Equine cutaneous amyloidosis derived from an immunoglobulin lambda-light chain. Immunohistochemical, immunochemical and chemical results

Paraneoplastic Syndromes in Horses

This article discusses the reported paraneoplastic syndromes (PNSs) in horses, including the possible pathogenesis, diagnostic methods, and any treatment options. The more commonly reported PNSs in horses include cancer anorexia and cachexia, fever and increased acute phase protein concentrations, and hypercalcemia and monoclonal gammopathy. As these conditions can often be more commonly diagnosed in non-neoplastic conditions, the diagnosis of a PNS and the accompanying neoplasia can be challenging. As signs of a PNS may precede signs of the underlying neoplasia, it is important that the clinician be aware of the possible presence of a PNS.

Systemic AL kappa chain amyloidosis in a captive Bornean orangutan (Pongo pygmaeus)

Systemic amyloid light-chain (AL) amyloidosis is an infrequent disease in which amyloid fibrils derived from the immunoglobulin light chain are deposited in systemic organs, resulting in functional impairment. This disease has been notably uncommon in animals, and nonhuman primates have not been reported to develop it. In this study, we identified the systemic AL kappa chain amyloidosis in a captive Bornean orangutan (Pongo pygmaeus) and analyzed its pathogenesis. Amyloid deposits were found severely in the submucosa of the large intestine, lung, mandibular lymph nodes, and mediastinal lymph nodes, with milder lesions in the liver and kidney. Mass spectrometry-based proteomic analysis revealed an abundant constant domain of the immunoglobulin kappa chain in the amyloid deposits. Immunohistochemistry further confirmed that the amyloid deposits were positive for immunoglobulin kappa chains. In this animal, AL amyloidosis resulted in severe involvement of the gastrointestinal submucosa and lymph nodes, which is consistent with the characteristics of AL amyloidosis in humans, suggesting that AL amyloid may have a similar deposition mechanism across species. This report enhances the pathological understanding of systemic AL amyloidosis in animals by providing a detailed characterization of this disease based on proteomic analysis.

Immunohistochemical Detection of Multiple Myeloma 1/Interferon Regulatory Factor 4 (MUM1/IRF-4) in Canine Plasmacytoma: Comparison with CD79a and CD20

Multiple myeloma oncogene 1/interferon regulatory factor 4 (MUM1/IRF4) is involved in lymphoid cell differentiation, particularly in the production of plasma cells. We examined the immunoreactivity of mouse monoclonal antibody Mum-1p to MUM1/IRF4 and compared it with expression of CD79a and CD20 in 109 plasmacytomas in 107 dogs. Tissues had been fixed in formalin and embedded in paraffin. One hundred one of 109 (93.5%) tumors were positive for MUM1/IRF4. The staining was nuclear with weak cytoplasmic reaction. Fifty-nine of 105 (56.2%) plasmacytomas were positive for CD79a; only 21 of 108 (19.4%) cases were positive for CD20. MUM1/IRF4 staining was performed on 139 other tumors including B- and T-cell lymphomas, histiocytic proliferations, mast cell tumors, and melanocytic tumors. The only MUM1/IRF4-positive nonplasmacytic tumors were 10 B-cell lymphomas and 1 anaplastic lymphoma. We conclude the following: 1) Antibody Mum-1p is very specific for canine plasmacytomas, 2) antibody Mum-1p is superior in sensitivity and specificity to CD79a and CD20 for the identification of canine plasmacytomas in formalin-fixed, paraffin-embedded tissues, 3) canine lymphomas that express MUM1/IRF4 are few and usually of B-cell origin, 4) other canine leukocytic and melanocytic tumors do not express MUM1/IRF4, and 5) prospective studies are needed to determine whether the expression of MUM1/IRF4, particularly in lymphomas, has prognostic significance.

Prion and prion-like diseases in animals

Transmissible spongiform encephalopaties (TSEs) are fatal neurodegenerative diseases characterized by the aggregation and accumulation of the misfolded prion protein in the brain. Other proteins such as β-amyloid, tau or Serum Amyloid-A (SAA) seem to share with prions some aspects of their pathogenic mechanism; causing a variety of so called prion-like diseases in humans and/or animals such as Alzheimer's, Parkinson's, Huntington's, Type II diabetes mellitus or amyloidosis. The question remains whether these misfolding proteins have the ability to self-propagate and transmit in a similar manner to prions. In this review, we describe the prion and prion-like diseases affecting animals as well as the recent findings suggesting the prion-like transmissibility of certain non-prion proteins.

