Carl J. O’Hara

Bone Marrow Core Biopsy Specimens in AL (Primary) Amyloidosis

We retrospectively reviewed 100 bone marrow core biopsy specimens from patients with AL (primary) amyloidosis. The morphologic and immunohisto-chemical features were assessed by standard histochemical stains (HEκ, 18) of cases. Amyloid deposits were observed in 60% of the bone marrow core biopsy specimens and, when present, were detected most often in blood vessel walls only (39/60). However, if present, interstitial amyloid deposition was significantly more associated with patients with a monoclonal κ light chain gammopathy ( P = .04). Through the careful analysis of standard histochemical and immunohistochemical stains, bone marrow core biopsy provides essential diagnostic information in cases of AL amyloidosis.

Amyloid deposits in the bone marrow of patients with immunoglobulin light chain amyloidosis do not impact stem cell mobilization or engraftment.

Amyloid deposits are often found in the bone marrow in patients with Immunoglobulin light chain (AL) amyloidosis. We sought to determine whether this affects stem cell collection or engraftment after high-dose melphalan and autologous stem cell transplantation (HDM-SCT). We reviewed data on 361 patients with AL amyloidosis who had Congo red staining of pretreatment bone marrow biopsy specimens and underwent HDM-SCT between July 1994 and December 2011. We analyzed data on stem cell yield, days of stem cell collection, and days to neutrophil and platelet engraftment posttransplantation. Bone marrow amyloid deposits were found in 65% of patients (n = 233). There were no significant differences in median number of stem cells collected and days to neutrophil or platelet engraftment between patients with bone marrow amyloid deposits and those without these deposits. Thus, our data indicate that although amyloid involvement of the bone marrow is common, it does not negatively affect stem cell mobilization or neutrophil and platelet engraftment after HDM-SCT.

A new lysozyme tyr54asn mutation causing amyloidosis in a family of Swedish ancestry with gastrointestinal symptoms

Familial amyloidoses are a group of inherited disorders that cause deposition of misfolded amyloidogenic proteins in various tissues, resulting in organ dysfunction. Point mutations in the coding region of seven different genes are known to cause clinically significant systemic amyloid disease. We describe a new mutation in exon 2 of the lysozyme gene associated with amyloidosis (ALys) in a 61-year-old woman with a 7-year history of non-bloody, watery diarrhea, and weight loss. Biopsies of the duodenum and stomach were positive for amyloid deposits in the lamina propria and blood vessels. Direct DNA sequencing of the lysozyme gene revealed a single base nucleotide transversion from T to A at the first position of codon 54, resulting in replacement of Tyr by Asn in the mature lysozyme protein (pTyr54Asn). Immunoblot analysis of amyloid fibrils extracted from a fat tissue sample confirmed lysozyme as the amyloid protein. Clinically, the phenotype associated with this lysozyme mutation featured chronic abdominal pain, diarrhea, weight loss, malabsorption, and sicca syndrome. There was no associated nephropathy as has been reported for other ALys mutations. We describe a new mutant lysozyme that presents with abdominal discomfort, diarrhea, weight loss, and sicca syndrome.

Lymphadenopathy as a manifestation of amyloidosis: a case series

Abstract Lymphadenopathy as a manifestation of amyloidosis is rare. Of 3008 new patients with amyloidosis evaluated from 1994 to 2013 at a single center, 47 (1.6%) presented with lymph node enlargement leading to a biopsy and the diagnosis. We conducted a retrospective review of the initial presentation, time to progression, and treatment outcomes for these patients. Upon initial evaluation, 14 (30%) had isolated lymphadenopathy while 33 (70%) had evidence of vital organ involvement. Thirty-nine patients (83%) had systemic AL amyloidosis at initial evaluation or developed it on follow up; there was a single case each of AA, wtTTR and V122ITTR and one untyped amyloidosis. Eleven patients (23%) had IgM monoclonal gammopathy and 3 (6%) had histology consistent with lymphoplasmacytic lymphoma. Of the 14 patients with isolated lymphadenopathy, 10 (71%) eventually progressed to other organ disease requiring treatment at a median time of 10 months (range 4–71). This series demonstrates that patients presenting with amyloid lymphadenopathy usually have AL amyloidosis, and should have a thorough evaluation for other organ involvement at diagnosis. If present, treatment should be similar to that of other patients with systemic AL amyloidosis, but if not, patients should be monitored regularly for development of other organ disease over time.

