Modulation of Toll-like receptors in psoriatic patients during therapy with adalimumab.

Toll-like receptors (TLRs) are a key part of the innate immune system that detect pathogen-associated molecular patterns (PAMPs) of microorganisms and their stimulation results in the activation of signaling pathways leading to the modulation of inflammatory and immune responses. Since psoriasis is a complex, inflammatory and immune skin disease, characterized by an abnormal immune response and increased proliferation of keratinocytes, with an increased production of proinflammatory cytokines, TLRs could play an important role in the pathogenesis of the disease. We propose to assess the modulation of TLR expression on psoriatic skin of patients treated with Adalimumab and systemic conventional therapies. We therefore recruited fifteen patients: ten were treated with adalimumab and five with systemic conventional therapies; their clinical conditions were analyzed by PASI index and skin biopsies were evaluated for TLR1 and TLR2 expression by immunohistochemistry assays. Our data suggest adalimumab is not only able to improve the clinical condition of psoriatic patients, but also to modulate TLR1 and TLR2 expression involved in psoriasis, as in healthy skin. Adalimumab is a most promising biological drug able to orchestrate immune and inflammatory responses in psoriatic lesions, recovering TLR expression on basal keratinocytes and improving clinical conditions of psoriatic patients, with no evident side effects.

Usefulness of the CD63 basophil activation test in detecting Anisakis hypersensitivity in patients with chronic urticaria: diagnosis and follow-up.

BACKGROUND: The basophil activation test (BAT) has been recently described as a useful in vitro tool for diagnosis of allergy to Anisakis species in patients with acute urticaria. AIM: To evaluate the relationship between sensitization to Anisakis simplex and chronic urticaria (CU), using flow cytometry analysis of in vitro BAT. Methods. A. simplex sensitization was evaluated in patients with CU (n = 57) and in atopic (n = 22) and healthy controls (n = 20) by means of skin prick test (SPT), specific IgE and Anisakis-induced BAT using a triple-labelled strategy with anti-CD123, anti-human leucocyte antigen DR and anti-CD63 antibodies. During a follow-up period of 6 months in 10 patients with CU who accepted a fish-free dietary regimen, the diagnostic performance of the in vivo and in vitro methods was calculated, and changes in specific IgE and BAT were evaluated with respect to clinical response. RESULTS: A significant association between CU and A. simplex sensitization was found, with an overall prevalence of 75.4% in patients with CU (43/57) compared with 18% (4/22) and 10% (2/20) of the atopic and healthy controls, respectively (P < 0.0001). BAT (cut-off > 13%) had the highest sensitivity and specificity, with significantly better ability than specific IgE testing for the identification of A. simplex sensitization in patients with CU. During the 6-month follow-up, clinical improvement was seen in all patients, and specific IgE and BAT results decreased to normal values in 6/10 (60%) and 10/10 (100%) patients, respectively. CONCLUSIONS: BAT can be considered a reliable new in vitro method to evaluate A. simplex hypersensitivity in patients with CU, supplementing standardized procedures in both diagnosis and follow-up.

Immunohistochemical expression of apoptotic markers in drug-induced erythema multiforme, Stevens-Johnson syndrome and toxic epidermal necrolysis.

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are considered to be severity variants of the same disease, which is almost always associated with drug intake. In contrast, erythema multiforme (EM) is a disorder regarded as only rarely caused by drugs. Keratinocyte apoptosis has been shown to play an important part in the pathogenesis of SJS and TEN, whilst its role in EM remains controversial. To determine the expression of apoptosis-associated molecules Fas, Fas ligand (FasL), Bcl-2 and Bax in the above disorders, an immunohistochemical analysis was performed. We studied both lesional skin from thirty patients having drug-induced EM and 5 cases classified within the SJS/TEN spec nottrum and normal skin samples. We found a keratinocyte overexpression of Fas antigen, an important molecule mediating apoptosis, not only in SJS and TEN but also in EM. Another noteworthy finding was the strong expression of Bcl-2, a protein known as blocking apoptosis, along the basal layer and in the dermal infiltrate both in SJS/TEN and in EM. Taken together, these findings suggest that Fas-dependent keratinocyte apoptosis may play a part in the pathogenesis of both SJS/TEN and EM. Fas-mediated cell death may be partially suppressed by the Bcl-2 protein.

Expression of cytokines and chemokine receptors in the cutaneous lesions of erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis.

BACKGROUND: Erythema multiforme (EM) and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) are caused by a dysregulation of cellular immunity. OBJECTIVES: To evaluate further the potential role of certain cytokines and chemokine receptors in cutaneous lesions of patients affected by EM and SJS/TEN and to establish whether such diseases are polarized preferentially towards a T-helper (Th) 1 or Th2 pattern. METHODS: Biopsy specimens from eight patients with EM, six with SJS/TEN and three healthy controls were stained for immunohistochemical examination using the alkaline phosphatase-antialkaline phosphatase method. The monoclonal antibodies used included those to tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-2, IL-5, IL-13, receptor 3 for C-C chemokines (CCR3), receptor 3 for C-x-C chemokines (CXCR3) and CXCR4. RESULTS: The SJS/TEN specimens showed significantly higher expression of all the cytokines and chemokine receptors (except CXCR3) tested than the EM specimens. Both lesional series showed significantly higher expression of all the receptors tested than the healthy control specimens, with the sole exception of a lower expression of CCR3 in EM specimens. Comparison between molecules associated with a Th1 or Th2 response revealed a predominance of Th1 response in EM and no significant imbalance between Th1 and Th2 in SJS/TEN. CONCLUSIONS: We have provided further evidence that TNF-alpha is strongly expressed in SJS/TEN lesions and therefore it may be involved in the epidermal necrosis featured in such diseases. IFN-gamma may play an important role both in EM and SJS/TEN. IL-2, IL-5 and IL-13 may contribute to the cutaneous immunoinflammation in these diseases. Chemokine receptors may be involved strongly in the recruitment of inflammatory cells in lesional skin. In our cases we found a sharp polarization towards a Th1 pattern in EM, while the SJS/TEN lesions showed a mixed Th1/Th2 pattern.

