Familial amyloid polyneuropathy type I (Portuguese): distribution and characterization of renal amyloid deposits

Renal amyloidosis has been considered rare and late in the evolution of the transthyretin (TTR) familial amyloid polyneuropathy (FAP) of the Portuguese type (type I). Renal biopsy has been performed systematically in 14 patients with FAP type I before liver transplantation. In all patients, TTR Met30 mutation was shown. Seven had proteinuria or abnormal microalbuminuria, whereas seven others had no urinary abnormalities. All had renal amyloid deposition predominantly in the medulla. Glomerular and vascular involvement was more prominent in patients with urinary abnormalities. Patients with the most extensive renal lesions represented a subgroup with a low score of polyneuropathy disability, a high prevalence of nephropathy in the proband generation, or a late onset for relatives with nephropathy. Immunohistochemistry studies showed that the amyloid substance corresponded to transthyretin. We have shown that renal TTR-derived amyloid deposition is common in patients with FAP type I, even in the absence of urinary abnormalities. The clinical presentation of nephropathy is not a late occurrence in the disease.     

Transthyretin-derived amyloid deposition on the gastric mucosa in domino recipients of familial amyloid polyneuropathy liver.

Familial amyloid polyneuropathy (FAP) is a form of hereditary generalized amyloidosis. Liver tissue explanted from FAP patients has normal structure and function, except for the production of amyloidogenic variant transthyretin (TTR), and domino liver transplantation (DLT) using grafts from FAP patients was first performed in 1995. FAP symptoms usually develop in genetically determined individuals after the age of 20, but it is difficult to estimate when FAP symptoms will appear in domino recipients. Concerning this problem, histological findings showing amyloid deposition have recently been obtained in a few domino recipients of FAP livers. This study investigated the presence of de novo amyloid deposition in the gastroduodenal mucosa of domino recipients transplanted at our institution. Biopsy of gastroduodenal mucosa was carried out in 5 recipients of FAP livers and TTR-derived amyloid deposits were detected in 2 patients, both of whom had undergone DLT 47 months previously. In FAP liver recipients, de novo systemic amyloid deposition may begin much sooner than previously supposed. Therefore, careful follow-up of domino recipients of FAP livers is required.     

No ocular involvement in familial amyloidotic polyneuropathy ATTR V30M domino liver recipients

In many transplantation centers domino liver transplantation is an established procedure, increasing the number of available liver grafts. Increasingly, grafts from familial amyloidotic polyneuropathy (FAP) patients are used. Ocular involvement is a well known manifestation of FAP, and can be vision-threatening. The aim of this study was to evaluate the risk of development of familial amyloidotic polyneuropathy ocular manifestations in domino liver recipients. Forty-four cirrhotic patients submitted to liver transplantation were studied, with an average of 6 years of follow up after the procedure. Twenty two patients had received a liver from a FAP donor (Group 1) and 22 had received a liver from a non-FAP cadaveric donor (Group 2). Both groups were similar for mean age and gender. Routine ophthalmological examinations with particular attention to amyloid deposition in the anterior segment and vitreous, peripheral retina state, lacrimal functions tests (Schirmer and tear break-up time) and pupillometry (dynamic and static) were performed. No statistically significant differences were observed in all studied ophthalmic parameters between the two groups. No FAP related ophthalmic manifestations were detected after 6 years of domino liver transplantation, but further prospective regular ophthalmological examinations are necessary to detect the eventual development of late ocular manifestations.     

Riesgos potenciales de la estimulación nerviosa eléctrica cubital para monitorización de la transmisión neuromuscular: reporte de un caso de polineuropatía amiloidótica familiar

Transthyretin familial amyloid polyneuropathy (FAP) is a rare autosomal dominant disease that provokes systemic deposition of amyloid. It affects the nervous system and it is characterized by progressive sensory, motor, and autonomic neuropathy. Patients with FAP often require surgery and anesthetic care for hepatic transplantation and cardioverter-defibrillator/pacemaker implantation. Peripheric neuropathy is a common finding, but there are no reported cases of its interference with anesthetic neuromuscular transmission monitoring.We report a case of a FAP patient where lack of awareness and distracting factors led to misinterpretation of neuromuscular monitoring and unnecessary sedation and ventilation in the post anesthetic care unit. FAP may interfere with the usual cubital nerve neuromuscular monitoring. Anesthesiologists should be aware of potential neuromuscular compromise to find the best monitoring location for each patient. Sugammadex was safe and reliable in the antagonism of rocuronium neuromuscular blockade in this case, despite the lack of adequate quantitative monitoring.     

