Tralokinumab does not impact vaccine-induced immune responses: Results from a 30-week, randomized, placebo-controlled trial in adults with moderate-to-severe atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease. Interleukin (IL) 13 is a type 2 cytokine that is key to the inflammation underlying AD. Tralokinumab is a first-in-class, fully human, monoclonal antibody that specifically binds with high affinity to IL-13, neutralizing it in AD. Immunomodulatory treatments may impair vaccine-induced immune responses. OBJECTIVE: Assess the immune responses to standard vaccines in adults with moderate-to-severe AD who are undergoing treatment with tralokinumab. METHODS: ECZema TRAlokinumab Trial No. 5 (ECZTRA 5; NCT03562377) was a phase 2, double-blind, randomized, placebo-controlled trial taking place over 30 weeks. Eligible adults were randomized 1:1, with 107 patients receiving tralokinumab 300 mg and 108 patients receiving a placebo every 2 weeks for 16 weeks. All patients received Tdap (tetanus/diphtheria/pertussis) and meningococcal vaccines at week 12. The primary end points were positive antitetanus and antimeningococcal responses between weeks 12 and 16 (noninferiority margin, -25%; responder, >3-fold increase in IgG). RESULTS: The noninferiority of tralokinumab versus placebo for immune response to Tdap (91.9% vs 96.1%) and meningococcal (86.0% vs 84.2%) vaccines was demonstrated at week 16. During treatment, the rates of adverse events were lower for tralokinumab than for the placebo, with most events being mild or moderate. LIMITATIONS: Responses to other vaccines (including influenza) were not examined. CONCLUSIONS: Treatment with tralokinumab 300 mg every 2 weeks did not affect immune responses to Tdap and meningococcal vaccines. Treatment was well tolerated when administered concomitantly with the vaccines and demonstrated a safety profile comparable to phase 3 trials.

Immunogenicity and skin clearance recapture in clinical studies of brodalumab.

BACKGROUND: Antidrug antibodies (ADAs) may change pharmacokinetic or pharmacodynamic profiles of biologic therapies, potentially decreasing efficacy. OBJECTIVE: To evaluate the potential effects of brodalumab immunogenicity on safety, efficacy, and retreatment. METHODS: Data from 1 phase 2 and 3 phase 3 studies of brodalumab in psoriasis were analyzed. RESULTS: Overall, 2.7% of patients had positive test results for binding ADAs after receiving brodalumab; ADAs were transient in 1.4% of patients, and there were no neutralizing ADAs. Among ADA-positive patients, 60.0% (3/5) achieved a static physician's global assessment score of 0 or 1 at week 12 in the group receiving the brodalumab 210 mg every 2 weeks, compared with 79.1% (1131/1429) of ADA-negative patients. All patients (100%) who experienced return of disease and were retreated with brodalumab 210 mg every 2 weeks (none were ADA positive) achieved at least a 75% improvement in Psoriasis Area And Severity Index, ≥90% of whom regained response by week 8 of retreatment. Hypersensitivity reactions were less frequent with brodalumab than with placebo. Injection site reactions occurred in 1.8% of patients treated with brodalumab versus 2% of patients treated with ustekinumab. LIMITATIONS: Retreatment could be assessed in only 1 phase 3 brodalumab study. CONCLUSION: Brodalumab compares favorably with other biologics in terms of immunogenicity and high rates of efficacy recapture upon retreatment.

Isatis tinctoria L.-derived Petroleum Ether Extract Mediates Anti-inflammatory Effects via Inhibition of Interleukin-6, Interleukin-33 and Mast Cell Degranulation.

Isatis tinctoria L. (woad) has been used in medicine for centuries and has demonstrated anti-inflammatory effects. However, to date, no well-defined extracts with precise analysis of active substances have been developed. The aim of this study was to develop novel extracts of Isatis tinctoria L., and to characterize their active ingredients and anti-inflammatory properties. Various extracts of Isatis tinctoria L. were analysed for their active ingredients, and screened for anti-inflammatory effects using cyclooxygenase-2 activity assays. A petroleum ether extract was found to have the best effects, and was tested in a mouse model of acute allergic contact dermatitis. In the mouse model the petroleum ether extract resulted in significantly reduced ear swelling, oedema and inflammatory cell density. In mouse skin and human keratinocyte cultures, petroleum ether extract inhibited pro-inflammatory cytokine expression. Furthermore, human mast cell degranulation was significantly inhibited in LAD2 cell cultures. In conclusion, novel woad extracts were developed and shown to have anti-inflammatory properties in a contact hypersensitivity animal model and human keratinocytes. The production of such extracts and further characterization of their specific properties will enable determination of their potential dermatological effects in the treatment of inflamed and irritated skin.

