Long-term follow-up of IgM monoclonal gammopathy of undetermined significance

Little effort has been made to quantitate adverse outcomes of monoclonal gammopathy of undetermined significance (MGUS) of the immunoglobulin M (IgM) class, which progresses to lymphoma or Waldenstr?m macroglobulinemia, whereas IgA and IgG MGUS progress to multiple myeloma, primary amyloidosis (AL), or a related plasma cell disorder. From 1960 to 1994, IgM MGUS was diagnosed in 213 patients in southeastern Minnesota. The end point was progression to lymphoma or a related disorder, as assessed with the Kaplan-Meier method. The 213 patients were followed up for 1567 person-years (median, 6.3 years per patient). Lymphoma developed in 17 patients (relative risk [RR], 14.8), Waldenstr?m macroglobulinemia in 6 (RR, 262), primary amyloidosis in 3 (RR, 16.3), and chronic lymphocytic leukemia in 3 (RR, 5.7). The relative risk of progression was 16-fold higher in the patients with IgM MGUS than in the white population of the Iowa Surveillance, Epidemiology, and End Results Program. Cumulative incidence of progression was 10% at 5 years, 18% at 10 years, and 24% at 15 years. On multivariate analysis, the serum monoclonal protein and serum albumin concentrations at diagnosis were the only risk factors for progression to lymphoma or a related disorder. Risk for progression to lymphoma or a related disorder at 10 years after the diagnosis of MGUS was 14% with an initial monoclonal protein concentration of 0.5 g/dL or less, 26% with 1.5 g/dL, 34% for 2.0 g/dL, and 41% for more than 2.5 g/dL.     

Acquired Fanconi syndrome is an indolent disorder in the absence of overt multiple myeloma

Adult-acquired Fanconi syndrome (FS) is a rare complication of monoclonal gammopathy. We retrospectively reviewed 32 patients diagnosed with adult-acquired FS between April 1968 and June 2002 at Mayo Clinic (Rochester, MN). At diagnosis, most patients had monoclonal gammopathy of undetermined significance (MGUS) or smoldering multiple myeloma (SMM), with a median creatinine level of 176.8 microM (2.0 mg/dL; range, 79.56-327.08 microM [0.9-3.7 mg/dL]) and evidence of osteomalacia. During the average 65 months (range, 2-238 months) of follow-up, 5 patients developed end-stage renal disease (ESRD) and only 1 of 14 patients with MGUS transformed to multiple myeloma (MM). Also, 14 deaths occurred, with only 1 from ESRD but 4 from alkylator-related leukemia or myelodysplastic syndrome. Chemotherapy offered little benefit on renal functions of MGUS or SMM patients. In conclusion, FS associated with monoclonal gammopathy does not appear to confer an additional risk of subsequent evolution to MM. ESRD occurs late in the disease process.     

Monoclonal gammopathies of undetermined significance

The monoclonal gammopathies include multiple myeloma (MM), monoclonal gammopathy of undetermined significance (MGUS), primary systemic amyloidosis (AL), and Waldenstr?m's macroglobulinemia (WM). At Mayo Clinic, almost 60% of patients with a monoclonal gammopathy have MGUS. MGUS is characterized by the presence of a serum monoclonal protein value <3 g/dL, fewer than 10% plasma cells in the bone marrow, no or a small amount of monoclonal protein in the urine, and absence of lytic bone lesions, anemia, hypercalcemia, or renal insufficiency related to the plasma-cell proliferative process. During long-term follow-up of 241 patients with MGUS seen at Mayo Clinic from 1956 to 1970, MM, WM, AL, or a related disorder developed in 64. To confirm the findings, we conducted a population-based study on MGUS in the 11 counties of southeastern Minnesota from 1960 to 1994. The risk of progression to a malignant plasma-cell disorder was 1% per year.     

