J.-F. Nicolas

Bullous Pemphigoid and Cicatricial Pemphigoid: Immunoblotting Detection of Involved Autoantigens

Bullous pemphigoid (BP) and cicatricial pemphigoid (CP) are subepidermal bullous autoimmune diseases which have distinct clinical features but identical immunological status. In order to determine whether these diseases could be dissociated on the basis of qualitative differences in serum antibodies to basement membrane zone (BMZ) antigens, the reactivity of sera from 7 CP and 29 BP patients with proteins extracted from normal human epidermal sheets (containing most of the lamina lucida components) was analysed using immunoblotting and compared to that of 10 normal sera. 20 out of the 29 BP sera contained antibodies recognizing one or several protein(s) of 240, 200, 180 and 165 kD molecular weight (MW). Antibodies in 4 out 7 CP sera specifically reacted with one or two polypeptides of 240 and 120 kD MW. These data confirm the heterogeneity of BP antigens and show the presence in CP of a novel 120 kD MW polypeptide which is found only in CP but not in BP. Taken together these findings demonstrate that in BP and CP, autoantibodies are directed to both common and specific BMZ antigens, their physiopathological significance need to be understood.

IgE Antibodies in Sera from Patients with Bullous Pemphigoid Are Autoantibodies Preferentially Directed Against the 230-kDa Epidermal Antigen (BP230)

Bullous pemphigoid (BP) is unique among autoimmune skin diseases in which a high serum IgE level has been detected. We sought to determine the antigenic specificity of these IgE antibodies in 39 BP sera by immunofluorescence microscopy, immunoblot, and ELISA. The patients sera contained IgG antibodies to 230-kDa (BP230) (n = 20), 180-kDa (BP180) (n = 9), and both BP230 and BP180 (n = 10) antigens. Serum IgE levels varied from 29 to 5000 kIU/L (mean ± SD, 856 ± 1426 kIU/L), among which sera containing IgG antibodies to BP230 had an IgE level on average 4.3 times higher than anti-BP180 sera. IgE antibodies in 18 sera were found to be autoantibodies reactive either with an epidermal component of basement membrane zone by immunofluorescence microscopy on 1 M NaCl-split skin or with a 230-kDa antigen by immunoblots of cultured human keratinocytes.7 The 230-kDa epidermal antigen recognized by IgE antibodies comigrated with the BP230 as labeled by a specific human monoclonal antibody. IgE anti-BP230 antibodies in patients sera were always associated with IgG autoantibodies. No sera contained IgE antibodies to BP180 or to any other epidermal or dermal antigens as verified by immunoblot and ELISA. A good correlation was found between the presence of IgE circulating autoantibodies and the level of serum IgE (P < 0.004). IgE antibodies to BP230, like IgG autoantibodies, were mapped primarily to the C-terminal end of the protein, as they labeled rBP55, a BP230 recombinant protein encoded by a cDNA for the C-terminal end of BP230.

Down-regulation of lymphocyte CD4 antigen expression by administration of anti-CD4 monoclonal antibody

Modulation of surface CD4 antigen expression was assessed by flow cytometry after calibration with 125I-labeled anti-CD4 monoclonal antibodies (mAbs). Three patients with severe psoriasis treated with BB14 (anti-CD4 mouse IgG1) and five patients with rheumatoid arthritis treated with BL4 (anti-CD4 mouse IgG2a) were analyzed for sequential changes in surface CD4 expression on CD4+ blood lymphocytes. Anti-CD4 mAb treatment induced a decrease of 50 to 80% of CD4 expression, with slow and partial recovery after cessation of mAb administration. CD4 modulation was related to mAb dosage and mAb concentration in plasma. It was achieved at nonsaturating concentration. In vitro incubation of blood mononuclear cells induced CD4 modulation of similar kinetics and magnitude, associated with decrease of 5-10% of CD3 expression. CD4 modulation required both an intact Fc part of the antibody and the presence of monocytes. The possible role of CD4 modulation should be considered along with other functional activities of anti-CD4 mAbs in analyzing the mechanisms of the clinical effects of these antibodies.

Invariant NKT Cells Suppress CD8+ T-Cell–Mediated Allergic Contact Dermatitis Independently of Regulatory CD4+ T Cells

Invariant natural killer T (iNKT) cells expressing a CD1d-restricted invariant αβTCR have key regulatory roles in autoimmunity, pathogen immunity, and tumor surveillance, but their function in the control of allergic skin diseases remains poorly documented. Using a model of contact hypersensitivity (CHS) to the hapten DNFB, we show here that iNKT cell deficiency results in enhanced skin inflammation due to augmented hapten-specific IFN-γ-producing CD8(+) effectors in skin draining lymph nodes (dLNs) and their massive recruitment into the allergen-exposed skin. Adoptive transfer and antibody depletion experiments as well as in vitro studies revealed that iNKT cells (1) reduce the severity of CHS, even in presensitized mice, (2) require hapten presentation by CD1d(+) dendritic cells (DCs) to dampen skin inflammation, and (3) produce IL-4 and IL-13 after CD1d-dependent in vitro stimulation by hapten-loaded DCs only in the presence of IFN-γ released from activated CD8(+) effector T cells. In corollary, mice double deficient in IL-4 and IL-13 exhibit an exacerbated CHS. Finally, iNKT-suppressive function is independent of Foxp3(+) regulatory T cells (Tregs). These data highlight that, besides Foxp3(+) Tregs, iNKT cells are potent downregulators of CD8(+) T cell-mediated CHS, and underscore that both cell types are important for the regulation of allergic skin inflammation.

