Risk of Progression to Autoimmune Disease in Severe Drug Eruption: Risk Factors and the Factor-Guided Stratification.

The identification of risk factors is key not only to uncover the pathogenesis of autoimmune disease but also to predict progression to autoimmune disease. Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms is likely the best prototypic example for analyzing the sequential events. We conducted a retrospective study of 55 patients with drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms followed up for the possibility of later development of autoimmune disease ∼18 years after resolution. Nine patients progressed to autoimmune sequelae regardless of treatment. The generation of autoantibodies was preceded by 8 years in eight of the nine patients. The combination of increases in lymphocyte counts, severe liver damage, a rebound increase in globulin, persistent reactivations of Epstein‒Barr virus and human herpesvirus-6, and low IL-2 and IL-4 at the acute/subacute phases were significant risk factors for the future development of autoimmune disease. On the basis of these factors, we established a scoring system that can identify high-risk patients. When stratified these patients into three risk categories (low/intermediate/high), occurrence of autoimmune disease was exclusively detected in the high group. Our data represent a scoring system to identify patients at high risk of developing autoimmune disease, although a larger study is required to validate the scoring system.

Monocyte-Independent and -Dependent Regulation of Regulatory T-Cell Development in Mycoplasma Infection.

BACKGROUND: Although Mycoplasma pneumoniae (MP) infection has been implicated in the pathogenesis of allergic diseases, the mechanism of this trigger remains unknown. We explored the mechanism for how MP infection could tilt the balance between regulatory T cells (Tregs) and Th17 cells. METHODS: We analyzed the frequency, phenotype, and function of Tregs in patients at the different stages of MP and various virus infections over a period of more than 1 year. We examined the effect of monocytes to elucidate signals that can regulate the balance between Treg and Th17 cells. RESULTS: The functional activity of Tregs was profoundly impaired during the acute stage of MP as well as viral infections. Upon resolution, however, the Treg function remained impaired even 1 year after MP infection. In the resolution stage, the impaired Treg function was associated with an increase in interleukin (IL) 17A+ Tregs and Th17 cells. Development of Th17 cells was dependent on the "aberrant" proinflammatory monocytes (pMOs), characterized by potent ability to produce IL-6 in a Toll-like receptor 2-dependent manner. CONCLUSIONS: Depending on the prevalence of the pMOs, Tregs and Th17 cells could mutually regulate the number and function of the other. The pMOs/IL-6 could be crucial therapeutic targets against MP-induced allergic diseases.

Intracellular accumulation of PD-1 molecules in circulating T lymphocytes in advanced malignant melanoma: an implication for immune evasion mechanism.

BACKGROUND: The blockade of cell surface PD-1 ((sur)PD-1) by monoclonal antibodies, represented by nivolumab, provides the strategy to treat advanced malignant melanoma (AMM). The intracellular presence of PD-1 molecules have been reported in some T cell subsets, however, their kinetic association with those expressed on the cell surface, let alone their significance in antitumor immunity has been ill-investigated. METHODS: Intracellular PD-1 expression status in T cell subsets in AMM cases during nivolumab administration was chronologically characterized. The kinetics of PD-1 molecules within AMM-derived T cells was assessed in vitro in conjunction with their functional properties. RESULTS: Increase in (sur)PD-1 and intracellular PD-1 ((int)PD-1+) expression was characteristic for AMM T cells. After short-term culture, virtually (sur)PD-1- nivolumab-treated AMM T cells restore (sur)PD-1 expression, which could not be explained by the detachment of nivolumab from PD-1 epitopes alone. The blockade of trans-Golgi network resulted in the decrease in the extent of (sur)PD-1 recovery, suggesting the translocation of accumulated (int)PD-1 to the cell surface. Antigen-specific PD-1+ T cells significantly increased in (int)PD-1+ cells after treatment. In addition, a surge in (int)PD-1+CD4+ T cells was observed prior to the emergence of skin rash as an immune-related adverse event (irAE). CONCLUSIONS: Accumulated (int)PD-1 in T cells may contribute to enhanced immune evasion in AMM. Evaluation of intracellular PD-1 expression would be useful for better management of nivolumab-treated AMM patients in view of predicting treatment response and the incidence of irAE. Our findings further support the necessity of periodical administration of nivolumab for treating AMM.

