Identification and characterization of different amyloid fibril proteins in tissue sections

Waldenström's Macroglobulinemia Associated With Generalized AA-Amyloidosis

The authors present a case of Waldenström's macroglobulinemia (WM) associated with generalized amyloidosis of amyloid-A type. A 77-year-old man with a 25-year history of degenerative joint disease and a 13-year history of WM died of multisystemic failure. At autopsy, generalized and severe amyloid deposits were detected. Special conventional stains and immunohistochemical examination revealed amyloid-A de posits, which are extinguishingly rare in WM. This is probably related to the disease being chronic, which results in excessive production of precursor protein. The detection of amyloid-A type fibrils was possible only through the application of the immunohis tochemical procedure. The authors emphasize using the immunohistochemical typing of amyloid deposits for the purpose of classification, therapy, and prognosis. Int J Surg Pathol 1 (2):123-128, 1993

Waldenström's macroglobulinemia associated with serum amyloid A protein amyloidosis: pitfalls in diagnosis and successful treatment with melphalan-based autologous stem cell transplant

Waldenström's macroglobulinemia (WM) is increasingly being associated with amyloidosis particularly of the amyloid light-chain variety. We report on one of the few cases of WM associated with serum amyloid A protein (AA) amyloidosis. Autologous stem cell transplant (ASCT) is now being increasingly used for the treatment of amyloidosis, but most studies are small case series. Traditionally AA amyloid is associated with connective tissue disorders and periodic fever syndromes and has been treated by addressing the underlying condition. We present the first case of serum amyloid A being treated with melphalan-based ASCT to deal with the underlying WM and thereby control the amyloid, thus demonstrating the viability of this novel approach for the treatment of this disorder.

Cardiac paraprotein associated with Waldenstrom's macroglobulinemia: a case report

A case of myocardial paraprotein deposition in a patient with Waldenstrom's macroglobulinemia is presented. Routine light microscopy revealed diffuse widening of interstitial regions by pale eosinophilic material that had a grayish cast on trichrome stains and was Congo red negative. Immunofluorescence showed strong immunoglobulin M and kappa light chain staining around blood vessels but predominantly around myocytes. Ultrastructural examination revealed massive deposition of flocculent electron-dense material around myocytes and occasionally around blood vessels.

Multinodular deposition of AA-type amyloid localized in the adrenal glands of an old man

Multinodular amyloid deposits localized in non-neoplastic adrenal glands were found incidentally at autopsy in an 83-year-old Japanese man. Clinically, the patient lacked evident deficiency of adrenal hormones. The nodules of the stromal amyloid deposits were scattered in the adrenal cortex, where the parenchymal cells were compressed and atrophic. The deposits were confirmed to be amyloid by Congo red staining and polarization microscopy. Amyloid fibrils were also demonstrated in the deposits by electron microscopy. The amyloid deposits were permanganate-sensitive and showed immunohistochemical staining for serum amyloid P component and serum amyloid A protein (SAA), implying that they were AA amyloid. There have been no reports describing localized amyloid deposits of the AA type in non-neoplastic adrenal glands. The pathogenesis and clinical significance of the amyloid deposition in the present case remain only speculative.

Seminal vesicle amyloid: the first example of exocrine cell origin of an amyloid fibril precursor

Amyloid fibrils have been extracted from seminal vesicles, and a dominant 14 kD amyloid fibril protein has been identified. An antiserum to this protein reacted both with amyloid and with epithelial cells in some normal seminal vesicles. These reactions were blocked with seminal vesicle secretion and seminal vesicle amyloid fibril protein, but not by degraded amyloid fibrils or fibril protein from other types of amyloid. It is concluded that seminal vesicle amyloid is derived from secretory proteins of the seminal vesicles. As such, it is the first amyloid described which appears to be the product of an exocrine secretory cell.