Studies on T-cell subsets in atopic dermatitis: Human T-cell subpopulations defined by specific monoclonal antibodies

Abstract Peripheral blood T lymphocytes and T-cell subsets were explored in 40 patients with atopic dermatitis and elevated serum IgE levels. The percentages of the different T-cell subpopulations were defined by indirect immunofluorescence using monoclonal antibodies OKT3, OKT4, and OKT8 which are specific markers of, respectively, total T cells, helper T cells, and suppressor/cytotoxic T cells. Decreased peripheral blood T cells (OKT3+) and abnormal distribution between helper and suppressor T cells subsets were found as compared to controls. Results were similar in the three age-matched groups (4 months–2 years, 2–15 years, 15–50 years) studied. Elevated helper/suppressor cells ratios with decreased percentages of suppressor (OKT8+) T cells were observed, although no correlation could be established with serum IgE levels.

Decreased levels of T-cells and cells with suppressor T-cell phenotype as defined by specific monoclonal antibodies in patients with atopic dermatitis

peripheral blood cells from forty patients with atopic dermatitis and elevated serum IgE levels were studied by indirect immunofluorescence using monoclonal antibodies OKT3, OKT4, OKT8 to, respectively, human T cells, helper‐inducer and suppressor‐cytotoxic T cell subsets.

Le TNF-δ dans la physiopathologie du psoriasis

Le psoriasis atteint 3 a 5 p. 100 de la population europeenne. C’est une des nombreuses maladies inflammatoires chroniques dues a des lymphocytes T. Il fait aussi partie de la liste des maladies autoimmunes les plus frequentes. Cependant l’autoantigene (les autoantigenes) du psoriasis n’est pas encore connu [1]. Le psoriasis est une maladie benigne dans la majorite des cas mais alors toujours associee d’une alteration de la qualite de vie. Dans 10 p. 100 des cas la maladie est severe soit par son etendue et sa resistance aux traitements classiques soit dans les formes graves (psoriasis erythrodermique, psoriasis pustuleux generalise, rhumatisme psoriasique associe) [2, 3].

UV Radiation Induces the Epidermal Recruitment of Dendritic Cells that Compensate for the Depletion of Langerhans Cells in Human Skin

UVR causes skin injury and inflammation, resulting in impaired immune function and increased skin cancer risk. Langerhans cells (LCs), the immune sentinels of the epidermis, are depleted for several days following a single UVR exposure and can be reconstituted from circulating monocytes. However, the differentiation pathways leading to the recovery of a normal pool of LCs is still unclear. To study the dynamic changes in human skin with UV injury, we exposed a cohort of 29 healthy human volunteers to a clinically relevant dose of UVR and analyzed sequential epidermal biopsies for changes in leukocyte and dendritic cell (DC) subsets. UV-induced depletion of CD1a(high) LC was compensated by sequential appearance of various epidermal leukocytes. CD14(+) monocytes were recruited as early as D1 post exposure, followed by recruitment of two inflammatory DC subsets that may represent precursors of LCs. These CD1a(low) CD207(-) and the heretofore unknown CD1a(low) CD207(+) DCs appeared at day 1 and day 4 post UVR, respectively, and were endowed with T-cell-activating properties similar to those of LCs. We conclude that recruitment of monocytes and inflammatory DCs appear as a physiological response of the epidermis in order to repair UVR-induced LC depletion associated with immune suppression.

Réactions d’allure immédiate aux anesthésiques locaux : démarche diagnostique et thérapeutique

Resume Introduction Les effets indesirables des anesthesiques locaux sont frequents, mais les accidents allergiques sont rares. Nous rapportons 80 cas adresses a la consultation pour accidents d’allure immediate aux anesthesiques locaux. Nous proposons une demarche diagnostique permettant de verifier la realite de l’hypersensibilite immediate aux anesthesiques locaux. Malades et methodes Nous avons analyse retrospectivement tous les dossiers des malades adresses dans l’unite par leur medecin ou chirurgien-dentiste entre septembre 2001 et mai 2004 pour manifestations d’allure immediate au decours d’une anesthesie locale. Ces malades ont eu des tests cutanes a la recherche d’une hypersensibilite immediate (pricks tests et intradermoreactions) avec lecture a 20 minutes. Resultats Quatre-vingts malades ont ete examines pendant cette periode dans l’unite. Les symptomes les plus frequemment rapportes etaient l’œdeme de la face et les malaises. Le delai de survenue des symptomes allait de quelques secondes apres l’injection a plus de 48 heures apres le geste. Les anesthesiques locaux responsables etaient de la famille des amides dans 91 p. 100 des cas et de la famille des esters dans 9 p. 100 des cas. Chez 79 malades, les tests cutanes etaient negatifs permettant d’ecarter le diagnostic d’hypersensibilite immediate aux anesthesiques locaux et de reintroduire la molecule anesthesique. Une seule malade se revelait authentiquement allergique a la lidocaine avec une reactivite croisee pour la mepivacaine. Discussion Les effets indesirables non allergiques des anesthesiques locaux sont frequents et sont de nature pharmaconeurologique ou toxique. En revanche, les accidents allergiques sont exceptionnels, le plus souvent a type d’hypersensibilites de type IV et beaucoup plus rarement a type d’hypersensibilite de type I avec moins de 10 cas authentiquement prouves recenses dans la litterature. Les tests cutanes sont fiables dans notre experience. Nous proposons une demarche diagnostique pour differencier les intolerances aux anesthesiques locaux des allergies vraies.

Immunohistopathological Study of Autoimmune Pemphigus

Paraneoplastic pemphigus (PNP) is a form of pemphigus considered to bear characteristic immunohistopathological features (vacuolar-interface dermatitis, keratinocyte dyskeratosis and reactivity of pat