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Biomedical subjects

R Ghohestani

Publications and source records attributed to R Ghohestani.

9 recordsLinked to original sources

Desmosomes and their autoimmune pathologies.

Desmosomes guarantee the integrity of the epidermis, by functioning both as an adhesive complex and as a cell-surface attachment site for the keratin intermediate filaments of the cytoskeleton. Considerable progress has been made in our knowledge of desmosomes and their components. The structure and function of many of the desmosomal molecules have been determined, and a number of the molecular interactions between desmosomal proteins have been elucidated. Desmosomal proteins are major antigens in pemphigus. Each type of pemphigus has its own antigenic targets, but in the last few years it has been shown that certain autoantibody populations are not restricted to just one form of pemphigus. The production of autoantibodies against multiple intracellular and extracellular desmosomal proteins, whose pathogenic role remains to be elucidated, suggests an overlapping distribution of antibody specificities among different forms of pemphigus.

Autoantibodies↗

[Epidermolysis bullosa acquisita and hepatitis C].

INTRODUCTION: Epidermolysis bullosa acquisita is a bullous dermatosis. Its etiology remains unknown and the efficacy of its treatment is low. OBSERVATION: We report the first association between epidermolysis bullosa acquisita, chronic hepatitis C and cryoglobulinemia, healing with interferon alpha and ribavirine. DISCUSSION: We suggest a role for hepatitis C virus in the pathogenesis of epidermolysis bullosa acquisita. We suppose a synthesis of autoimmune antibodies in a dysimmune environment. Interferon alpha and ribavirine might be a new therapeutic avenue but further studies are necessary to confirm it.

Adult↗

Identification of a new antibody population directed against a desmosomal plaque antigen in pemphigus vulgaris and pemphigus foliaceus.

Pemphigus vulgaris and pemphigus foliaceus are characterized by autoantibodies directed against transmembrane glycoproteins of desmosomes. F12, a human monoclonal autoantibody that binds to the desmosomal plaque, recognizes a 180-190-kDa doublet when immunoblotted against bovine tongue epithelium. Because F12 was derived from the peripheral blood lymphocytes of a patient with pemphigus vulgaris, we looked for the presence of anti-180-190-kDa antibodies in pemphigus vulgaris and pemphigus foliaceus serum. By immunoblot analysis, a third of the pemphigus serum contained anti-180-190-kDa antibodies that belonged to IgG subclass 1 or 3, unlike those that recognized desmogleins 1 and 3 (IgG4). By immunoelectron microscopy analysis on human oral mucosa and human skin with mAb to human IgG3, pemphigus serum containing anti-180-190 kDa antibodies recognized desmosomal plaques. The presence of antibodies with F12 properties in pemphigus serum was further demonstrated by a rabbit anti-F12 idiotype antiserum that allowed detection of F12 idiotype in serum with anti-180-190-kDa antibodies. These results indicate that some pemphigus vulgaris and pemphigus foliaceus serums contain antibodies that react with both intra- and extracellular structures of desmosomes and further demonstrate the heterogeneity of the autoimmune response in both types of pemphigus.

Antibodies, Monoclonal↗

Autoantibody formation against a 190-kDa antigen of the desmosomal plaque in pemphigus foliaceus.

We report changes in the antigen recognition pattern of sera from two pemphigus foliaceus patients with a long-term follow-up. The patients' sera were analysed by immunoblotting using different antigenic sources: cultured human keratinocytes, bovine tongue epithelium and a recombinant protein corresponding to the C-terminal end of the 230-kDa bullous pemphigoid antigen. While initial serum samples reacted exclusively with the 160-kDa desmoglein 1, the later sera reacted both with desmoglein 1 and a 190-kDa antigen immunolocalized to the desmosomal plaque, previously demonstrated to be recognized by sera of some patients with paraneoplastic pemphigus. IgG subclass analysis further showed that antidesmoglein 1 antibodies were of IgG1 and/or IgG4 subclasses, while anti-190-kDa antibodies were IgG3. The patients were free of malignancy.

Aged↗

IgE autoantibodies directed against the major bullous pemphigoid antigen in patients with a severe form of pemphigoid.