Role of different hematologic variables in defining the risk of malignant transformation in monoclonal gammopathy

The presenting clinico-hematologic features of 386 patients with nonmyelomatous monoclonal gammopathy (MG) were correlated with the frequency of malignant transformation to evaluate the most important variables conditioning its evolution into multiple myeloma (MM) or Waldenstrom macroglobulinemia (WM). Most of the patients (335) had monoclonal gammopathy of undetermined significance (MGUS: 39 IgA, 242 IgG, 54 IgM): the remaining 51 patients (12 IgA, 39 IgG) fulfilled all of the MGUS diagnostic criteria (according to Durie) except that bone marrow plasma cell (BMPC) content was 10% to 30%, and so they were defined as having monoclonal gammopathy of borderline significance (MGBS). There were no significant differences between the MGUS and MGBS groups in terms of age, sex, or median follow-up. After a median follow- up of 70 and 53 months, respectively, 23 of 335 MGUS and 19 of 51 MGBS patients had undergone a malignant evolution. Univariate analysis of the IgA and IgG patients showed that the cumulative probability of the disease evolving into MM correlated with diagnostic definition (MGBS v MGUS), BMPC content (> or = 10% v < 5% and < or = 5% v > 5%) and reduced serum polyclonal Ig. In the IgG cases, there was also a significant correlation with detectable Bence Jones proteinuria, serum monoclonal component (MC) levels and age at diagnosis (> 70 v < = or 55 years). In the IgG cases as a whole, the same variables remained in the Cox model where the BMPC percentage was considered after natural logarithmic transformation and the monoclonal component as g/dL value. The relative risks of developing MM are the following: 2.4 for each 1 g/dL increase of IgG, serum MC, 3.5 for detectable light chain proteinuria, 4.4 for the increase of 1 unit in log. BMPC percentage, 6.1 for age > 70, 3.6 and 13.1 for a reduction in one or two polyclonal Ig. In conclusion, our study allows the identification of a particular subset of MGUS patients (MC < = or 1.5 g/dL, BMPC < 5%, no reduction in polyclonal Ig and no detectable light chain proteinuria) at very low- risk of evolution, who can be considered as having benign monoclonal gammopathies. We also describe a previously undefined group of MG patients (with monoclonal gammopathy of borderline significance) who are at high-risk of malignant evolution. These findings could have a considerable impact on the cost/benefit ratio of monitoring programs in these patients.     

Differentiation of monoclonal gammopathy of undetermined significance and multiple myeloma using flow cytometric characteristics of plasma cells

BACKGROUND AND OBJECTIVES: The differential diagnosis between multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) may be uncertain in some cases; this problem is reflected by discrepancies between different classification systems with an accordance in only 2/3 of cases. We studied whether flow-cytometric characteristics of plasma cells (PC) can be used for the differentiation between MGUS and MM. DESIGN AND METHODS: Patients were divided into 3 groups: Group A included 13 myeloma patients with a plasma cell infiltration of the bone marrow of 10-30%, serum M-protein < or = 3.5 g/dL (IgG) or < or = 2 g/dl (IgA) and without bone lesions in conventional radiography. Group B consisted of 53 patients who fulfilled the Durie and Salmon diagnostic criteria including at least one major criterion, and group C individuals with MGUS (n=17). The ratio of immunophenotypically normal (i.e. CD19(+)/CD56(-)) to all bone marrow plasma cells (BMPC), the number of peripheral blood PC (PBPC), the percentage of BMPC in S-phase and the DNA content of BMPC were analyzed. RESULTS: All individuals with MGUS and no patient with MM in group A or group B had a ratio of phenotypically normal to all BMPC > or = 20%. The median of monoclonal PBPC was 0/microL (range 0-2/ microL) in MGUS, 1/microL (range 0-30/microL) in MM group A and 2.4/microL (range 0-211/microL) in MM group B. The median percentage of BMPC in S-phase was 1.6% both in MGUS and in group A and 3% in group B. Aneuploidy was found in 12%, 11% and 41% in MGUS, group A and group B, respectively. INTERPRETATION AND CONCLUSIONS: The ratio of immunophenotypically normal to all BMPC was the only flow-cytometric parameter for the differentiation of MGUS and MM group A (p<0.0005). The other parameters were significantly different between MGUS and MM group B, but not group A.     

