Pulmonary light chain deposition disease: report of five cases and review of the literature

Light chain deposition disease (LCDD) in the lung is a rare occurrence. We describe 5 new cases of this entity, review the literature, and compare pulmonary light chain deposits to pulmonary amyloidosis. In addition, we identified 17 patients with pulmonary LCDD in the literature with sufficient clinical information to allow evaluation of clinical presentation, laboratory findings, histologic appearance, and disease progression. In these 22 patients, 2 different histologic patterns were appreciated: diffuse and nodular. A parallel with the diffuse and nodular forms of pulmonary amyloidosis is suggested. The 10 patients with nodular LCDD had an overall better prognosis compared with the 12 patients with diffuse pulmonary LCDD. However, when compared to what is reported in the literature for nodular pulmonary amyloidosis, the patients with nodular LCDD had a higher incidence of an associated lymphoproliferative and/or plasma cell dyscrasia and renal failure. Light chain deposits in the lung are histologically similar to amyloid but are not Congophilic. Their electron microscopic appearance is distinctly different with fibrils in amyloid and granular deposits in LCDD. As the diffuse forms of LCDD and amyloidosis have a similarly poor prognosis, differentiating the 2 entities is probably not critical. However, when present as nodules, LCDD is more frequently associated with an underlying plasma cell dyscrasia or renal failure than is amyloidosis, and therefore the distinction may be clinically important.     

Current treatment of AL amyloidosis

Systemic AL amyloidosis is a rare complication of monoclonal gammopathies. Renal manifestations are frequent, mostly characterized by heavy proteinuria, with nephrotic syndrome and renal failure in more than half of the patients at diagnosis. Without treatment, median survival does not exceed 12 months. Amyloid heart disease and diffusion of amyloid deposits are associated with reduced survival. Treatment of systemic AL amyloidosis has been profoundly modified with the introduction of international criteria for the definition of organ involvement and hematologic response, and with the use of sensitive tests for the measurement of serum-free light chain levels. Melphalan plus dexamethasone is now established as the gold standard for first line treatment of systemic AL, with similar efficacy and reduced treatment-related mortality compared to high-dose therapy. Modern chemotherapy regimens, based on the use of novel agents such as bortezomib and lenalidomide, might further improve patient survival.     

κ I light chain AL amyloidosis presenting with rapidly progressive renal and hepatic failure with unusual renal amyloid distribution

A 65-year-old man suffering from generalized edema and jaundice was admitted to our hospital. Laboratory findings revealed marked renal dysfunction with heavy proteinuria as well as liver dysfunction with severe obstructive jaundice. On renal biopsy, the diagnosis of AL amyloidosis associated with κ I light chain was made. Interestingly, amyloid deposits were restricted to the glomeruli. Although hemodialysis was initiated, the patient died due to further deterioration of hepatic function. On autopsy, severe intrahepatic cholestasis was observed, and there was marked deposition of AL amyloid in the liver. Literature reviews showed that rapidly progressive renal failure is common in AL amyloidosis patients who presented with acute hepatic failure due to severe intrahepatic cholestasis. However, the detailed renal pathology in this condition has not been documented. The present case is very interesting because rapidly progressive renal and hepatic failure was simultaneously observed, and renal amyloid deposition was restricted to the glomeruli.     

轻链沉积病肾损害的诊断与治疗

轻链沉积病(LCDD)为单克隆免疫球蛋白轻链在肾脏、心脏、肝脏等组织的沉积。LCDD肾损害起病时多伴有慢性肾功能不全。典型的LCDD肾损害有相对特殊的临床表现,血、尿蛋白电泳及游离轻链定量有助于诊断,确诊需行肾组织病理学检查,包括光镜、荧光显微镜及电镜等检查。LCDD肾损害的治疗应综合考虑B细胞增殖程度和单克隆免疫球蛋白对肾功能造成的损害。应积极控制B细胞增殖,但治疗时应选择肾毒性较小的药物如硼替佐米,必要时改用大剂量马法兰＋周围血干细胞移植(HDM/ASCT)方案。     

Renal involvement in systemic amyloidosis: an Italian collaborative study on survival and renal outcome.

