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Background: Keratinocyte cancers (KC) are common and pose a significant financial burden globally. Ultraviolet radiation is a significant factor in their development, through mutagenesis promotion but also through local and systemic immunosuppression. Although systemic immunosuppression is well understood, cutaneous immunity has been more difficult to evaluate., Objectives: This study used a contact sensitizer, diphencyprone (DPCP), which elicits a contact hypersensitivity reaction in skin, to compare the degree of reactivity to DPCP in patients with a high KC burden versus those with a low KC burden., Methods: A prospective study was performed in immunocompetent patients aged 70 ± 5 years of age, comparing patients with a high KC burden (>10 previous KC) with those with a low KC burden (<2 previous KC). All patients were sensitized with 2% DPCP and then patch tested two weeks later with eight different concentrations of DPCP with the threshold concentration and total degree of reaction recorded., Results: Nine patients were recruited, 5 in the 'high cancer' group and 4 in the 'low cancer' group. All patients were Fitzpatrick skin type 1 or 2. All patients developed a reaction to DPCP. Patients in the low cancer group developed a reaction at a significantly lower threshold DPCP concentration than the high cancer group (P = 0.039). The cumulative intensity of reaction was higher in the low cancer group (P = 0.087)., Conclusion: Patients with a high KC burden required a higher threshold concentration of DPCP to elicit a hypersensitivity reaction, supporting the concept of a lower skin immunity in these patients. DPCP reactivity threshold could be a useful tool in the evaluation of skin immunity and propensity to develop keratinocyte cancers., (© 2019 European Academy of Dermatology and Venereology.)

Aims: To quantify the anti-inflammatory potency of topical corticosteroids and topical calcineurin inhibitors by measuring the contact allergic response to a diphenylcyclopropenone (DPCP) challenge in de novo sensitized human volunteers., Methods: Two randomized, double-blind, vehicle-controlled studies were performed encompassing 76 volunteers: 29 in the first and 47 in the second study. Topical drugs were applied pre- and/or post-treatment in block designs. The compounds were tested simultaneously under occluded patch tests covering DPCP-induced dermatitis. Inhibitory responses were assessed by visual scoring and measurements of the oedema thickness with ultrasound., Results: When applied both before and after the DPCP challenge, significant anti-inflammatory effects were seen in descending order for tacrolimus 0.1% ointment, clobetasol propionate ointment, betamethasone valerate ointment and hydrocortisone butyrate ointment, while pimecrolimus cream, hydrocortisone ointment and vehicles had no significant effect. Only tacrolimus ointment (P < 0.01) demonstrated a consistent significant pre-treatment inhibitory effect compared with an untreated DPCP control., Conclusions: This human testing method in which the inflammation of experimentally induced allergic patch test reactions is quantified by objective measurement allows an analysis of the anti-inflammatory potency of not only topical corticosteroids, but also of drugs that have no effect on vasoconstriction. The method allowed comparison of the potencies of four topical corticosteroids and two calcineurin inhibitors., (© 2018 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Background: Carbohydrate (CHO) supplementation during prolonged exercise is widely acknowledged to blunt in vitro immunoendocrine responses, but no study has investigated in vivo immunity., Purpose: To determine the effect of CHO supplementation during prolonged exercise on in vivo immune induction using experimental contact hypersensitivity with the novel antigen diphenylcyclopropenone (DPCP)., Methods: In a double-blind design, 32 subjects were randomly assigned to 120 min of treadmill exercise at 60 % [Formula: see text] with CHO (Ex-CHO) or placebo (Ex-PLA) supplementation. Responses were also compared to 16 resting control (CON) subjects from a previous study (for additional comparison with a resting non-exercise condition). Standardised diets (24 h pre-trial) and breakfasts (3.5 h pre-trial) were provided. Subjects received a primary DPCP exposure (sensitisation) 20 min after trial completion, and exactly 28 days later the strength of immune reactivity was quantified by magnitude of the cutaneous response (skin-fold thickness and erythema) to a low dose-series DPCP challenge. Stress hormones and leucocyte trafficking were also monitored., Results: CHO supplementation blunted the cortisol and leucocyte trafficking responses, but there was no difference (P > 0.05) between Ex-CHO and Ex-PLA in the in vivo immune responses (e.g. both ~46 % lower than CON for skin-fold response)., Conclusions: CHO supplementation does not influence the decrease in in vivo immunity seen after prolonged exercise. The effects with more stressful (or fasted) exercise remain to be determined. However, there appears to be no benefit under the conditions of the present study, which have practical relevance to what many athletes do in training or competition.