Proteomic analysis of highly prevalent amyloid A amyloidosis endemic to endangered island foxes

Amyloid A (AA) amyloidosis is a debilitating, often fatal, systemic amyloid disease associated with chronic inflammation and persistently elevated serum amyloid A (SAA). Elevated SAA is necessary but not sufficient to cause disease and the risk factors for AA amyloidosis remain poorly understood. Here we identify an extraordinarily high prevalence of AA amyloidosis (34%) in a genetically isolated population of island foxes (Urocyon littoralis) with concurrent chronic inflammatory diseases. Amyloid deposits were most common in kidney (76%), spleen (58%), oral cavity (45%), and vasculature (44%) and were composed of unbranching, 10 nm in diameter fibrils. Peptide sequencing by mass spectrometry revealed that SAA peptides were dominant in amyloid-laden kidney, together with high levels of apolipoprotein E, apolipoprotein A-IV, fibrinogen-α chain, and complement C3 and C4 (false discovery rate ≤ 0.05). Reassembled peptide sequences showed island fox SAA as an 111 amino acid protein, most similar to dog and artic fox, with 5 unique amino acid variants among carnivores. SAA peptides extended to the last two C-terminal amino acids in 5 of 9 samples, indicating that near full length SAA was often present in amyloid aggregates. These studies define a remarkably prevalent AA amyloidosis in island foxes with widespread systemic amyloid deposition, a unique SAA sequence, and the co-occurrence of AA with apolipoproteins.

A concise review of amyloidosis in animals

Amyloidosis refers to a group of protein misfolding diseases characterized by deposition of a particular amyloid protein in various organs and tissues of animals and humans. Various types and clinical forms of amyloidosis, in which the pathology and pathogenesis is diverse depending upon the underlying causes and species affected, are reported in domestic and wild animals. The clinical findings are also quite variable consequent to the variation of the tissues and organs involved and the extent of functional disruption of the affected organs in various animal species. The affected organs may be enlarged and exhibit variable pallor grossly, or the amyloid deposit may be discernible only after microscopic examination of the affected tissues. Amyloid appears as a pale eosinophilic homogenous extracellular deposit in tissues. However, microscopic examination and Congo red staining with green birefringence under polarized light are needed to confirm amyloid and differentiate it from other apparently similar extracellular deposits such as collagen and fibrin. Identifying the type of amyloid deposit needs immunohistochemical staining, ultrastructural characterization of the amyloid fibril, and if feasible also genetic studies of the involved species for clinical and prognostic purposes. This paper provides a concise review of the occurrence of amyloidosis in domestic and wild animals.

Increasing fatal AA amyloidosis in hunting falcons and how to identify the risk: a report from the United Arab Emirates

In hunting falcons, a fatal syndrome of wasting, weight loss, green mutes and, finally, sudden death of emaciated birds has been observed in the United Arab Emirates (UAE). Histological examination using Congo red has revealed amyloid in most organs, in particular in the liver, spleen, kidney, and adrenal glands. Moreover, a retrospective study revealed amyloidosis in 100 cases among a total of 623 necropsied falcons between August 1995 and March 2004 in Dubai/UAE (16%; varying from 8 to 30% in different raptor bird species). The amyloid was immunohistochemically classified as amyloid A (AA), which was confirmed by Western blot analysis and N-terminal amino acid sequence analysis, suggesting it to be secondary to a chronic inflammatory process. Retrospective analysis has indicated a significantly increased prevalence of bumble foot and visceral gout among falcons with amyloidosis. In addition, a significant increase of amyloidosis from 5.6% of necropsied falcons with amyloidosis in 1995 to 40.0% in 2004 has been noticed. Finally, a semi-quantitative serum test for falcon serum amyloid A (f-SAA) has been developed. Among 38 falcons with fatal AA amyloidosis, f-SAA was increased pathologically in 36, whereas f-SAA was elevated in only one of 15 apparently disease-free falcons (p < 0.001). This significant result indicates that a normal f-SAA will indicate a minimal or even absent risk of succumbing to AA amyloidosis.

Systemic AL amyloidosis associated with multiple myeloma in a horse

AL amyloidosis is the most common type of systemic amyloidosis in humans, and it is frequently associated with multiple myeloma. But, AL amyloidosis is very rare in domestic animals. A 16-year-old Quarter horse gelding was diagnosed with systemic AL amyloidosis associated with multiple myeloma. Clinical problems were rapid weight loss, muscle atrophy, soft unformed stool, and ventral edema. Grossly, diffuse gastrointestinal hemorrhage, markedly thickened jejunal mucosa, and splenomegaly were present. Microscopically, diffuse severe amyloid deposits were present in the lamina propria of glandular stomach, duodenum, and jejunum. Much of the spleen and sternal bone marrow was replaced by neoplastic round cells, and multiple foci of amyloid were also present in the spleen and bone marrow. Electron microscopy revealed the neoplastic round cells to be of plasma cell origin, and the amyloid showed a strongly positive immunoreactivity with polyclonal anti-human immunoglobin lambda light-chain antisera. To our knowledge, this is the second report describing systemic AL amyloidosis in domestic animals-associated plasma cell neoplasia and the first associated with multiple myeloma, as is common in humans.