Evaluation of expression pattern of selected genes associated with IL12/23 signaling paths in psoriatic patients during cyclosporine A therapy.

Molecular analysis is key to a better understanding of drug resistance during therapy. The aim of this study was to evaluate changes in the expression of tumor necrosis factor α (TNF-α), interleukin (IL)-IL12A, IL12B, IL23A, interferon gamma (IFN-γ) in psoriatic patients during 84 days of treatment and TNF-α on the protein level. The study group consisted of 32 psoriatic patients during cyclosporine A therapy. The molecular analysis was made by using real-time reverse transcription polymerase chain assay (RTqPCR) and MALDI ToF mass spectroscopy three times: after 0, 42, 84 days of treatment. Statistically significant differences (p < .05) in transcriptional activity were observed for genes: TNF-α (0 vs. 42nd days p = .006; 0 vs. 84th days p = .005), IL23A (0 vs. 42nd days p = .041), IFN-γ (0 vs. 42th days p = .040; 0 vs. 84th days p = .041), IL17 (0 vs. 42nd p = .000003 0 vs. 84th p = .001650), IL12A (0 vs. 42nd p = .0047 vs. 84th p = .0063). The expression of TNF-α was downregulated during therapy, IL23A was upregulated during CsA treatment, while the expression of IFN-γ and IL17 were higher after 42 days and lower after 84 days compared to 0 days of CsA treatment. It seems that TNF-α, IL12A, IL23A, IFN-γ, and IL17 can be useful complementary molecular markers to assess the efficacy of psoriasis treatment.

Secukinumab, a fully human anti-interleukin-17A monoclonal antibody, exhibits low immunogenicity in psoriasis patients treated up to 5 years.

BACKGROUND: Secukinumab is a fully human monoclonal antibody that selectively neutralizes IL-17A, a key cytokine involved in psoriasis and psoriatic arthritis development, and has shown rapid and long-lasting efficacy and safety in the complete spectrum of psoriasis manifestations. Monoclonal antibody therapies may be associated with the production of treatment-emergent antidrug antibodies (TE-ADAs) that can affect drug pharmacokinetics, diminish clinical responses via inhibition of target binding or cause hypersensitivity reactions. Secukinumab exhibited minimal immunogenicity up to 52 weeks in patients with moderate-to-severe plaque psoriasis, as evidenced by TE-ADA in <1% patients. OBJECTIVE: To investigate the immunogenicity of secukinumab treatment up to 5 years in two phase 3 extension studies (NCT01640951 and NCT01365455) in patients with moderate-to-severe plaque psoriasis. METHODS: Immunogenicity was evaluated up to Week 268 (5 years). TE-ADAs were defined as positive antidrug antibody (ADA) signals detected in post-treatment samples from patients with negative baseline signals. Confirmed positive samples were further analysed for their neutralizing potential. RESULTS: In total, 1821 patients entered the extension studies. Among patients receiving secukinumab and evaluated for ADAs (n = 1636), 32 developed TE-ADA, which resulted in an incidence of new TE-ADA cases below 1% per year. Neutralizing antibodies were detected in 9/32 (28%) patients with TE-ADA. Half of ADA-positive cases were transient. Among pharmacokinetic samples measured at the times of immunogenicity determination (n = 9992), 544 (5.4%) had secukinumab concentrations higher than the drug tolerance level of 53.8 µg/mL. There was no effect of TE-ADA, including neutralizing antibodies, on efficacy, safety or pharmacokinetics of secukinumab. CONCLUSION: The yearly secukinumab immunogenicity incidence over 5 years of treatment was consistently below 1% in patients with moderate-to-severe plaque psoriasis. Any TE-ADAs, including neutralizing antibodies, were not associated with loss of secukinumab efficacy or with clinical concerns.

Multiple switches between GP2015, an etanercept biosimilar, with originator product do not impact efficacy, safety and immunogenicity in patients with chronic plaque-type psoriasis: 30-week results from the phase 3, confirmatory EGALITY study.

