data and consensus regarding screening of gammopathies. This study explores utility of screening in Porto Alegre, Brazil, and Cincinnati, Ohio. A retrospective analysis of clinical information and laboratory data from GD1 patients was performed. Over 19 years, 68 individuals with GD1 (31 males, 37 females) underwent screening, and 20 (29.4%) had abnormalities. Twelve (17.6%) had polyclonal gammopathy (mean age 24.2 years, p = .02), seven (10%) had monoclonal gammopathy of uncertain significance (MGUS; mean age 52.7 years, p = .009). One had multiple myeloma (age 61 years). Risk factors for MGUS included male gender (p = .05), p.N409S allele (p = .032). MGUS developed in six of 62 treated and two of four untreated individuals. Of those with MGUS receiving treatment, four were on enzyme replacement therapy (ERT) and one on substrate reduction therapy (SRT). Gammopathy normalized in 13 treated individuals (10 polyclonal, three MGUS) and remained abnormal in two treated individuals (two polyclonal, two MGUS). Gammopathy relapse was seen in one individual with MGUS and three with polyclonal gammopathy. This study describes screening for gammopathies and identifies risk factors in individuals with GD1.

Marginal zone lymphoma in a dog

A 13-year-old spayed female American Cocker Spaniel was presented for evaluation of a cough and weight loss. Physical exam revealed generalized lymphadenopathy. The patient was diagnosed with marginal zone lymphoma (MZL) on histopathology of an extirpated lymph node. This report demonstrates an unusual case of a pleomorphic neoplastic population documented on cytologic evaluation that had moncytoid features and peripheral blood involvement; a previously undocumented IgG1 monoclonal gammopathy was also an interesting feature of this canine MZL. The patient did not undergo chemotherapy for lymphoma and was euthanized over 4 years after the initial presentation.

Antibody- and macrophage-mediated segmental demyelination in chronic inflammatory demyelinating polyneuropathy: clinical, electrophysiological, immunological and pathological correlates

BACKGROUND AND PURPOSE

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a heterogeneous autoimmune disorder critically lacking diagnostic biomarkers. Autoantibodies to nodal and paranodal components have recently been described in a small subset of patients. Here, the diagnostic value of immune reactivity toward the myelin compartment was investigated.

METHODS

Ninety-four French CIDP patients were retrospectively studied. The reactivity toward the peripheral nerve was investigated. Sural nerve biopsies were examined by electron microscopy and immunofluorescence.

RESULTS

Twenty-one patients (22%) and three patients (3%) presented with a strong immunoglobulin G or immunoglobulin M reactivity respectively against the myelin compartment. The clinical, electrophysiological and morphological features were examined in nine of these patients for whom sural nerve biopsies were available. Seven patients were electrodiagnosed with definite CIDP, one with possible CIDP and one was unclassifiable but sural nerve biopsy argued for CIDP diagnosis. Electron microscopy of sural nerve biopsies demonstrated the presence of macrophage-mediated demyelination restricted to the internode in all nine patients. Immunolabelling for voltage-gated sodium channels, myelin and axonal markers confirmed the presence of segmental demyelination and of remyelination. The nodal and paranodal regions, however, were unaffected in these patients. Nerve conduction studies corroborated the multifocal and segmental profile, and seven patients showed increased duration of proximal (1.5-5.1 times) and/or distal (1.2-3.4 times) compound muscle action potential in at least two nerves.

CONCLUSION

Antibody- and macrophage-mediated demyelination appears responsible for conduction alterations in CIDP patients and nerve immunostaining assays may serve as a supportive diagnostic biomarker.

Pyoderma gangrenosum in hematologic malignancies: A systematic review

BACKGROUND

Pyoderma gangrenosum (PG) is a devastating neutrophilic dermatosis that may be associated with trauma or systemic diseases. The associations, characteristics, and temporal relationship of PG with hematologic malignancies are not well understood.

OBJECTIVE

We performed a systematic review of PG associated with hematologic malignancies using data from case reports, case series, and retrospective studies.

METHODS

We searched MEDLINE, EMBASE, Scopus, and Web of Science from each database's inception to December 12, 2018. Two reviewers independently selected studies and extracted data.

RESULTS

Two hundred seventy-nine publications met the inclusion criteria (340 cases). Myelodysplastic syndrome (MDS) was the most commonly reported hematologic malignancy associated with PG, followed by monoclonal gammopathy of undetermined significance and acute myeloid leukemia. The mean age of patients was 56.5 years, with males being more common. There was a predominance of the ulcerative PG subtype and multifocal distributions across all hematologic malignancies. The majority of MDS cases preceded PG, which was reversed for MGUS.