Importance of Water Content of the Stratum Corneum in Mouse Models for Contact Hypersensitivity.

Although a marked rise in the prevalence of allergic diseases over the past few decades may be related to environmental factors in industrialized countries, evidence for the protective effect of humidity on the barrier function of the skin is still awaited. We asked whether an increase in the water content of stratum corneum at the site of hapten application had a strong impact on the magnitude of contact hypersensitivity (CHS). The magnitude of CHS, induced by either lipid-soluble or water-soluble hapten, was inversely correlated with the water content of stratum corneum at the hapten application site in the elicitation phase. An increase in the water content induced by exposure to high humidity for 6 hours was sufficient to ameliorate the magnitude of CHS even in mice with the genetic defect in attenuating the CHS responses, such as flaky tail mice. The reduced CHS was associated with downregulation of IL-1α, IL-4, and IFN-γ mRNA expression. Epicutaneously applied hapten can penetrate more readily through the stratum corneum with lower water content than that with higher water content, even after tape-stripping. These findings indicate that increased levels of water in the stratum corneum serve to ameliorate the CHS beyond the genetic effects.

Sweat as an Efficient Natural Moisturizer.

Although recent research on the pathogenesis of allergic skin diseases such as atopic dermatitis has focused on defects in skin genes important for maintaining skin barrier function, the fact that excreted sweat has an overwhelmingly great capacity to increase skin surface hydration and contains moisturizing factors has long been ignored: the increase in water loss induced by these gene defects could theoretically be compensated fully by a significant increase in sweating. In this review, the dogma postulating the detrimental role of sweat in these diseases has been challenged on the basis of recent findings on the physiological functions of sweat, newly recognized sweat gland-/duct-related skin diseases, and therapeutic approaches to the management of these diseases. We are now beginning to appreciate that sweat glands/ducts are a sophisticated regulatory system. Furthermore, depending on their anatomical location and the degree of the impairment, this system might have a different function: sweating responses in sweat glands/ducts located at the folds in hairy skin such as on the trunk and extremities could function as natural regulators that maintain skin hydration under quiescent basal conditions, in addition to the better-studied thermoregulatory functions, which can be mainly mediated by those at the ridges. The normal functioning of sweat could be disturbed in various inflammatory skin diseases. Thus, we should recognize sweating disturbance as an etiologic factor in the development of these diseases.

Sequelae in 145 patients with drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms: survey conducted by the Asian Research Committee on Severe Cutaneous Adverse Reactions (ASCAR).

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is a severe adverse drug reaction caused by specific drug. It is characterized by visceral organ involvement and reactivation of various human herpesviruses. Although sporadic reports have documented certain conditions that appear after the resolution of DIHS/DRESS, little information is available on sequelae after resolution of DIHS/DRESS in a large patient population. The Asian Research Committee on Severe Cutaneous Adverse Reactions, comprised of doctors from Japan and Taiwan, conducted a survey on sequelae and deterioration of the underlying disease in patients with DIHS/DRESS. This was achieved by directly interviewing patients who had been followed-up by experts or through a questionnaire mailed to patients. Questions were asked about new onset cardiovascular disease, collagen disease or autoimmune disease, gastrointestinal disease, renal disease, respiratory disease, neoplasms, and other diseases such as herpes zoster and diabetes mellitus, as well as deterioration of the underlying disease. A total of 145 patients were analyzed in this study. The following newly developed diseases after recovery from DIHS/DRESS were observed: Graves' disease (n = 2), Hashimoto's disease (n = 3), painless thyroiditis (n = 2), fulminant type 1 diabetes mellitus (n = 5), and infectious diseases (n = 7). Several DIHS/DRESS patients with pre-existing renal dysfunction required lifelong hemodialysis. DIHS/DRESS is a condition that increases the risk of new onset of disease. Long-term observation of DIHS/DRESS can provide an opportunity to investigate substantial diseases from onset to the full-blown stage. Patients with DIHS/DRESS require careful long-term follow-up.