Use of subcutaneous abdominal fat biopsy specimen for detailed typing of amyloid fibril protein-AL by amino acid sequence analysis

A simple technique for the purification of amyloid fibril proteins from patients with systemic amyloidosis was used on a 45 year old woman. The method is based on the use of a surgical subcutaneous fat tissue biopsy specimen which was used for the characterisation of the amyloid as a kappa I AL-protein by amino acid sequence analysis. The method permits the exact typing of amyloid in many patients with systemic amyloidosis, which, until now has been almost exclusively confined to necropsy tissue.

Pathology of dysproteinemia: light chain amyloidosis, non-amyloid immunoglobulin deposition disease, cryoglobulinemia syndromes, and macroglobulinemia of Waldenström

This review has dealt with four syndromes associated with dysproteinemia, and has emphasized studies of the tissue deposits and forms of tissue injury which occur in such patients. However, similar tissue deposits and tissue damage occasionally occur in the absence of a serum or urine paraprotein, in which case other clinical data are necessary to suggest the need for examination of tissue for Ig heavy and light chain determinants in order to provide a correct diagnosis of dysproteinemia. In such cases, one may speculate that there is a low rate of paraprotein production and secretion, in addition to tissue tropism. Some paraproteins are antibodies, in which case they may circulate and/or deposit as immune complexes, or bind to tissue antigens with immune complex formation in situ. Some paraproteins are also cryoproteins, and clues to this property can also be found in the tissue, particularly at the ultrastructural level. Thus, a wide spectrum of clinical manifestations of a B cell proliferative disorder may be associated with any of a variety of circulating paraproteins and a variety of forms of tissue deposit and injury. Consequently, the best understanding of an individual patient requires correlation of the clinical features of the disorder, the immunochemical characterization of the circulating and excreted paraproteins, and an immunohistochemical analysis of the tissue deposits and associated morphologic abnormalities. This should be correlated with histologic and immunohistologic assessment of bone marrow, looking for overt B cell neoplasia, the more difficult to define "lymphoproliferative disorders," or alterations in kappa to lambda plasma cell ratios which may correlate with the deposited material. Studies of the Ig synthesized by cultured bone marrow plasma cells, and biochemical analyses of the deposited material, have demonstrated structural abnormalities of paraproteins which may be responsible for their tissue deposition.

Methods for staining amyloid in tissues: a review

The traditional way of identifying amyloid in tissue sections has been staining with Congo red and demonstration of green birefringence under crossed polarizers. The original method of Congo red staining, described by Bennhold in 1922, has undergone several modifications to improve its sensitivity, specificity, and reliability. The most common modification is the alkaline Congo red method described by Puchtler and co-workers in 1962. Specificity is improved by using freshly prepared stain and a staining solution fully saturated with sodium chloride. Amyloid proteins can be further distinguished by autoclaving or by treating the tissue with potassium permanganate or alkaline guanidine. Autoclaving the tissues at 120 C for 30 min causes protein AA to lose its affinity for Congo red. Prolongation of autoclaving to 120 min abolishes the Congophilia of protein AL, but prealbumin-related amyloid shows little or no change. Treatment of the tissue with potassium permanganate causes protein AA and B2-microglobulin amyloid to lose their affinity to Congo red. Protein AA fails to stain with Congo red after treatment with alkaline guanidine for 1 min and protein AL and systemic senile amyloid protein (SSA) after 2 hr. Familial amyloid protein (FAP), prealbumin type, can stand 2 hr of alkaline guanidine treatment without losing its ability to stain with Congo red. Other methods of detection of amyloid include fluorescent stains, e.g., thioflavin T or S, and metachromatic stains such as crystal violet. Immunofluorescence and immunoperoxidase methods are used to identify and classify amyloid proteins in tissues. Antibodies against the P component, proteins AA and AL and FAP have been used with great precision. Due to cross-reactivity, these methods do not differentiate between some types of familial and senile systemic amyloidosis.