Intestinal multinodular A lambda-amyloid deposition associated with extramedullary plasmacytoma in three dogs: clinicopathological and immunohistochemical studies

Intestinal extramedullary plasmacytomas (EMPs) are rare tumours in dogs. Three cases of canine intestinal EMP with amyloid deposits are described in this report. These tumours, which were located in the rectal submucosa, had variable numbers of well-differentiated plasma cells and fewer multinucleated giant cells of plasmacytoid and histiocytic morphology, admixed with abundant amyloid. Two cases had metaplastic cartilage and bone within the amyloid deposits. Immunohistochemically, the plasma cells of all three tumours reacted for lambda-light chains of immunoglobulins but not for kappa-chains, indicating monoclonality. Plasma cells of two tumours were also positive to CD79a antiserum. Amyloid deposits were labelled with an A lambda (amyloid of immunoglobulin lambda-light chain origin) antiserum but not with antisera against its precursor protein, the immunoglobulin lambda-light chains, indicating possible conformational changes of amyloidogenic proteins during their transformation into amyloid.

Identification of lambda light chain amyloid in eight canine and two feline extramedullary plasmacytomas

Amyloid deposition in varying amounts and with variable patterns of distribution (focal or diffuse) was demonstrated in eight canine and two feline extramedullary plasmacytomas expressing lambda light chains. Frequently, the neoplastic plasma cells had been displaced by the amyloid deposits. Foreign-body giant cells were regularly detected in the vicinity of the amyloid. In all 10 cases, Congo-red staining of the amyloid was resistant to potassium permanganate oxidation. Immunohistochemically, the amyloid reacted positively with cross-reacting antibodies against human and equine A lambda amyloids. Extramedullary plasmacytomas accompanied by localized AL amyloidosis have so far been described in human beings, dogs, cats and horses.

Immunohistochemical examination of light-chain expression (lambda/kappa ratio) in canine, feline, equine, bovine and porcine plasma cells

Five species of domestic animals were examined immunohistochemically and the light-chain ratios of the immunoglobulins produced by plasma cells analysed. Forty dogs, 11 cats, 10 horses, 11 cattle and 14 pigs were tested using the sequential indirect immunoperoxidase and immunophosphatase methods. Tissues from the tonsils, spleen and cervical lymph nodes were analysed. It could be seen that the lambda/kappa ratio in dogs, cats, horses and cattle is largely dominated by the lambda chains (lambda/kappa ratio in dogs: 91/9%, in cats; 92/8%; in horses: 96/4%; in cattle: 91/9%). A more or less balanced ratio was observed only in the case of the pigs (52/48%).

Senile amyloidoses of the pituitary and adrenal glands. Morphological and statistical investigations

The pituitary and adrenal glands are a functional endocrine unit affected by local or organ-limited senile amyloid syndromes. These occur as interstitial (pituitary only) or intracellular (pituitary and adrenal) varieties. The pituitary and right adrenal glands of each of 108 consecutive autopsy cases of individuals aged 85 years and over were investigated for the prevalence, distribution and immunostaining characteristics of local amyloid. Intracellular amyloid was detected in 77 (71%) pituitaries and 73 (68%) adrenals. Interstitial amyloid was found in 86 pituitaries (80%). Immunohistochemical studies, investigating different amyloid fibril proteins, amyloid P component, ubiquitin, intermediate filaments and pituitary hormones, failed to demonstrate any similarities, and a common origin is unlikely. Statistical analyses demonstrated significant correlations between the occurrences of all three local amyloids. The clinical and histopathological significance of local pituitary and adrenal amyloid remains obscure. The results suggested that the pathogenesis of the local senile amyloidoses of the pituitary and adrenals may be influenced by a common, still uncharacterized variable. It is not clear whether this variable also contributes to the pathogenesis of other senile amyloid syndromes, such as those associated with Alzheimers' disease.