Crucial Role of Viral Reactivation in the Development of Severe Drug Eruptions: a Comprehensive Review.

A growing number of cells, mediators, and pathways have been implicated in severe drug eruptions. Fifteen years ago, we published landmark studies that sparked the current advances in our understanding of the role of viral reactivations in severe drug eruptions. Viral reactivations then became critically important as diagnostic tools, but how precisely they participated in the pathogenesis remained less well-defined. The question of whether viral reactivations are pathogenic or are instead as epiphenomenon of severe tissue damage has plagued the field of drug allergy for some decades. Recent evidence points to a crucial role for tissue-resident memory T (TRM) cells in immune protection against viral infections. Yet immune protection against viral infections is but one side of a coin, the other side of which comprises effector cells capable of mediating severe immunopathology: Once drug antigen is cross-recognized by these T cells, they could be activated to kill surrounding epidermal cells, resulting in drug-induced tissue damage. Such TRM cells could persistently reside in the skin lesions of fixed drug eruptions (FDE) and are most likely a major cell type responsible for the development of FDE. We also discuss the role of regulatory T (Treg) cells in the setting of drug allergy, in which herpesviruses are reactivated in sequence. Although many details of the complicated interactions among viruses, anti-viral immune responses, TRM cells, and Treg cells remain to be elucidated, we review the current status of this rapidly advancing field.

Evidence for reactivation of human herpesvirus 6 in generalized lymphadenopathy in a patient with drug-induced hypersensitivity syndrome.

The present case provides direct evidence of human herpesvirus 6 reactivation in resected lymph node tissue in a patient with drug-induced hypersensitivity syndrome. This case clearly demonstrates that appropriate pathological evaluation of lymphadenopathy for drug-induced hypersensitivity syndrome, which mimics malignant lymphoma in clinical, radiological, and pathological findings, is required.

A syringotropic variant of cutaneous sarcoidosis: presentation of 3 cases exhibiting defective sweating responses.

BACKGROUND: Although nodular collections of epithelioid histiocytes and multinuclear cells can be present at all levels of the dermis in cutaneous sarcoidosis, sarcoidal granulomas characterized by marked syringotropism of epithelioid histiocytes have not been previously reported to our knowledge. OBJECTIVE: We sought to determine whether syringotropic sarcoidosis bears characteristic clinical and histologic features and exhibits defective sweating responses. METHODS: We investigated the clinical, histologic, and immunohistochemical features of syringotropic sarcoidosis, and sweating responses to thermal stress in 3 patients. RESULTS: Multiple erythematous patches/plaques predominantly affected the extensor aspect of the lower legs and thighs. Immunohistochemical analyses of the sweat glands surrounded by syringotropic granulomas exhibited profoundly decreased expression of dermcidin and aquaporin 5, both of which are constitutively expressed in sweat glands of control subjects, suggesting functional defects. Indeed, sweating responses to thermal stress were markedly decreased in the involved area, as compared with those in the uninvolved area and in healthy control subjects. LIMITATIONS: There were a limited number of cases in our study. CONCLUSION: A syringotropic variant of cutaneous sarcoidosis might be a distinct entity clinically and histologically or represent an abortive variant.

Short- and long-term outcomes of 34 patients with drug-induced hypersensitivity syndrome in a single institution.