Severe Anemia Due to Cold Agglutinin Syndrome in a COVID-19 Patient with IgM Monoclonal Gammopathy of Undetermined Significance Successfully Treated with Corticosteroids

Secondary cold agglutinin syndrome (CAS) is autoimmune hemolytic anemia secondary to infections and lymphoid disorder. We here report the first Asian case of CAS secondary to novel coronavirus disease 2019 (COVID-19). A 72-year-old Japanese woman presented with a 2-week history of dyspnea and cough, and laboratory data revealed severe hemolytic anemia with a hemoglobin level of 4.7 g/dL. She was diagnosed with COVID-19, CAS, and monoclonal gammopathy of undetermined significance (MGUS). The anemia responded to corticosteroids administered for COVID-19 and required maintenance therapy. Although corticosteroids are not a standard therapy for CAS, they might be effective for CAS secondary to COVID-19 complicated with MGUS.     

Risk of acute myeloid leukemia and myelodysplastic syndromes after multiple myeloma and its precursor disease (MGUS)

Using population-based data from Sweden, we identified all multiple myeloma (MM) patients (n = 8740) and 5652 monoclonal gammopathy of undetermined significance (MGUS) patients diagnosed between 1986 and 2005. We calculated standardized incidence rates (SIRs) for all subsequent hematologic and nonhematologic malignancies for MM patients diagnosed before/after 1995 (introduction of high-dose melphalan/autologous stem cell transplantation [HDM-ASCT]) and 2000 (introduction of immunomodulatory drugs [IMiDs]), respectively. MM patients had an 11.51-fold (95% confidence interval: 8.19-15.74) increased risk of acute myeloid leukemia (AML)/myelodysplastic syndromes (MDS); risk was very similar before/after 1995 and 2000, respectively. MGUS patients had an 8.01-fold (5.40-11.43) increased risk of AML/MDS. Risk was confined to IgG/IgA, while no IgM MGUS patients developed AML/MDS; patients with monoclonal-protein (M-protein) concentrations > 1.5 g/dL (SIR = 11.12; 3.61-25.96) had higher risk than those < 1.5 g/dL (SIR = 4.67; 1.71-10.16). An excess risk of nonmelanoma skin cancer was observed subsequent to both MM (SIR = 2.22; 1.74-2.80) and MGUS (SIR = 3.30; 2.76-3.90). Our novel observations of an excess risk for AML/MDS following IgG/IgA (but not IgM) MGUS, and the highest risk associated with M-protein concentrations > 1.5 g/dL, support a role for nontreatment-related factors in plasma cell dyscrasias. AML/MDS risk following MM was the same before/after the introduction of HDM-ASCT. Longer follow-up is needed to characterize second tumor risks in the IMiD era.     

Primary sclerosing cholangitis complicating plasma cell dyscrasia (PCD): remission of PCD following liver transplant

We report the first case of primary sclerosing cholangitis (PSC) complicated with plasma cell dyscrasia (PCD) in which liver transplant resulted in unexpected therapeutic benefit of PCD. A 61-year-old man with 12 yr history of PSC presented with a monoclonal gammopathy of undetermined significance (MGUS) with an IgG level of 3400 mg/dL. It was stable initially for 3 yr but progressed to features consistent with multiple myeloma (MM): IgG rose to 5290 mg/dL along with development of terminal stage of liver failure. Liver transplant was performed in desperation. Unexpectedly, MM underwent clinical remission following transplant. At 3 and 14 months following transplant, IgG stayed below 2080 mg/dL and he was able to return to full-time employment. This case may suggest that chronic antigenic stimulation from cirrhotic liver contributed to MGUS and subsequent transformation to MM. Liver transplant eliminated chronic antigenic stimulation, apparently leading to remission of MM. Since PCD is often associated with other chronic liver diseases, similar benefit may accrue to a range of patients with chronic liver diseases complicating PCD.     

Incidental finding of monoclonal gammopathy in blood donors: a follow-up study

Background.The incidental finding of monoclonal immunoglobulin in the sera of healthy blood donors is a relatively frequent event and in such cases the subjects are commonly deferred permanently from donating blood. However, no follow-up studies of these cases have been published so far.Results.Out of 8,197 regular blood donors, monoclonal gammopathy was detected in 104 subjects (1.3%). The median age at detection was 53 years, the median monoclonal protein concentration was 0.2 g/dL and the cumulative follow-up of these cases amounted to 763 person/years. In two cases asymptomatic multiple myeloma was diagnosed within 6 months of detection of the gammopathy and in 14 cases, the monoclonal gammopathy was transient. The remaining 88 cases were classified as having monoclonal gammopathy of undetermined significance (MGUS). Out of these, two events related to monoclonal gammopathy were observed during the follow up: one lymphoma and one light chain deposition nephropathy.Discussion.According to current prognostic staging systems, the majority of blood donors with monoclonal gammopathy were classified as having low-risk MGUS and had a very low incidence of lymphoproliferative diseases. Permanent deferral of blood donors with stable MGUS causes about a 1% loss of potential blood donations and it represents a “precautionary measure” that needs to be substantiated and validated.     

