Cryoglobulinemic Vasculitis in Disguise: Cryofibrinogenemia as Variant of Monoclonal Gammopathy of Renal Significance.

Monoclonal gammopathy with cryoactivity (ie, cryoglobulins) that causes glomerulonephritis is considered within the spectrum of monoclonal gammopathy of renal significance. Cryofibrinogenemia (cryoactivity of coagulation factors) is very rarely associated with glomerulonephritis. We present a 39-year-old woman with a relapsing nephrotic syndrome. Laboratory investigation detected cryofibrinogen; the precipitate consisted of fibrinogen and a monoclonal immunoglobulin (M-protein; IgG-λ), and the latter was also detected in serum (4g/L). Initial conventional immunosuppressive therapy resulted in temporary renal remission. In view of the M-protein, subsequent therapy consisted of bortezomib/dexamethasone and high-dose melphalan followed by autologous hematopoietic stem cell transplantation, and resulted in a very good partial hematological response and temporary renal remission. However, after hematological and renal relapse, we performed unique experiments to clarify the role of the M-protein. Mixing patient serum with donor plasma resulted in cryoactivity, composed of M-protein+fibrinogen. Patient plasma deprived of M-protein did not have cryoactivity. Therefore, cryoactivity was dependent on the M-protein. We started lenalidomide, which resulted in very good partial hematological and renal remission. Thus, cryofibrinogenemia can be the consequence of an M-protein, which we suggest should be defined as monoclonal gammopathy of renal significance.

Monoclonal gammopathy-associated peripheral neuropathies: Uncovering pearls and challenges.

Monoclonal gammopathy-related peripheral neuropathies encompass a spectrum of clinical presentations in which the monoclonal protein directly damages the tissues, including the peripheral nervous system. Given the prevalence of both peripheral neuropathy and monoclonal gammopathy in the general population, these conditions may overlap in clinical practice, posing a challenge for clinicians in determining causality. Therefore, a comprehensive understanding of primary clinical syndromes and their neurophysiological patterns is of great importance for accurate differential diagnoses and effective treatment strategies. In this article, we examine the main forms of monoclonal gammopathies that affect the peripheral nerve. We explore the clinical and electrophysiological aspects and their correlation with each syndrome's corresponding monoclonal protein type. This knowledge is essential for healthcare professionals to diagnose better and manage patients presenting with monoclonal gammopathy-related peripheral nervous system involvement.

TEMPI syndrome: A clinical, light-microscopic and phenotypic evaluation with review of the literature.

BACKGROUND AND OBJECTIVES: TEMPI (telangiectasias, elevated erythropoietin and erythrocytosis, monoclonal gammopathy, perinephric fluid collections, and intrapulmonaryshunting) syndrome is a rare multisystemic disease classified as a monoclonal gammopathy of cutaneous significance. The pathogenesis and etiology of TEMPIare not well known because of the rarity of this disorder. Although telangiectasias are the hallmark of this syndrome, skin biopsies are rarely performed. We aim to further characterize TEMPI syndrome through the evaluationof a skin biopsy. METHODS: We reviewed the histopathology and immunophenotypic profile of a skin biopsy from a 53-year-oldwoman diagnosed with TEMPI syndrome. Other components of her syndromic complex included an IgA myeloma, elevated vascular endothelial growth factor (VEGF), and erythrocytosis. RESULTS: A biopsy showed prominent vascular ectasia with some degree of microvascular basement membranezone thickening. Our patient had a reduction in neoplastic plasma cell burdenand clearing of her telangiectasias following myeloma directed treatment. CONCLUSIONS: TEMPI can beviewed as a reactive vascular paraneoplastic syndrome in the setting of a plasma cell dyscrasia. Elaboration of VEGF from neoplastic plasma cells is likely pathogenetically implicated and appears to be a common link that explains other vascular lesions associated with monoclonal gammopathy syndromes.

Paraproteinaemic keratopathy simulating a crystalline keratopathy.