Diphencyprone (DPCP) is a hapten that induces delayed-type hypersensitivity (DTH) reactions. MicroRNAs (miRNAs) are short non-coding RNAs that negatively regulate gene expression and have been implicated in various inflammatory skin diseases, but their role in DTH reactions is not well understood. We generated global miRNA expression profiles (using next-generation sequencing) of DPCP reactions in skin of seven healthy volunteers at 3, 14 and 120 days after challenge. Compared to placebo-treated sites, DPCP-challenged skin at 3 days (peak inflammation) had 127 miRNAs significantly deregulated. At 14 days (during resolution of inflammation), 43 miRNAs were deregulated and, at 120 days (when inflammation had completely resolved), six miRNAs were upregulated. While some miRNAs have been observed in psoriasis or atopic dermatitis, most of the deregulated miRNAs have not yet been studied in the context of skin biology or immunology. Across the three time points studied, many but not all miRNAs were uniquely expressed. As various miRNAs may influence T cell activation, this may indicate that the miRNAs exclusively expressed at different time points function to promote or resolve skin inflammation, and therefore, may inform on the paradoxical ability of DPCP to treat both autoimmune conditions (alopecia areata) and conditions of ineffective immunity (melanoma)., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: To examine the effects of intensity and duration of exercise stress on induction of in vivo immunity in humans using experimental contact hypersensitivity (CHS) with the novel antigen diphenylcyclopropenone (DPCP)., Methods: Sixty-four healthy males completed either 30 min running at 60% V˙O2peak (30MI), 30 min running at 80% V˙O2peak (30HI), 120 min running at 60% V˙O2peak (120MI), or seated rest (CON). Twenty min later, the subjects received a sensitizing dose of DPCP; and 4 wk later, the strength of immune reactivity was quantified by measuring the cutaneous responses to a low dose-series challenge with DPCP on the upper inner arm. Circulating epinephrine, norepinephrine and cortisol were measured before, after, and 1 h after exercise or CON. Next, to understand better whether the decrease in CHS response on 120MI was due to local inflammatory or T-cell-mediated processes, in a crossover design, 11 healthy males performed 120MI and CON, and cutaneous responses to a dose series of the irritant, croton oil (CO), were assessed on the upper inner arm., Results: Immune induction by DPCP was impaired by 120MI (skinfold thickness -67% vs CON; P < 0.05). However, immune induction was unaffected by 30MI and 30HI despite elevated circulating catecholamines (30HI vs pre: P < 0.01) and greater circulating cortisol post 30HI (vs CON; P < 0.01). There was no effect of 120MI on skin irritant responses to CO., Conclusions: Prolonged moderate-intensity exercise, but not short-lasting high- or short-lasting moderate-intensity exercise, decreases the induction of in vivo immunity. No effect of prolonged moderate-intensity exercise on the skin's response to irritant challenge points toward a suppression of cell-mediated immunity in the observed decrease in CHS. Diphenylcyclopropenone provides an attractive tool to assess the effect of exercise on in vivo immunity.

p-Phenylenediamine (PPD) and Diphenylcyclopropenone (DPCP) are two potent haptens. Both haptens are known to cause delayed-type hypersensitivity, involving a cytokine response and local infiltration of T-cell subpopulations, resulting in contact dermatitis. We investigated the systemic immune effects of PPD and DPCP, two relatively unexplored skin allergens. The dorsal sides of the ears of BALB/c mice were exposed to PPD or DPCP (0.1% w/v or 0.01% w/v), or vehicle alone. Mice were treated once daily for 3 days (induction period) and subsequently twice per week for 8 weeks. Local and systemic immune responses in the auricular and pancreatic lymph nodes, spleen, liver, serum, and ears were analyzed with cytokine profiling MSD, flow cytometry, and qPCR. Ear swelling increased significantly in mice treated with 1% PPD, 0.01% DPCP or 0.1% DPCP, compared with vehicle treatment, indicating that the mice were sensitized and that there was a local inflammation. Auricular lymph nodes, pancreatic lymph nodes, spleen, and liver showed changes in regulatory T-cell, B-cell, and NKT-cell frequencies, and increased activation of CD8(+) T cells and B cells. Intracellular cytokine profiling revealed an increase in the IFN-γ- and IL-4-positive NKT cells present in the liver following treatment with both haptens. Moreover, we saw a tendency toward a systemic increase in IL-17A. We observed systemic immunological effects of PPD and DPCP. Furthermore, concentrations too low to increase ear thickness and cause clinical symptoms may still prime the immune system. These systemic immunological effects may potentially predispose individuals to certain diseases.

