Defective regulatory T cells in patients with severe drug eruptions: timing of the dysfunction is associated with the pathological phenotype and outcome

DRESS syndrome

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, initially recognized as a serious form of cutaneous drug adverse reaction, is now viewed as a drug-related syndrome that can cause life-threatening organ dysfunctions. Characteristic features include a long time interval from first drug exposure to symptom onset and a prolonged course, often with flares, even after discontinuation of the causal drug. The pathophysiology of DRESS syndrome remains incompletely understood but involves reactivation of herpes viruses (HHV-6, HHV-7, EBV, and CMV), against which the body mounts a strong immune response. The culprit drugs may not only affect epigenetic control mechanisms, thereby promoting viral reactivation, but also induce an antiviral T-cell response by interacting with the major histocompatibility complex receptor in individuals with genetic susceptibility factors. Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome is a potentially life-threatening form of cutaneous drug adverse reaction. The severity of this syndrome is related to the systemic manifestations, which can result in multiorgan failure. DRESS syndrome is characterized by highly specific features, most notably regarding the timing of the manifestations. New insights into the underlying pathophysiological mechanisms indicate a role for immunogenetic susceptibility factors and for reactivation of human herpes viruses (HHVs), chiefly HHV-6. We report a typical case of DRESS syndrome and discuss recent data about this condition.

[DRESS syndrome. Rare and potentially lethal allergic reaction to carbamazepine - a case report]

A 64-year-old man with chronic low back pain had been treated with tramadol, meloxicam and metamizole for several years. Due to additional neuropathic pain in the lower extremities, the medication was complemented with carbamazepine. After 5 weeks of treatment, the patient developed maculopapulose exanthema and fever, followed by hepatitis, leukocytosis and eosinophilia. The patient was diagnosed with so-called DRESS (drug rash with eosinophilia and systemic symptoms) syndrome, a severe anaphylactic reaction to carbamazepine treatment. Immunosuppressive therapy was complicated by an additional septic reaction. After recovery, the patient was referred to our clinic for a multimodal pain therapy. Fear, depressive episodes and fear-avoidance behavior were additional social factors responsible for the chronic pain syndrome of the patient. The previously diagnosed neuropathic pain syndrome cannot be verified. After appropriate modification of therapy, the patient's pain perception was significantly reduced, allowing for complete withdrawal of pain-relieving medication. This case report illustrates that merely pharmacological treatment of chronic pain syndromes bears only little prospect of success but increased risk of side effects.

Stevens-Johnson Syndrome associated with mogamulizumab treatment of adult T-cell leukemia / lymphoma

We report an adult T-cell leukemia/lymphoma patient suffering from Stevens-Johnson Syndrome (SJS) during mogamulizumab (humanized anti-CCR4 monoclonal antibody) treatment. There was a durable significant reduction of the CD4(+) CD25(high) FOXP3(+) regulatory T (Treg) cell subset in the patient's PBMC, and the affected inflamed skin almost completely lacked FOXP3-positive cells. This implies an association between reduction of the Treg subset by mogamulizimab and occurrence of SJS. The present case should contribute not only to our understanding of human pathology resulting from therapeutic depletion of Treg cells, but also alert us to the possibility of immune-related severe adverse events such as SJS when using mogamulizumab. We are currently conducting a clinical trial of mogamulizumab for CCR4-negative solid cancers (UMIN000010050), specifically aiming to deplete Treg cells.

Idiosyncratic adverse drug reactions: current concepts

Idiosyncratic drug reactions are a significant cause of morbidity and mortality for patients; they also markedly increase the uncertainty of drug development. The major targets are skin, liver, and bone marrow. Clinical characteristics suggest that IDRs are immune mediated, and there is substantive evidence that most, but not all, IDRs are caused by chemically reactive species. However, rigorous mechanistic studies are very difficult to perform, especially in the absence of valid animal models. Models to explain how drugs or reactive metabolites interact with the MHC/T-cell receptor complex include the hapten and P-I models, and most recently it was found that abacavir can interact reversibly with MHC to alter the endogenous peptides that are presented to T cells. The discovery of HLA molecules as important risk factors for some IDRs has also significantly contributed to our understanding of these adverse reactions, but it is not yet clear what fraction of IDRs have a strong HLA dependence. In addition, with the exception of abacavir, most patients who have the HLA that confers a higher IDR risk with a specific drug will not have an IDR when treated with that drug. Interindividual differences in T-cell receptors and other factors also presumably play a role in determining which patients will have an IDR. The immune response represents a delicate balance, and immune tolerance may be the dominant response to a drug that can cause IDRs.