A different amyloid formation mechanism: de novo oculoleptomeningeal amyloid deposits after liver transplantation

BACKGROUND: Liver transplantation has served as a treatment for patients with familial amyloidotic polyneuropathy (FAP) because variant transthyretin (TTR), the pathogenic protein of FAP, is predominantly produced by the liver. However, the effect on amyloid formation of TTR that is synthesised by the retina and the choroid plexus remains to be elucidated in FAP patients with liver transplants. OBJECTIVE: To investigate changes in ocular tissues and the central nervous system (CNS) of FAP patients after liver transplantation. DESIGN: Clinical study. SETTING: Graduate School of Medical Sciences, Kumamoto University, Japan. INTERVENTION: Transplantation of livers from cadaveric or living donors. MEASUREMENTS: Preoperative measures and postoperative (16-108 months) follow-up of clinical data, including routine ophthalmologic, neurologic, and laboratory evaluations. RESULTS: In 22 patients with FAP related to the amyloidogenic TTR (ATTR) Val30Met and 3 patients with FAP ATTR Tyr114Cys, after liver transplantation, 3 patients began to show evidence of de novo glaucoma, and 1 had vitreous opacity that was caused by the variant TTR. Another three patients showed new amyloid deposits in the pupillary margin, which could lead to glaucoma and vitreous opacity. As for changes in the CNS and levels of total protein and TTR in cerebrospinal fluid (CSF), after liver transplantation, two FAP ATTR Tyr114Cys patients exhibited de novo amyloid deposition in the leptomeninges, and total protein and TTR levels in CSF were significantly increased. CONCLUSIONS: Oculoleptomeningeal involvement in FAP was not prevented by liver transplantation because variant TTR produced by the retina and the choroid plexus forms amyloid fibrils in situ.     

Characterization of end-stage renal disease after liver transplantation in transthyretin amyloidosis (ATTR V30M)

Transthyretin (TTR) amyloidosis, an autosomal-dominant disease, is characterized by peripheral and autonomic neuropathy—familial amyloidotic polyneuropathy (FAP). End-stage renal disease (ESRD) occurs at 10 years after the onset of neuropathy. Orthotopic liver transplantation (OLT) is the usual treatment of choice. We evaluated FAP patients, ATTR V30M, before and after OLT who started dialysis within 3 months after surgery. The 11 patients had an age at the onset of neuropathy of 31.9 ± 6.3 years with a mean evolution of disease to OLT of 4.54 ± 2.5 years. The glomerular filtration rate was <60 mL/min in 2 patients, 2 displayed nephrotic range proteinuria, and 3 had microalbuminuria. Elective pacemaker implantation was necessary in 8 subjects. Post-OLT 3 patients developed proteinuria, 2 of whom showed increasing nephrotic syndrome. Dysautonomia worsened leading to bladder catheterization in 6. In patients with previous normal renal function and proteinuria <3 g/d, the evolution of neuropathy to the first dialysis was 14.6 ± 4.2 years versus 7.5 ± 1.1 among the other subjects. Overall, dialysis was implemented at 7.4 ± 4.9 years after surgery. There was no liver graft dysfunction. The heart evaluation post-OLT showed the following: 3 patients with de novo dysrhythmias requiring pacemaker implantation and 3 with N-terminal pro-natriuretic peptide levels >10,000 pg/mL. Death occurred in 4 subjects at an average of 26 months after initiation of dialysis. Concerning ESRD, there was no clear benefit of transplantation in the early stages. Patients with normal renal function and lower levels of proteinuria showed slower progression to ESRD, irrespective of their duration of neuropathy.     

Changes in renal function in patients with familial amyloid polyneuropathy treated with orthotopic liver transplantation.