The aim was to assess the effect of high altitude on the development of new immune memory (induction) using a contact sensitization model of in vivo immunity. We hypothesized that high-altitude exposure would impair induction of the in vivo immune response to a novel antigen, diphenylcyclopropenone (DPCP). DPCP was applied (sensitization) to the lower back of 27 rested controls at sea level and to ten rested mountaineers 28 hours after passive ascent to 3777 m. After sensitization, mountaineers avoided strenuous exercise for a further 24 hours, after which they completed alpine activities for 11-18 days. Exactly 4 weeks after sensitization, the strength of immune memory induction was quantified in rested mountaineers and controls at sea level, by measuring the response to a low, dose-series DPCP challenge, read at 48 hours as skin measures of edema (skinfold thickness) and redness (erythema). Compared with control responses, skinfold thickness and erythema were reduced in the mountaineers (skinfold thickness,-52%, p=0.01, d=0.86; erythema, -36%, p=0.02, d=0.77). These changes in skinfold thickness and erythema were related to arterial oxygen saturation (r=0.7, p=0.04), but not cortisol (r<0.1, p>0.79), at sensitization. In conclusion, this is the first study to show, using a contact sensitization model of in vivo immunity, that high altitude exposure impairs the development of new immunity in humans.

Background: Epicutaneous vaccination has gained increasing interest during the past decade as it offers a safe, needle-free, and patient-friendly alternative to invasive vaccine administrations. Recently, the safety and early efficacy of epicutaneous immunotherapy were also demonstrated in patients with hay fever, as an alternative to conventional subcutaneous allergen-specific immunotherapy (SCIT). One major challenge to epicutaneous vaccination is the barrier function of the stratum corneum, which must be overcome either by abrasive methods or by hydration. Such barrier function of the stratum corneum also hampers the use of common adjuvants used to enhance the efficacy of vaccination., Methods: In a mouse model of allergy, we tested the adjuvant potential of diphenylcyclopropenone (DCP), a strong contact sensitizer, which is currently used for the treatment of a T cell-mediated hair loss disease (alopezia areata)., Results: Diphenylcyclopropenone enhanced antigen-specific IgG2a antibody responses as well as IL-10 cytokine production after epicutaneous immunization with ovalbumin (OVA). Epicutaneous allergen-specific immunotherapy (EPIT) with OVA and DCP also protected sensitized mice from anaphylaxis and asthma. The protective effect was more robust than that of conventional SCIT, which did not significantly alleviate the symptoms of allergy in the murine models of anaphylaxis and asthma., Conclusions: This preclinical study confirmed previous clinical data that have demonstrated the potential of the skin as a target for allergen immunotherapy. The study also suggests that epicutaneous immunization or immunotherapy can be improved when an appropriate adjuvant such as DCP is used., (© 2012 John Wiley & Sons A/S.)

In this study we explored the immunization route-dependent adjuvanticity of cationic liposomes loaded with an antigen (ovalbumin; OVA) and an immune potentiator (CpG). Mice were immunized intranodally, intradermally, transcutaneously (with microneedle pre-treatment) and nasally with liposomal OVA/CpG or OVA/CpG solution. In vitro, OVA/CpG liposomes showed enhanced uptake by DCs of both OVA and CpG compared to OVA+CpG solution. A similar enhanced uptake by DCs was observed in vivo when fluorescent OVA/CpG liposomes were administered intranodally. However, after transcutaneous and nasal application a lower uptake of OVA/CpG liposomes compared to an OVA+CpG solution was observed. Moreover, the IgG titers after nasal and transcutaneous administration of OVA/CpG liposomes were reduced compared to administration of an OVA+CpG solution. Although serum IgG titers may suggest limited added value of liposomes to the immunogenicity, for all routes, OVA/CpG liposomes resulted in elevated IgG2a levels, whereas administration of OVA+CpG solutions did not. These data show that encapsulation of antigen and adjuvant into a cationic liposome has a beneficial effect on the quality of the antibody response in mice after intranodal or intradermal immunization, but impairs proper delivery of antigen and adjuvant to the lymph nodes when the formulations are administered transcutaneously or nasally., (Copyright © 2011 Elsevier B.V. All rights reserved.)