Generalised AA-amyloidosis in a bat (Pipistrellus pipistrellus)

Generalized amyloidosis was found to be the cause of death in a female adult insectivorous pipistrelle bat (Pipistrellus pipistrellus) after chronic wound inflammation. Large amounts of amyloid were detected in liver, spleen, kidneys, stomach, intestine, lymphatic tissues, and endocrine and salivary glands. Congo red staining and green birefringence identified amyloid; the Congo red staining was sensitive to potassium permanganate oxidation. The amyloid was further classified immunohistochemically. The deposits reacted with two anti-human-AA-amyloid monoclonal antibodies in a peroxidase-antiperoxidase reaction, whereas no reaction was found with antibodies specific for other types of amyloid. Thus, the bat amyloid deposits were identified as generalized reactive AA-amyloidosis.

Amyloid Deposits in Pituitaries and Pituitary Adenomas: Immunohistochemistry and In Situ Hybridization

The patterns of deposition and immunoreactivity of interstitial amyloid were studied in 11 pituitary glands obtained at autopsy and 9 surgically resected pituitary adenomas using Congo red staining and a panel of antisera directed against 5 major amyloid fibril proteins and all pituitary hormones. The deposition pattern of amyloid in pituitary glands differed from that in adenomas but all amyloid deposits showed an immunostaining with anti-amyloid X-light chain. The remaining antisera were immunonegative. In situ hybridization using an oligodeoxyribonucleotide-probe complementary to the mRNA coding for the constant region of human X-light chain yielded no hybridization signals in the pituitaries or pituitary adenomas, excluding local synthesis and secretion of immunoglobulins. Since no case studied suffered from generalized AX-amyloidosis and adsorption of immunoglobulins to the unknown amyloid fribril protein of the pituitary seems to be unlikely, crossreaction of the polyclonal antisera with an undefined antigen is probable. The similar immunostaining properties of amyloid deposits in "normal" pituitaries and pituitary adenomas suggest they both originate from the same precursor protein.

Amyloid deposits of the pituitary in old age: Correlation with histopathological alterations

The prevalence and quantification of amyloid formation and the frequency of histomorphological alterations affecting the pituitary gland were studied in a consecutive autopsy series performed on 109 patients older than 84 years of age; 87 (80%) pituitaries had amyloid in the anterior lobe. A polyclonal antibody directed against amyloid of A-light chain origin immunostained pituitary amyloid in every specimen, whereas all other antisera directed against the precursor proteins of the remaining major amyloid syndromes and pituitary hormones did not. Because no case studied suffered from a generalized A-light chain amyloidosis, immunostaining might be due to crossreaction with a hitherto unidentified precursor protein. Histomorphological alterations were observed in many pituitaries, and they were differentiated into regressive changes, cysts of the intermediate zone, so called basophilic invasion of the posterior lobe, hyperplasia, Erdheim's squamous epithelia, and adenomas. Statistical analysis failed to reveal any correlations between the presence of histopathological alterations and the frequency or the amount of interstitial amyloid. Nonetheless, we were not able to explain amyloid formation in old age, especially none that was due to histomorphological alterations of the pituitary gland. Thus, other diseases that primarily do not affect the pituitary may actually influence pituitary amyloid formation.

Gastrointestinal amyloid deposits in old age. Report on 110 consecutive autopsical patients and 98 retrospective bioptic specimens

The prevalence of gastrointestinal amyloid was determined in 110 consecutive autopsy patients aged 85 years and older. Paraffin sections from the esophagus, stomach, small intestine, colon and rectum were stained with Congo red and inspected in polarized light. Amyloid was found in 38 patients (36%). Four patients had generalized amyloidosis and the remaining 34 revealed more localized varieties of amyloid. Immunohistochemical classification with a panel of antisera directed against five major amyloid fibril proteins displayed at least four different types of amyloid. Twenty cases exhibited amyloid of transthyretin origin, five cases were of lambda light chain origin and one case was of amyloid A-type. Thus far, unclassifiable amyloid deposits were found in 18 cases, 16 of which were strictly localized in subserosal veins. This consecutive autopsy series was compared with 98 randomly-selected bioptical gastrointestinal tissues with amyloid according to distribution pattern, sex, frequency of the various types of amyloid and associated diseases.

Light microscopic, ultrastructural, and immunohistochemical examinations of two calcifying epithelial odontogenic tumors (CEOT) in a dog and a cat

Two calcifying epithelial odontogenic tumors from a 10-year-old cross-breed dog and a 9-year-old cat were characterized histologically and electron microscopically. Important characteristics were plexiform to squamous epithelial structure, amyloid in the tumor tissue with partial calcification (Liesegang's rings), and a low rate of mitosis. The amyloid found in the tumors was subjected to immunohistochemical examination, using a series of antibodies (anti-AA, -AL, -AF, -ASc1, -AB, -cytokeratin, -vimentin, -desmin, -laminin). The exclusive reaction to anti-cytokeratin and anti-laminin suggests that the amyloid is of epithelial origin.