T-cell receptor and carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis: understanding a hypersensitivity reaction

Ample evidence exists to support the view that drug hypersensitivity is mediated by adaptive immunity, which involves MHC-restricted drug presentation, activation and clonal expansion of T cells. The specific MHC molecules implicated in hypersensitivity have been identified; for example, HLA-B*5701 in abacavir-induced drug hypersensitivity and HLA-B*1502 in carbamazepine-induced Stevens-Johnson syndrome. However, little is known about the role of drug-specific T cells and their T-cell receptors (TCRs) in the pathogenesis of drug hypersensitivity. Using the combination of a strong HLA-B*1502 predisposition in carbamazepine-induced Stevens-Johnson syndrome and applying global analysis of the TCR repertoire, restricted and common TCR usage in the development of severe drug hypersensitivity have recently been documented. This article reviews recent advances in the understanding of the pathogenic role of drug-specific T cells and their TCRs in the development of drug hypersensitivity and provides an analysis of their potential clinical implications.

Immunological mechanisms of epidermal damage in toxic epidermal necrolysis

PURPOSE OF REVIEW

The purpose of the present review is to introduce recent findings on the pathomechanisms of toxic epidermal necrolysis (TEN), which is characterized by widespread epidermal detachment due to keratinocyte apoptosis.

RECENT FINDINGS

In the mechanism of epidermal damage, the roles of drug metabolites, cytotoxic lymphocytes, and apoptosis-inducing factors have been noted. In addition, recent studies have focused on monocytes/macrophages, which may participate in epidermal damage through the production of apoptosis-inducing factors and the expression of costimulatory factors with the ability to activate CD8 T cells.

SUMMARY

Epidermal keratinocyte death is a hallmark of TEN. In a very high proportion of cases, drugs are responsible for TEN. It has been suggested that toxic drug metabolites produced by keratinocytes act like electrophilic agents to induce apoptosis and inflammation. Next, cytotoxic lymphocytes and monocytes function in the development of widespread epidermal damage through direct or indirect cytotoxic pathways. In addition, T-cell activation may be strengthened by the impairment of regulatory T-cell function and activated monocytes. The development of epidermal damage in TEN may require the coordinated action of these factors.

Treatment of DIHS/DRESS syndrome with combined N-acetylcysteine, prednisone and valganciclovir--a hypothesis

Background

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is a rare and severe adverse drug reaction with an associated mortality of 10–20%. Clinical worsening despite discontinuation of the culprit drug is considered a characteristic feature of DIHS/DRESS. Besides the early recognition of the syndrome and discontinuation of its causative drug, the mainstay of treatment is systemic corticosteroids. Nevertheless, treatment of severe DIHS/DRESS is not well defined, as corticosteroids may sometimes not be effective, and decreasing the dose may be associated with flaring of the disease.

Case Report

A 38-year-old woman with high fever, malaise, abdominal pain, rash, and elevated liver enzymes received immediate high-dose N-acetylcysteine, because acetaminophen hepatotoxicity was suspected. N-acetylcysteine administration was associated with a significant clinical improvement. However, within the next week DIHS/DRESS syndrome was diagnosed, which explained all the symptoms, and which was subsequently treated with prednisone and valganciclovir.

Conclusions

New options necessary to improve treatment of severe DIHD/DRESS have to consider its sequential pathogenetic mechanisms. N-acetylcysteine might neutralize the drug-derived reactive metabolites, which are responsible for protein adduct formation and specific T cell stimulation, and replete the glutathione stores that counterbalance oxidative stress. Prednisone might inhibit lymphoproliferation and valganciclovir might prevent complications related to HHV-6 reactivation. We therefore propose the unprecedented combination of N-acetylcysteine, prednisone and valganciclovir as a treatment option for DIHS/DRESS.

Drug allergy: causes and desensitization

Allergic drug reactions occur when a drug, usually a low molecular weight molecule, has the ability to stimulate an immune response. This can be done in one of two ways. The first is by binding covalently to a self-protein, to produce a haptenated molecule that can be processed and presented to the adaptive immune system to induce an immune response. Sometimes the drug itself cannot do this but a reactive breakdown product of the drug is able to bind covalently to the requisite self-protein or peptide. The second way in which drugs can stimulate an immune response is by binding non-covalently to antigen presenting or antigen recognition molecules such as the major histocompatibility complex (MHC) or the T cell receptor. This is known as the p-I or pharmacological interaction hypothesis. The drug binding in this situation is reversible and stimulation of the response may occur on first exposure, not requiring previous sensitization. There is probably a dependence on the presence of certain MHC alleles and T cell receptor structures for this type of reaction to occur.