BACKGROUND: Few data are available from large population-based studies on survival and renal outcome of patients with renal involvement and different types of systemic amyloidosis. METHODS: Two hundred and ninety of over 373 patients affected from systemic amyloidosis with renal involvement diagnosed in Italy between January 1995 and December 2000 were followed from diagnosis to death or until the last available clinical control. Eighty-three patients were excluded from analysis either because the amyloid type remained undetermined or they were lost at follow-up. Clinical and laboratory information was collected according to the different types of amyloidosis using a specific form which included renal function with 24 h proteinuria at diagnosis and at the end of follow-up, the type and the date of onset of dialysis and the kind of treatment they underwent. RESULTS: The median time of follow-up was 24 months in primary (AL) amyloidosis (range: 1-88 months), 16 months in AL with associated multiple myeloma (MM + AL: range 1-76 months), 30 months in reactive (AA) amyloidosis (range: 1-99 months) and 52 months in patients with familial forms (AF: range 14-82 months). Patients with AL showed a significantly shorter survival than AA. Despite no significant differences of renal outcome or survival on dialysis being observed between the two groups, a lower renal survival with a higher number of patients who progressed to end-stage renal disease (ESRD) was observed in patients with AA. Overall survival was markedly improved in patients with AL who underwent a specific therapy (conventional chemotherapy or autologous stem cell transplantation (ASCT)) even in the absence of a positive kidney response. Multivariate analysis showed cardiac involvement and specific therapy to significantly influence survival in AL whereas age, serum creatinine (sCr) and heart involvement significantly affected survival in AA. In both groups, sCr and heart involvement were the most relevant predictors for renal outcome, together with urinary protein excretion, in patients with AA. CONCLUSIONS: Our results show a worse survival in AL due to the higher prevalence of heart involvement in this group and emphasize that a specific therapy significantly prolongs survival and slows the progression of renal disease in patients with AL. We suggest that a late nephrological referral is likely the cause of the higher sCr found at presentation in patients with AA and probably accounts for the lower renal survival observed in the short term in these patients. At the time being, renal transplantation and ASCT are still rare therapeutic options for renal patients affected from systemic amyloidosis.     

Liver transplantation as rescue treatment in a patient with primary AL kappa amyloidosis

Although involvement of the liver is common in systemic amyloidosis, clinical manifestations of hepatic dysfunction and liver biochemical abnormalities are often absent or only mild. Here we report on a patient with primary amyloidosis and rapid development of liver failure, who was successfully treated by liver transplantation. The patient is a 61-year-old Swedish man who was admitted to the local hospital for spontaneous rupture of the spleen. Before admission, he had suffered from diffuse upper abdominal discomfort, diminished appetite, and had lost 15 kg in 6 months. Shortly after splenectomy, he developed cholestatic liver failure with moderate hepatomegaly, jaundice, ascites and hyponatremia. Over a period of 3 weeks his liver failure progressed, renal function deteriorated rapidly, and he developed encephalopathy. Liver transplantation was performed on the 35th day after splenic rupture. Histological examination revealed extensive deposits of amyloid in the spleen and liver. ¶N-terminal amino acid sequence analysis of the amyloid protein, purified from the patient's native liver, revealed an AL protein of kappa ¶I-type origin. The postoperative course was uncomplicated, apart from one episode of sepsis and one course of treatment for acute rejection. He was discharged from hospital with normal liver function and good kidney function. One year after surgery, he was in good condition, with normal liver function. However, a liver biopsy taken at the same time showed de novo amyloid deposits in the grafted liver. We conclude that liver transplantation may be indicated as a life-saving procedure in rapidly progressing hepatic amyloidosis with cholestatic jaundice, although the underlying disease has not changed.     