BACKGROUND: Paraproteinemic keratopathy is a rare disorder characterized by the bilateral accumulation of polychromatic deposits diffusely in all corneal layers together or not with diffuse or patchy pseudo lipid deposits. We present an atypical case of paraproteinemic keratopathy which lead to an initial misdiagnosis of infectious crystalline keratopathy. CASE PRESENTATION: a 69-year-old woman with an asymptomatic keratopathy detected during a cataract intervention. Slit-lamp examination revealed several hyper refringent subepithelial foci with fern-shaped branches, resembling crystalline keratopathy, in her left eye. Anterior segment optical coherence tomography revealed exclusively subepithelial hyperreflective lesions limited to the anterior stroma. The progressive bilateralization and progression of the condition prompted us to include other entities with crystalline corneal deposits in our differential diagnosis. Hematological analysis showed a high number of free Kappa light chains. Despite the typical clinical appearance of crystalline keratopathy, the atypical evolution and test results led us to consider that monoclonal gammopathy could be the cause of this entity. CONCLUSIONS: Paraproteinemic keratopathy may present in its early stages as a unilateral subepithelial crystalline keratopathy. Thus, it must always be taken into account in the differential diagnosis of any crystalline keratopathy, particularly when there are no predisposing factors for an infectious crystalline keratopathy. Early recognition of this rare entity is important to address the associated potentially serious systemic disease.

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.

C3 Glomerulopathy With Concurrent Thrombotic Microangiopathy: Clinical and Immunological Features.

RATIONALE & OBJECTIVE: C3 glomerulopathy (C3GN) and atypical hemolytic uremic syndrome (aHUS) are 2 distinct rare kidney diseases caused by dysregulation of the alternative complement pathway. Patients with C3GN and concurrent kidney lesions of thrombotic microangiopathy (TMA) have been rarely reported. We characterized the clinical features and underlying immunological abnormalities in these patients. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Patients with C3GN and concomitant TMA lesions on biopsy registered from 2009 to 2019 in the French National Registry of C3GN. FINDINGS: Among 278 registered patients with C3GN, 16 (6%) had biopsy-proven glomerular and/or vascular TMA lesions. Their median age at diagnosis was 39 years (range, 7-76), and 59% were female. Fourteen of the 16 patients (88%) had an estimated glomerular filtration rate of<30mL/min/1.73m2 and 3 of 16 (19%) required dialysis. Twelve of the 14 evaluated patients (86%) showed evidence of mechanical hemolysis. Fifty percent of the patients had low C3 levels. Six of the 14 evaluated patients had a rare variant in complement genes, and 4 of the 16 patients (25%) had monoclonal gammopathy. Among the 16 patients, 10 (63%) received eculizumab, 5 (31%) received immunosuppressive therapy, and 4 (25%) received clone-targeted chemotherapy. Median kidney survival was 49 months. LIMITATIONS: Small retrospective case series with a limited number of biopsies including electron microscopy. CONCLUSIONS: Concomitant C3GN and TMA is extremely rare and is associated with poor kidney outcomes. Genetic or acquired abnormalities of the alternative complement pathway are common as is the presence of monoclonal gammopathy, which may inform the selection of treatment approaches.

Non-crystalline light chain proximal tubulopathy, a morphologically protean entity.

BACKGROUND: Light chain proximal tubulopathy (LCPT) is a rare form of paraprotein-related disease, occurring in two main histopathological forms: crystalline and non-crystalline. The clinicopathological features, treatment strategies and outcomes, especially of the non-crystalline form, are not well described. METHODS: We conducted a single-centre retrospective case series of 12 LCPT patients, 5 crystalline and 7 non-crystalline, between 2005 and 2021. RESULTS: The median age was 69.5 years (range 47-80). Ten patients presented with CKD and significant proteinuria (median estimated glomerular filtration rate of 43.5 ml/min/1.73 m2; urine protein:creatinine ratio 328 mg/mmol). Only six patients had known haematological disease at the time of renal biopsy. Multiple myeloma (MM) was diagnosed in seven patients cases and monoclonal gammopathy of renal significance (MGRS) in five patients. A clone was detected in all cases combining serum/urine electrophoresis and free light chain (LC) assays. Crystalline and non-crystalline variants had similar clinical presentations. For the non-crystalline variant, a diagnosis was reached based on a combination of CKD without another cause, haematological workup, LC restriction on immunofluorescence and abnormalities on electron microscopy (EM). Nine of 12 patients received clone-directed treatment. Patients who achieved haematological response (including all non-crystalline LCPT) had improved renal outcomes over a median follow-up of 79 months. CONCLUSIONS: The non-crystalline variant may go unrecognised because of its subtle histopathological features and requires EM to distinguish it from 'excessive LC resorption without tubular injury'. Clone-directed treatment with good haematological response improves renal outcomes in both variants but limited data exist in MGRS. Multicentre prospective studies are needed to better define the clinicopathological characteristics associated with poor outcomes and optimize treatment strategies in patients with MGRS.