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease characterized in part by circulating and tissue-bound IgG autoantibodies directed against the basement membrane zone. In addition, most of the patients with BP have increased serum IgE levels which seem to be correlated with the disease activity, whereas the presence of circulating anti-basement membrane zone IgE Abs has been reported in some patients. To elucidate whether IgE-dependent mechanisms play a role in the physiopathology of BP, we looked for the presence of IgE Abs specifically directed against the major BP Ag (BPAg1) in sera of BP patients at the onset and after remission of the disease. A radioimmunoassay and a 55-kDa recombinant protein (rBP55) obtained from a cDNA sequence, encoding the C-terminal region of the BPAg1 and containing the BPAg1 immunodominant epitopes, were used. Anti-rBP55 IgE Abs were found in 12 of the 19 sera tested. When the patients were divided into two groups according to the disease severity, anti-rBP55 IgE Abs were found only in patients with a severe form of the disease. Cytophilic IgE was detected on approximately 20% of peripheral blood eosinophils purified from BP patients. Immunohistochemistry studies suggested that some of the IgE-bearing cells in the lesional skin of BP patients are eosinophils. Immunostaining experiments revealed the existence of FcepsilonRI on both peripheral blood and tissue eosinophils. Taken together, these results suggest that IgE-dependent mechanisms could participate in the constitution of the lesions in BP.

Antibody Specificity↗

[Linear IgA bullous dermatosis in children with autoantibodies against 180 kDa pemphigoid antigen].

BACKGROUND: Linear IgA bullous dermatosis (LABD) is an autoimmune subepidermal blistering disease defined on the basis of direct immunofluorescence findings. CASE REPORT: An 18 month-old girl suffering from LABD was studied by indirect immunofluorescence on salt-split skin and by Western blot in an attempt to characterize the involved autoantigen. Direct immunofluorescence showed an exclusive linear IgA deposit at the dermal-epidermal junction. Indirect immunofluorescence revealed circulating autoantibodies that reacted with the epidermal side of salt-split skin; they reacted by Western blot with a 180 kDa epidermal antigen, as in bullous pemphigoid. CONCLUSION: This dermatosis fulfilling the clinical features and direct immunofluorescence criteria for childhood LABD seems to represent a case of IgA bullous pemphigoid. It further underscores the nosologic heterogeneity of LABD, which probably includes, apart from bullous pemphigoid, epidermolysis bullosa acquisita and cicatricial pemphigoid.

Autoantibodies↗

Comparative sensitivity of indirect immunofluorescence to immunoblot assay for the detection of circulating antibodies to bullous pemphigoid antigens 1 and 2.

The sera of 263 patients with bullous pemphigoid (BP) were tested by indirect immunofluorescence (IIF) on salt-split skin (SSS) and immunoblot (IB) assay, in order to assess the diagnostic sensitivity of these techniques. Among the 263 sera tested, 198 sera (75%) contained antibasement membrane zone antibodies demonstrable by IIF reacting to the epidermal (98%) or both the dermal and epidermal sides (2%) of SSS. One hundred and eighty-two of the 263 sera (69%) reacted by IB with BP antigens (Ag), most commonly the BPAg1 (93 cases, 51%), and a complex of BPAg1 and the 180 kDa minor BP antigen (BPAg2) (47 cases, 26%). BPAg2 alone was found in 42 cases (23%). A good correlation was found between the detection of autoantibodies by IIF and labelling of BPAg1 and/or BPAg2 by IB assay, in which 152 of 198 sera with an epidermal pattern in IIF identified a BP antigen. IB analysis of the 65 sera negative by IIF yielded positive results in 30 cases (46%). Thirty-one percent (13 of 42) of sera recognizing by IB BPAg2, were negative by IIF, as compared with 12% (11 of 93) of those recognizing BPAg1 (P < 0.01). Comparing the sensitivity of the two tests, IIF (75%) was found to be more sensitive than IB (69%). Thirty-five of the 263 sera (13%) remained negative by both techniques. It can be concluded from this study that IIF on SSS appears to be a sensitive and reliable assay for screening BP; IB should be performed for the sera that are negative by IIF as it may reveal circulating antibodies, particularly to BPAg2.

Adult↗