Rapid deterioration of renal function in a patient with multiple myeloma associated with amyloid and light chain depositions

Here we report a 75-year-old man with multiple myeloma who developed acute deterioration of renal function. Systemic AL amyloid deposition was found in the stomach, duodenum and brachial artery. A small amount of proteinuria without significant abnormal urinary sediments, increased excretion of urinary low-molecular-weight proteins and Bence Jones protein were observed. Significant renal Ga-67 uptake suggested acute tubulointerstitial lesions. Renal necropsy after sudden death 40 days after introduction of hemodialysis revealed mesangial expansion with glomerular basement membrane thickening, tubular basement membrane thickening with or without tubular atrophy and massive tubulointerstitial fibrosis. Slight amyloid depositions in the mesangium and vessels, and massive granular electron-dense deposits and deposition of monoclonal light chain λ in renal basement membranes and vessels were found, indicating the rare condition of co-existence of amyloidosis and light chain deposition disease (LCDD). The rapid progression of renal failure may have been caused by massive deposition of monoclonal light chains in our patient.     

Association of a POEMS syndrome and light chain deposit disease: first case report.

Monoclonal immunoglobulin (Ig) deposition diseases are characterized by deposition in tissues of excessive amounts of the Ig, compromising organ functions. Light chain deposition disease (LCDD) and AL amyloidosis are the commonest [Buxbaum 1992]. LCDD is usually characterized by rapidly progressive renal failure with glomerular and tubular deposits of Ig fragments mostly composed by kappa light chain. Monoclonal Ig production can also be observed associated with various symptoms, that, taken together, have been described as the Crow-Fukase syndrome or POEMS syndrome. It associates polyneuropathy, organomegaly, endocrinopathy, monoclonal Ig, and skin changes. In POEMS syndrome, renal abnormalities are rare and are reported as a moderate renal insufficiency with mild proteinuria or acute functional renal insufficiency leading in some cases to end-stage renal failure [Fukatsu et al. 1991]. Although a monoclonal Ig is produced, no Ig deposit disease had been described in POEMS syndrome except a case of AL amyloidosis [Toyokuni et al. 1992]. Here, to our knowledge, we report the first case of an LCDD associated with a POEMS syndrome. Although an autologous bone marrow graft was realized, the monoclonal component reappeared and was responsible for end-stage renal disease, cachexia and death.     

Recurrence of light chain deposit disease after renal allograft transplantation: potential role of rituximab?

Light chain deposit disease (LCDD) is a monoclonal plasma cell disorder characterized by tissue deposition of nonamyloid immunoglobulin light chains, predominantly kappa chains, causing renal insufficiency. LCDD reoccurs almost invariably after renal grafting, leading to early graft loss, usually within a time span of months to years. We describe a female patient with LCDD who lost her first living donor graft after 1 year due to extensive recurrence of kappa chain deposition. Rituximab was administered on the seventh day after her second transplantation with a graft from a deceased donor, in order to prevent early recurrence of LCDD. The 2-year protocol biopsy - similarly to the completely normal 1-year protocol biopsy - revealed persistent absence of light chain deposition on light microscopy but immunohistochemical staining and electron microscopy showed very mild recurrence of light chain deposits. A second 4-week course of rituximab was repeated because of these electron microscopic findings. Subsequently, free kappa light chain concentration decreased from 693 to 74 mg/l and remained low 4 months after completion of therapy. Rituximab could be considered for delaying early LCDD recurrence in patients in whom treatment of the underlying bone marrow disorder failed or is contraindicated, but maintenance therapy is apparently necessary to consolidate this response.     