Treatment-responsive glycogen storage myopathy in a patient with POEMS syndrome: A new monoclonal gammopathy-associated myopathy.

BACKGROUND: Myopathies associated with monoclonal gammopathy are relatively uncommon and underrecognized, treatable myopathies, and include sporadic late onset nemaline myopathy, light chain amyloid myopathy, and a recently described vacuolar myopathy with monoclonal gammopathy and stiffness (VAMGS). Herein, we report a new subtype of monoclonal gammopathy-associated myopathy (MGAM) in a polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes (POEMS) patient. METHOD: Case report. RESULTS: A 51-year-old woman presented with a 6-month history of progressive bilateral foot drop, lower limb edema, and a 15-lb weight loss. She denied muscle stiffness. Neurologic exam showed severe distal weakness, mild proximal weakness, and length-dependent sensory deficits. Laboratory studies revealed biclonal gammopathy (IgG kappa and IgA lambda), thrombocytosis, and elevated vascular endothelial growth factor. Creatine kinase was normal. Electrodiagnostic studies identified mixed demyelinating and axonal polyradiculoneuropathy and a superimposed proximal myopathy. Gluteus medius biopsy demonstrated scattered fibers with glycogen-filled vacuoles, similar to VAMGS, with additional rare myofibers containing polyglucosan bodies. She was diagnosed with POEMS syndrome and concomitant glycogen storage myopathy. Next-generation sequencing of glycogen storage and polyglucosan body myopathy-related genes was unrevealing. Proximal weakness resolved after autologous stem cell transplant. CONCLUSIONS: This patient expands a spectrum of MGAM. Recognition of this condition and other subtypes of MGAM is of utmost important because they are treatable.

Clinical characteristics and outcome of 318 families with familial monoclonal gammopathy: A multicenter Intergroupe Francophone du Myélome study.

Familial forms of monoclonal gammopathy, defined as multiple myeloma (MM) or Monoclonal Gammopathy of Undetermined Significance (MGUS), are relatively infrequent and most series reported in the literature describe a limited number of families. MM rarely occurs in a familial context. MGUS is observed much more commonly, which can in some cases evolve toward full-blown MM. Although recurrent cytogenetic abnormalities have been described in tumor cells of sporadic cases of MM, the pathogenesis of familial MM remains largely unexplained. In order to identify genetic factors predisposing to familial monoclonal gammopathy, the Intergroupe Francophone du Myélome identified 318 families with at least two confirmed cases of monoclonal gammopathy. There were 169 families with parent/child pairs and 164 families with cases in at least two siblings, compatible with an autosomal transmission. These familial cases were compared with sporadic cases who were matched for age at diagnosis, sex and immunoglobulin isotype, with 10 sporadic cases for each familial case. The gender distribution, age and immunoglobulin subtypes of familial cases were unremarkable in comparison to sporadic cases. With a median follow-up of 7.4 years after diagnosis, the percentage of MGUS cases having evolved to MM was 3%. The median overall survival of the 148 familial MM cases was longer than that of matched sporadic cases, with projected values of 7.6 and 16.1 years in patients older and younger than 65 years, respectively. These data suggest that familial cases of monoclonal gammopathy are similar to sporadic cases in terms of clinical presentation and carry a better prognosis.

PARAKID: Navigating the relation between paraproteins and kidney lesions: A multi-center retrospective observational study.

INTRODUCTION: Monoclonal gammopathy is a heterogeneous group of disorders due to the clonal proliferation of immunoglobulin-producing plasma cells or B lymphocytes. Patients develop kidney disease not only due to malignant transformation but also due to the idiosyncratic properties of the M protein and the host factors. We aim to study the spectrum of kidney diseases in patients with paraproteinemia. MATERIALS AND METHODS: A retrospective observational study was performed at three tertiary care centers in Southern India. Kidney biopsies conducted in these three centers were reviewed from June 1, 2020 to November 30, 2022. All biopsies suggestive of monotypic immunoglobulin or light chain restriction were included in the study. RESULTS: A total of 122 patients were included in the study with an incidence of 2.4%. The mean age was 52.27 ± 13.27 years, and majority (63.1%) were males. AL amyloidosis was most common in the monoclonal gammopathy of renal significance (MGRS) group, and cast nephropathy was most common in the multiple myeloma (MM) group. On histopathology, 83.6% had a single lesion, followed by 14.8% with double lesion, and 1.6% with triple lesion. CONCLUSION: Paraproteinemia is associated with a myriad of kidney lesions. MGRS and MM are usually present in the 6th decade of life and beyond, while proliferative glomerulonephritis with monoclonal immunoglobulin deposits is more common in the younger age group. Older age group, high creatinine, hyperuricemia, hyperphosphatemia, presence of more than one lesion on kidney biopsy, and presence of cast nephropathy was significantly associated with the requirement of kidney replacement therapy.