High prevalence of polyclonal hypergamma-globulinemia in adult males in Ghana, Africa

Chronic antigenic stimulation is associated with hypergamma-globulinemia. Higher rates of hypergamma-globulinemia in tropical populations are maintained even with migration to temperate regions. We conducted a population-based screening study to assess the prevalence and risk factors for hypergamma-globulinemia in Ghana, Africa. 917 Ghanaian males (50-74 years) underwent in-person interviews and health examinations. Serum from all persons was analyzed by electrophoresis performed on agarose gel; serum with a discrete/localized band was subjected to immunofixation. 54 persons with monoclonal proteins were excluded and 17 samples were insufficient for analysis. Using logistic regression and Chi-square statistics we analyzed patterns of hypergamma-globulinemia. Among 846 study subjects, the median γ-globulin level was 1.86 g/dL. On the basis of a U.S. reference, 616 (73%) had hypergamma-globulinemia (>1.6 g/dL) and 178 (21%) had γ-globulin levels >2.17 gm/dl. On multivariate analyses, lower education status (P = 0.0013) and never smoking (P = 0.038) were associated with increased γ-globulin levels. Self-reported history of syphilis was associated with hypergamma-globulinemia. We conclude that three quarters of this population-based adult Ghanaian male sample had hypergamma-globulinemia with γ-globulin levels >1.6 g/dL. Future studies are needed to uncover genetic and environmental underpinnings of our finding, and to define the relationship between hypergamma-globulinemia, monoclonal gammopathy of undetermined significance (MGUS), and multiple myeloma.     

Lower bone mineral density in geriatric patients with monoclonal gammopathy of undetermined significance

The aim of this study was to investigate the prevalence of monoclonal gammopathy of undetermined significance (MGUS) in a geriatric population in Turkey and compare bone mineral densities and related laboratory parameters of MGUS patients with those who do not have MGUS. Among 1,012 patients enrolled, monoclonal band was detected in serum samples of 22 patients (2.17%), most of which were IgG type. Further tests revealed multiple myeloma and lung carcinoma in two patients. The remaining 20 patients were diagnosed with MGUS (1.97%). The clinical and laboratory parameters of patients with and without MGUS were mostly comparable; however, bone mineral density measurements of patients with MGUS were significantly lower than those without MGUS (p = 0.007). We suggest evaluation of geriatric patients with MGUS for the presence of osteopenia/osteoporosis considering the high frequency observed in this study.     

High serum transferrin receptor level in anemia of chronic disorders indicates coexistent iron deficiency

Blood transferrin receptor (TR) level is largely determined by the quantum of erythropoiesis and by intracellular iron content of the cells of the erythroid lineage. Hence, a high serum TR level has been found to be useful in distinguishing iron deficiency anemia (IDA) from anemia of chronic disorders (ACD). In order to examine its potential role in the diagnosis of concomitant iron deficiency in ACD, we determined serum TR levels in 130 cases of ACD, in 25 cases of IDA, and in 40 normal adults. As expected, all patients of IDA had significantly higher serum TR levels compared to the normal subjects (4.2-19.2 microg/dL vs. 1.3-3.0 microg/dL) (P < 0.002). In 11/25 cases of IDA, the total iron-binding capacity (TIBC) was in the normal range although bone marrow iron store was absent and serum TR levels were high, thereby highlighting the superiority of TR level in the diagnosis of iron deficiency compared to TIBC. Although 54% (70/130) patients of ACD had normal or low serum TR levels (0.9-3.0 microg/dL) as expected, in 46% (60/130) of ACD patients, serum TR levels were high (3.2-11.0 microg/dL). Mean corpuscular volume, red cell distribution width, and transferrin saturation were significantly lower (P < 0.001) in the latter group of patients compared to the former, and these parameters resembled those in IDA patients. Also, serum iron was lower and TIBC was higher in this group of ACD patients compared to those with normal or low serum TR. All these features point to an "IDA-like" profile of ACD patients with high TR and support the possibility of co-existent iron deficiency in this subgroup of ACD patients. In light of these observations it would be prudent to treat ACD patients with high serum TR levels with iron replacement therapy.     