Dysregulation of miRNAs in AL amyloidosis

Bone marrow plasma cells (BMPCs) were purified using anti-CD138 immunomagnetic beads, from aspirates obtained with permission of the Boston University Medical Campus Institutional Review Board, from patients with immunoglobulin light chain (AL) amyloidosis and from controls. Expression levels of MicroRNAs (miRNAs) were compared by microarray; 10 were found to be increased more than 1.5-fold. These results were confirmed using stem-loop RT-qPCR for the most highly upregulated miRNAs, miR-148a, miR-26a, and miR-16. miR-16, a micro-RNA linked to other hematopoietic diseases, was significantly increased in the AL group at diagnosis, and also in treated patients with persistent monoclonal plasma cells in the bone marrow, but not in patients who achieved a hematologic remission after therapy. miR-16 can be derived from the miR-16-1/mirR-15, a cluster on chromosome 13 or the miR-16-2/miR-15b cluster on chromosome 3. The expression of miR-15b was much higher than miR-15a in both AL and control BMPC, suggesting that miR-16 in plasma cells is mainly derived from miR-16-2/miR-15b. The anti-apoptosis gene BCL-2, a putative target mRNA that can be downregulated by miR-16, was expressed in BMPCs from AL patients, despite elevated levels of miR-16. Our data suggests that miRNAs are dysregulated in clonal plasma cells in AL amyloidosis and may be potentially useful as biomarkers of disease.

Simultaneous presentation of kappa-restricted chronic lymphocytic leukemia and lambda light chain AL amyloidosis

Abstract We report on a 58-year-old man who presented with simultaneous kappa-restricted chronic lymphocytic leukemia (CLL) and a lambda-restricted plasma cell dyscrasia causing AL amyloidosis involving the kidney and GI tract. While monoclonal immunoglobulins occasionally produced by CLL has previously been implicated in AL amyloidosis, this is the first case of AL amyloidosis resulting from a distinct plasma cell dyscrasia that is not clonally related to the concurrent CLL. Appropriate treatment depended on detailed pathologic diagnosis of both disease processes.

Hereditary Renal Amyloidosis Associated With a Novel Apolipoprotein A-II Variant

To the Editor: Systemic amyloidosis is characterized by the extracellular deposition of misfolded proteins as insoluble amyloid fibrils in various tissues. The familial forms of amyloidosis (AF) comprise a group of autosomal dominant diseases associated with mutations in a number of genes encoding amyloid precursor proteins. These diseases collectively exhibit various phenotypes, including ages of onset, organ involvements, rates of progression, and prognoses. Hereditary nonneuropathic, renal amyloidosis was first reported by Ostertag; since that report, mutations in lysozyme, fibrinogen A-a chain, transthyretin, gelsolin, apolipoprotein (apo) A-I, A-II, A-IV, C-II, and C-III have been linked to the disease. apoA-II Amyloidosis (AApoAII) is an exceedingly rare form of AF; only 3 APOA2 mutations have been reported in 4 families worldwide. In each case, a nucleotide replacement at the stop codon of APOA2 resulted in a variant apoA-II with a 21-residue C-terminal extension, 78Argext21, 78Serext21, and 78Glyext21. Human apoA-II (77 amino acids, 17 kDa) is expressed in the liver and is found as a disulfide-linked homodimer in circulation. Nearly all circulatingwild-type apoA-II is strongly bound to plasma high-density lipoprotein (HDL) via the unusually large apolar faces of its amphipathic a-helices. Similar to other exchangeable apolipoproteins, lipid-bound apoA-II acquires a highly a-helical structure on HDL. Strong binding to HDL makes wild-type apoA-II practically nonexchangeable and protected frommisfolding in vivo. However, in the absence of bound lipids in vitro, apoA-II becomes largely unfolded and labile to misfolding and proteolysis. Therefore, a population shift from HDL-bound to HDL-unbound apolipoprotein is thought to augment the development of AApoAII amyloidosis. Notably, apoA-II is the most hydrophobic member of the apolipoprotein family with the highest predicted propensity to form amyloid. Here, we report a family with renal amyloidosis associated with a novel stop codon mutation in APOA2 and the apoA-II variant, 78Leuext21.

