Antikeratin autoantibodies in the amyloid deposits of lichen amyloidosus and macular amyloidosis

Summary In order to characterize immunoglobulins found on amyloid deposits of lichen amyloidosus and macular amyloidosis, an elution from cryostat sections was performed with citrate buffer, glycine buffer, NaCl, and PBS. Resulting eluates (mainly IgG) were examined with dot immunoblotting and SDS-PAGE immunoblotting and were found to react with the human epidermal keratin of 50 and 67 kD. Antikeratin autoantibody activities in normal murine and human sera were examined using a dot immunoblotting assay. In murine sera, titers of IgG and IgM autoantibodies were higher in older mice. The human cord blood showed significantly lower IgM autoantibody titers, whereas IgG antibody titers showed no significant differences from adults' sera, probably due to the permeability of IgG through the placental barrier. A stronger antibody activity in older individuals was thought to be due to the repeated exposures to keratin proteins derived from apoptotic keratinocytes. Sera from lichen amyloidosus and macular amyloidosis patients did not show any difference from normal controls in their antikeratin titers. It was concluded that the patients with lichenoid or macular amyloidosis are capable of producing a normal level of antikeratin autoantibodies. However, the removal of opsonized keratin-type amyloid from the skin is slow or deficient due to as yet unknown factors.Part of this study was reported on May 5, 1987 at the 48th Annual Meeting of the Society for Investigative Dermatology at San Diego, CA, USA     

Cytokeratin expression in lichen amyloidosus and macular amyloidosis

AIM: To understand the role of epidermal cells in the pathogenesis of lichen amyloidosus (LA) and macular amyloidosis (MA). METHODS: We carried out immunohistochemical investigations on cytokeratins (CKs) in amyloid deposits in formalin-fixed and paraffin-embedded tissue specimens from eight persons with LA and 12 with MA. The primary antibodies of CK1-8 (AE3), CK10 (DEK-10), CK14 (LL002), CK17 (E3), CK18 (DC10), CK19 (KS19.1), CK5/6/18 (LP34) and CK8/18 (5D3) were used in the study. RESULTS: In amyloid deposits, immunoreactivity with only two monoclonal antibodies (CK1-8 and CK5/6/18) was observed in 14 cases (eight LA and six MA), confirming the hypothesis that epidermal cells participate in amyloid formation of LA and MA. COMMENTS: All of the CKs detected in amyloid deposits were basic type (type II). It seems plausible either that acidic CKs might be degraded faster than basic types in amyloidogenesis or that paraffin-embedded tissue specimens are less sensitive than frozen tissue sections. The results of our study suggest that when paraffin-embedded specimens are investigated by immunohistochemical methods, CK5 antibody is useful in the diagnosis of LA and MA.     

Keratin expression in normal skin and epidermal neoplasms demonstrated by a panel of monoclonal antibodies

The tissue labelling of a panel of monoclonal antikeratin antibodies (LL001, LL002, LL003, LP2K, BA17, LP34, CAM5.2, and LH1) recognising keratins 1, 5, 8, 10, 14, 18, and 19 were investigated in frozen and formalin-fixed normal skin. Antibodies LL001, LL003, BA17, LP34, CAM5.2, and LH1 were found to be reactive in formalin-fixed material and were used to study 23 basal cell carcinomas, 8 squamous cell carcinomas, 5 keratoacanthomas, 5 Bowen's disease, and 6 clear cell acanthomas. All these tumours demonstrated a loss of keratin 10 expression as demonstrated by loss of labelling with LH1. Keratin 14 expression, as demonstrated by LL001, was reduced but present in all the tumours except squamous cell carcinomas and keratoacanthomas where increased labelling was observed in the more differentiated areas of these tumours. Simple epithelial keratin expression was demonstrated by positive labelling with CAM5.2 and keratin 19 by BA17 in a third of basal cell carcinomas and squamous cell carcinomas. Three of the five keratoacanthomas labelled with BA17, indicating the presence of keratin 19 in these lesions. These results support the concept that keratin expression is a phenotypic marker of the state of differentiation or malignant transformation and that patterns of keratin expression are not specific to any particular premalignant or malignant disorder.     