BACKGROUND: Familial amyloid polyneuropathy (FAP) is an autosomal dominant disease caused by a point mutation in the gene encoding transthyretin, which is secreted by the liver. Orthotopic liver transplantation (OLT) has been proposed to prevent disease progression. Little is known about long-term changes in renal function and lesions after OLT. METHODS: The renal function of 33 patients with FAP was evaluated (proteinuria, serum creatinine, creatinine clearance) before OLT and over a period of at least 5 years afterwards. A pre-transplantation renal biopsy was performed in 14 patients and a follow-up biopsy in eight patients. RESULTS: Before transplantation, mean serum creatinine concentration was 86 micromol/l (47-126 micromol/l) and creatinine clearance was 71.9+/-31.6 ml/min/1.73 m(2). Proteinuria was detected in 54% of patients (0.3-4 g/day). Pre-transplant renal biopsies (n = 14) revealed glomerular, tubular and vascular amyloid deposits in 90, 58 and 66% of patients, respectively. Eleven patients (33%) died after OLT. Death occurred most frequently in patients having weight losses >7 kg (P<0.05). After transplantation, 25 patients (76%) suffered acute renal failure but only one required dialysis. One month after transplantation, the mean serum creatinine concentration was 134.1+/-73 micromol/l and remained constant during follow-up. Eight patients underwent a second renal biopsy 2 years after transplantation. No significant changes in deposits or renal toxicity due to calcineurin inhibitors were detected. CONCLUSION: Although liver transplantation in FAP does not affect existing renal amyloid deposits, it prevents the progression of renal disease.     

Corino-andrade disease (familial amyloidotic polineuropathy type I) in Spain: Urological and andrological disorders

In our hospital, we have followed a group of patients with familial amyloidotic polyneuropathy (FAP), type I. This disease is characterized by a progressive sensitive-motor and autonomic polyneuropathy. The amyloid fibrils of FAP I contain a mutant transthyretin (TTR) molecule. More than 90% of TTR production occurs in the liver. Thus, therapy with liver transplantation has proved useful. All our patients received this treatment. In this study we describe the urological and andrological disorders caused by FAP type I in 12 patients with low bladder pressure and bladder neck obstruction with micturition disorders. In some males, it was accompanied by impotence and retrograde ejaculation produced by autonomic neuropathy. We believe hepatic transplantation may be the best treatment for this disease.     

The long-term impact of liver transplantation on kidney function in familial amyloidotic polyneuropathy patients

The aim of the study is to evaluate the long-term kidney function after liver transplantation (LTx) in familial amyloidotic polyneuropathy (FAP) Portuguese type patients and compare the findings with patients transplanted for chronic liver disease of other origin. We analysed the medical records of 32 FAP patients who underwent transplantation between 1990 and 1999 with a follow-up of more than 1 year after LTx. The control group consisted of 61 patients who had undergone LTx for chronic liver disease. Kidney function was measured by the glomerular filtration rate (GFR), serum creatinine and urea. There were no differences between the groups in creatinine and urea levels during the follow-up. However, during the first year after transplantation, the increase in creatinine and urea was significantly higher in the control group (P < 0.01). The decline in GFR after transplantation was also more pronounced in the controls (P < 0.01). Initially after LTx, kidney function deteriorated in both FAP and control patients, but the deterioration was more pronounced in the controls. The decline of the FAP patients' kidney function after LTx was not more pronounced than that observed in control patients, although many FAP patients' kidney function was impaired before the procedure, suggesting that LTx may halt the progression of kidney damage caused by amyloid deposition.     

Progression of cardiomyopathy and neuropathy after liver transplantation in a patient with familial amyloidotic polyneuropathy caused by tyrosine-77 transthyretin variant.

Familial amyloidotic polyneuropathy is an inherited form of amyloidosis associated with a mutant form of a protein called transthyretin. The Methionine-30 variant is the most frequent mutation observed. This disorder is caused by deposition of this protein as amyloid in several organs, such as the heart, kidneys, and peripheral nervous system. The disease is always progressive and fatal, and patients die 7 to 10 years after the onset of symptoms. Liver transplantation is at present the only choice for these patients because it provides improvement of symptoms and/or stops progression of the disease in most patients. We report the case of a patient who showed clear progression of cardiomyopathy and neuropathy after liver transplantation.     

Temporary auxiliary liver transplantation from a living donor to an adult recipient with familial amyloid polyneuropathy

A 33-year-old patient with familial amyloid polyneuropathy (FAP) underwent temporary auxiliary partial orthotopic liver transplantation (APOLT) from a living donor with a small-for-size graft. The auxiliary left lobar graft, which weighed only 230 g, was orthotopically transplanted after resection of the recipient's left lobe. The right portal vein was transected to induce compensatory hypertrophy of the left lobar graft. Posttransplant computed tomography showed atrophy of the native liver and hypertrophy of the graft, the volume of which had increased to 446 ml by postoperative day 41. The remnant native liver was removed 6 weeks after APOLT, and there were no signs of liver dysfunction during the postoperative course. Our experience with this case suggests that temporary APOLT is the treatment of choice, guaranteeing a sufficient margin of safety for both donor and recipient, in living donor liver transplants for FAP where the donor's left lobe is disproportionately small.     