Demonstration and classification of amyloidosis in needle biopsies of the kidneys, with special reference to amyloidosis of the AA-type

To examine whether sequence-specific antibodies directed against serum amyloid A were useful in the demonstration and classification of amyloidosis, needle biopsy specimens from the kidneys of 152 cases with renal disorders were investigated using the avidin-biotin-peroxidase complex technique of immunohistochemistry. A distinct immunoreactivity of protein AA was seen in biopsies from all 42 individuals who were clinically classified as having the AA-type of amyloidosis. The stained areas coincided with deposits stained by Congo red. Four of these cases demonstrated immunoreactivity of both protein AA and light immunoglobulin chains and all biopsies except one showed immunoreactivity for the amyloid P-component. After treatment with potassium permanganate, the amyloid deposits in the biopsies of all 42 cases lost their affinity for Congo red. Ten patients with clinical and laboratory findings compatible with the AL-type of amyloidosis were also investigated. All their biopsies demonstrated Congophilic amyloid deposits but none of them showed any immunoreactivity of protein AA. Amyloid deposits of lambda light immunoglobulin chains-but not kappa-were demonstrated in biopsies from four patients. The amyloid P-component was found in biopsies from six individuals and positive Congo red staining after treatment with potassium permanganate was seen in biopsies from four of the cases. Biopsies of 100 patients suffering from non-amyloid renal disorders were also examined. None of them displayed any immunoreactive deposits of protein AA. The investigation shows that amyloid deposits of the AA-type can be identified in needle biopsies when sequence-specific antibodies against serum amyloid A are used in the avidin-biotin-peroxidase complex technique. Both the diagnostic sensitivity (42 of 42) and specificity (110 of 110) of the assay were optimal (1.0). The method was found to be superior to other investigated techniques and useful for classifying amyloidosis in formalin-fixed renal biopsies.

The prevalence of renal amyloidosis of the AA-type in a series of 1,158 consecutive autopsies

To determine the prevalence of renal amyloidosis of the AA-type in a defined population, formalin-fixed specimens from the kidneys of all the cases autopsied in 1983 at The General Hospital of Malmö, Sweden, were investigated using immunohistochemical techniques. Amyloid deposits of protein AA were found in 10 of 1,158 investigated cases and the calculated prevalence was 0.86 per cent. The mean age at death of the individuals with the AA-type of amyloidosis was 79 years. Six of the cases with amyloidosis had rheumatoid arthritis. The avidin-biotin-peroxidase complex technique was found to be superior to the immunofluorescence method and a high sensitivity and specificity was achieved when sequence-specific antibodies against a synthetized nonapeptide corresponding to a hydrophilic segment of the polypeptide chain of protein AA were used in the assay. Nine cases with other types of amyloid deposits in the kidneys were also detected. None of these cases showed any AA immunoreactivity but all of them demonstrated Congophilic deposits which were immunohistochemically stained by antibodies against the amyloid P-component. The prevalence of renal amyloidosis comprising all types of amyloid protein deposits was 1.64 per cent.

Characterization of different amyloids with immunological techniques

We studied 71 cases of amyloidosis from the autopsy material of our institute. 17 cases were secondary amyloidosis of which 7 had initially been diagnosed as primary amyloidosis; all cases reacted positively with an anti-substance A antibody; 13 showed a suppression and 4 a strong reduction of the Congo red staining following tissue incubation in KMnO4. 25 cases were identified as primary amyloidosis of which 7 had initially not been recognized as such. In 16 cases amyloid deposits reacted positively with antibodies specific for the light chains of the immunoglobulins (3 X kappa, 13 X lambda). A monoclonal plasmacytic cell proliferation in the bone marrow was seen in 14 cases. In all cases deposits were KMnO4 resistant, but 1 case showed a slight reduction of staining intensity. 27 cases were cardio-vascular (senile) amyloidosis; in 20 cases at least 3 organs showed deposits; 12 cases had deposits in 5 and more organs. 2 cases were heredofamilial amyloidosis. In those 29 cases deposits reacted positively with an anti-prealbumin antibody, but were negative for AA and the light chains of the immunoglobulins; the Congo red staining remained strong in all cases when previously incubated in KMnO4. KMnO4-Congo red staining and antisera specific for AA, L-chains and prealbumin proved of value for classification of amyloidosis and for its organ distribution.