Renal granular monoclonal light chain deposits: morphological aspects in 11 cases

Eleven cases of renal light chain deposition without amylo?dosis are reported (7 multiple myeloma, one Waldenstr?m's disease, 3 without multiple myeloma without spike in serum or urine). Ten had kappa light chain deposits and 1 lambda light chain deposits along tubular basement membranes and in glomeruli. Ultrastructural study showed granular electron dense material on the external side of tubules with a very dark appearance in 4 cases and lighter appearance in the others. Five cases had nodular glomerulosclerosis with a finely granular, light appearance, corresponding to membrane-like material with kappa fixation in 4. Granular light chain deposition is analogous to type AL amylo?dosis in that their distribution is identical and both originate from light chains. The major difference between AL type amylo?dosis and light chain deposits lies in their ultrastructural appearance. Amylo?d substance is characterized by a fibrillar appearance and light chain substance by a granular appearance.     

Renal involvement in systemic amyloidosis--an Italian retrospective study on epidemiological and clinical data at diagnosis.

BACKGROUND: Few data are available on epidemiology and clinical picture of renal involvement in different forms of systemic amyloidosis. METHODS: Patients with biopsy-proven systemic amyloidosis diagnosed in Italy between January 1995 and December 2000 were selected from 49 Nephrology and Internal Medicine Units provided they showed signs characteristic of renal involvement. Clinical and laboratory information were collected by using a specific data form for diagnosis integrated by a questionnaire on diagnostic tools. Collected data were matched both with the Italian Registry of Renal Biopsies (IRRB) and the Registry of the Italian Society of Amyloidosis (SIA) in order to approximate the incidence of the disease. RESULTS: Of all patients, 373 were finally selected throughout Italy with an estimated mean incidence of renal amyloidosis of 2.1 per million population (p.m.p.) per year. Of those, 237 were affected from AL (primary) amyloidosis, 104 from AA (secondary) amyloidosis and 6 from AF (heredofamilial) forms. In 26 cases the type of amyloidosis remained undetermined. Among patients with AL, 36 presented an associated multiple myeloma (MM). Rheumatoid arthritis (RA) was the commonest underlying disease in AA. Median age ranged between 63 and 65 years in all groups. Males were prevalent in AL and females in AA. The main clinical features of renal involvement were represented by nephrotic syndrome and renal failure observed in 59 and 54% of cases, respectively. The presence of a lambda light chain, either in serum or urine was significantly associated to a more elevated urinary protein loss and to a reduced renal function. Patients with AA showed a worse renal function at presentation than patients with AL, possibly due to a late diagnosis and/or referral to nephrology units. Diagnosis was obtained by renal biopsy in 315 cases, by abdominal fat tissue (AFT) aspiration/biopsy in 156 patients and by other organ biopsies in 47 patients. Characterization of deposits was extremely variable among referring centres. CONCLUSIONS: Our results point to an increased incidence of renal amyloidosis observed in Italy over the period 1996-2000 with AL as the prevalent type. Characterization of amyloid deposits still remains the major diagnostic challenge of the disease. The institution of networks dedicated to rare diseases is strongly recommended in order to effectively afford this challenge.     

AL amyloidosis with renal involvement

Primary (AL amyloidosis) is a systemic disease characterized by an amyloid deposition process in many organs, with unsatisfactory survival of patients. The monoclonal light chains form the fibrils that deposit and accumulate in tissues. Renal involvement is very frequent in AL amyloidosis and could lead to development of nephrotic syndrome followed by the renal failure in many cases. Classic therapeutic combination melphalan and prednisone has been supplemented with drugs with different mechanisms of action in this group of patients: high-dose dexamethasone, high-dose dexamethasone with melphalan, combination of vincristine, doxorubicin, and dexamethasone or newly high-dose melphalan supported by peripheral blood stem cell transplantation. This progressive therapy leads to the better survival and prognosis in the majority of patients. Alternative therapeutic approaches include thalidomide (alone or in combination with cyclophosphamide), lenalidomide, iododoxorubicin, etanercept and rituximab. The development of immunotherapy is expected in the near future.     