Recent progress of elucidating the mechanisms of drug hypersensitivity

Recent technical approaches to investigating drug hypersensitivity have provided a great deal of information to solve the mechanisms that remain poorly understood. First, immunological investigations and in silico analysis have revealed that a novel interaction between T cells and antigen-presenting cells, namely the pharmacological interaction concept, is involved in drug recognition and the hapten theory. Second, progress in immunology has provided a new concept of CD4+ T cell subsets. Th17 cells have proven to be a critical player in acute generalized exanthematous pustulosis. Our recent findings suggest that this subset might contribute to the pathogenesis of Stevens-Johnson syndrome/toxic epidermal necrolysis. Third, alarmins, molecules associated with innate immunity, are also associated with exaggeration and the persistence of severe drug hypersensitivity. The latest innovative techniques are providing a new landscape to examine drug hypersensitivity.

Drug reaction with Eosinophilia and Systemic Symptoms (DRESS) / Drug-induced Hypersensitivity Syndrome (DIHS): a review of current concepts

The Drug Reaction with Eosinophilia and Systemic Symptoms syndrome, also known as Drug Induced Hypersensitivity Syndrome presents clinically as an extensive mucocutaneous rash, accompanied by fever, lymphadenopathy, hepatitis, hematologic abnormalities with eosinophilia and atypical lymphocytes, and may involve other organs with eosinophilic infiltration, causing damage to several systems, especially to the kidneys, heart, lungs, and pancreas. Recognition of this syndrome is of paramount importance, since the mortality rate is about 10% to 20%, and a specific therapy may be necessary. The pathogenesis is related to specific drugs, especially the aromatic anticonvulsants, altered immune response, sequential reactivation of herpes virus and association with HLA alleles. Early recognition of the syndrome and withdrawal of the offending drug are the most important and essential steps in the treatment of affected patients. Corticosteroids are the basis of the treatment of the syndrome, which may be associated with intravenous immunoglobulin and, in selected cases, Ganciclovir. The article reviews the current concepts involving this important manifestation of adverse drug reaction.

Aging of the CD4 T Cell Compartment

Higher morbidity and mortality following infections, particularly influenza, is observed in the elderly population. Because of this, people over 65 years old are often targeted for preventive immunization. Many vaccines, however, are not as effective in generating protective antibodies in older individuals. CD4⁺ T cells, through their B cell helper functions, play a central role in the humoral response. Aging has deleterious effects on the immune system, and understanding how aging impairs CD4⁺ T cell functions is of critical importance to design new immunization and treatment strategies targeted to the elderly population. In this paper, we review some of the qualitative and quantitative changes in the CD4⁺ T cell compartment that arise with aging. We also summarize the age-related intrinsic defects that impact naïve, memory and regulatory CD4⁺ T cell functions.

Distinguishing between erythema multiforme major and Stevens-Johnson syndrome/toxic epidermal necrolysis immunopathologically

The early clinical presentations of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are similar to that of erythema multiforme major (EMM). Cytotoxic molecules, especially granulysin, are expressed in the skin lesions of SJS/TEN and cause extensive keratinocyte death. It is postulated that the function of regulatory T cells (Treg) in SJS/TEN is inadequate. This study examined whether an immunohistological examination of cytotoxic molecules and the immunophenotype of Treg is useful for discriminating SJS from EMM in the early period. Over the past 9 years, the lesional skin of 14 patients with SJS/TEN and 16 patients with EMM was biopsied. Double immunofluorescence labeling of CD8 and granulysin, perforin, or granzyme B was performed, and immunohistochemical analyses of granulysin, perforin, granzyme B, CD1a, CD3, CD4, CD8, CD68 and Foxp3 were conducted using a highly sensitive indirect immunoperoxidase technique. The number of cells positive for each antibody per five high-power fields was counted. The proportions of granulysin(+) cells/CD8(+) cells (P = 0.012) and perforin(+) cells/CD8(+) cells (P = 0.037) in SJS/TEN were significantly higher than in EMM. The number of Foxp3(+) cells/five high-power fields in SJS/TEN was significantly lower than in EMM (P = 0.004). Similarly, the number of CD4(+) cells/five high-power fields in SJS/TEN was significantly lower than in EMM (P = 0.0017). These data suggest that these panels of antibodies for labeling cytotoxic molecules, CD4 and Treg are useful for discriminating early SJS/TEN and EMM with a skin biopsy.