BACKGROUND: EGALITY was a phase III confirmatory efficacy and safety study conducted in patients with plaque-type psoriasis as a part of totality of evidence gathered during the development of GP2015, an etanercept biosimilar. OBJECTIVE: To demonstrate equivalent efficacy and comparable safety and immunogenicity of GP2015 and the etanercept originator product (ETN, Enbrel® ) and evaluate effects of repeated switching between GP2015 and ETN. Results for efficacy, safety and immunogenicity during treatment period (TP) 2 (TP2) are presented pooling the two continued treatment arms (pooled continued) versus the two treatment arms with repeated switches (pooled switched). METHODS: Patients (n = 531) were randomized 1:1 to self-administer GP2015 or ETN twice-weekly subcutaneously during TP1. Patients with a ≥50% improvement in Psoriasis Area and Severity Index (PASI 50) at week 12 were re-randomized for TP2 to continue the same treatment at once-weekly dosing or to undergo three consecutive treatment switches between GP2015 and ETN until week 30. Patients continued the last-assigned treatment during TP2, until week 52. RESULTS: Mean (standard deviation [SD]) PASI scores at baseline were similar in patients who underwent multiple switches compared to those with continued treatments during TP2. During TP2, PASI 50, PASI 75 and PASI 90 response rates, percent change from baseline in PASI scores and all other efficacy parameters were similar between the pooled switched and pooled continued treatment groups at all time points. The incidence of treatment-emergent adverse events including injection site reactions was comparable between the pooled switched (36.7%) and pooled continued (34.9%) groups. None of the patients in either treatment group were positive for binding anti-drug antibodies in TP2. CONCLUSION: Treatment efficacy, safety and immunogenicity were similar between the pooled continued and pooled switched treatments during TP2, indicating that there are no effects in the short term on clinical data of multiple switches between GP2015 and ETN.

Secukinumab, a fully human anti-interleukin-17A monoclonal antibody, exhibits minimal immunogenicity in patients with moderate-to-severe plaque psoriasis.

BACKGROUND: The proinflammatory cytokine interleukin (IL)-17A plays a pivotal role in psoriasis pathogenesis. Secukinumab, a fully human monoclonal antibody (mAb) that selectively targets IL-17A, has been demonstrated to be highly efficacious for the treatment of moderate-to-severe psoriasis, starting at early time points, with a sustained effect and a favourable safety profile. mAb therapies may be associated with production of antidrug antibodies (ADAs) that can affect drug pharmacokinetics, diminish response or cause hypersensitivity reactions. OBJECTIVES: To investigate the immunogenicity of secukinumab across six phase III clinical trials in which patients with plaque psoriasis were treated with secukinumab for up to 52 weeks and additionally followed up at week 60. METHODS: Immunogenicity in patients with plaque psoriasis exposed to secukinumab was evaluated at baseline and at weeks 12, 24, 52 and 60. Treatment-emergent (TE)-ADAs were defined as a positive ADA signal detected in post-treatment samples from patients with a negative baseline signal. Confirmed positive samples were further analysed for their drug-neutralizing potential. RESULTS: Among 2842 patients receiving secukinumab and evaluated for ADAs, 11 (0·4%) developed TE-ADAs. Associations between TE-ADAs and secukinumab dose, frequency or mode of administration were not observed. Neutralizing antibodies were detected in three of nine evaluable patients with TE-ADAs. CONCLUSIONS: Secukinumab immunogenicity was low, as shown by TE-ADA detection in only 11 of 2842 (0·4%) patients with moderate-to-severe plaque psoriasis treated with secukinumab. All but one of the patients with TE-ADAs were biologic naive. Neither TE-ADAs nor neutralizing antibodies were associated with loss of secukinumab efficacy or issues of clinical concern.

Clinical similarity of the biosimilar ABP 501 compared with adalimumab after single transition: long-term results from a randomized controlled, double-blind, 52-week, phase III trial in patients with moderate-to-severe plaque psoriasis.