Primary amyloidosis--involving principally intrarenal blood vessels

We analysed renal biopsies from 34 nephrotic patients with renalamyloidosis, seven with primary form kappa chain (AL amyloidosis)and 27 with secondary amyloidosis associated with the otherchronic diseases. Renal biopsy specimens were analysed usingoptical and immunofluorescence microscopy. The extent of amyloiddeposits was graded from 0 to + + + +. Intrarenal blood vesseldeposits were more prominent than intraglomerular in five ofseven patients with AL amyloidosis, while they were identicalin one, and in one, intraglomerular amyloid deposits were dominant.The results were different in the group of patients with secondaryamyloidosis: a lower degree of intrarenal blood vessels depositionthan glomerular was noted in 22 of 27 cases, the degree of depositionwas identical in 4 of 27 cases and more expressed blood vesseldeposition was present in only one case. Granular or combineddeposits (granular + linear) were found on immunofluorescencemicroscopy in primary form, but the dominant form of depositionwas amorphous in secondary amyloid.     

Diagnosis and treatment of multiple myeloma and AL amyloidosis with focus on improvement of renal lesion

Multiple myeloma (MM) and AL amyloidosis are caused by the expansion of monoclonal plasma cells and secretion of dysproteinemia (Bence Jones protein and free light chain) and some patients require the hemodialysis. Myeloma kidney is mainly caused by the cast nephropathy of the distal tubuli, whereas, AL amyloid-protein is mainly deposited in glomeruli with massive fibrillar involvement. Therefore, almost MM patients presents a symptom of renal insufficiency, whereas, almost patients of AL amyloidosis present a nephrotic syndrome with severe hypoalbuminemia. These two diseases have some similar characteristics such as up-regulation of cyclin D1 gene by 11:14 chromosomal translocation. High-dose chemotherapy supported with autologous peripheral blood stem cells is effective for these two diseases. However, they are still difficult to be cured and require long-term disease control. In recent years, introduction of novel agents has changed their treatment strategies from the palliation therapy to the clinical cure.     

Spectrum of renal involvement in familial Mediterranean fever.

Kidney biopsies were performed on fifteen patients with a long-standing history of familial Mediterranean fever (FMF) and evidence of renal involvement. On light microscopy, seven patients were found to have amyloidosis, six mesangial proliferative glomerulonephritis (MsPGN) and two patients rapid progressive glomerulonephritis (RPGN). Immunofluorescent studies of the six biopsies with MsPGN were positive for mesangial IgA deposits (IgA nephropathy) in three patients and IgM mesangial deposits in three (IgM nephropathy). We conclude that in patients with FMF and renal involvement, non-amyloid renal lesions (IgA nephropathy, IgM nephropathy and RPGN) should be considered in the differential diagnosis in addition to amyloidosis.     