Characterization of tissue amyloid by immunofluorescence microscopy

Immunohistochemical classification of amyloid type was possible in 44 of 50 (88%) patients as judged by the concordance of immunofluorescence, clinical, serum, and urine immunoelectrophoresis, and bone marrow data. In frozen tissue sections incubated with a panel of antisera monospecific for immunoglobulin heavy chains, kappa and lambda light chains, and amyloid-A-related protein, the amyloid was classified as AL in 20 and AA in 24. In 6 patients the amyloid could not be classified because of the absence of reactivity in 2 and overlap staining in 4. The findings indicate that routine immunofluorescence examination of diagnostic biopsies is an important adjunct in the classification of amyloid.

Diagnosis of the type of amyloid in paraffin wax embedded tissue sections using antisera against human and animal amyloid proteins

Different histochemical techniques were compared on paraffin wax embedded tissue sections for routine classification of amyloid; the following methods were used: potassium permanganate, the indirect immunoperoxidase method using polyclonal anti-human amyloid antisera (anti-AA, anti-A lambda, anti-A kappa and anti-AF) and the peroxidase-antiperoxidase (PAP) method using antisera against human, bovine, hamster and canine AA amyloid. Anti-human AA antiserum appeared to be a useful tool in this respect. Polyclonal anti-AL antisera may be helpful in diagnosing AL amyloid, but were less of value than anti-AA serum. Strong cross reactivity between anti-bovine AA antiserum and human AA amyloid deposits was found. This indicates that animal amyloid AA antisera can also be used for the diagnosis of AA amyloid in human tissues.

An investigation of the protein components of amyloid using immunoperoxidase and permanganate methods on tissue sections

Amyloid deposits in tissue from 8 patients with generalized primary amyloidosis, 11 patients with generalized secondary amyloidosis, 11 nasopharyngeal carcinomas, 11 basal cell carcinomas, 4 islet cell tumours, 4 medullary carcinomas of the thyroid and 9 cases of lichen amyloidosis were studied using the indirect immunoperoxidase and peroxidase-antiperoxidase methods with specific antisera against Amyloid A (AA) protein and human immunoglobulin lambda and kappa light chains. The permanganate method of Wright was also applied to tissue sections. Positive staining for AA protein was observed only in secondary amyloidosis. There was excellent correlation between AA positivity and permanganate sensitivity. Positivity for immunoglobulin light chains was not observed in secondary amyloidosis but was noted in 5 (63%) cases of primary amyloidosis and 18-27% of intratumour amyloidosis. Lichen amyloidosis did not stain for AA protein or light chains. It is shown that assessment of the permanganate reaction and AA positivity of amyloid deposits can reliably differentiate secondary from primary amyloidosis and may contribute significantly to selection of patients for appropriate therapy.

Isolation and characterization of a kappa amyloid fibril protein

The fibril in primary amyloidosis (AL) is composed of a monoclonal light chain or portions thereof. No unique primary structure has been identified that predisposes certain light chains to form amyloid fibrils. Currently, classification of amyloidosis is based on the biochemistry of the amyloid fibril. We determined the NH2-terminal sequence of an amyloid fibril and found it to be of the kappa I immunoglobulin subgroup. No structural alterations were detected to account for the conversion of the light-chain fragment to an amyloid fibril. Antiserum produced to the fibril protein did not react in immunodiffusion with purified LEP or MAG antigens, which are kappa I proteins. This antiserum may be directed to antigenic sites unique to the immunizing protein and is unable to recognize homologous proteins, rendering it unsuitable for immunochemical identification of amyloid deposits of light-chain origin. PAG represents the 10th reported variable kappa I amyloid fibril protein subjected to partial sequence analysis. Antisera that recognize antigenic determinants present in all members of an immunoglobulin subgroup need further development.