Endotracheal hamartoma case report: Two contrasting clinical presentations of a rare entity

Highlights • Hamartomas are benign tumors that are rarely localized to the trachea.• Symptoms often gradual, mimicking those of chronic obstructive pulmonary disease.• Successful management of Endotracheal Hamartomas is feasible using a bronchoscopic approach.• Etiology of endotracheal hamartomas is unknown.• Early suspicion in patients with obstructive pulmonary symptoms can prevent easily avoidable fatal complications.

Retinol-binding protein 4 in transthyretin-associated forms of cardiac amyloidosis: differences in the pathobiologies of mutant (ATTRm) and wild-type (ATTRwt) diseases

The role of retinol-binding protein 4 (RBP4), a natural binding partner of plasma circulating transthyretin (TTR), in TTR-associated cardiomyopathies is unknown. RBP4 is a small (21 kDa) protein that normally functions as a transporter for all-trans retinol (Vitamin A) and travels in the bloodstream as a ternary complex bound to TTR. Previous in vitro studies have demonstrated that RBP4 stabilizes native (tetrameric) TTR and prevents its disassembly into monomers, the key step in TTR amyloid fibril formation. Though increased serum concentrations of RBP4 have been reported in non-amyloidotic cardiomyopathies, there is little information about circulating levels in the inherited (ATTRm) and acquired (ATTRwt) forms of TTR-associated cardiac amyloid disease. Our study objectives were to investigate TTR amyloid-infiltrated cardiac tissue for the presence of RBP4 and to compare serum levels of the protein in ATTRm, ATTRwt and controls. We hypothesized that there would be histological and serological differences in RBP4 between ATTR patient and control samples. In the present study, we demonstrate that RBP4 is highly abundant in ATTRm cardiac tissue surrounding amyloid-infiltrated regions and, to a lesser extent, in ATTRwt specimens. Serum levels of RBP4 are significantly lower in ATTRm compared to ATTRwt (p < 0.0001) and healthy controls (p < 0.0011), with significant correlation between circulating RBP4 concentration and cardiac troponin-I (c-TnI) in our ATTRwt cohort. These data suggest, for the first time, that the pathobiologies of ATTRm and ATTRwt are dissimilar, and provide support for RBP4 as a serum biomarker of amyloid cardiomyopathy in ATTRm. Correspondence to: Lawreen H. Connors, PhD, Amyloidosis Center, Boston University School of Medicine, K-507, 715 Albany Street, Boston, MA 02118, USA. Phone: 617 638-4313; Fax: 617 638-4493; E-mail: lconnors@bu.edu

Transbronchial biopsies safely diagnose amyloid lung disease

Abstract Background: Autopsy identifies lung involvement in 58–92% of patients with the most prevalent forms of systemic amyloidoses. In the absence of lung biopsies, amyloid lung disease often goes unrecognized. Report of a death following transbronchial biopsies in a patient with systemic amyloidosis cautioned against the procedure in this patient cohort. We reviewed our experience with transbronchial biopsies in patients with amyloidosis to determine the safety and utility of bronchoscopic lung biopsies. Methods: We identified patients referred to the Amyloidosis Center at Boston Medical Center with lung amyloidosis diagnosed by transbronchial lung biopsies (TBBX). Amyloid typing was determined by immunohistochemistry or mass spectrometry. Standard end organ assessments, including pulmonary function test (PFT) and chest tomography (CT) imaging, and extra-thoracic biopsies established the extent of disease. Results: Twenty-five (21.7%) of 115 patients with lung amyloidosis were diagnosed by TBBX. PFT classified 33.3% with restrictive physiology, 28.6% with obstructive disease, and 9.5% mixed physiology; 9.5% exhibited isolated diffusion defects while 19% had normal pulmonary testing. Two view chest or CT imaging identified focal opacities in 52% of cases and diffuse interstitial disease in 48%. Amyloid type and disease extent included 68% systemic AL disease, 16% localized (lung limited) AL disease, 12% ATTR disease, and 4% AA amyloidosis. Fluoroscopy was not used during biopsy. No procedure complications were reported. Conclusions: Our case series of 25 patients supports the use of bronchoscopic transbronchial biopsies for diagnosis of parenchymal lung amyloidosis. Normal PFTs do not rule out the histologic presence of amyloid lung disease.