Emanual Maverakis

Light, Including Ultraviolet

Ultraviolet (UV) light is intricately linked to the functional status of the cutaneous immune system. In susceptible individuals, UV radiation can ignite pathogenic inflammatory pathways leading to allergy or autoimmunity. In others, this same UV radiation can be used as a phototherapy to suppress pathogenic cutaneous immune responses. These vastly different properties are a direct result of UV lights ability to ionize molecules in the skin and thereby chemically alter them. Sometimes these UV-induced chemical reactions are essential, the formation of pre-vitamin D(3) from 7-dehydrocholesterol, for example. In other instances they can be potentially detrimental. UV radiation can ionize a cells DNA causing adjacent pyrimidine bases to chemically bond to each other. To prevent malignant transformation, a cell may respond to this UV-induced DNA damage by undergoing apoptosis. Although this pathway prevents skin cancer it also has the potential of inducing or exacerbating autoreactive immune responses by exposing the cells nuclear antigens. Ultraviolet-induced chemical reactions can activate the immune system by a variety of other mechanisms as well. In response to UV irradiation keratinocytes secrete cytokines and chemokines, which activate and recruit leukocytes to the skin. In some individuals UV-induced chemical reactions can synthesize novel antigens resulting in a photoallergy. Alternatively, photosensitizing molecules can damage cells by initiating sunburn-like phototoxic reactions. Herein we review all types of UV-induced skin reactions, especially those involving the immune system.

The Adaptor Protein AP-3 Is Required for CD1d-Mediated Antigen Presentation of Glycosphingolipids and Development of Vα14i NKT Cells

Relatively little is known about the pathway leading to the presentation of glycolipids by CD1 molecules. Here we show that the adaptor protein complex 3 (AP-3) is required for the efficient presentation of glycolipid antigens that require internalization and processing. AP-3 interacts with mouse CD1d, and cells from mice deficient for AP-3 have increased cell surface levels of CD1d and decreased expression in late endosomes. Spleen cells from AP-3–deficient mice have a reduced ability to present glycolipids to natural killer T (NKT) cells. Furthermore, AP-3–deficient mice have a significantly reduced NKT cell population, although this is not caused by self-tolerance that might result from increased CD1d surface levels. These data suggest that the generation of the endogenous ligand that selects NKT cells may also be AP-3 dependent. However, the function of MHC class II–reactive CD4+ T lymphocytes is not altered by AP-3 deficiency. Consistent with this divergence from the class II pathway, NKT cell development and antigen presentation by CD1d are not reduced by invariant chain deficiency. These data demonstrate that the AP-3 requirement is a particular attribute of the CD1d pathway in mice and that, although MHC class II molecules and CD1d are both found in late endosomes or lysosomes, different pathways mediate their intracellular trafficking.

Diagnosis and classification of psoriasis.

Psoriasis is a chronic inflammatory multi organ disease with well characterized pathology occurring in the skin and often the joints. Although the disease has many characteristic and even pathognomonic features, no established diagnostic criteria exist for cutaneous psoriasis and there is no unified classification for the clinical spectrum of the disease. Prior approaches that have been taken to classify psoriasis include age of onset, severity of the disease, and morphologic evaluation. The latter has yielded plaque, guttate, pustular, and erythrodermic as subtypes of psoriasis. Unlike other autoimmune diseases, histopathological examination and blood tests are generally not valuable tools in making the diagnosis of psoriasis. However, on occasion, dermatopathologic evaluation may be helpful in confirming the diagnosis of psoriasis. Thus, in most cases the diagnosis of psoriasis is dependent primarily on pattern recognition that is morphologic evaluation of skin lesions and joints.

Galectin-3 negatively regulates TCR-mediated CD4+ T-cell activation at the immunological synapse

We have investigated the function of endogenous galectin-3 in T cells. Galectin-3-deficient (gal3−/−) CD4+ T cells secreted more IFN-γ and IL-4 than gal3+/+CD4+ T cells after T-cell receptor (TCR) engagement. Galectin-3 was recruited to the cytoplasmic side of the immunological synapse (IS) in activated T cells. In T cells stimulated on supported lipid bilayers, galectin-3 was primarily located at the peripheral supramolecular activation cluster (pSMAC). Gal3+/+ T cells formed central SMAC on lipid bilayers less effectively and adhered to antigen-presenting cells less firmly than gal3−/− T cells, suggesting that galectin-3 destabilizes the IS. Galectin-3 expression was associated with lower levels of early signaling events and phosphotyrosine signals at the pSMAC. Additional data suggest that galectin-3 potentiates down-regulation of TCR in T cells. By yeast two-hybrid screening, we identified as a galectin-3-binding partner, Alix, which is known to be involved in protein transport and regulation of cell surface expression of certain receptors. Co-immunoprecipitation confirmed galectin-3-Alix association and immunofluorescence analysis demonstrated the translocation of Alix to the IS in activated T cells. We conclude that galectin-3 is an inhibitory regulator of T-cell activation and functions intracellularly by promoting TCR down-regulation, possibly through modulating Alixs function at the IS.