Effect of tacrolimus and partial hepatectomy on transthyretin metabolism in rats

Liver transplantation, which serves as treatment of familial amyloidotic polyneuropathy (FAP), and domino liver transplantation, which utilizes resected livers from patients with FAP for treatment of liver diseases, may induce changes in transthyretin (TTR), a pathogenic FAP-related protein. To evaluate this possibility, we performed a 70% hepatectomy or administered tacrolimus to Dark Agouti (DA) rats for 7 days and then measured changes in liver TTR mRNA levels and changes in serum TTR concentrations. After hepatectomy, TTR mRNA levels decreased by 77%; at day 3, they returned to preoperative levels. Except for slightly elevated serum TTR concentrations 12 h after operation, serum TTR levels remained unchanged. Thus, partial hepatectomy did not influence serum TTR concentrations. After tacrolimus administration, TTR mRNA declined by 56% 12 h after the experiment started; however, after day 3, a rebound phenomenon occurred until day 7. Tacrolimus may facilitate serum TTR degradation, although production of TTR in the liver also increased. This finding -- that TTR, the source of FAP-inducing amyloid, did not increase after transplantation -- may help post-transplantation treatment of patients who have FAP and other liver diseases.     

Domino liver transplantation in living donors

Domino liver transplantation (DLT) has been developed as a method to expand the donor pool. In living donors DLT, the prime concern is to avoid any disadvantage to the donor and the first recipient. Seven DLTs were performed among 211 patients who underwent living donor liver transplantation. The domino recipients included six with hepatocellular carcinoma and one with citrullinemia. The domino grafts were obtained from patients with familial amyloid polyneuropathy (FAP) including the left liver in three cases and the right liver in four. Among the seven domino recipients, a 64-year-old woman with advanced hepatocellular carcinoma died of lung metastasis. The other six domino recipients are alive without FAP symptoms. In living donor liver transplantation, because the vessels of the graft from the first donor are not long enough for anastomosis, the hepatic vessels must be left as long as possible when removing the liver from the FAP patients in order to ensure sufficient safety for vascular reconstruction. With careful decision making during the procedure, such as where to divide the vessels in the FAP patients, DLT may help address the shortage of liver grafts.     

Manifestations of transthyretin-related familial amyloidotic polyneuropathy: Long-term follow-up of Japanese patients after liver transplantation

Purpose

To observe which symptoms of transthyretinrelated familial amyloidotic polyneuropathy (FAP) progressed in the long term after liver transplantation (LT), focusing on cardiac, kidney, and ocular symptoms.

Methods

We reviewed the medical records of 34 Japanese patients with FAP, who underwent LT between 1994 and 2006. The mean follow-up period (±SD) after LT was 9.6 ± 3.4 years. Of the 34 patients, 30 had FAP amyloidogenic transthyretin (ATTR) Val30Met, 1 had FAP ATTR Ser50Ile, and 3 had FAP ATTR Tyr114Cys.

Results

The 10-year survival rates from the onset of FAP and from the time of LT were 100% and 91.4%, respectively. Progression of ocular amyloidosis was seen in 17 (50%) patients, 13 of whom had de novo amyloid deposits in the vitreous body; progression of cardiac amyloidosis was seen in 10 (29%) patients, 4 of whom had newly granular sparkling echo on echocardiography, and 9 of whom had newly implanted pacemakers or implantable cardioverter-defibrillators. Although the mean serum creatinine levels did not increase significantly after LT in any of the patients, the estimated glomerular filtration rate had decreased significantly by 7 years after LT.

Conclusion

Although LT is life-saving for patients with FAP, we observed progression of the ocular and cardiac symptoms of FAP in a significant number of these patients over the long term after LT.     

Familial ATTR amyloidosis: microalbuminuria as a predictor of symptomatic disease and clinical nephropathy.

