Regulatory CD4(+)CD25(+) T cells are important in suppressing immune responses. The requirements for the maintenance of peripheral CD4(+)CD25(+) T cells remain incompletely understood. Receptor activator of NF-kappaB (RANK) and its ligand (RANKL; also known as CD254, OPGL and TRANCE) are key regulators of bone remodeling, mammary gland formation, lymph node development and T-cell/dendritic cell communication. Here we report that RANKL is expressed in keratinocytes of the inflamed skin. RANKL overexpression in keratinocytes resulted in functional alterations of epidermal dendritic cells and systemic increases of regulatory CD4(+)CD25(+) T cells. Thus, epidermal RANKL expression can change dendritic cell functions to maintain the number of peripheral CD4(+)CD25(+) regulatory T cells. Epidermal RANKL mediated ultraviolet-induced immunosuppression and overexpression of epidermal RANKL suppressed allergic contact hypersensitivity responses and the development of systemic autoimmunity. Therefore, environmental stimuli at the skin can rewire the local and systemic immune system by means of RANKL.

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Background Pemphigus encompasses a group of life‐threatening autoimmune bullous diseases characterized by blisters and erosions of the mucous membranes and skin. Before the era of immunosuppressive treatment, pemphigus was almost always fatal. Due to its rarity, only few randomized controlled therapeutic trials are available. Recently, rituximab has been approved as first‐line treatment for moderate and severe pemphigus vulgaris in Europe and the United States. Objectives The Autoimmune blistering diseases Task Force of the European Academy of Dermatology and Venereology (EADV) has initiated a throughout update of the guideline for the management of patients with pemphigus. Results The guidelines for the management of pemphigus were updated, and the degree of consent among all task force members was included. The final version of the guideline was consented by the European Dermatology Forum (EDF) and several patient organizations.

Specific inhibition of the entry of encephalitogenic T lymphocytes into the central nervous system in multiple sclerosis would provide a means of inhibiting disease without compromising innate immune responses. We show here that targeting lymphocyte interactions with endothelial basement membrane laminins provides such a possibility. In mouse experimental autoimmune encephalomyelitis, T lymphocyte extravasation correlates with sites expressing laminin alpha4 and small amounts of laminin alpha5. In mice lacking laminin alpha4, laminin alpha5 is ubiquitously expressed along the vascular tree, resulting in marked and selective reduction of T lymphocyte infiltration into the brain and reduced disease susceptibility and severity. Vessel phenotype and immune response were not affected in these mice. Rather, laminin alpha5 directly inhibited integrin alpha(6)beta(1)-mediated migration of T lymphocytes through laminin alpha4. The data indicate that T lymphocytes use mechanisms distinct from other immune cells to penetrate the endothelial basement membrane barrier, permitting specific targeting of this immune cell population.

Mechanisms linking innate immunity and autoimmune responses are poorly understood. Myeloid-related protein-8 (Mrp8) and Mrp14 are damage-associated molecular pattern molecules (DAMPs) highly upregulated in various autoimmune disorders. We show in a mouse autoimmune model that local Mrp8 and Mrp14 production is essential for the induction of autoreactive CD8+ T cells and the development of systemic autoimmunity. This effect is mediated via Toll-like receptor 4 (TLR4) signaling leading to increased interleukin-17 (IL-17) expression. Notably, expression of Mrp8 and Mrp14 was upregulated in cutaneous lupus erythematosus, and stimulation of CD8+ T cells from individuals with lupus erythematosus with MRP proteins resulted in an upregulation of IL-17, suggesting a key role for MRP8 and MRP14 for the development of autoreactive lymphocytes during human autoimmunity as well. These results demonstrate a link between local expression of DAMP molecules and the development of systemic autoimmunity.

Epicutaneous application of haptens to UV-exposed skin induces hapten-specific tolerance. This is mediated via regulatory T cells (Tr), as i.v. injection of T cells from UV-tolerized mice into naive animals renders the recipients unresponsive to the respective hapten. However, when UV-induced Tr are injected i.v. into sensitized mice, contact hypersensitivity (CHS) is not suppressed, suggesting that Tr inhibit the induction, but not the elicitation, of CHS and are inferior to T effector cells. As sensitization takes place in the lymph nodes, but elicitation occurs in the area of challenge, we postulated that Tr injected i.v. locate to the lymph nodes and not to the periphery and therefore only suppress the induction, not the elicitation, of CHS. Indeed, i.v. injection of Tr into sensitized mice did not inhibit CHS, although injection of Tr into the ears of sensitized mice suppressed the challenge. Inhibition was hapten specific, as injection of dinitrofluorobenzene (DNFB)-specific Tr into the ears of oxazolone (OXA)-sensitized mice did not affect challenge with OXA. However, when ears of OXA-sensitized mice were injected with DNFB-specific Tr and painted with DNFB before OXA challenge, CHS was suppressed. Inhibition correlated with the local expression of IL-10. Depletion studies and FACS analysis revealed that Tr express the lymph node-homing receptor L-selectin, but not the ligands for the skin-homing receptors E- and P-selectin, suggesting that UV-induced Tr, although able to inhibit T effector cells, do not suppress the elicitation of CHS upon i.v. injection, because they obviously do not migrate into the skin.