A public T cell clonotype within a heterogeneous autoreactive repertoire is dominant in driving EAE

Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis. Immunization of B10.PL mice with the Ac1-9 peptide, the immunodominant determinant of myelin basic protein (MBP), produced a single episode of EAE followed by recovery and resistance to reinduction of disease. Using the CDR3 length spectratyping technique, we characterized the clonal composition of the Ac1-9-specific T cell repertoire from induction through onset and resolution of disease. Two clonally restricted subsets within a heterogeneous self-reactive repertoire were found in mouse lymph nodes, spleen, and spinal cord soon after immunization, before any sign of EAE. These clonotypes, designated BV8S2/BJ2S7 and BV16/BJ2S5, were present in all mice examined and thus considered public. BV8S2/BJ2S7 was found in far greater excess; was exclusively Th1 polarized; disappeared from the spinal cord, spleen, and lymph nodes concomitantly with recovery; and transferred disease to naive recipients. In contrast, BV16/BJ2S5 and numerous private clonotypes were either Th1 or Th2 and persisted following recovery. These results are consistent with the hypothesis that the public clonotype BV8S2/BJ2S7 is a driver of disease and necessary for its propagation.

Metastatic melanoma – A review of current and future treatment options

Despite advances in treatment and surveillance, melanoma continues to claim approximately 9,000 lives in the US annually (SEER 2013). The National Comprehensive Cancer Network currently recommends ipilumumab, vemurafenib, dabrafenib, and high-dose IL-2 as first line agents for Stage IV melanoma. Little data exists to guide management of cutaneous and subcutaneous metastases despite the fact that they are relatively common. Existing options include intralesional Bacillus Calmette-Guérin, isolated limb perfusion/infusion, interferon-α, topical imiquimod, cryotherapy, radiation therapy, interferon therapy, and intratumoral interleukin-2 injections. Newly emerging treatments include the anti-programmed cell death 1 receptor agents (nivolumab and pembrolizumab), anti-programmed death-ligand 1 agents, and oncolytic vaccines (talimogene laherparepevec). Available treatments for select sites include adoptive T cell therapies and dendritic cell vaccines. In addition to reviewing the above agents and their mechanisms of action, this review will also focus on combination therapy as these strategies have shown promising results in clinical trials for metastatic melanoma treatment.

The etiology of paraneoplastic autoimmunity.

Although they may sometimes appear similar, paraneoplastic autoimmunity has a unique pathogenesis, different from the classical autoimmune diseases not associated with cancer. When distinguished clinically, paraneoplastic autoimmunity is more severe and often presents with a broader range of clinical signs and symptoms. Management of these patients is difficult and is usually centered in part on treatment of the underlying malignancy. Self-antigens recognized in the setting of paraneoplastic autoimmunity can be diverse, and the number of determinants recognized within a single antigen can be numerous. This review uses prototypic examples of paraneoplastic immune-mediated diseases and their associated malignancies to describe the mechanisms by which immune dysregulation can occur in the setting of cancer. Specific diseases covered include paraneoplastic pemphigus, Sweet’s syndrome, pyoderma gangrenosum, thymoma-associated multiorgan autoimmunity, myasthenia gravis, autoimmune hemolytic anemia, immune thrombocytopenia, and the paraneoplastic neurological syndromes. The malignancies discussed include thymoma, non-Hodgkin’s lymphoma, and chronic lymphocytic leukemia, among others. The mechanisms by which cancers induce autoimmunity are broken down into the following categories: disruption of central tolerance, peripheral immune dysregulation, and alteration of self-antigens. For each category, examples of paraneoplastic autoimmune diseases and their associated malignancies are discussed. Finally, mechanisms by which cancer treatment can lead to autoimmunity and examples of polymorphisms that are linked to both cancer and autoimmunity are discussed.

Aging predisposes to acute inflammatory induced pathology after tumor immunotherapy

Aging strongly promotes inflammation responses, which may predispose individuals after cancer therapies to lethal system toxicities and pathology that can be partially prevented by TNF blockade.

Management of recalcitrant hidradenitis suppurativa with ustekinumab.

Hidradenitis suppurativa (HS) is a chronic inflammatory disease resulting from occlusion of the pilosebaceous units within the intertriginous regions of the body. It is characterized by very tender papules, nodules, and neutrophilic abscesses. Sinus tracts with malodorous drainage and scarring can develop. Long-term complications include lymphoedema and fistulae formation. We present here a difficult case of HS that responded well to ustekinumab.

Biologic Therapies in the Treatment of Psoriasis: A Comprehensive Evidence-Based Basic Science and Clinical Review and a Practical Guide to Tuberculosis Monitoring

The treatment of psoriasis has undergone a revolution with the advent of biologic therapies including infliximab, etanercept, adalimumab, efalizumab, golimumab, certolizumab, alefacept, secukinumab, abatacept, and ustekinumab. These medications are designed to target specific components of the immune system and are a major technological advancement over traditional immunosuppressive medications. Herein, we present a comprehensive, unbiased comparison of these medications focusing on their differences. For example, TNF antagonists can differ in the way they are dissolved and administered, the effector molecules they can bind, serum peak and trough levels, the types of intracellular signals they can induce, the in vivo complexes that they can form, their protein structure, and their incidence and timing of rare adverse events, among other things. A critical review of the clinical studies that have tested the efficacy of these molecules is also presented including head-to-head comparison trials. The safety of biologics in terms of their long-term adverse events is discussed, as is their use in different types of psoriasis and in different patient populations. Finally, all anti-TNF agents have been associated with a variety of serious and “routine” opportunistic infections, particularly tuberculosis. For this reason, anti-tuberculosis testing both prior to the initiation of a biologic therapy and annually during treatment is pertinent. The uses and limitations of both the tuberculin skin test (TST) and QuantiFeron®-TB Gold (QFT) are discussed, as is the care of patients who present with latent tuberculosis infection prior to the initiation of biologic therapy. Recommendations for tuberculosis monitoring are provided.