Monoclonal gammopathy of undetermined significance (MGUS) in patients with solid tumors: effects of chemotherapy on the monoclonal protein

The aim of this study was to assess the effect of systemic chemotherapy on the monoclonal protein levels of patients with solid tumors who also have a monoclonal gammopathy of undetermined significance (MGUS). All patients with solid tumors who were referred to our department for consideration of systemic chemotherapy were evaluated with serum protein electrophoresis (SPEP) for the presence of MGUS. When MGUS was confirmed with immunofixation, serial SPEP was performed during and after completion of chemotherapy. Over a 6-year period, 21 patients with solid tumors and MGUS were prospectively identified and assessed. At least 50% reduction of serum monoclonal protein was noted in 4 of 11 patients treated with paclitaxel or docetaxel with a platinum analogue and in 5 of 7 patients who received an irinotecan-containing regimen. Our data indicate that in MGUS patients treated with irinotecan-containing chemotherapy regimens, a high incidence of reduction in their monoclonal protein levels is observed. Since topotecan, another topoisomerase I inhibitor, has some activity in multiple myeloma, further evaluation of irinotecan may be warranted. Evaluation of larger numbers of MGUS patients treated with chemotherapy for their underlying malignancy may help identify in vivo potentially active agents and regimens for patients with overt myeloma.     

Role of receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin and macrophage protein 1-alpha (MIP-1a) in monoclonal gammopathy of undetermined significance (MGUS)

The aim of this study was to evaluate the role of markers of bone remodelling, and osteoclast activation/function in patients with monoclonal gammopathy of undetermined significance (MGUS). We have measured serum levels of soluble RANKL (sRANKL), osteoprotegerin (OPG), macrophage inflammatory protein-1alpha (MIP-1alpha), markers of bone resorption [N-telopeptide of collagen type-I (NTX), and tartrate-resistant acid phosphatase isoform-5b (TRACP-5b)] and bone formation [bone-alkaline phosphatase (bALP)] in 40 MGUS patients. These parameters were compared with those of 42 newly diagnosed myeloma patients, and 45 healthy, gender- and age-matched controls. MGUS patients had elevated levels of NTX, sRANKL, and sRANKL/OPG ratio compared with controls (P < 0.0001). Furthermore, TRACP-5b, MIP-1alpha and NTX were decreased in patients with MGUS compared with myeloma patients (P < 0.001), while OPG and bALP were increased (P < 0.001). Serum levels of MIP-1alpha, as well as TRACP-5b, and sRANKL/OPG ratio were reduced, while bALP was increased in MGUS patients, even when compared with myeloma patients who had stage I/II disease. These results demonstrate that increased osteoclastogenesis leading to increased bone resorption is present in MGUS but seems to be compensated for by normal bone formation, which is absent in MM. Furthermore MIP-1alpha, bALP, and sRANKL/OPG may be useful tools for distinguishing between cases of MGUS and early myeloma.     

Presence of monoclonal free light chains in the serum predicts risk of progression in monoclonal gammopathy of undetermined significance

We hypothesized that the presence of monoclonal free light chains (FLC) in the serum of patients with monoclonal gammopathy of undetermined significance (MGUS) is a marker of clonal evolution and a risk factor for progression. Forty-seven patients with MGUS and documented progression to myeloma or related malignancy were compared with 50 age- and gender-matched patients with MGUS and no evidence of progression after 5 or more years of follow-up. The presence of an abnormal kappa/lambda FLC ratio in the serum was associated with a higher risk of MGUS progression (relative risk 2.5; 95% confidence interval: 1.6-4.0; P < 0.001).     