Non-crystalline light chain proximal tubulopathy associated with monoclonal gammopathy of renal significance: A case report and review of the literature.

BACKGROUND: Light chain proximal tubulopathy (LCPT) is a rare M-proteinemia-related nephropathy. Non-crystalline LCPT is even rarer. We herein report an unusual case of renal dysfunction and proteinuria due to κ-restricted and non-crystalline LCPT in a context of monoclonal gammopathy of renal significance (MGRS) without Fanconi syndrome (FS). CASE PRESENTATION: A 67-year-old man was admitted for a 2-year history of proteinuria and renal dysfunction. Fanconi syndrome (FS) was not observed. He was noted to have IgG-κ M protein, and the previous bone marrow biopsy revealed that atypical plasma cells accounted for 1.5% of the cells, which did not meet the diagnostic criteria for multiple myeloma. A renal biopsy revealed proximal tubular injury, including increased lysosomes with irregular contours and a mottled appearance without crystalline structure and the accumulation of κ light chains. He was diagnosed with non-crystalline LCPT with MGRS. Concurrently, we reviewed the non-crystalline LCPT cases previously published in the literature. Our patient finally received chemotherapy with a bortezomib and dexamethasone regimen. The patient did not seem to achieve evident nephrological and hematological remission after chemotherapy, but he was in a stable condition. CONCLUSION: Very few similar cases are reported in the literature. It is considered crucial to enhance our knowledge about these cases to establish the definition of the non-crystalline LCPT entity and allow for early diagnosis. Chemotherapy may not be necessary for all patients to maintain good renal function. Future prospective clinical research studies are necessary.

Acquired von willebrand syndrome secondary to monoclonal gammopathy of undetermined significance: long-term remission after treatment with bortezomib.

Monoclonal gammopathy of undetermined significance (MGUS) is a plasma cell disorder that can precede the diagnosis of multiple myeloma. MGUS is characterized by the presence of a monoclonal paraprotein without evidence of multiple myeloma or other lymphoplasmacytic malignancies. Even though MGUS is an asymptomatic condition that does not require management strategies other than periodic follow-up to prevent complications, secondary nonmalignant diseases may arise, requiring control of the plasma cell clone. Acquired von Willebrand syndrome (AVWS) is a rare bleeding disorder that occurs in patients with no prior personal or family history of bleeding. It is associated with several other disorders, such as neoplasia, mainly hematological (including MGUS and other lymphoproliferative disorders), autoimmune, infectious and cardiac diseases. At diagnosis, patients usually present with cutaneous and mucosal bleeding, including gastrointestinal bleeding. Here, we report a case of a patient with MGUS who developed AVWS after one year of follow-up. The patient was refractory to glucocorticoids and cyclophosphamide and achieved remission only after monoclonal paraprotein was eradicated following treatment with bortezomib and dexamethasone. Our report sdemonstrates that, for refractory cases, eradication of the monoclonal paraprotein may be necessary to treat bleeding complications due to MGUS-associated AVWS.

Necrobiotic Xanthogranuloma With Associated Monoclonal Gammopathy Presenting as an Eyelid Nodule.

Necrobiotic xanthogranuloma (NXG) is a progressive non-Langerhans cell histiocytosis with a predilection for the periorbital area. NXG is most commonly associated with monoclonal gammopathy and ophthalmic complications. The authors present a 69-year-old man who was evaluated for a left upper eyelid nodule and plaques on the lower extremities, trunk, abdomen, and right upper extremity. Biopsy of the eyelid was supportive for NXG. Serum protein electrophoresis was positive for a monoclonal gammopathy, IgG light chain kappa. MRI showed preseptal involvement. The periocular nodules cleared with a high dose of prednisone; however, the other skin lesions persisted. Bone marrow biopsy showed kappa-restricted 6% plasma cells and he was treated with intravenous immunoglobulin. This case illustrates the importance of clinicopathologic correlations to render an NXG diagnosis.

Therapy of necrobiotic xanthogranuloma - case series and review of the literature.