BACKGROUND: Portuguese type familial amyloid polyneuropathy (FAP) is a neuropathic amyloidosis caused by a mutant transthyretin (TTR). Varying degrees of renal involvement have been reported. Our aim was to assess the value of microalbuminuria (MA) for predicting clinical neurological disease and overt nephropathy in TTR-related amyloidosis. METHODS: All subjects had the TTR Val30Met mutation, and were recruited between 1993 and 1999. We have prospectively evaluated 22 asymptomatic gene carriers (7 male, 15 female; mean age 41.6+/-9.6 years) and 32 patients with neuropathy (14 male, 18 female; 36.8+/-8.8 years, on average, 33.0+/-9.3 years at the onset of neuropathy). We measured urinary albumin excretion every year, if asymptomatic, or every 6 months if already affected. Kidney biopsies were performed in patients with normal urinary albumin excretion, MA, and overt nephropathy, respectively. RESULTS: In asymptomatic carriers, persistent MA was detected in eight (36%) subjects. The presence of MA in asymptomatic gene carriers, compared with those having normal urinary albumin excretion, conferred a 4.8-fold risk of developing neuropathy, usually within the subsequent 3 years. Once neurological signs appeared, nephropathy, manifested as MA, progressed to overt nephropathy in one-half of subjects. In patients with neuropathy, 24 (75%) had MA during follow-up: evolution towards clinical renal disease occurred in 14 (58%) and renal failure occurred in five (21%), always after a course of MA. Proteinuria or renal failure without prior persistent MA were never observed in the present patient cohort. Histopathological evaluation did not reveal glomerular lesions other than amyloid deposits to explain abnormal urinary albumin excretion. The amount of mesangial and vascular-pole amyloid deposits was correlated with the degree of albuminuria. CONCLUSIONS: Microalbuminuria represents the first stage of clinical TTR amyloid nephropathy and is premonitory of neuropathy. Its presence identifies a subgroup of patients who are more prone to develop overt nephropathy. Screening of MA may be important to assess disease onset and to recommend liver transplantation in individuals at risk.     

Clinical and biochemical outcome of hepatorenal transplantation for hereditary systemic amyloidosis associated with apolipoprotein AI Gly26Arg

BACKGROUND: Treatment of systemic amyloidosis comprises measures to support failing organ function coupled with attempts to reduce the supply of the respective amyloid fibril precursor protein. Orthotopic hepatic transplantation is effective in familial amyloid polyneuropathy associated with variant transthyretin, because this protein is produced almost exclusively in the liver. Hepatic transplantation has not been performed in hereditary apolipoprotein AI (apoAI) amyloidosis, and the liver's contribution to plasma apoAI levels has not been determined in vivo. METHODS: A 57-year-old Irish man with hereditary systemic amyloidosis associated with apoAI Gly26Arg, which had led to end-stage renal failure and progressive liver dysfunction, underwent hepatorenal transplantation. His outcome was followed clinically and his amyloid deposits were monitored with serum amyloid P component scintigraphy. The proportion of variant apoAI in the plasma was estimated by quantitative isoelectric focusing before and after liver transplantation. RESULTS: Plasma levels of variant apoAI decreased by 50% after liver transplantation, and the patient was asymptomatic 2 years after surgery. Subclinical amyloid deposits that were present in his spleen and heart preoperatively have regressed and stabilized respectively. CONCLUSIONS: Orthotopic liver transplantation substantially reduces the supply of the amyloid fibril precursor protein in hereditary apoAI amyloidosis, and the excellent outcome in this patient probably reflects the balance between deposition and turnover of amyloid having been altered in favor of the latter. These findings support the use of liver transplantation in patients with hereditary apoAI amyloidosis who develop hepatic dysfunction.     

Temporary Auxiliary Partial Orthotopic Liver Transplantation Using a Small Graft for Familial Amyloid Polyneuropathy

Donor shortage is a major issue in liver transplantation. We have successfully performed temporary auxiliary partial orthotopic liver transplantation (APOLT) using a small volume graft procured from a living donor for recipients with familial amyloid polyneuropathy (FAP). The aim of this study was to evaluate this procedure by comparing it with standard living donor liver transplantation (LDLT). We compared 13 recipients undergoing this procedure with 23 recipients undergoing a standard LDLT for the treatment of FAP. The estimated donor graft volume and the graft volume/recipient's standard liver volume ratio were significantly smaller in the temporary APOLT group than in the standard LDLT group. Postoperative complications were comparable, although the hospital stay was longer in the temporary APOLT group. All the patients safely underwent a remnant native liver resection about 2 months after their first operation in the temporary APOLT group. No symptoms related to FAP developed before the remnant liver resection, and no significant differences in graft and patient survival were observed between the two groups. We successfully performed temporary APOLT using a small volume liver graft without postoperative liver failure for FAP. Temporary APOLT for FAP might be a useful alternative procedure for expanding the donor pool for LDLT.     