Nodular mediastinal amyloidosis

A 67-year-old woman presented with supraclavicular lymphadenopathy, a large mediastinal mass, marrow plasmacytosis, and paraproteins, including free lambda light chains, in the serum and urine. Biopsies of the lesions demonstrated nodular amyloidosis, which was confirmed by ultrastructural and cytochemical analyses. Immunoperoxidase staining indicated that the amyloid was composed of lambda light chains. Nodular mediastinal amyloidosis is a rare manifestation of amyloidosis and appears to be a form of immunocytic amyloidosis.

Occurrence of protein SAA-like material in human endothelial cells in culture and smooth-muscle cells in vessel walls

In the present study human endothelial cells were isolated from the veins of umbilical cord by collagenase treatment and kept in primary culture. Antiserum with monospecific activity against protein SAA was used in an indirect immunofluorescence study. SAA-like material was shown to be present in the cytoplasm of endothelial cells that were grown on glass discs and formed a typical uniform monolayer. It was oriented in a cytoplasmic filament pattern. SAA-like material was also demonstrated in the cytoplasm of smooth-muscle cells in vessel walls in cryostat sections from placenta and umbilical cord.

Reactive (secondary) amyloidosis and its pathogenesis

Recent advances in amyloid research have broadened our understanding of amyloidogenesis in connection with chronic inflammatory and infectious conditions. Experimental and clinical studies have clarified many of the mechanisms of induction, synthesis and regulation of the amyloid-related serum component SAA and have shed light on the enzymatic processes involved in the cleavage of SAA and degradation of fibrillar AA protein. The current pathogenetic model emphasizes the dynamic character of amyloid disease.

Microdeposits of amyloid in sclerocalcific heart valves: a histochemical and immunofluorescence study

Amyloid associated with seven sclerotic and two normal aortic and mitral valves was studied. The sclerotic valve amyloid contained microfibrils with typical random orientation and a fibril width of 9.5-12.5 nm. The amyloid deposits demonstrated permanganate-resistant Congophilia and contained the amino acid tryptophan. Immunofluorescence studies showed P-component in amyloid deposits of 6 of 7 valves, but none of the sclerotic valves contained amyloid fibril proteins of the AL (primary), AA (secondary), AEt (medullary thyroid carcinoma) or ASc1 (senile cardiac) types. Two non-sclerotic valves, removed from a patient with systemic amyloidosis, showed permanganate-sensitive Congophilic amyloid deposits which contained amyloid fibril protein AA.

Frequency and distribution of senile cardiovascular amyloid. A clinicopathologic correlation

Atrium, ventricle, aorta, lung, kidney, and rectum were removed at autopsy from 85 consecutive elderly patients (aged 80 years or older) and examined for amyloid with Congo red. All tissues containing amyloid were counterstained with an antiserum specific for amyloid fibril protein ASc1 and studied by immunofluorescence. Three distinct forms of amyloid were found: (1) all patients had senile aortic amyloid; (2) 78 percent of patients had isolated atrial amyloid; and (3) 25 percent of patients had senile cardiac amyloid of the ASc1 type. The cardiac amyloid deposits were small and widely scattered in more than 80 percent of patients with isolated atrial amyloid and in more than 50 percent of patients with ASc1-type amyloid. Of 21 patients with ASc1 amyloid, 19 had extracardiac involvement (lung in 81 percent of cases and rectum in 57 percent of cases). The kidney was not involved in any patient. The mean heart weight, frequency of atrial fibrillation, percentage of patients with heart failure, and frequency of myocardial infarction were increased in patients with cardiac amyloid, but these differences failed to reach statistical significance. There was no difference in the mean left ventricular wall thickness or degree of coronary atherosclerosis.