LIMITATIONS

The data were limited by reporting bias because PG subtypes rely on the rendered diagnosis reported. In addition, the classification for hematologic malignancies has evolved since 1978.

CONCLUSION

Patients with PG should be evaluated for hematologic malignancies, with MDS being the most common.

Immunoglobulin Heavy Chain Gene Rearrangements in Patients with Gaucher Disease

BACKGROUND

Several studies support the evidence of increased incidence of hematological complications in Gaucher disease including monoclonal and polyclonal gammopathies and blood malignancies, especially multiple myeloma.

METHODS

Serum concentrations of immunoglobulins and PCR analysis of the IGH gene rearrangements were performed. The clonal PCR products were directly sequenced and analyzed with the appropriate database and tools. Serum monoclonal proteins were detected and identified by electrophoresis.

RESULTS

Among 27 Gaucher patients, clonal IGH rearrangement was discovered in eight, with 5/8 having also serum monoclonal protein. Elevated immunoglobulins were detected in 9/27 patients. Follow-up data for 17 patients showed that the clonal rearrangement remained the same in four of them, however, in one patient it disappeared after the follow-up period. The remaining 12/17 patients were without previous IGH clonal rearrangement and remained so after the follow-up.

CONCLUSIONS

Although clonal expansion may occur relatively early in the disease course, at least judging by the IGH gene rearrangements in Gaucher patients, the detected clones may be transient. A careful clinical follow-up in these patients is mandatory, including monitoring for lymphoid neoplasms, especially multiple myeloma.

IgG,kappa monoclonal gammopathy of unknown significance with AL amyloidosis simulating giant cell arteritis

Monoclonal gammopathies complicated by AL amyloidosis can mimic giant cell arteritis (GCA). We hereby present the case of a 63 year old woman in whom symptoms consistent with GCA were the first manifestations of a monoclonal gammopathy of unknown significance (MGUS) associated with amyloidosis. A 63 year old woman was admitted for temporal headache, maseterine claudication, neck and shoulder stiffness. She was recently diagnosed with carpal tunnel syndrome. On physical examination she had prominent temporal arteries, macroglosia and orthostatic hypotension. Muscular strength was normal. She had high ESR and CRP; in this clinical context, GCA was suspected. A gamma spike on serum protein electrophoresis raised the suspicion of monoclonal gammopathy (MG). Immunoelectrophoresis revealed monoclonal bands for IgG and kappa chains. Massive deposits of amyloid and no inflammation were found on temporal artery biopsy. Multiple myeloma and lymphoma were ruled out. A diagnosis of AL amyloidosis complicating MGUS was formulated. She did well on therapy with bortezomib, cyclophosphamide and dexamethasone. Cases published in medical literature reveal amyloidosis mimicking GCA in the setting of established MGUS. As far as we know, this is the first case of MGUS with IgG and kappa chains in which a GCA-like picture induced by amyloidosis was present from the very onset.

Lysosomal Storage Disorders and Malignancy

Lysosomal storage disorders (LSDs) are infrequent to rare conditions caused by mutations that lead to a disruption in the usual sequential degradation of macromolecules or their transit within the cell. Gaucher disease (GD), a lipidosis, is among the most common LSD, with an estimated incidence of 1 in 40,000 among the Caucasian, non-Jewish population. Studies have indicated an increased frequency of polyclonal and monoclonal gammopathy among patients with GD. It has been shown that two major sphingolipids that accumulate in GD, namely, β-glucosylceramide 22:0 (βGL1-22) and glucosylsphingosine (LGL1), can be recognized by a distinct subset of CD1d-restricted human and murine type II natural killer T (NKT) cells. Investigations undertaken in an affected mouse model revealed βGL1-22- and LGL1-specific NKT cells were present and constitutively promoted the expression of a T-follicular helper (TFH) phenotype; injection of these lipids led to downstream induction of germinal center B cells, hypergammaglobulinemia, and the production of antilipid antibodies. Subsequent studies have found clonal immunoglobulin in 33% of sporadic human monoclonal gammopathies is also specific for the lysolipids LGL1 and lysophosphatidylcholine (LPC). Furthermore, substrate reduction ameliorated GD-associated gammopathy in mice. It had been hypothesized that chronic antigenic stimulation by the abnormal lipid storage and associated immune dysregulation may be the underlying mechanism for the increased incidence of monoclonal and polyclonal gammopathies, as well as an increased incidence of multiple myeloma in patients with GD. Current observations support this proposition and illustrate the value of investigations into rare diseases, which as 'experiments of nature' may provide insights into conditions found in the general population that continue to remain incompletely understood.