Necrobiotic xanthogranuloma is a rare disease that is part of the non-Langerhans cell histiocytoses. It is characterized by yellowish skin lesions, which are typically periorbitally localized. Extracutaneous manifestations of all organs are possible and can cause potentially life-threatening complications. The disease also belongs to the facultative paraneoplasias and is often associated with paraproteinemia. These aspects should be considered regarding further diagnostics. Due to the rarity of the disease, there are no standardized guidelines for therapy so far. The combination of prednisolone and chlorambucil as well as intravenous immunoglobulins seem to be effective therapeutic options. We present four cases from our clinic as well as the current results of the literature in this mini-review and would like to highlight the therapeutic challenge as well as the need for the development of guidelines.

Prevalence and risk factors of monoclonal gammopathy in patients with autoimmune inflammatory rheumatic disease: A systematic review and meta-analysis.

OBJECTIVE: To systemically investigate the prevalence and risk factors of monoclonal gammopathy (MG) in patients with autoimmune inflammatory rheumatic disease (AIIRD). METHODS: A literature search was conducted using databases of PubMed, EMBASE, and Web of Science for relevant studies from inception to 31 July 2021. The pooled prevalence, odds ratio (OR), weighted mean difference (WMD), and 95% confidence interval (CI) were calculated with Stata 16.0 using a random or fixed effects model. RESULTS: In 17 included studies involving 6667 AIIRD patients, the pooled prevalence of MG in AIIRD patients was 7% (95%CI: 0.06-0.09). Compared to general populations, patients with Sjögren's syndrome (SS) possessed the highest risk for MG (OR 4.51; 95%CI: 3.39-5.74), followed by systemic lupus erythematosus (OR 3.99; 95%CI: 2.84-5.14), ankylosing spondylitis (OR 2.04; 95%CI: 1.11-2.97), and rheumatoid arthritis (OR 2.00; 95%CI: 1.79-2.22). Older age (WMD = 5.17 years; 95%CI: 0.68-9.66), higher erythrocyte sedimentation rate (WMD = 14.04 mm/H; 95%CI: 7.77-20.30), higher serum gammaglobulins level (WMD = 1.92 mg/dl, 95%CI: 0.51-3.32) were associated with a greater risk of MG in AIIRD patients. CONCLUSIONS: MG prevalence was higher in AIIRD patients, especially in SS patients. Older age, higher erythrocyte sedimentation rate, and hypergammaglobulins were risk factors for MG in AIIRD patients.

Erythroblastic synartesis associated with lymphoproliferative disorder: There can be more than meets the eye.

Erythroblastic synartesis is a rare cause of acquired dyserythropoiesis. Only 9 cases have been previously reported. We hereby report 3 cases of patients diagnosed with erythroblastic synartesis associated with monoclonal immunoglobulin and an overt malignant lymphoid disorder. A different B-cell clone may produce the monoclonal immunoglobulin, forming a biclonal disorder. In light of these data and literature review, treatment targeting the paraprotein seems to be efficient to control synartesis and correct anemia. In the case of monoclonal gammapathy associated with chronic lymphocytic leukemia, therapeutics should be adapted to control both chronic lymphocytic leukemia and monitored monoclonal immunoglobulin titer.

Monoclonal gammopathy in autoimmune diseases: Analysis and follow-up of 160 cases in a tertiary center in China.

Monoclonal gammopathy (MG) is common in autoimmune diseases (AID), but its progression to hematological neoplasm (HN) and the predictors for the progression are unclear. Patients diagnosed with AID and MG in our hospital from January 2010 to June 2017 were reviewed and followed. Cox proportional hazard regression analysis was applied. Of 160 patients with AID and MG, the most common AID was primary SjÓ§gren's syndrome (37, 23.1%). Thirty-nine (24.4%) patients developed HN during follow-up (median: 3.7 years, IQR: 0.3-5.5 years). The cumulative probability of HN progression was 21.8% at one year and 29.3% at six years after the finding of MG. High levels of monoclonal protein (> 14.35% of total serum protein) (HR 11.71, 95%CI: 5.37-25.54), significant weight loss (HR 6.24, 95%CI: 2.87-13.59), and reduction of other types of immunoglobulins (HR 3.02, 95%CI: 1.40-6.48) are independent risk indicators for HN whose presence warrants vigorous follow-up and monitoring.

Kidney Transplantation in Patients With Monoclonal Gammopathy of Renal Significance (MGRS)-Associated Lesions: A Case Series.