An inverse relation between contact allergy and autoimmune diseases is suggested from epidemiological studies. The aim of this study was to investigate susceptibility and reactivity in patients with psoriasis, patients with diabetes and healthy controls in an experimental sensitization study. We sensitized 68 adult individuals (23 patients with psoriasis, 22 patients with diabetes and 23 healthy controls) with diphenylcyclopropenone (DPCP) and assessed challenge responses with visual scoring and ultrasound. Skin biopsies from challenged skin were investigated for differences in down-regulatory mechanisms with immunohistochemistry and gene-expression profiles using microarray technology. The sensitization ratios were 26%, 36% and 65% for the psoriatic, diabetic and healthy groups, respectively. Logistic regression analysis gave an odds ratio (OR) for a patient with psoriasis or diabetes type I of being sensitized to 0·18 [95% confidence interval (CI): 0·039-0·85], P = 0·031 and 0·74 (95% CI: 0·548-1·008), P = 0·056, respectively. A high degree of forkhead box P3-positive (FoxP3(+) ) cells were found in biopsies of positively challenged reactions, but only limited numbers in negatively challenged reactions, with no difference among the groups. No specific mRNA expression was found in the challenged skin of negative elicitation reactions, also indicating no sign of active down-regulation. The study contibutes strongly to the evidence of a decreased susceptibility to develop contact allergy in individuals with autoimmune diseases such as psoriasis., (© 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology.)

Little is known about the influence of exercise on induction and elicitation phases of in vivo immunity in humans. We used experimental contact-hypersensitivity, a clinically relevant in vivo measure of T cell-mediated immunity, to investigate the effects of exercise on induction and elicitation phases of immune responses to a novel antigen. The effects of 2 h-moderate-intensity-exercise upon the induction (Study One) and elicitation of in vivo immune memory (Study Two) to diphenylcyclopropenone (DPCP) were examined. Study One: matched, healthy males were randomly-assigned to exercise (N=16) or control (N=16) and received a primary DPCP exposure (sensitization), 20 min after either 2 h running at 60% V O(2peak) (EX) or 2 h seated rest (CON). Four weeks later, participants received a low, dose-series DPCP challenge (elicitation) on their upper inner arm, which was read at 24 and 48 h as clinical score, oedema (skinfold thickness) and redness (erythema). Study Two: pilot; 13 healthy males were sensitized to DPCP. Elicitation challenges were repeated every 4 weeks until responses reached a reproducible plateau. Then, N=9 from the pilot study completed both EX and CON trials in a randomized order. Elicitation challenges were applied and evaluated as in Study One. Results demonstrate that exercise-induced stress significantly impairs both the induction (oedema -53% at 48 h; P<0.001) and elicitation (oedema -19% at 48 h; P<0.05) phases of the in vivo T-cell-mediated immune response. These findings demonstrate that prolonged moderate-intensity exercise impairs the induction and elicitation phases of in vivo T-cell-mediated immunity. Moreover, the induction component of new immune responses appears more sensitive to systemic-stress-induced modulation than the elicitation component., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: To evaluate the efficacy of two topically applied immunomodulative agents through the detection of lymphocyte subsets using monoclonal antibodies against CD4, CD8 and MHC II., Methods: Fifty patients from the Departments of Medical Biochemistry, Dermatology and Pathology at Cairo University with different degrees of alopecia areata (AA) were included in this study. They were classified into two groups each of 25 patients. Each patient was treated with the immunomodulative agent on one side of the scalp and the other side was left as a control. Biopsies were taken from all patients at the beginning of treatment and at the end of the study. Tissue specimens were prepared for histologic and immunophenotypic analysis. The main outcome measures were the uses of diphencyprone (DPCP) and topical tacrolimus as two topical immunotherapeutic modalities in the treatment of AA., Results: A clinical response of 68% was achieved in group A (treated with DPCP) while group B (treated with 0.1% tacrolimus) showed an insignificant clinical response. Decreased expression of CD4 and increased expression of CD8 and MHC II was detected in the post-treated areas compared with pretreated areas in cases treated with DCPC. In tacrolimus-treated cases, there was a decrease in CD4 and MHC II, with no change in CD8 between the pre- and post-treated areas., Conclusion: DCPC is one of the most accepted therapeutic modalities in the treatment of AA, with a favourable prognosis among patchy hair loss. MHC II expression was the one correlating with clinical response. Tacrolimus, though beneficial in other dermatoses, could not be considered effective in the treatment of AA.