Variant transthyretin in blood circulation can transverse the blood-cerebrospinal barrier: qualitative analyses of transthyretin metabolism in sequential liver transplantation

BACKGROUND: Although the choroid6 plexus of the brain is one of the most important production sites of transthyretin (TTR), the metabolism of TTR secreted in cerebrospinal fluid (CSF) remains to be elucidated. METHODS: To perform qualitative analysis of variant TTR in CSF of patients who underwent a sequential liver transplantation using an explanted familial amyloidotic polyneuropathy (FAP) ATTR Val30 Met patient's liver, levels and forms of TTR of the two patients were analyzed by means of enzyme linked immunosorbent assay (ELISA) and matrix-assisted laser desorption/time-of-flight mass spectrometer (MALDI/TOF-MS), respectively. RESULTS: After the operation, variant TTR levels in serum increased, and in CSF, a significant peak of free form of ATTR Val30 Met was detected in the transplanted patients whose CSF had shown no variant TTR before the operation. CONCLUSIONS: These findings suggest that the variant TTR can cross-the blood-CSF barrier and migrate into CSF from blood circulation. Because leptomeningeal amyloidosis occurs in FAP ATTR Val30 Met as the progression of the disease, this information suggests that in addition to peripheral neuropathy, disorders of the central nervous system (CNS) should be given an attention in patients who underwent sequential liver transplantation using an explanted FAP ATTR Val30 Met patient's liver.     

Operative Risks of Domino Liver Transplantation for the Familial Amyloid Polyneuropathy Liver Donor and Recipient: A Double Analysis

Although domino liver transplantation (LT) is an established procedure, data about the operative risks are limited. This study aimed at evaluating the operative risks of domino LT. Two retrospective analyses were conducted (comparison of familial amyloid polyneuropathy [FAP] liver donors [61 patients] vs. FAP nondonors [39 patients] and FAP liver recipients [61 patients] vs. deceased donor liver recipients [61 patients]). First analysis showed a 60‐day mortality of 6.6% for FAP donors and 7.7% for FAP nondonors (p = 1.0). No patient developed primary graft nonfunction. Acute rejection was higher in FAP nondonors compared to FAP donors (38.5% vs. 13.1%). Both groups had similar vascular and biliary complication rates. ICU stay was similar, whereas total hospitalization was longer for FAP nondonors. Both groups had similar 1‐ and 5‐year patient and graft survival rates (83.4% vs. 87.2%, and 79.8% vs. 71.8%, p = 0.7) and (83.3% vs. 87.2%, and 79.1% vs.71.8%, p = 0.7). The second analysis showed a 1.6% mortality for FAP liver recipients vs. 3.2% of the control group (p = 1). Both groups had similar morbidity and technical complication rates (18.0% vs. 13.1%, p = 0.45) and (0.18 vs. 0.15, p = 0.65). The domino procedure does not add any risk to FAP donor or recipient. It increases the organ pool allowing transplantation of marginal recipients who otherwise are denied deceased donor liver transplantation.     

Presence of autoantibody against ATTR Val30 Met after sequential liver transplantation

BACKGROUND: Recently, sequential liver transplantation has been performed with an explanted liver from a patient with familial amyloidotic polyneuropathy (FAP) because of the shortage of donors. However, metabolism of amyloidogenic transthyretin (ATTR), the pathogenic protein of FAP, has not been well studied in patients who have undergone sequential liver transplantation. The purpose of this study was to examine the changes in serum ATTR levels and to investigate the presence of an autoantibody in patients who underwent sequential liver transplantation with an explanted organ from a patient with heterozygotic FAP (FAP ATTR Val30Met). METHODS: This was a case study performed at the Kumamoto University School of Medicine, Kumamoto, Japan, and Kyoto University School of Medicine, Kyoto, Japan. Intervention occurred by sequential liver transplantation with an explanted FAP patient's liver. Levels of normal TTR and ATTR in the two patients who received the transplanted liver were analyzed by means of an enzyme-linked immunosorbent assay (ELISA) and a matrix-assisted laser desorption/time-of-flight mass spectrometry. In addition, the presence of an autoantibody against ATTR Val30Met was evaluated via ELISA using purified ATTR Val30Met from homozygotic FAP patients' sera. RESULTS: After the operation, the variant TTR levels were unexpectedly lower than levels of normal TTR in serum samples from patients with a transplanted liver from the FAP patient. An autoantibody against the variant TTR was detected on day 3 after the operation in the serum of those patients and continued to be present for at least 2 months after the operation. CONCLUSIONS: An autoantibody against the variant TTR may reduce the serum levels of variant TTR. Although the antibody may play a beneficial role in reducing the pathogenic protein, the long-term effect of the antibody must be investigated further.