Stability of epitheliotrophic factors in autologous serum eye drops from chronic Stevens-Johnson syndrome dry eye compared to non-autoimmune dry eye

PURPOSE

To compare the concentrations of epitheliotrophic factors in autologous serum eye drops (ASE) prepared from sera of chronic Stevens-Johnson syndrome (SJS) patients with dry eyes to those prepared from non-autoimmune dry eye controls and to study the stability of the epitheliotrophic factors in different storage conditions.

METHODS

Twenty-percent ASE were prepared from 10 chronic SJS patients with dry eyes and 10 age-matched non-autoimmune dry eye controls. The concentrations of major epitheliotrophic factors comprising epidermal growth factor (EGF), transforming growth factor-beta1 (TGF-β1), transforming growth factor-beta2 (TGF-β2), and fibronectin in those ASE preparations were determined by enzyme-linked immunosorbent assay (ELISA) at baseline and after different storage conditions: at 4 °C for 1 week and 1 month; and at -20 °C for 1, 3 and 6 months.

RESULTS

There were no significant differences in the concentrations of EGF, TGF-β1, TGF-β2 and fibronectin in 20% ASE between the SJS and control groups (EGF: 176.9 ± 40.9 vs. 185.5 ± 36.9 pg/mL, TGF-β1: 9.5 ± 2.1 vs. 9.5 ± 1.9 ng/mL, TGF-β2: 55.3 ± 30.0 vs. 63.91 ± 45.6 pg/mL and fibronectin: 70.5 ± 20.2 vs. 62.2 ± 21.3 µg/mL, respectively). These factors were stable at 4 °C for up to 1 month. Storage at -20 °C for up to 6 months resulted in a slight decrease in TGF-β1 (SJS: from 9.5-8.4 ng/mL, p < 0.01 and control: from 9.5-8.1 ng/mL, p < 0.01).

CONCLUSIONS

The results suggested that the epitheliotrophic capacity of ASE from chronic SJS should be comparable to those from non-autoimmune dry eye patients, and that ASE should be sufficiently stable for up to 6 months, if stored properly at -20 °C.

Multiple drug hypersensitivity: normal Treg cell function but enhanced in vivo activation of drug-specific T cells

BACKGROUND

  Up to 10% of patients with severe immune-mediated drug hypersensitivity reactions have tendencies to develop multiple drug hypersensitivities (MDH). The reason why certain individuals develop MDH and the underlying pathomechanism are unclear. We investigated different T cell subpopulations in MDH patients and compared them with patients allergic to a single drug and with healthy controls (HC).

METHODS

  We analyzed the in vitro reactivity of peripheral blood mononuclear cells from MDH patients (n=7), patients with hypersensitivity to a single drug (monoallergic, n=6), and healthy controls (HD) (n=6) to various drugs (mainly antibiotics and antiepileptics). By depleting and selectively re-adding CD4(+)  CD25(bright) T cells (T regulatory cells, Treg), their effect on drug-specific T cell reactivity was analyzed. The phenotype of reacting T cells was determined ex vivo by staining for markers of activation (CD38) and cell exhaustion (PD-1).

RESULTS

  No functional deficiency of Treg cells was observed in all drug-allergic patients. Drug-reactive T cells from MDH patients were found in the CD4(+) CD25(dim) T cell fraction and showed enhanced CD38 and PD-1 expression, while those from monoallergic patients reside in the resting CD4(+)  CD25(neg) T cell fraction.

CONCLUSION

  In patients with MDH, the drug-reactive T cells are contained in an in vivo pre-activated T cell fraction. Therefore, they may show a lower threshold for activation by drugs. The reason for this in vivo T cell pre-activation needs further investigations.

A recent update of pharmacogenomics in drug-induced severe skin reactions

In some adverse drug reactions (ADRs), genetic predisposition plays a significant role in pathogenesis, and the skin is the most frequently reported target. These severe cutaneous ADRs include bullous fixed drug eruptions (FDE), acute generalized exanthematous pustulosis (AGEP), drug-induced hypersensitivity syndrome (HSS), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). The putative contribution of individual effector cells in drug hypersensitivity is briefly mentioned. To trigger these drug hypersensitivities, certain class I HLA alleles (e.g., HLA-A and HLA-B alleles) and certain class II HLA alleles (e.g., HLA-DR alleles) have been recently found to be the genetic determinants. One of the best characterized examples mentioned in this article is HLA-B*1502 to determine the incidence of carbamazepine-induced SJS. How drugs are processed and presented by these HLA alleles to activate immune responses has been explained by several hypotheses. Further implication of pharmagenomic findings to prevent drug-induced severe skin reactions can be achieved by pre-screening putative risk HLA alleles before using drugs.