BACKGROUND: ABP 501, a U.S.A. Food and Drug Administration- and European Medicines Agency-approved biosimilar, is highly similar to adalimumab in structure, function and pharmacokinetics. OBJECTIVES: To demonstrate similarity in efficacy, safety and immunogenicity of ABP 501 vs. adalimumab for moderate-to-severe plaque psoriasis (clinical trial: NCT01970488). METHODS: Patients were randomized (1 : 1) to receive ABP 501 or adalimumab 40 mg every 2 weeks for 16 weeks. At week 16, patients with ≥ 50% improvement from baseline in Psoriasis Area and Severity Index (PASI) score were eligible to continue to week 52. Patients receiving ABP 501 continued; adalimumab patients were rerandomized (1 : 1) to continue adalimumab or undergo a single transition to ABP 501. Key efficacy assessments included percentage PASI improvement from baseline, PASI responders and mean change in affected body surface area from baseline to weeks 16, 32 and 50. Safety was monitored via adverse events (AEs) and antidrug antibodies (ADAs) were assessed. RESULTS: A total of 308 patients were rerandomized at week 16 (ABP 501/ABP 501, n = 152; adalimumab/adalimumab, n = 79; adalimumab/ABP 501, n = 77). PASI percentage improvements from baseline were similar across groups for weeks 16, 32 and 50 (range: 85·8-88·2%), with no significant differences detected across groups in percentages of PASI 50, 75, 90 and 100 responders. Changes from baseline in percentage body surface area affected were similar across groups and time points. No new safety signals were detected. AEs were balanced between groups. Percentages of patients with binding and neutralizing ADAs were similar across treatments. CONCLUSIONS: ABP 501 and adalimumab have similar clinical efficacy, safety and immunogenicity profiles over 52 weeks, including after single transition, in this patient population.

Switching to biosimilar infliximab (CT-P13): Evidence of clinical safety, effectiveness and impact on public health.

CT-P13, the biosimilar of infliximab, has been recently approved in the EU, Australia, Canada, Japan and many other countries. Thus, it was the first biosimilar approved in the field of rheumatology, dermatology and gastroenterology. Since there has been debate about the issue of switching from RMP to the biosimilar and some national societies have expressed concerns, this review was written with the following objectives: The review concludes that whilst prudent switching practices should be employed, growing safety experience accumulated thus far with CT-P13 and other biosimilars is favorable and does not raise any specific concerns.

Topical Lyogel Containing Corticosteroid Decreases IgE Expression and Enhances the Therapeutic Efficacy Against Atopic Eczema.

Hydrocortisone cream intended for atopic eczema often produces unwanted side effects after long-term use. These side effects are essentially due to repeated percutaneous administration of the medication for skin dermatitis, as atopic eczema is a relapsing disorder. Hence, there is a need to develop a new hydrocortisone formulation that will deliver the drug more effectively and require a reduced dosing frequency; therefore, the side effects could be minimized. In this study, a hydroxypropyl methylcellulose (HPMC) lyogel system based on 80% organic and 20% aqueous solvents containing 1% hydrocortisone was formulated. The hydrocortisone lyogel physicochemical characteristics, rheological properties, stability profile, and in vitro Franz cell drug release properties, as well as the in vivo therapeutic efficacies and dermal irritancy in Balb/c mice were investigated. The HPMC lyogel appeared clear and soft and was easy to rub on the skin. The lyogel also showed a higher drug release profile compared with commercial hydrocortisone cream. Similar to the cream, HPMC lyogels exhibited pseudoplastic behavior. From the mouse model, the hydrocortisone lyogel showed higher inflammatory suppressive effects than the cream. However, it did not reduce the transepidermal water loss as effectively as the control did. The dermal irritancy testing revealed that the hydrocortisone lyogel caused minimal irritation. In conclusion, HPMC lyogel is a promising vehicle to deliver hydrocortisone topically, as it showed a higher drug release in vitro as well as enhanced therapeutic efficacy in resolving eczematous inflammatory reaction compared with commercial cream.

Influence of neutralizing antibodies to adalimumab and infliximab on the treatment of psoriasis.