Alopecia areata, a disease of the hair follicles with multifactorial etiology and a strong component of autoimmune origin, has been extensively studied as far as the role of several cytokines is concerned. So far, IFN-gamma, interleukins, TNF-alpha, are cytokines that are well known to play a major role in the pathogenesis of the disease, while several studies have shown that many more pathways exist. Among them, MIG, IP-10, BAFF, HLA antigens, MIG, as well as stress hormones are implicated in disease onset and activity. Within the scope of this paper, the authors attempt to shed light upon the complexity of alopecia areata underlying mechanisms and indicate pathways that may suggest future treatments.

It is well known that ultraviolet (UV) radiation induces erythema, immunosuppression and carcinogenesis. We hypothesized that chronic exposure to solar UV radiation induces adaptation that eventually prevents the suppression of acquired immunity. We studied adaptation for UV-induced immunosuppression after chronic exposure of mice to a suberythemal dose of solar simulated radiation (SSR) with Cleo Natural lamps, and subsequent exposure to an immunosuppressive dose of solar or UVB radiation (TL12). After UV dosing, the mice were sensitized and challenged with either diphenylcyclopropenone (DPCP) or picryl chloride (PCl). To assess the adaptation induced by solar simulated radiation, we measured the proliferative response and cytokine production of skin-draining lymph node cells after immunization to DPCP, the contact hypersensitivity (CHS) response to PCl, and thymine-thymine (T-T) cyclobutane dimers in the skin of mice. After induction of immunosuppression by SSR or by TL12 lamps, the proliferative response of draining lymph node cells after challenge with DPCP, or the CHS after challenge with PCl, showed significant suppression of the immune response. Chronic irradiation from SSR preceding the immunosuppressive dose of UV failed to restore the suppressed immune response. Reduced lipopolysaccharide-triggered cytokine production (of IL-12p40, IFN-gamma, IL-6 and TNF-alpha) by draining lymph node cells of mice sensitized and challenged with DPCP indicated that no adaptation is induced. In addition, the mice were not protected from T-T dimer DNA damage after chronic solar irradiation. Our studies reveal no evidence that chronic exposure to low doses of SSR induces adaptation to UV-induced suppression of acquired immunity.

Though many therapies exist for alopecia areata, one of the most unique is topical sensitization. By altering the pathogenic inflammatory response with few side effects, sensitizers offer an attractive treatment option for many patients with alopecia areata, including those who have previously failed more traditional treatments and those who have extensive disease.

Contact sensitization has been an accepted topical immunotherapy in the treatment of alopecia areata (1, 2). Whether the age of patients is a significant factor in the treatment results is a matter of controversy. In our study, we investigated the correlation between age of the patients and diphenylcyclopropen-one contact sensitization in vivo and in vitro (3, 4).

Background: Topical immunotherapy with a contact allergen is effective in alopecia areata (AA). However, the mechanism of the effect is still unknown, and pretreatment prediction of the outcome of therapy in each patient remains difficult., Objectives: To predict the clinical effect of this therapy in AA patients, we investigated the relationship between clinical responses to topical immunotherapy and in vitro proliferative responses of peripheral blood mononuclear cells (PBMC) to T-cell stimulants., Methods: PBMC were taken from 67 AA patients before or during diphenylcyclopropenone immunotherapy and from 14 healthy controls, and proliferative responses to phytohaemagglutinin and staphylococcal enterotoxin B were evaluated by measuring [3H]-thymidine incorporation., Results: PBMC from the AA patients with a good clinical response to immunotherapy showed a normal level of proliferation, whereas PBMC from the poor responders showed a markedly suppressed proliferative response and interleukin (IL)-2 production, but increased IL-4 production compared with the controls., Conclusions: The proliferative response of PBMC to T-cell stimulants may be one of the indicators of the clinical effect of topical immunotherapy for AA.