RATIONALE & OBJECTIVE: Data on kidney transplantation outcomes among patients with monoclonal gammopathy of renal significance (MGRS) are lacking. STUDY DESIGN: Case series of patients with MGRS, some of whom received clone-directed therapies before kidney transplantation. SETTING & PARTICIPANTS: 28 patients who underwent kidney transplantation from 1987 through 2016 after diagnosis with MGRS-associated lesions including light-chain deposition disease (LCDD), C3 glomerulopathy with monoclonal gammopathy (C3G-MG), and light-chain proximal tubulopathy (LCPT). FINDINGS: Of the 19 patients with LCDD, 10 were treated before kidney transplantation and 9 were treatment-naive. Among the treated patients with LCDD, 3 (30%) experienced histologic recurrence, 2 (20%) grafts failed, and 2 (20%) died during a median follow-up of 70 (range, 3-162) months after transplant. In the treatment-naive LCDD group, 8 (89%) had histologic recurrence, 6 (67%) grafts failed, and 4 (44%) patients died during a median follow-up of 60 (range, 35-117) months. Of the 5 patients who had a complete response before transplant, none died, and only 1 experienced graft failure, 162 months after transplant. Of 5 patients with C3G-MG, 3 were treatment-naive before transplant. Both patients who were treated before transplant had histologic recurrence, and 1 experienced graft failure and died. Among the 3 patients with treatment-naive C3G-MG, histologic recurrence occurred in all, and graft loss and death were observed in 2 and 1, respectively. In the LCPT group (n=4), histologic recurrence was observed in all 3 patients who did not receive clone-directed therapies before transplant, and 2 of these patients died, 1 with a functioning kidney. The 1 patient with LCPT who received therapy before transplant did not have histologic recurrence or graft loss and survived. LIMITATIONS: Small sample size, nonstandardized clinical management, retrospective design. CONCLUSIONS: Recurrence is very common in all MGRS-associated lesions after kidney transplant. Achieving a complete hematologic response may reduce the risks of recurrence, graft loss, and death. More studies are needed to determine the effects of hematologic response on outcomes for each MGRS-associated lesion.

Complement Activation and Thrombotic Microangiopathy Associated With Monoclonal Gammopathy: A National French Case Series.

RATIONALE & OBJECTIVE: Hemolytic uremic syndrome (HUS), a thrombotic microangiopathy (TMA) with kidney involvement, is a rare condition in patients with monoclonal gammopathy. In the absence of known causes of TMA, the role of complement activation in endothelial injury in patients with monoclonal gammopathy remains unknown and was the focus of this investigation. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: We studied the 24 patients in the French national registry of HUS between 2000 and 2020 who had monoclonal gammopathy without other causes of secondary TMA. We provide the clinical histories and complement studies of these patients. FINDINGS: Monoclonal gammopathy-associated TMA with kidney involvement is estimated to be 10 times less frequent than adult atypical HUS (aHUS) in the French national registry. It is characterized by severe clinical features, with 17 of 24 patients requiring dialysis at disease onset, and with median renal survival of only 20 months. TMA-mediated extrarenal manifestations, particularly cutaneous and neurological involvement, were common and associated with poor overall prognosis. Complement studies identified low C3, normal C4, and high soluble C5b-9 levels in 33%, 100%, and 77% of tested patients, respectively, indicating a contribution of the alternative and terminal complement pathways in the pathophysiology of the disease. Genetic abnormalities in complement genes known to be associated with aHUS were found in only 3 of 17 (17%) who were tested. LIMITATIONS: Retrospective study without comparison group; limited number of patients, limited available blood samples. CONCLUSIONS: Within the spectrum of TMA, TMA associated with monoclonal gammopathy represents a distinct subset. Our findings suggest that HUS associated with monoclonal immunoglobulin is a complement-mediated disease akin to aHUS.

Light Chain Deposition Disease: An Unusual Cause of Portal Hypertension.

Light chain deposition disease (LCDD) is a rare entity that is generally discovered in the setting of solid organ dysfunction. The monoclonal gammopathy leads to abnormal deposition of light chains in tissues, most often manifested by way of renal dysfunction. Other organ systems may also be affected, the liver being the second-most common after the kidneys. Liver involvement rarely leads to clinically significant disease, with few case reports in the literature. We present the case of a patient referred to a hepatology clinic for the evaluation of new-onset ascites resulting from portal hypertension secondary to LCDD involving the liver.