Poor relevance of a lymphocyte proliferation assay in lamotrigine-induced Stevens-Johnson syndrome or toxic epidermal necrolysis

BACKGROUND

Prior use of 'lymphocyte transformation test' (LTT) in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) provided conflicting results, possibly dependent on sampling dates (acute vs. late).

OBJECTIVE

Evaluation of LTT in patients with SJS or TEN who reacted to lamotrigine (LTG). In a small subgroup we explored the possible role of regulatory T cells (T-reg).

METHODS

Acute phase samples (9) and post-recovery samples (14) from cases of SJS or TEN to LTG were provided by the RegiSCAR-study group. Controls were persons never exposed to LTG (12), patients exposed without reaction (6), and patients who developed a mild eruption to LTG (6). LTT was performed by measuring (3) H-thymidine incorporation after 3 days of incubation with phytohemmaglutinin, LTG (10 μg/mL) or medium. Stimulation index ≥ 2 was considered positive. In 16 cases LTT was redone after depletion of T-reg by fluorescence activated cell sorting.

RESULTS

Positive LTT was observed in 3/6 cases of mild eruptions, 1/9 SJS/TEN-cases tested during the acute phase and 3/14 SJS/TEN-cases tested after recovery. We noted a very mild and nonsignificant trend for an increased response after depletion of T-reg in late samples from SJS or TEN patients.

CONCLUSIONS AND CLINICAL RELEVANCE

With the largest number of LTT performed in patients with SJS or TEN to a single drug, we confirmed that reactive cells are rarely detected in these reactions. Poor reactivity did not seem related to T-reg. Other in vitro assays than those testing proliferation should be evaluated, before raising the hypothesis that specific cells disappeared by undergoing apoptosis during the reaction.

Death ligand TRAIL, secreted by CD1a+ and CD14+ cells in blister fluids, is involved in killing keratinocytes in toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is characterized by an acute detachment and destruction of keratinocytes, affecting large areas of the skin. It is often related to adverse drug reactions. Previous studies have shown that effector CD8+ T cells, which accumulate in the blister fluid, are functionally cytotoxic and act through a classical perforin/granzyme B pathway. It has recently been shown that these cytotoxic T cells also secrete granulysin peptide, which is lethal to keratinocytes. These cytotoxic T cells exert their killer activity against autologous keratinocytes in the presence of the drug. However, they are unlikely to be the only effectors of TEN. We therefore searched for soluble death factors in the blister fluids that might kill keratinocytes. We found that the amounts of interferon-γ, TRAIL and TNF-α proteins were significantly greater in TEN blister fluids than in all controls (normal sera, TEN sera, burns and Eosinophilic pustular folliculitis blister fluids) and TNF-like weak inducer of apoptosis (TWEAK) amounts are also greater in all controls except burns. We showed that these proteins acted in synergy to induce the death of keratinocytes in vitro. We also found that TRAIL and TWEAK were secreted by CD1a+ and CD14+ cells present in the blister fluids. Thus, in addition to MHC class I-restricted cytotoxic T lymphocytes (CTLs), which lyse keratinocytes, ligands secreted by non-lymphoid cells capable of inducing keratinocyte death in an MHC class I-independent manner, also seem to be present in the blister fluids of patients with TEN.

Drug hypersensitivity reactions: pathomechanism and clinical symptoms

Small molecules, used as drugs, can induce immune reactions by binding covalently as haptens to a carrier protein, which is thereby modified and immunogenic. In addition, drugs bind to proteins via hydrogen bonds, electrostatic force, and van der Waals forces, and may directly interact with immune receptors such as T cell receptors or major histocompatibility complex molecules (pharmacologic interaction with immune receptors, so-called p-i concept). Even this noncovalent interaction may stimulate T cells. The ensuing immune response based on hapten-peptide presentation or direct drug-receptor interaction results in many distinct clinical situations. Based on progress in T cell immunology, this heterogeneity of T cell reaction is now also reflected in a subclassification of type IVa to IVd reactions.

[What's new in dermatological research?]

Fundamental research in Dermatology has been once more very active during the past year and more specifically focused on immunological grounds of inflammatory diseases, the identification of risk loci associated with psoriasis and tumors, cutaneous lymphomas and on the genodermatosis where large international collaborative studies provided with a molecular understanding of an increasing amount of conditions especially affecting pigmentation and differentiation. In silico investigations become increasingly prominent especially with the rising power of new actor, China, the demographical and resulting epidemiological weight of which can hardly be challenged. Some of these fundamental breakthroughs might result in practical interventions although in an undefined future.