049 Development of active mouse models to recapitulate pemphigus subtypes and to evaluate response to therapy

Abstract

Pemphigus is an autoimmune bullous disease characterized by loss of adhesion caused by autoantibodies (PVIgG) against keratinocyte antigens, desmogleins (Dsg1 and Dsg3) and non-Dsg proteins, such as acetylcholine receptors (AChR) or Desmocollin (Dsc3). Different PVIgG result in diverse clinical phenotypes. In order to recapitulate the features of human pemphigus, to evaluate the role of different antigens, and to test the response to therapy, we generated an active mouse model. We produced murine recombinant proteins (rDsg1, rDsg3, rDsc3, rAChRM3, rAChRNa7 and rAChRNa9). We then immunized Dsg3-/-mice with mouse rDsg3, and adoptively transferred their splenocytes into C57BL/6 Rag2-/-(Rag2) immunodeficient mice, that express Dsg3. Recipient mice stably produce the pathogenic anti-Dsg3 IgG and exhibit the features of pemphigus vulgaris, as shown by clinical score and Dsg3 levels (ELISA). We also generated the pemphigus foliaceous active mouse model, by breaking the immunological tolerance in WT mice with rDsg1. Similarly, we created a Dsg1/Dsg3 mouse model by transferring the combined splenocytes from mice immunized with rDsg1 and mice immunized with rDsg3 into Rag2 mice. The Dsg1/Dsg3 mouse model displays the most severe phenotype, reproduces symptoms of mucocutaneous PV in patients, as well as the same level of intraepithelial detachment and inter-keratinocyte deposits of IgG. Moreover, only the Dsg1/Dsg3 mice significantly responded to treatment with methylprednisolone in a time-dependent manner (clinical score and ELISA). In conclusion, we created new tools that could 1. improve the knowledge on pemphigus pathomechanisms; 2. serve for the identification of new therapeutic targets; 3. allow a long-term pre-clinical observation with or without current and novel therapies 050 Patients with hidradenitis suppurativa have altered populations of circulating B cells J Musilova and B Kirby Dermatology, St. Vincents University Hospital, Dublin, Ireland Hidradenitis suppurativa (HS) is a chronic inflammatory disease characterized by painful deep-seated recurrent nodules and abscesses in axillary, inguinal, perineal and mammary areas. HS is a complex disease whose aetiology includes genetic variations, environmental factors as well as abnormal immune functions. B cells are the key mediators of humoral immune responses by producing antigen-specific antibodies and by orchestrating CD4+ T cell activation. It is becoming clear that abnormalities during the B cell development and differentiation give rise to a diverse array of immunological diseases including autoimmunity and immunodeficiency. In this study, we investigated the B cell subsets in the peripheral blood mononuclear cells (PBMC) from HS patients compared to healthy controls (HC). PBMCs from HS patients (n¼10, 80% female and 20% male with a mean age 37.8 AE 6.2 years) and HC (n¼11, blood transfusion donors) were surface stained using B cell-specific markers and B cell populations were detected by flow cytometry. We observed that HS patients had significantly elevated ...