Absence of p53 deletions in bone marrow plasma cells of patients with monoclonal gammopathy of undedetermined significance

We have recently shown that presence of a p53 deletion in multiple myleoma is an independent predictor for short survival. We therefore investigated whether or not this chromosomal abnormality can be identified in patients with monoclonal gammopathy of undetermined significance (MGUS). Using a triple staining method combining staining for cytoplasmic immunoglobulins and fluorescence in situ hybridization (FISH) with chromosome 17-centromere and p53-gene specific probes, we studied plasma cells from 15 patients with MGUS. In all patients, concordant signal numbers with both probes were obtained (including one patient with trisomy 17), indicating that allelic loss of p53 does not occur in MGUS.     

Co-occurrence of monoclonal gammopathy and myelodysplasia: a retrospective study of fourteen cases

We report a series of 14 patients with myelodysplastic syndrome (MDS) accompanied by a monoclonal gammopathy unrelated to therapy. Twelve of these had monoclonal gammopathy of undermined significance (MGUS) and two had smoldering multiple myeloma. These cases represent 10.2 % of all MDS cases seen at our institution over a 14-year period (January 2000 to December 2013). The incidence of MGUS was determined to be significantly higher in MDS than in age-matched concurrent controls by χ ² test. Absence of prior chemotherapy and simultaneous presentation of MDS and MGUS in most cases suggest true co-occurrence of the two disorders. MGUS was found in all WHO subtypes of MDS with a wide range of risk factors. However, 11 out of the 12 MDS cases accompanied with MGUS had relatively low karyotypic risks. In addition, serum M protein levels remained largely unchanged in 4 cases of MGUS for which serial determinations were performed. These findings indicate that MGUS may not affect the prognosis of MDS.     

MGUS: Proposal for outpatient management

The term monoclonal gammopathy of undetermined significance (MGUS) indicates the presence of a monoclonal protein (M-protein) without features of multiple myeloma, Waldenström’s macroglobulinemia, primary amyloidosis or malignant lymphoproliferative disorders (LPD). While several guidelines on the treatment of LPD exist, many doubts and perplexities still exist on who should treat a MGUS, when and how. Even where MGUS does not require any therapy, the risk of progression to a LPD is 1% per year. This risk does not diminish over time and persists even in patients (pts) whose condition has remained stable for decades, and a prolonged follow up is, therefore, recommended. We met primary care doctors to share and agree on criteria for the management of outpatients with MGUS. Our aim is to draw up guidelines or, at least, suggestions that may help to determine which MGUS pts could be cared for by the primary care doctor and which should be followed by the hematologist. We suggest that once a MGUS is diagnosed, the primary care physician will attend patients with M-protein < 15 g/L if IgG and pts with M-protein < 10 g/L if IgA or IgM, without end-organ damage and without signs and symptoms of LPD. However, a hematological evaluation is recommended for patients with M-protein IgG > 15 g/L, or M-protein IgA > 10 g/L, or IgM > 10 g/L, or any M-protein with end-organ damage (not attributable to any others causes) or with signs and symptoms of LPD, or rapidly increasing M-protein (> 5 g/L per year).     

Paraproteins of familial MGUS/multiple myeloma target family-typical antigens: hyperphosphorylation of autoantigens is a consistent finding in familial and sporadic MGUS/MM

Paratarg-7 (P-7) is a frequent paraprotein target in monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM), and Waldenstr?m macroglobulinemia. Patients with P-7-specific paraproteins carry a hyperphosphorylated paratarg-7 (pP-7). Because pP-7 carrier state is dominantly inherited, we determined the paraprotein targets in 4 families with familial MGUS/MM. No antigenic target was identified for the paraproteins from 2 members of one family. Paraproteins from affected members of 2 other families targeted P-7, and paraproteins from 4 affected members of a fourth family targeted P-8, which is encoded by the ATG13 gene. P-8 was hyperphosphorylated in the affected family members (pP-8) and pP-8 carrier state is inherited in a dominant fashion. Six additional autoantigenic nonfamilial paraprotein targets were also hyperphosphorylated in the respective patients compared with normal controls. We conclude that paraproteins of affected members with familial MGUS/MM share family-typical hyperphosphorylated antigens and hyperphosphorylation of paraprotein targets might be a general mechanism underlying the pathogenesis of MGUS/MM.