The concept of tumor surveillance implies that specific and nonspecific components of the immune system eliminate tumors in the early phase of malignancy. Understanding the biochemical mechanisms of tumor immunosurveillance is of paramount significance because it might allow one to specifically modulate spontaneous antitumor activity. We report that inactivation of the E3 ligase Casitas B cell lymphoma-b (Cbl-b) confers spontaneous in vivo rejection of tumor cells that express human papilloma virus antigens. Moreover, cbl-b−/− mice develop significantly fewer ultraviolet B (UVB)–induced skin malignancies and reject UVB-induced skin tumors. CD8+ T cells were identified as key players in the spontaneous tumor rejection response. Loss of Cbl-b not only enhances antitumor reactivity of CD8+ T cells but also occurs in the absence of CD4+ T cells. Mechanistically, cbl-b−/− CD8+ T cells are resistant to T regulatory cell–mediated suppression and exhibit enhanced activation and rapid tumor infiltration. Importantly, therapeutic transfer of naive cbl-b−/− CD8+ T cells is sufficient to mediate rejection of established tumors. Even up to 1 yr after the first encounter with the tumor cells, cbl-b−/− mice carry an “anticancer memory.” These data identify Cbl-b as a key signaling molecule that controls spontaneous antitumor activity of cytotoxic T cells in different cancer models. Inhibition of Cbl-b is a novel approach to stimulate long-lasting immunity against cancer.

The dupilumab regimen of 300 mg every 2 weeks is approved for uncontrolled, moderate to severe atopic dermatitis (AD). OBJECTIVE To assess the efficacy and safety of different dupilumab regimens in maintaining response after 16 weeks of initial treatment. DESIGN, SETTING, AND PARTICIPANTS The Study to Confirm the Efficacy and Safety of Different Dupilumab Dose Regimens in Adults With Atopic Dermatitis (LIBERTY AD SOLO-CONTINUE) was a randomized, double-blind, phase 3 clinical trial conducted from March 25, 2015, to October 18, 2016, at 185 sites in North America, Europe, Asia, and Japan. Patients with moderate to severe AD who received dupilumab treatment and achieved an Investigator's Global Assessment score of 0 or 1 or 75% improvement in Eczema Area and Severity Index scores (EASI-75) at week 16 in 2 previous dupilumab monotherapy trials (LIBERTY AD SOLO 1 and 2) were rerandomized in SOLO-CONTINUE. After completing SOLO-CONTINUE, patients were followed up for up to 12 weeks or enrolled in an open-label extension. Data were analyzed from December 5 to 12, 2016. INTERVENTIONS High-responding patients treated with dupilumab in SOLO were rerandomized 2:1:1:1 to continue their original regimen of dupilumab, 300 mg, weekly or every 2 weeks or to receive dupilumab, 300 mg, every 4 or 8 weeks or placebo for 36 weeks. MAIN OUTCOMES AND MEASURES Percentage change in EASI score from baseline during the SOLO-CONTINUE trial, percentage of patients with EASI-75 at week 36, and safety. RESULTS Among the 422 patients (mean [SD] age, 38.2 [14.5] years; 227 [53.8%] male), continuing dupilumab treatment once weekly or every 2 weeks maintained optimal efficacy, with negligible change in percent EASI improvement from SOLO 1 and 2 baseline during the SOLO-CONTINUE trial (−0.06%; P < .001 vs placebo); percent change with the other regimens dose-dependently worsened (dupilumab every 4 weeks, −3.84%; dupilumab every 8 weeks, −6.84%; placebo, −21.67%). More patients taking dupilumab weekly or every 2 weeks (116 of 162 [71.6%]; P < .001 vs placebo) maintained EASI-75 response than those taking dupilumab every 4 weeks (49 of 84 [58.3%]) or every 8 weeks (45 of 82 [54.9%]) or those taking placebo (24 of 79 [30.4%]). Overall adverse event incidences were 70.7% in the weekly or every 2 weeks group, 73.6% in the every 4 weeks group, 75.0% in the every 8 weeks group, and 81.7% in the placebo group. Treatment groups had similar conjunctivitis rates. Treatment-emergent antidrug antibody incidence was lower with more frequent dupilumab dose regimens (11.3% in the placebo group and 11.7%, 6.0%, 4.3%, and 1.2% in the dupilumab every 8 weeks, every 4 weeks, every 2 weeks, and weekly groups, respectively). CONCLUSIONS AND RELEVANCE In this trial, continued response over time was most consistently maintained with dupilumab administered weekly or every 2 weeks. Longer dosage intervals and placebo resulted in a diminution of response for both continuous and categorical end points. No new safety signals were observed. The approved regimen of 300 mg of d...