Topical therapy using contact sensitizers has been practised since the 1960s to treat conditions associated with an altered immunological state. Dinitrochlorobenzene, squaric acid dibutyl ester and diphencyprone are most commonly employed in the therapy of alopecia areata and viral warts. Few dermatology departments in the U.K. provide such treatment. This systematic review discusses the various contact sensitizers used for topical immunotherapy, the methodology of treatment, factors influencing efficacy and likely adverse effects.

The loss of hepatic allografts to the rejection processes is now relatively rare, and the reduction of adverse effects related to immunosuppressive therapy is becoming more important as patients survive longer after transplantation. We therefore investigated the response to a contact neoantigen before liver transplantation as a predictor of acute rejection after transplantation. Forty-one patients with chronic liver disease were sensitized with 0.1% diphenylcyclopropenone while on the waiting list for orthotopic liver transplantation. Fourteen days later an elicitation reaction was performed with 5 different concentrations of diphenylcyclopropenone. Nineteen responded to diphenylcyclopropenone (score range, 1-9). Twenty-two patients had no response. Three patients died before transplantation (all nonresponders). Twelve (63%) of 19 responders had treatment for acute rejection compared with 1 of 19 nonresponders (P < .0001). In addition univariate analysis revealed recipient age, donor age, Child-Pugh class, and immunosuppressive agent to be associated with acute rejection. On multivariate analysis only skin test response was a significant predictor of acute rejection (P = .02). All nonresponders had no or only mild rejection on biopsy, but 12 of 19 responders had moderate or severe acute rejection on biopsy. All patients requiring additional therapy to a single course of corticosteroids for acute rejection had skin test scores greater than 1. We concluded that patients who do not respond to diphenylcyclopropenone sensitization before transplantation develop at most mild acute rejection and that skin test scores identify patients with troublesome rejection. Evaluation of skin test responses to a contact neoantigen may facilitate tailoring of immunosuppressive therapy.

Ultraviolet-B (UVB, 280-320 nm) interferes with the generation of cell-mediated immunity to contact allergens applied epicutaneously on the irradiated site. To investigate whether pretreatment with UVA-1 (340-400 nm) protects against the UVB-induced immune suppression we sensitized human volunteers with diphenylcyclopropenone (DPCP) on normal buttock skin (n= 12), on UVB-irradiated buttock skin (n=21), on buttock skin pretreated with UVA-1 (n= 12), and on buttock skin pretreated with UVA-1 and thereafter irradiated with UVB (n=22). Sensitization on UVB-irradiated skin reduced the immunization rate to DPCP compared with sensitization on non-irradiated skin (p<0.01) and skin pretreated with UVA-1 (p<0.01). In contrast, the immunization rate in the group of volunteers sensitized on skin pretreated with UVA-1 before UVB irradiation was significantly higher than the immunization rate in the group of volunteers sensitized on UVB-irradiated skin alone (p<0.05). These results indicate that pretreatment with UVA-1 under certain conditions offers partial protection against the UVB-induced reduction in the immunization rates to epicutaneous allergens.

We hypothesized that intradermal delivery of granulocyte-macrophage colony-stimulating factor (GM-CSF) would alter the number and differentiation state of local antigen-presenting cells and thereby alter immunization strength at that site in humans. GM-CSF or placebo was administered intradermally on consecutive days prior to contact sensitization at that site. In GM-CSF-treated skin, epidermal CD1a(+)S100(+) Langerhans cells were reduced in number and had altered morphology, while the number of dermal CD1a(+), HLA-DR(+), and S100(+) cells was increased. In the deep dermis CD68(+) macrophages were increased. Expression of the APC activation markers CD40 and ICAM-1 was also increased in the dermis. Subjects were sensitized to DNCB through GM-CSF- or placebo-pretreated skin and to DPCP through untreated skin. Subjects immunized through GM-CSF-treated sites exhibited 64% greater elicitation responses to DNCB than placebo-treated subjects. GM-CSF-treated subjects also showed 43% lower responses to DPCP than placebo-treated subjects. The difference between DNCB (local) and DPCP (distant) responses was significantly greater for GM-CSF-treated subjects than for placebo responses (n = 8, P < 0.05). Therefore, local immunization site pretreatment with intradermal GM-CSF enhances immunization efficiency at that site., (Copyright 2000 Academic Press.)