Immunofluorescence study of "non-idiopathic" renal amyloidosis

The authors report the results of immunofluorescence (IF) studies of 17 cases of "non-idiopathic" renal biopsy-proven amyloidosis and 18 cases of various nephropathies and normal kidneys (as controls), investigated by IF by simultaneous use of antisera against routine IgG, IgM, IgA, C3, C4, Clq, beta-lipoprotein, albumin, and fibrinogen. Antisera against kappa and lambda light chains and amyloid A and amyloid P components were also used. Six of the 17 cases of amyloidosis were associated with immunocyte dyscrasia, and 11 were cases of reactive systemic amyloidosis associated with chronic infections or inflammatory and neoplastic disorders. In amyloidosis, IF deposits appeared for all antisera as homogeneous staining of mesangial nodules, and, more rarely, there was staining along the glomerular basement membranes. Overall immunoglobulins and C3 were present in 11 cases (64 per cent). Kappa and lambda light chains were demonstrated in 14 (82 per cent) and 12 (70 per cent) cases, respectively. In immunocyte dyscrasia associated with amyloidosis, immunoglobulin and light-chain deposits corresponding to a paraprotein abnormality were demonstrated in glomeruli and in tubular casts. Amyloid P component was always present in glomeruli with a bright and characteristic fluorescence, and it was frequently observed in arterioles. Amyloid A component was observed in six cases of reactive systemic amyloidosis but also in one case of immunocyte dyscrasia with amyloidosis. In view of the diversity of amyloid fibril types and their chemical nature, IF studies confirm the presence of different constituents but do not warrant any conclusion concerning the pathogenesis of this disease.

Immunofluorescence and histochemical studies of localized cutaneous amyloidosis

Lichen amyloidosus (LA) and macular amyloidosis (MA) are two forms of localized cutaneous amyloidosis in which the amyloid occurs as larger and smaller deposits respectively in the papillary dermis. The histogenesis of the amyloid of these conditions is unknown. By using an indirect immunofluorescence technique we showed that LA and MA do not react with antibodies against different previously characterized amyloid fibril proteins. These results indicate that the amyloid of LA and MA is different from other known types of amyloid. Protein AP, which was demonstrated in amyloid of MA and LA, is known to be present in all forms of amyloid and is of unknown significance. Antiserum against keratin did not react with the larger homogeneous amyloid bodies, but showed a weak reaction with some small deposits. Histochemical staining failed to show keratin in any of the tissues containing LA or MA.

Thickening of glomerular capillary walls: a guide to differential diagnosis by electron microscopy

Thickening of capillary walls is a feature of many glomerular diseases. Widening of the wall may be produced by deposits and other changes affecting either subepithelial and subendothelial regions or the glomerular basement membrane itself. Careful light microscopic examination using special stains can distinguish some patterns of capillary wall thickening, but electron microscopy is needed to demonstrate most lesions clearly. In this brief review, a guide to the major causes for capillary wall thickening is discussed, using a simple classification, and some of the patterns are illustrated. Precise delineation of the capillary wall changes in glomerular diseases is important to insure accurate classification and a clear understanding of pathogenetic mechanisms.

Immuno-electron microscopic identification and classification of amyloid in tissue sections by the postembedding protein-A gold method

Amyloid deposits from 3 patients with amyloid of the AA, A lambda, or A kappa type were investigated on ultrathin sections using the protein-A gold method and affinity purified amyloid-type-specific immunoglobulins. Anti-AA, -A lambda, and -A kappa reacted specifically with the corresponding amyloid fibril visualized by the agglomeration of the gold colloid particles. Therefore, this method can identify and classify amyloid fibrils and can distinguish them from other fibrillar proteins at the electron microscopic level.