The ultrastructural basis of renal pathology in monoclonal gammopathies

The kidney is frequently involved in the course of monoclonal gammopathies (MG). Renal involvement presents different clinical-morphological patterns, which can occur either at the onset or in a late phase of the hematological disease, as well as after chemotherapy. The reasons for the organ tropism of monoclonal immunoglobulins (Igs) are still unknown. Currently, it is well known that some primary structure alterations in monoclonal Igs and/or in their segments correlate to nephrotoxicity. On the other hand, it is impossible to predict the pathogenicity and the clinical manifestations induced by a specific monoclonal Ig based on its specific conformational modifications. Pathogenicity and organ tropism are probably complex phenomena, which involve specific protein factors, patient factors, target organ characteristics and monoclonal plasmacellular mass entities. However, aminoacidic sequence analysis of nephrotoxic Igs and some recent in vitro studies have allowed two different monoclonal light chain (LC) types to be distinguished. Glomerulopathic LCs (G-LCs) in the mesangium recognize their target structure and induce two distinct mesangiopathies, monoclonal Ig deposition disease (MIDD) and AL-amyloidosis (AL). Tubulopathic LCs (T-LCs) act on the proximal or on the distal tubule and cause, respectively, Fanconi syndrome (FS) and cast nephropathy. Pathogenic monoclonal Igs have the propensity to deposit in different renal parenchymal structures in extracellular sites, because of the transformation of soluble precursors in insoluble products. Evidence suggests that somatic mutations can destabilize the normal LCs globular soluble structure and this could be the major driving force for precipitation. Based on these features, MG can be classified as conformational and depositional diseases. Electronmicroscopy (EM) analysis of renal biopsies in MG patients with glomerular diseases distinguishes two morphological aspects. MIDD and a recently identified entity named proliferative glomerulonephritis (GN) with monoclonal IgG deposits are both characterized by non-organized granular electrondense deposits. AL, immunotactoid (IT) glomerulopathy and monoclonal cryoglobulinemia are, instead, characterized by organized deposits such as fibrils or microtubules. Tubular diseases in MG patients produce two different histological patterns. In FS, monoclonal Igs form crystals in the renal interstitium able to induce a local intense flogosis, while in cast nephropathy monoclonal Igs precipitate with Tamm-Horsfall protein (THP) in the proximal tubular lumen and induce tubular obstruction. The different morphological aspects are unrelated to specific clinical manifestations, while renal biopsy can diagnose different entities that can respond to different therapeutical schedules. This reveals the importance of the renal biopsy in the clinical management of the renal pathology in plasma cells dyscrasias, mainly when supported by the most advanced techniques of immunoelectronmicroscopy and polymerase chain reaction (PCR)-mediated analysis. Further elucidation of the molecular events involved in the pathogenesis of the different forms of renal damage is needed to design new and more effective therapeutical strategies. In particular, urinary proteomics seem to be promising in this setting.     

Living Donor Kidney and Autologous Stem Cell Transplantation for Primary Systemic Amyloidosis (AL) with Predominant Renal Involvement

Primary systemic amyloidosis (AL) is characterized by multiorgan deposition of monoclonal immunoglobulin light chain. Renal involvement is common and impaired kidney function is associated with reduced median survival. Autologous stem cell transplantation (SCT) for AL achieves superior response rates compared to chemotherapy alone but patients with end-stage renal disease (ESRD) may be excluded from consideration. A treatment approach consisting of living donor kidney transplantation (LDKTx) followed by autologous SCT was developed for AL with ESRD. Eight patients underwent LDKTx with immediate graft function. Two suffered unanticipated complications post-KTx and died 10 and 3 months later. Two cases of subclinical acute cellular rejection (ACR) and one case of clinical ACR occurred--all reversible with corticosteroid. Six patients had successful stem cell harvests performed and five of these underwent SCT with satisfactory trilineage engraftment. Renal function remained stable following SCT in four and was reduced in one due to infectious and bleeding complications. One patient, who has thus far elected not to undergo SCT, has proteinuria and histologic evidence of recurrent renal amyloidosis. This experience supports the feasibility of sequential living donor KTx and autologous SCT for carefully selected patients with ESRD due to AL.     

Delayed autologous stem cell transplantation following cardiac transplantation experience in patients with cardiac amyloidosis

This study sought to retrospectively investigate the outcomes of patients with light‐chain amyloidosis (AL) with advanced cardiac involvement who were treated with a strategy of heart transplantation (HT) followed by delayed autologous stem cell transplantation (ASCT) at 1‐year posttransplant. Patients with AL amyloidosis with substantial cardiac involvement have traditionally had very poor survival (eg, several months). A few select centers have reported their outcomes for HT followed by a strategy of early ASCT (ie, 6 months) for CA. The outcomes of patients undergoing a delayed strategy have not been reported. All patients with AL amyloidosis at a single institution undergoing evaluation for HT from 2004‐2018 were included. Retrospective analyses were performed. Sixteen patients underwent HT (including two combined heart‐kidney transplant) for AL amyloidosis. ASCT was performed in a total of nine patients to date at a median 13.5 months (12.8‐32.9 months) post‐HT. Survival was 87.5% at 1 year and 76.6% at 5 years, comparable to institutional outcomes for nonamyloid HT recipients. In addition to these 16 patients, two patients underwent combined heart‐lung transplantation. A strategy of delayed ASCT 1‐year post‐HT for patients with AL amyloidosis is feasible, safe, and associated with comparable outcomes to those undergoing an earlier ASCT strategy.     