Low doses of ultraviolet B (UVB) can induce localized immunosuppression in skin. This effect may be important in the induction of skin cancers and is thought to be mediated by tumour necrosis factor (TNF) alpha and interleukin (IL) 10 in conjunction with other factors. In humans a transition polymorphism in the TNF-alpha gene may affect TNF-alpha secretion and the promoter region of the IL-10 gene contains a CA repeat polymorphism which may affect gene function. We have therefore investigated the association of these polymorphisms with UVB-induced immunosuppression in humans. Volunteers (n = 42) were irradiated with UVB then sensitized on irradiated skin with diphenylcyclopropanone (DPCP) and subsequently antigen challenged with DPCP. DNA was extracted from blood samples and volunteers genotyped for the TNF-alpha polymorphism by polymerase chain reaction (PCR) and restriction digestion. The CA repeat polymorphism was amplified by PCR and sized by gel electrophoresis. Twenty-four volunteers were susceptible to UVB-induced immunosuppression and 18 were resistant. The association of allele frequencies and phenotype was statistically tested using a chi2-test. For both the TNF-alpha and IL-10 polymorphisms, there was no statistically significant association between allele types and response to UVB. These results indicate that variation in the immune response to UVB in humans is not associated with the TNF-alpha-308 transition or IL-10 CA repeat polymorphisms, although other as yet undetected DNA sequence variants of these genes may be involved.

Delayed-type hypersensitivity (DTH) reactions to the experimental allergen diphenylcyclopropenone (DCP) were measured in four groups, which either trained (+) or did not train in relaxation (-) during the sensitization and/or the challenge phase. All groups consisted of high and low hypnotic susceptible subjects. While there were no differences in erythema, the mean induration of the group which trained in relaxation in both the sensitization and the challenge phase (+/+) was significantly greater than that of the group which trained in relaxation in the challenge phase only (-/+). Significant correlations were found between induration and hypnotic susceptibility scores, and between induration and degree of perceived relaxation during challenge. High hypnotic susceptible subjects experienced a higher degree of perceived relaxation and exhibited greater indurative and erythematous DTH reactions to DCP than low hypnotic susceptible subjects in all four experimental conditions. Though the mediating mechanisms remain unclear, our results suggest that relaxation may affect the DTH reaction, and support previous findings of higher psychophysiologic reactivity of high hypnotic susceptible subjects.

Ultraviolet-B (UVB), in addition to direct effects on DNA, induces immunological changes in the skin that predispose to the development of skin cancer. Whether ultraviolet-A (UVA) induces similar changes is unknown. This effect can be investigated in humans in vivo using epicutaneous antigens as a model of tumour antigens. Volunteers (n = 46) were randomly assigned to received no sensitization, sensitization with the allergen diphenylcyclopropenone (DPCP) on non-UV-exposed normal skin, or sensitization with DPCP on skin exposed to three minimal erythema doses (MED) of either UVA or UVB radiation 3 days before sensitization. Three weeks after sensitization all volunteers were challenged with five different concentrations of DPCP. The challenge reactions were scored clinically and the increase in skin thickness was measured using a micrometer. Sensitization on UVB-exposed skin reduced the immunization rate compared with sensitization on non-irradiated skin (P < 0.03) as previously described. In contrast, sensitization on skin exposed to three MED UVA radiation did not result in a decreased immunization rate compared with non-irradiated skin. These results indicate that in humans erythemagenic doses of UVA radiation do not reduce the immunization rates to epicutaneous allergens. Thus UVB and UVA irradiation have contrasting effects on cell-mediated immunity in humans. These findings may at least in part explain the less carcinogenic effect of UVA irradiation.