Amyloidogenesis in organ-limited cutaneous amyloidosis: an antigenic identity between epidermal keratin and skin amyloid

Epidermal keratin was extracted and antibody against this protein was produced in rabbits. Various forms of organ-limited cutaneous amyloidosis (lichenoid, macular, and nodular amyloidosis, and basal cell epithelioma) and primary systemic amyloidosis were immunohistochemically examined to test the identity between epidermal keratin and skin amyloid. Amyloids in lichenoid and macular amyloidoses, and in basal cell epithelioma had an identical antigenicity with epidermal keratin, whereas amyloids in nodular amyloidosis and systemic amyloidosis did not have this identity. In addition, amyloid in lichen amyloidosis contained disulfide bonds as in keratin. Connective tissue components including filaments of fibroblasts and vascular endothelial cells did not react with this antikeratin antibody. It was concluded that at least some of the amyloid substance in organ-limited cutaneous amyloidosis is derived from degenerated epidermal keratinocytes through filamentous degeneration or apoptosis.

Diagnosis and classification of amyloidosis by an immuno-histological method

Following the recent classification of amyloidosis by the amyloid proteins involved, we decided to approach its tissue diagnosis and chemical classification by an immunohistological method. Post-mortem tissue specimens from various organs of patients with primary and secondary amyloidosis were examined by the immunoperoxidase technique with specific antibodies against proteins AL and AA which respectively characterize primary and secondary amyloidosis. The major advantage of this technique is that it can be applied to formalin fixed, paraffin embedded tissues. The immunoperoxidase technique proved to be extremely sensitive for the detection of amyloid deposits. Moreover, the deposited proteins could be clearly characterized as AL or AA by the specific anti-sera. We therefore believe that the immunooperoxidase technique is extremely useful for the early tissue diagnosis and chemical classification of amyloidosis.

Differentiation of amyloid fibril proteins in tissue sections. Two simple and reliable histological methods applied to fifty-one cases of systemic amyloidosis

The potassium permanganate method and the unlabeled immunoperoxidase (PAP) method were applied for distinguishing different types of amyloid fibril proteins in conventionally fixed, paraffin-embedded tissue sections obtained from fifty-one autopsied cases of systemic amyloidosis and three control cases of well-analysed fibril proteins. All of the eighteen cases "sensitive" to permanganate treatment, whose amyloid deposits lost completely their affinity to Congo red and birefringence under polarized light, were shown to have AA antigenic determinants by the PAP method. Meanwhile, all of the remaining thirty-three "resistant" cases, where Congo red affinity and birefringence were retained at various degree even only in minimal areas, were negative for AA antigenicity. This indicated the feasibility of potassium permanganate method for the identification of AA protein based on this criterion of "sensitivity". Twenty-eight cases were classified as AA, A lambda, A kappa or AA+[A kappa] the remaining twenty-three cases were unclassified, and there were some discrepancies between the preliminary clinicopathological classification and the protein nature of the amyloid. It is important to differentiate the types of amyloid fibril protein of individual patients because the expedience of selective therapeutic approaches had been suggested. The two methods applied herein are handy and useful for this purpose.

Amyloidosis associated with juvenile rheumatoid arthritis

Clinical and pathological findings are reported in a Japanese girl who died of secondary amyloidosis associated with juvenile rheumatoid arthritis two years after the onset of symptoms. The patient had intermittent high fever, rheumatoid rash, polyarthralgia, and hepatosplenomegaly. The joints showed the typical histologic changes of juvenile rheumatoid arthritis. Amyloid deposition was found in various tissues; however, remarkable deposition of amyloid was observed in the gastrointestinal tract, especially in the ileum. The amyloid protein in this patient was identified as protein AA using the methods of potassium permanganate treatment and the peroxidase-antiperoxidase unlabeled antibody technique.