Clinicopathological characteristics of renal light chain deposition disease coexisted with cast nephropathy

Objective To investigate the clinicopathological characteristics of renal light chain deposition disease coexisted with cast nephropathy (LCDD&LCN). Methods Patients with LCDD&LCN (n=10), isolated LCDD (I-LCDD, n=21) and isolated LCN(I-LCN, n=17) diagnosed by renal biopsy in Peking University First Hospital from January 1, 2000 to March 31, 2018 were enrolled, and all cases were examined by light microscopy, immunofluorescence (IF) (including light chain) and electron microscopy (EM). The semi-quantitative evaluation of the main features of renal pathology was performed. The clinical manifestations and pathological features were reviewed and compared. Results LCDD&LCN was more prevalent in middle-aged males. Nine patients showed acute renal insufficiency with small molecular proteinuria (97.1%) and microscopic hematuria. The hematologic diseases included 9 patients of multiple myeloma. The type of monoclonal light chain in serum and urine by immunofixation electrophoresis showed λ dominant (5/8). By light microscopy, glomerular lesions presented with mild mesangial proliferation in most patients, and only one of them displayed mesangial nodular sclerosis. At the same time, acute tubular injury with light chain casts was the prominent feature, and the clinical manifestations and histological features of LCDD&LCN were similar to that of I-LCN. IF revealed linear staining of monoclonal light chain along the glomerular basement membrane (GBM), tubular basement membrane (TBM) and Bowman's capsule, and also positive in tubular casts. By electron microscopy, diffuse powder-like or granular electron-dense deposits located in the inner side of the GBM, the outer layer of the TBM, renal interstitium and arteriolar walls were observed. Conclusions Patients with LCDD&LCN manifest as acute renal insufficiency, and the majority have multiple myeloma. The pathology of LCDD&LCN possesses the features of both I-LCDD and I-LCN. The IF stain of light chains(κ, λ) and ultrastructural examination by electron microscopy are the inevitable methods for the diagnosis of LCDD&LCN.     

Long-term prognosis of AL and AA renal amyloidosis: a Japanese single-center experience

Background

Few studies have been conducted on the long-term prognosis of patients with amyloid light chain (AL) and amyloid A (AA) renal amyloidosis in the same cohort.

Methods

We retrospectively examined 68 patients with biopsy-proven renal amyloidosis (38 AL and 30 AA). Clinicopathological findings at the diagnosis and follow-up data were evaluated in each patient. We analyzed the relationship between clinicopathological parameters and survival data.

Results

Significant differences were observed in several clinicopathological features, such as proteinuria levels, between the AL and AA groups. Among all patients, 84.2 % of the AL group and 93.3 % of the AA group received treatments for the underlying diseases of amyloidosis. During the follow-up period (median 18 months in AL and 61 months in AA), 36.8 % of the AL group and 36.7 % of the AA group developed end-stage renal failure requiring dialysis, while 71.1 % of the AL group and 56.7 % of the AA group died. Patient and renal survivals were significantly longer in the AA group than in the AL group. eGFR of >60 mL/min/1.73 m² at biopsy and an early histological stage of glomerular amyloid deposition were identified as low-risk factors. A multivariate analysis showed that cardiac amyloidosis and steroid therapy significantly influenced patient and renal survivals.

Conclusions

Our results showed that heart involvement was the major predictor of poor outcomes in renal amyloidosis, and that the prognosis of AA renal amyloidosis was markedly better than that in previously reported cohorts. Therapeutic advances in inflammatory diseases are expected to improve the prognosis of AA amyloidosis.