Immunohistochemical staining properties of amyloids with anti-keratin antibodies using formalin-fixed, paraffin-embedded sections

Immunohistochemical staining properties of amyloids with anti-keratin antibodies were investigated using an avidin-biotin-peroxidase complex (ABC) system on formalin-fixed, paraffin-embedded sections. Anti-keratin antibody EAB-903 which recognize 66K and 57K daltons keratin peptides reacted with amyloid deposits in both lichen amyloidosus (LA) and macular amyloidosis (MA), but did not react with either primary systemic amyloidosis (AL), secondary systemic amyloidosis (AA) or heredofamilial amyloid polyneuropathy (AF). However, anti-keratin antibodies EAB-904 and MAK-6 did not react with any types of amyloids. These results suggested that immunohistochemical staining with anti-keratin antibody EAB-903 using formalin-fixed, paraffin-embedded sections appeared to be a useful method in making differential diagnosis of primary localized cutaneous amyloidosis (AD).     

A study of cytokeratin profiles in localized cutaneous amyloids

The major component of localized cutaneous amyloids may be derived from cytokeratin (CK). However, the CK profiles of primary cutaneous amyloidosis (PCA) and secondary cutaneous amyloidosis (SCA) remain obscure. Paraffin-embedded sections of skin tissue from 64 patients with PCA, 111 with SCA and 3 with systemic amyloidosis were analyzed immunohistochemically using 12 different polyclonal or monoclonal anti-CK antibodies (34βE12, MNF116, LP34, AE1/AE3, anti-CK1, CK5, CK6, CK7, CK10, CK14, CK16 and CK17). In addition, frozen skin tissues from 12 patients with PCA were analyzed for comparison with the paraffin-embedded tissue. In all 64 PCA paraffin sections, the amyloid deposits were immunopositive for anti-CK5 antibody and 34βE12. In all 12 frozen sections of PCA, the amyloid deposits were immunopositive for anti-CK5 antibody, 34βE12, MNF116 and LP34, and seven (58.3%), three (25%) and one (8.3%) were immunopositive for anti-CK1, CK14, and CK10 antibodies, respectively. In all SCA sections, the amyloid deposits were immunopositive for CK5 and 34βE12. In addition, MNF116 immunolabeled amyloids of all sections from patients with basal cell carcinoma and trichoepithelioma, and MNF116 and LP34 immunolabeled amyloids of sections from patients with porokeratosis. Our results indicate that CK5 is the major CK present in the amyloid deposits of PCA and SCA, and “amyloid-K” is mainly derived from basal keratinocytes.     

A monoclonal anti-keratin antibody reactive with amyloid deposit of primary cutaneous amyloidosis

Specimens from cutaneous amyloidoses (lichen amyloidosis and macular amyloidosis) were stained immunohistochemically with monoclonal anti-keratin antibodies. One monoclonal antibody raised against hair keratin (HKN-6) reacted with the amyloids of both primary amyloidoses. Another monoclonal antibody, HKN-2, did not decorate the amyloid deposit. HKN-6 did not stain the interfollicular epidermis, but HKN-2 did. The possible explanations of these findings are 1) amyloid deposits contain keratin protein modulated to react with HKN-6; 2) amyloid deposits contain a protein unrelated to keratin protein, but reactive to HKN-6.     

Two different pathogenetic pathways in lichen amyloidosus and macular amyloidosis

Summary In lichen amyloidosus (LA) and macular amyloidosis (MA), small amyloid deposits occur in the upper papillary dermis. Previous electron-microscopic studies have indicated an epidermal origin of the amyloid, where degenerating keratinocytes drop into the dermis and undergo transformation to amyloid. While this mechanism seems possible at least in MA, we suggest an alternative pathogenetic pathway in LA, in which amyloid fibrils seem to form on the dermal surface of living basal keratinocytes. It is possible that the different morphology of the amyloid in LA and MA is explained by partially different pathogenetic mechanisms although the amyloid in both conditions may be chemically closely related.     

Immunohistochemical studies on fibrillin in amyloidosis, lichen ruber planus and porphyria.

The pathogenesis of macular amyloidosis and lichen amyloidosis remains unsolved and the primary amyloid fibril protein(s) has not yet been identified. Ultrastructural association of skin amyloid with elastin associated microfibrils has been noted earlier. The presence of fibrillin in conjunction with such microfibrils was recently demonstrated immunohistochemically. The presence of fibrillin immunoreactivity in the amyloid deposits in skin biopsies from 3 patients with macular amyloidosis and 3 patients with lichen amyloidosis was studied, using monoclonal anti-fibrillin antibodies. For comparison, skin specimens were studied from five patients with lichen ruber planus, four patients with erythropoietic protoporphyria and from a patient with myeloma-associated cutaneous amyloidosis. Renal specimens from two cases of the amyloid A type of renal amyloidosis also were investigated. There was no immunostaining either of the keratin bodies in specimens of lichen ruber planus, the cutaneous PAS-positive vascular deposits in patients with erythropoietic protoporphyria, or the amyloid deposits in specimens of systemic amyloidosis and it was faint or absent in amyloid deposits in the specimens from patients with lichen amyloidosis. In contrast, distinct fibrillin immunoreactivity could be demonstrated in amyloid deposits in specimens from patients with macular amyloidosis. It was sometimes absent in deposits located in the upper part of the papillary dermis, close to the dermal epidermal junction zone, while consistently strong in deposits located lower down in the dermis. The results suggest that fibrillin or part of the fibrillin molecule may be present in some of the amyloid deposits in specimens of macular amyloidosis.     