B cell lymphoma and myeloma in murine Gaucher's disease

Multiple myeloma and B cell lymphoma are leading causes of death in Gaucher's disease but the nature of the stimulus driving the often noted clonal expansion of immunoglobulin-secreting B cells and cognate lymphoid malignancy is unknown. We investigated the long-term development of B cell malignancies in an authentic model of non-neuronopathic Gaucher's disease in mice: selective deficiency of β-glucocerebrosidase in haematopoietic cells [Gba(tm1Karl/tm1Karl)Tg(Mx1-cre)1Cgn/0, with excision of exons 9-11 of the murine GBA1 gene, is induced by poly[I:C]. Mice with Gaucher's disease showed visceral storage of β-glucosylceramide and greatly elevated plasma β-glucosylsphingosine [median 57.9 (range 19.8-159) nm; n = 39] compared with control mice from the same strain [median 0.56 (range 0.04-1.38) nm; n = 29] (p < 0.0001). Sporadic fatal B cell lymphomas developed in 11 of 21 GD mice (6-24 months) but only two of eight control animals developed tumours by age 24 months. Unexpectedly, most mice with overt lymphoma had absent or few Gaucher cells but local inflammatory macrophages were present. Eleven of 39 of Gaucher mice developed monoclonal gammopathy, but in the control group only one animal of 25 had clonal immunoglobulin abnormalities. Seven of 10 of the B cell lymphomas were found to secrete a monoclonal paraprotein and the lymphomas stained intensely for pan-B cell markers; reactive T lymphocytes were also present in tumour tissue. In the Gaucher mouse strain, it was notable that, as in patients with this disease, CD138(+) plasma cells frequently surrounded splenic macrophages engorged with glycosphingolipid. Our strain of mice, with inducible deficiency of β-glucocerebrosidase in haematopoietic cells and a high frequency of sporadic lethal B cell malignancies, faithfully recapitulates human Gaucher's disease: it serves as a tractable model to investigate the putative role of bioactive sphingolipids in the control of B cell proliferation and the pathogenesis of myelomatosis-the most prevalent human cancer associated with this disorder.

Inflammatory demyelinating neuropathies and neuropathies associated with monoclonal gammopathies: treatment update

This review focuses on recent data regarding inflammatory demyelinating neuropathies and neuropathies associated with monoclonal gammopathies. We describe both acute and chronic inflammatory neuropathies, and we discuss conditions ranging from mostly cell-mediated to antibody-mediated disorders. These diseases are characterized by proximal and distal sensory motor involvement. Treatments are based on immune-modulation and/or immune-suppression. Work-up sequence and therapeutical modes are discussed in the light of recently published data, with a special interest on new treatment modalities.

Harnessing host immune responses to preneoplasia: promise and challenges

Preneoplastic lesions are more common than clinical cancer and define a population at increased risk for the development of malignancy. Recent studies suggest that the immune system has the capacity to recognize these lesions, and enrichment of preneoplasia-specific immune effectors can be detected in the tumor bed of some preneoplastic lesions such as monoclonal gammopathies. Here, I discuss the promise and challenges of harnessing the immune response against preneoplasia. Approaches to boost the natural host response to these lesions may have a major impact on reducing net cancer burden.

Amino-terminal identity of co-existent amyloid and non-amyloid immunoglobulin kappa light chain deposits. A human disease to study alterations of protein conformation

Tissue deposition of monoclonal immunoglobulin light chains is a serious complication in some patients with B cell proliferative disorders. The deposits are typically fibrillar and Congophilic in amyloid (AL) and non-fibrillar and Congophobic in light chain deposition disease (LCDD), and rarely coexist in the same patient. From post-mortem tissue of an individual with fibrillar and non-fibrillar kappa light chain deposits in different sites, we separately extracted and analysed biochemically and immunochemically the non-amyloid deposits from isolated glomeruli, the amyloid from isolated renal arteries and the amyloid from myocardium in which the only deposits were amyloid restricted to mural arteries. Western blotting analysis of both the extracted amyloid and the non-amyloid deposits demonstrated 25-kD bands immunoreactive with anti-kappa antibody, and the identity of the N-terminal amino acid sequences that belong to the variable region kappaIV light chain subgroup. This is the first human disease in which antigenically similar but morphologically different deposits have been separately biochemically analysed. We propose that combined LCDD and AL is an ideal human disease to study the relationships and the factors that influence the conversion of non-amyloidogenic to amyloidogenic conformations.