Subepithelial argyrophilic spicular structures in renal amyloidosis--an aid in diagnosis. Pathogenic considerations

Eighteen cases of amyloidosis with renal involvement were classified utilizing clinical and laboratory data as to the most likely major amyloid fibril protein type and studied as to their histological, tinctorial, immunofluorescence, and electron microscopic features. No differences could be appreciated between the AA and AL types of amyloidosis. Immunofluorescence did not aid in the diagnosis of amyloidosis and was confusing in some cases owing to apparent absorption of serum proteins. Subepithelial spicular structures were noted in the glomerular capillary loops in 14 of 18 cases (78 per cent), and similar structures were found related to tubular epithelial cells in six of these cases and were related to the parietal epithelium of Bowman's membrane in one case. These spicular structures were a valuable aid in the diagnosis of early amyloidosis by light microscopy, but electron microscopy was essential for confirmation. We postulate that because of the intense staining quality of spicular structures using argyrophilic techniques, these spicules result from a unique interaction between amyloid fibrils and locally produced substances, most probably renal epithelial basement membrane glycoprotein.

Further structural and antigenic studies of light-chain amyloid proteins

The major subunit protein of amyloid fibrils (758) isolated from a patient with systemic amyloidosis and studied by N-terminal amino acid sequence analysis was found to be almost identical to the sequence of a V lambda IV Bence-Jones protein and a previously described A lambda IV amyloid protein. The two A lambda IV amyloid proteins showed strong antigenic cross-reaction, appearing as antigenic identity in double immunodiffusion tests using anti-A lambda IV antiserum raised against one or the other of the two proteins. In addition, another new A lambda V amyloid fibril protein (R.S.) showed strong amino acid sequence homology and antigenic identity in double immunodiffusions with the prototype of the A lambda V subgroup (the AR protein). Finally, 20 primary or myeloma-associated amyloid proteins were characterized using antisera against the AA and several Ig light-chain-derived amyloid proteins.

Structure and antigenic behaviour of kappa I-immunoglobulin light-chain amyloid proteins

N-terminal amino acid sequence analysis of three amyloid fibril subunit proteins from three different patients revealed a primary structure homologous to KI immunoglobulin light chains. In double immunodiffusion an antiserum against one of these amyloid proteins reacted with all three amyloids showing one line of identity, while an antiserum against one of the other amyloid proteins reacted with only one of the nonhomologous amyloids, appearing as partial identity, These two antisera did not react with any amyloid of lambda I, lambda IV or lambda VI type. The results confirm previous experiments, in which it has been shown that some antisera against amyloid proteins of immunoglobulin origin give a reaction of identity with other amyloids in the same immunoglobulin subgroup, probably owing to subgroup specific antigenic determinants in the variable segments. It was found that the distribution of amyloid varied widely among the three patients. There does not seem to be any correlation between the type of manifestation of amyloidosis and the type of immunoglobulin light chain forming the amyloid fibril.

Demonstration of amyloid in murine and human secondary amyloidosis by the immunoperoxidase technique

A specific rabbit anti-murine amyloid A protein (anti-AA) has been used in the immunoperoxidase (IP) technique for the detection of amyloid in formalin-fixed, paraffin-embedded, tissue obtained from amyloidotic mice and a post-mortem kidney specimen from a patient with amyloidosis secondary to osteomyelitis. Amyloidosis was induced in five out of 20 white mice by weekly intraperitoneal injections of complete Freund's adjuvant. Amyloid deposits were clearly demonstrated both by the Congo Red and by the IP techniques. The antibody against murine AA was found to be cross-reactive with human AA. These preliminary results suggest that the IP technique with the use of specific antibodies against the different amyloid proteins might be extremely useful for the histological dianosis and classification of amyloidosis.

Amyloid typing using antisera to prototype fibril proteins. A brief note

Amyloid fibril proteins from three patients with generalized amyloidosis were isolated and chemically characterized by N-terminal amino-acid sequence studies in two of them. As they belonged to three different amyloid classes they served as prototypes for the preparation of antisera specific for each class. Using these antisera in immunodiffusion, amyloid fibril proteins of 15 additional cases with generalized amyloidosis have been investigated. These could be grouped into four categories: seven belonging to the amyloid A type, three to the amyloid L, lambda type, and three to the amyloid L, kappa type; the amyloid fibril proteins of two patients could not be classified by these agents and may represent still unidentified amyloid types.