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.     

Biphasic amyloidosis arising from friction melanosis

A 40-year-old woman who had used nylon towels in the bath for about 10 years noticed hyperpigmentation on the prominent regions over the bones of the trunk and extremities. She also developed lichenoid papules with itching on her back. Histologically, both the pigmented and the papular lesions had amyloid deposits beneath the epidermis. In this case it is presumed that the papular lesions with amyloid (lichen amyloidosus) developed initially from friction melanosis which became macular pigmented lesion (macular amyloidosis). The etiologic factor of these sequential pathologic changes is considered to be repeated scrubbing with nylon towels.     

Clinical effect of tocoretinate on lichen and macular amyloidosis

Lichen amyloidosis and macular amyloidosis are commonly therapy-resistant. Tocoretinate is a hybrid compound of retinoic acid and tocopherol that is commonly used for the treatment of skin ulcers. Although beneficial effect of oral retinoic acid on lichen amyloidosis is reported, tocoretinate has not been reported to be useful for the treatment of lichen amyloidosis or macular amyloidosis. We evaluated the effects of topical tocoretinate on lichen amyloidosis and macular amyloidosis lesions. Tocoretinate was topically applied daily to the lesions and clinical improvement and histological changes were evaluated. The outcome was very good for four, good for two, moderate for two and poor for two of 10 treated patients. Epidermal hypertrophy was reduced and expression of involucrin, keratin 1 and keratin 10 was decreased by tocoretinate treatment, suggesting the normalization of epidermal differentiation. Amyloid deposits remained histologically detectable, even in clinically responsive patients. Together, topical application of tocoretinate reduced the clinical symptoms of lichen amyloidosis and macular amyloidosis, and normalized disturbed epidermal differentiation.     

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 immunofluarescence 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.     

细胞角蛋白和波形蛋白在皮肤淀粉样变淀粉样蛋白中表达的研究

目的:探讨皮肤淀粉样变淀粉样蛋白的生物学来源.方法:应用免疫组化染色技术检测4种角蛋白(cytokeratins,CKs)及波形蛋白在20例斑状或苔藓样型皮肤淀粉样变淀粉样蛋白中的表达情况.结果:①CK3413E12和CK5/6在20例标本的淀粉样蛋白团块中均呈阳性表达:而AE1/AE3、CK10/13和波形蛋白在淀粉样蛋白团块中均呈阴性表达;②淀粉样蛋白团块中波形蛋白表达阳性的成纤维细胞明显增生.结论:淀粉样蛋白主要来源于凋亡的表皮基底细胞而非真皮组织.     

Amyloid in localized cutaneous amyloidosis: immunofluorescence studies with anti-keratin antiserum especially concerning the difference between systemic and localized cutaneous amyloidosis

Amyloid of localized cutaneous amyloidosis and systemic amyloidosis were subjected to study with an indirect immunofluorescence technique using anti-keratin antiserum. Anti-keratin antiserum was prepared ad modum Sun & Green. Amyloid of localized cutaneous amyloidosis was positively stained for the antiserum, whereas amyloid of systemic amyloidosis (primary and multiple myeloma-associated) was negative. There was no difference between primary localized cutaneous amyloidosis (lichen amyloidosus and macular amyloidosis) and secondary localized cutaneous amyloidosis (amyloidosis associated with skin tumor). These results indicate that amyloid of localized cutaneous amyloidosis contains components derived from epidermal fibrous protein, probably tonofilaments of keratinocytes.     

Lichen amyloidosus with subepidermal blister formation

We report a 74-year-old man who presented with multiple, itchy keratotic papules or plaques on the trunk and extremities. Erosions and vesicles were also intermingled on keratotic lesions. Histopathologic examination of biopsy specimens taken from three different lesions showed a subepidermal blister with amyloid deposits in the dermal papillae. No systemic disease or involvement of other organs was detected. The clinical and histological findings were compatible with a bullous variant of lichen amyloidosus. Although bullous amyloidosis has been reported in systemic amyloidosis, bullous lesions associated with lichen amyloidosus are very rare.     