BACKGROUND: Drug-induced hypersensitivity syndrome (DIHS)/drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe systemic hypersensitivity reaction caused by specific drugs, in which herpesvirus reactivations and organ dysfunction occur during the course of the disease. Although recent reports have documented the development of autoimmune disease after complete resolution of DIHS/DRESS, relatively little is known about long-term outcomes after complete resolution of the disease. OBJECTIVE: The aim of this study was to retrospectively analyze complications and sequelae in the early and late phases of DIHS/DRESS according to treatment. METHODS: In all, 34 patients were classified into 2 groups: 14 patients with oral corticosteroid treatment; and 20 with noncorticosteroid treatment. The disease time course was divided into 2 periods: the first 6 months after onset of the drug reaction (early phase); and the period thereafter (late phase). Investigations to detect the presence of viral/bacterial infectious diseases, organ dysfunction, and autoantibodies were performed in both early and late phases. RESULTS: Herpesvirus infections and pneumonia were detected in 6 and 2 patients, respectively, in the corticosteroid treatment group in the early phase. In the noncorticosteroid treatment group, 2 patients developed autoimmune diseases, namely lupus erythematosus and autoimmune thyroiditis. Autoantibodies were detected in 44.4% of patients examined in the late phase of the disease. LIMITATIONS: This study only evaluated a small number of autoantibodies. CONCLUSION: The need for anti-inflammatory effects from systemic corticosteroids should be balanced with the risk of infectious diseases and the benefits of preventing the appearance of later autoimmune conditions in patients with DIHS/DRESS.

Defective sweating responses in atopic dermatitis.

While sweat is thought to be one of the important factors provoking exacerbations of clinical symptoms in atopic dermatitis (AD), little attention has been drawn to a beneficial role of sweat in the development of AD lesions. However, if the permeability barrier and antimicrobial barrier dysfunction represents the primary event in the development of AD, an evaluation of sweating responses in AD is a logical place to look for changes that predispose to the disease. In this regard, there have been conflicting data regarding whether sweating responses are impaired, normal or enhanced in AD patients. Consistent with the results of most recent studies, our recent study showed that most AD patients exhibit a defective ability to deliver sweat to the skin surface in response to thermal stress. Despite such defective sweating responses observed in the most part, a marked augmentation in the sweating response with delayed kinetics can be paradoxically detected in some sweating glands of these AD patients, indicating compensatory hyperhidrosis. Dermcidin, a new antimicrobial peptide exclusively produced by sweat glands, was abundantly detected not only in the sweat glands and ducts, and the lumen, but also in the dermal tissues adjacent to the sweat glands. These results indicate that the sweat may be retained in the lumen or pour into the dermal tissues, thereby causing inflammation. Thus, chronic inflammation in AD may be caused in part by a dysfunction of the sweat delivery system.

Relationship between cytomegalovirus reactivation and dermatomyositis.

Dermatomyositis (DM) is an autoimmune disease manifested by muscle weakness and characteristic cutaneous eruptions. Cytomegalovirus (CMV) belongs to the ß-herpesvirinae subfamily of herpesviridae that cause morbidity and mortality in immunocompromised patients. With respect to the relationship between CMV and DM, it remains unknown whether CMV plays a pathogenetic role or whether CMV disease is an opportunistic infection due to immunosuppressive treatment. We report two patients with DM who developed cutaneous CMV ulcers within one month after the initiation of systemic corticosteroid treatment. In this context, we retrospectively studied the clinical characteristics of six DM patients with CMV reactivation and the effect of corticosteroid treatment on CMV reactivation in these patients. We also examined possible predictive parameters of CMV reactivation during the course of DM. Our results suggest that CMV reactivation occurs more frequently in DM patients than previously recognized; CMV reactivation occurs regardless of the dosage and duration of corticosteroid administration or the presence of underlying disease. Furthermore, our study shows that a reduction in platelets, serum globulin and IgG levels during the course of DM may be useful predictive parameters for CMV reactivation in patients with DM.