BACKGROUND: Current treatment with biologics has produced dramatic therapeutic effects in patients with psoriasis, although these agents occasionally decrease in efficacy. One of the main factors responsible for this attenuation is attributed to the development of antidrug antibodies (ADAs). OBJECTIVES: To analyse the relationship between serum drug concentrations, the presence of ADAs and treatment efficacy of adalimumab and infliximab, and to determine the optimal use of these biologics. METHODS: This was a 1-year prospective study in the dermatology departments of Kobe University Hospital and collaborating hospitals. All patients starting a regimen of adalimumab and infliximab for psoriasis were included. We measured the serum concentration of the drugs and titres of antibodies to adalimumab and infliximab, as well as the Psoriasis Area and Severity Index scores at weeks 0, 4, 12, 24 and 48 during the first year of treatment. RESULTS: We observed a 50% positive rate of ADAs to adalimumab, and a 41% positive rate of ADAs to infliximab. The titres of ADAs showed a wide range from low to high titres. In the high-titre groups, the patients exhibited a decreased clinical response, and demonstrated a negative correlation between titre and clinical response. However, an equivalent therapeutic effect was observed between the low-titre group and the group with no antibodies detected for adalimumab. For infliximab, the patients with ADAs showed decreased clinical response. An apparent negative correlation between antibody production and reduced clinical response was observed. CONCLUSIONS: Two biologics, adalimumab and infliximab, showed different therapeutic behaviour. The measurement of ADAs and drug concentrations has important implications for treatment with biologics.

Antidrug antibodies in psoriasis: a systematic review.

Antidrug antibodies (ADAs) against biological agents may be clinically significant and potentially alter a biological drug's treatment efficacy. This systematic review aims to (i) determine the prevalence of ADAs against infliximab, etanercept, adalimumab and ustekinumab in patients with psoriasis; (ii) ascertain whether ADAs are associated with changes in drug efficacy; and (iii) explore the use of concomitant methotrexate to prevent ADA formation. Through a systematic search using Medline and Embase from 29 January 1950 to 29 March 2013, we identified 25 studies that met the inclusion criteria. Of 7969 patients with psoriasis, 950 tested positive for ADAs. Antibodies against infliximab, etanercept, adalimumab and ustekinumab were reported in 5·4-43·6%, 0-18·3%, 6-45% and 3·8-6% of patients, respectively. Anti-infliximab antibodies were associated with lower serum infliximab concentrations in three studies, and decreased treatment response in five studies. ADAs against etanercept were non-neutralizing and not associated with any apparent effects on clinical response. Antiadalimumab antibodies were associated with lower serum adalimumab concentrations in three of five studies, and reduced clinical efficacy in four studies. Two of six studies reported that antiustekinumab antibodies were associated with lower Psoriasis Area and Severity Index responses, and three ustekinumab studies noted that most of these antibodies were neutralizing. Although the use of concomitant methotrexate with biological agents to prevent ADA formation in other immune-mediated diseases is promising, their use in psoriasis is sparse. ADA development remains a challenge with biological therapies and therefore should be considered in patients with psoriasis who experience diminished treatment response.

Strategies to maximize treatment success in moderate to severe psoriasis: establishing treatment goals and tailoring of biologic therapies.

Achieving treatment success among patients with moderate to severe psoriasis is a clinically relevant and important issue facing clinicians and patients. Despite advances in systemic therapy, most patients with moderate to severe psoriasis are not satisfied with their treatment. We will discuss strategies to maximize treatment success through the establishment of treatment goals and tailoring of biologic therapy for patients with difficult-to-treat psoriasis. Specifically, we provide evidence-based highlights on the development of biologics, recommendations by psoriasis expert groups on treatment goals, approaches to achieve treatment to defined targets, and therapeutic strategies to customize biologic treatment for nonresponders. The discussion on nonresponders focuses on subpopulations of interest including patients with significant obesity, antidrug antibody formation, personal preferences for medication administration, and treatment nonadherence. We also highlight circumstances where the selection of the systemic medication is driven by safety considerations. As expectation for efficacy and safety increases with continued biologic development for psoriasis, devising real-world treatment strategies to maximize treatment success is critical to improve the overall physical and psychosocial wellbeing of psoriasis patients.

Autoantibodies in psoriasis as predictors for loss of response and anti-infliximab antibody induction.