Local cutaneous amyloidoses. Report of 3 cases with lichen amyloidosus and 2 cases with nodular amyloidosis

We report on the clinical and histological features of lichen amyloidosus (3 cases) as well as localized nodular amyloidosis (2 cases: a man and a woman). Regarding lichen amyloidosus, our morphological and immunohistochemical findings suggest that amyloid is derived from keratinocytes. In nodular amyloidosis, the origin of amyloid may possibly be connected with plasma cells.     

Immunofluorescence studies in primary localized cutaneous amyloidosis

Immunofluorescence studies were carried out on 47 patients with primary localized cutaneous amyloidosis. The majority had the macular, maculopapular or papular forms of lichen amyloidosus, although 3 patients had the nodular type. All biopsies fluoresced positively for immunoglobulins or complement, particularly IgM and C3. Staining for kappa and lambda light chains was positive. The consistent immunofluorescent patterns observed were similar in some respects to lichen planus, suggesting that colloid bodies and amyloid may share similar properties in acting as a filamentous sponge on to which immunoglobulins and complement are absorbed. The pathogenesis of lichen amyloidosus is compared with that of lichen planus.     

Nylon brush macular amyloidosis

Long-term use of a nylon brush for back scratching by a 53-year-old white woman was associated with the development of typical macular amyloidosis. EKH4 monoclonal antikeratin antibody, which recognizes 50-kd neutral and acidic keratin species, labeled this amyloid. Confirmation of amyloid substance in the lesion included positive staining with Dylon and thioflavin T; immunohistochemical reactions with monoclonal and polyclonal antibodies against elastic fiber microfibrils (NKH1 and anti-P component), immunoglobulins (IgG, IgM, and IgA), and complement (C3); and electron microscopic identification of 6- to 10-nm straight filaments. Type IV collagen staining demonstrated a breakage and/or thickening of the dermoepidermal basement membrane above the amyloid deposition in the papillary dermis. Electron microscopic findings confirmed this phenomenon.     

Lichen amyloidosus: A consequence of scratching

Background: Lichen amyloidosus (LA) is generally said to be a pruritic type of amyloidosis of unknown cause. Histopathologically, it is characterized by epidermal changes of lichen simplex chronicus and by deposits of amyloid in the papillary dermis that are derived from keratin peptides of necrotic keratinocytes. Chronic scratching is responsible for the development of lichen simplex chronicus and may lead to necrosis of individual keratinocytes. Objective: Our purpose was to evaluate whether chronic scratching may also be responsible for the formation of amyloid in LA. Methods: We studied patients with LA in regard to histopathologic findings, onset of pruritus, associated diseases, and response to treatment. Results: In most cases, pruritus had preceded the skin lesions. Eight of nine patients suffered from diseases other than LA that may be associated with pruritus. Histopathologically, amyloid was confined to areas that also showed signs of lichen simplex chronicus. Systemic treatment with sedating antihistamines and intense local treatment with corticosteroids were found to be effective. Conclusion: LA is considered to be a variant of lichen simplex chronicus in which scratching leads to necrosis of keratinocytes and eventually to the formation of amyloid in the papillary dermis. Because chronic scratching seems to be the cause and not the result of the deposits of amyloid, treatment should be directed at the amelioration of pruritus. (J Am Acad Dermatol 1997;37:923-8.)     

Immunologic characteristics of keratins in extramammary Paget's disease

Six cases of extramammary Paget's disease were immunohistochemically investigated with several antikeratin monoclonal antibodies. Paget cells and surrounding epidermal keratinocytes were equally stained with an antikeratin monoclonal antibody, HKN-4, which recognizes a broad spectrum of keratins. However, Paget cells were clearly distinguished from the surrounding epidermal keratinocytes by HKN-2, which does not react with keratins of secretory cells but does react with keratins of ductal and myoepithelial cells of sweat glands and with epidermis and hair tissue of the normal skin. The HKN-2 did not bind to Paget cells, but the surrounding keratinocytes were positive. CK7, LE41, RGE53, and LP2K, which recognize simple epithelium-type keratins 7 (molecular weight [MW], 54,000; type II), 8 (MW, 52,500; type II), 18 (MW, 45,000; type I), and 19 (MW, 40,000; type I), respectively, stained Paget cells but not the surrounding keratinocytes. Two cases of Merkel cell carcinoma, examined as controls, showed positivity to LE41 and RGE53 but not to CK7 and LP2K. Since in the normal skin the secretory cells of sweat glands showed the same keratin expression as that of Paget cells, Paget cells of extramammary Paget's disease may be derived from or differentiate to the secretory cells of sweat glands.