Healthy volunteers (n = 14, age range 20-31 years, mean 23) were irradiated on the inside of the left forearm on four consecutive days with their individual minimal erythemal dose of ultraviolet B (UVB) prior to sensitization in the same skin area with a 2% solution of diphenylcyclopropenone (DPCP). The reaction patterns were compared with 14 alopecia areata patients (age range 16-69 years, mean 40) starting topical immunotherapy with DPCP, sensitized without prior UVB treatment. Primary allergic reactions occurred in ten volunteers and in four alopecia areata patients. Patch testing on the upper back with serial dilutions of DPCP (1% to 10(-8)%) showed minimal dermatitis-eliciting concentrations ranging from 1 to 10(-4)% (mean 0.19%) in the volunteers as compared with 10(-1) to 10(-8)% (mean 0.025%) in the alopecia areata patients. Two patterns were discernible within the volunteers with respect to the intensity of the primary allergic and elicitation reactions. Ten volunteers reacted in a similar way to the alopecia areata patients, whereas four probands demonstrated very high minimal dermatitis-eliciting concentrations and overall less severe reactions. The DPCP-specific T-cell response using blood macrophages and B lymphocytes as antigen-presenting cells was measured in an in vitro assay in two alopecia areata patients and two volunteers having similar skin reactions as well as in two volunteers with overall less severe skin reactions. B lymphocytes from the alopecia areata patients and the volunteers with similar skin reactions induced a significant DPCP-specific T-cell proliferation exceeding the responses obtained using macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Twelve children with extensive alopecia areata or alopecia totalis were treated with the contact allergen diphencyprone. The duration of treatment ranged from 5 months to 1 year. Eight of the 12 (67%) regrew scalp hair and in four (33%) there was a complete regrowth. Six months after treatment was discontinued three of the four children with complete regrowth maintained their hair, one had lost all the regrowth and a further child with patchy regrowth at the end of treatment subsequently regrew hair completely while off therapy.

A 30-year-old man with bilateral plantar warts of the mosaic type which had been resistant to standard treatment modalities was treated with diphenylcyclopropenone. After 10 weeks, the treated warts had disappeared; the untreated warts, although showing some involution, still persisted. The untreated warts, serving as a control to prove the effectiveness of topical immunotherapy, responded likewise to subsequent treatment with diphenylcyclopropenone. Wart regression was reflected histopathologically by decreases in acanthosis, papillomatosis, granular vacuolation, and hyperkeratosis. Immunohistochemically, Ki-67 expression was markedly reduced, and a reversal of the CD4/CD8 ratio was seen. These findings suggest a major role of a cell-mediated immune response in the spontaneous resolution of warts.

A new synthetic substance - diphenylcyclopropenone - has been proven to be responsible for contact dermatitis in three persons handling it in chemical laboratories. A student of chemistry developed a dermatitis of the hands that lasted for more than two months. Based on the case history this dermatitis was considered to be an allergic one. The sensitizing capacity of diphenylcyclopropenone was proven experimentally in guinea pigs by use of the open epicutaneous sensitization method. All 25 animals became strongly sensitive. Sensitization could also be induced by a single application of low concentrations, for example with 3% in acetone. Cross-reactions could be elicited in the sensitized animals by intermediate produts and the synthesis like alpha, alpha'-dibromdibenzylketone and the remaining procduct called "red oil". The intermediate product is a mixture of racemic d- and l-forms and a meso-form as well, whereas the "red oil" consists of polymerized carbonyl compounds, from which diphenylcyclopropenone is extracted with boiling cyclohexane. Risk of contact with the sensitizer is greatest in the last step of synthesis. Care should not only be taken while handling this new substance in chemical laboratories, but contact should also be avoided with the intermediate and end products in cases where a diphenylcyclopropenone contact allergy is present.

Ten patients with malignant melanoma were simultaneously sensitized with dinitrochlorobenzol (DNCB) and diphenylcyclopropenon (DPCP) (500 micrograms each). Fourteen days after sensitization the patients were challenged with 0.04-25 micrograms doses of DNCB and DPCP. The reactions of all of the subjects tested were the same for DNCB as for DPCP. The results were statistically significant. To achieve a skin reaction of the same intensity, the necessary doses of DPCP were much lower than those of DNCB.