BACKGROUND: Infliximab is successfully used to treat psoriasis and psoriatic arthritis. However, some patients lose therapeutic response after several cycles. Antibodies to infliximab (infliximab-Abs) are induced during treatment in a subgroup of patients and are thought to be associated with loss of response (LOR). Routine screening for infliximab-Abs is expensive and not regularly performed. A reliable and affordable method for identifying patients who are at risk for LOR to infliximab is desirable. OBJECTIVES: To analyse the development of antinuclear antibodies (ANA)/antidouble-stranded DNA antibodies (anti-dsDNA) over time in patients with psoriasis receiving infliximab. To analyse if there is an association between ANA titres/anti-dsDNA concentrations, infliximab-Ab status and LOR. METHODS: A retrospective data analysis of 29 patients with psoriasis receiving infliximab was carried out. ANA titres and anti-dsDNA concentrations were regularly monitored in these patients and sera were tested for infliximab-Abs by enzyme-linked immunosorbent assay. RESULTS: Median ANA titres increased from 1 : 80 [interquartile range (IQR) 0 to 1 : 320, n = 29] pretreatment, to 1 : 1280 (IQR 1 : 640 to 1 : 1920, n = 15) after infusion 10, and 1 : 1920 (IQR 1 : 1280 to 1 : 2560, n = 10) after infusion 20. Infliximab-Abs were found in 21% of patients. Infliximab-Ab-positive patients and patients with LOR had significantly higher pretreatment anti-dsDNA concentrations and higher pretreatment ANA titres than infliximab-Ab-negative and responsive patients, respectively. CONCLUSIONS: The results of this study suggest a role for autoantibodies in the identification of patients with psoriasis at higher risk of developing infliximab-Abs and of LOR under treatment with infliximab.

Rosacea: The cytokine and chemokine network.

Rosacea is one of the most common dermatoses of adults. Recent studies have improved our understanding of the pathophysiology of rosacea. Current concepts suggest that known clinical trigger factors of rosacea such as UV radiation, heat, cold, stress, spicy food, and microbes modulate Toll-like receptor signaling, induce reactive oxygen species, as well as enhance antimicrobial peptide and neuropeptide production. Downstream of these events cytokines and chemokines orchestrate an inflammatory response that leads to the recruitment and activation of distinct leukocyte subsets and induces the characteristic histopathological features of rosacea. Here we summarize the current knowledge of the cytokine and chemokine network in rosacea and propose pathways that may be of therapeutic interest.

Does Systemic Isotretinoin Treatment Constitute a Predisposition to Allergic Sensitization?

13-cis-retinoic acid (13-cRA) is a safe treatment for severe acne, as it has immunomodulatory effects such as enhancing the antigen-presenting activity of epidermal Langerhans cells (LCs) and T-cell activity. The aim of this study was to prospectively show the alteration of sensitization and irritation reactions in acne patients undergoing 13-cRA therapy. This cross-sectional descriptive study consisted of 65 severe to refractory acne patients. The standard thin-layer rapid-use epicutaneous test (T.R.U.E. test) was used to screen sensitization and irritation reactions before and after 3-month 13-cRA treatment. Patch test results after 13-cRA therapy revealed an increase in newly formed sensitization and irritation reactions. Sensitization rate was significantly higher (43.1%) in the second patch test, when compared with the first patch test results (27.7%; P = 0.002). No statistical difference was found in irritation rates. In this study, the sensitization rate was higher after treatment, which could be attributed to the greater antigen penetration due to the disrupted barrier and/or the upregulation of antigen-presenting activity in LC. This would cause a more prominent immune reaction to antigens. Based on these findings, we suggest that 13-cRA may have a sensitization effect, and physicians should be aware of this complication due to 13-cRA treatment. (SKINmed. 2021;19:-0).

[Histamine as an immunomodulator]. / Histamin als Immunmodulator.

The role of histamine as an important proinflammatory mediator has been well known for nearly 100 years. In regards to the immediate type allergic response, there is no debate about the importance of histamine. In addition, histamine has immunomodulatory functions, some of which are related to the histamine H2 receptor. However, with the discovery of the histamine H(4) receptor in the year 2000, the role of histamine as an immunomodulator became more obvious. The histamine H(4) receptor is expressed on several hematopoietic cells; along with the chemotaxis of immune cells, this recently characterized receptor modulates also the cytokine and chemokine secretion of some hematopoietic cells. Highly selective histamine H(4) receptor antagonists display promising results in animal models of allergic inflammatory diseases and also in in vitro studies on animal and human cells. These first results indicate that the histamine H(4) receptor is an interesting new pharmacological target for the treatment of allergic inflammatory disorders. This review summarizes the most important immunomodulatory functions of histamine and points to some possible indications in dermatology.