Serum-induced basophil CD63 expression by means of a tricolour flow cytometric method for the in vitro diagnosis of chronic urticaria.

BACKGROUND: Functional autoantibodies against the alpha-chain of the high-affinity IgE receptor (FcepsilonRIalpha) identify a subset of patients with chronic urticaria (CU) due to autoreactivity, as assessed by an in vivo positive response to autologous serum skin test (ASST). We performed a study to standardize the serum-induced basophil activation assay by flow cytometry (FCM) using a new tricolour method, assessing the diagnostic performance of this test in discriminating between ASST+ and ASST- CU patients. METHODS: Sera of 64 CU patients (22 ASST+ CU and 42 ASST- CU) and 10 healthy subjects were tested for their ability to induce basophil CD63 expression when incubated with whole blood of both atopic (DA) and non-atopic donors (DNA). Using a triple-labelled strategy with anti-CD123, anti-HLA-DR and anti-CD63 antibodies, CD63+ basophils were identified on a selected population of CD123+ HLA-DR- cells. In 3 ASST+ CU patients who underwent cyclosporine therapy, the assay was performed before and after treatment. RESULTS: The ASST+ CU sera resulted in a significant higher induction of basophil CD63 expression compared with ASST- CU and healthy donors sera; when whole blood from DA was used, sensitivity and specificity of the assay were 95.5% and 90.5% respectively. ASST+ CU serum activity was significantly decreased during cyclosporine A treatment, in parallel with clinical remission. CONCLUSIONS: Chronic urticaria serum-induced CD63 expression assay performed on DA whole blood by means of our tricolour FCM method could be the most useful tool for identification of a subset of patients with autoimmune CU and may become a promising tool also for monitoring treatment efficacy.

The CD40/CD40 ligand system is expressed in the cutaneous lesions of erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis spectrum.

BACKGROUND: Erythema multiforme (EM) and Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) are determined by a dysregulation of cellular immunity. OBJECTIVES: To evaluate the effector role of cellular immunity and the involvement of the CD40/CD40 ligand (CD40L) system in the pathogenesis of EM and SJS/TEN. METHODS: Biopsy specimens from eight patients with EM and six with SJS/TEN were stained for immunohistochemical examination using the alkaline phosphatase/antialkaline phosphatase method. The monoclonal antibodies used included those to CD1a, CD4, CD8, CD40, CD40L, CD68, Fas, Fas ligand (FasL) and myeloperoxidase. RESULTS: The cellular infiltrate in both EM and SJS/TEN lesions was composed mainly of T lymphocytes and CD68+ macrophages. We also detected large amounts of neutrophils. Fas and FasL were very highly expressed in SJS and TEN, but weakly in EM. CD40 staining was strong in all tissue sections; there were numerous CD40L+ cells in SJS/TEN but much fewer in EM. CONCLUSIONS: Activated T lymphocytes and macrophages, but also neutrophils, are presumably the main triggers of mucocutaneous damage in the SJS/TEN disease spectrum. The Fas/FasL system is significantly expressed in SJS/TEN lesions, but not in EM, where this apoptotic pathway presumably does not play a pivotal role in the epidermal damage. We suggest that the CD40/CD40L system may represent an important pathway of induction of SJS/TEN lesions, while in EM it would contribute to the immunoinflammation only as a second-line mechanism.

Cytokine and chemokine levels in systemic sclerosis: relationship with cutaneous and internal organ involvement.

Systemic sclerosis (SSc) is a connective tissue disorder characterized by excessive collagen deposition in the skin and internal organs. Several cytokines and chemokines have been implicated in the induction of fibrosis, but a definitive relationship between specific cytokines and organ involvement has not been established yet. Serum samples, PBMC and T cell lines (TCL) obtained from 54 patients affected by SSc and 20 healthy donors (HD) were examined by ELISA for Interferon-gamma (IFN-gamma ), interleukin (IL)-4, IL-6, IL-10, IL-18, Transforming growth factor (TGF)-beta1, Tumour necrosis factor (TNF)-alpha, sCD30, Macrophage derived chemokine (MDC), Monocyte chemoattractant protein (MCP)-1, Macrophage inflammatory protein (MIP)-1alpha and Regulated on activation normal T-cell expressed and secreted (RANTES). In all the SSc serum samples, we found significantly increased levels of IL6, TNFalpha and MCP-1 but reduced amounts of gamma-IFN and MDC. IL6, IL10, IL18, MIP-1alpha and TNFalpha measured in supernatants from PHA-stimulated PBMC and IL6, MCP-1 and RANTES in supernatants from stimulated TCL were also increased in patients. MDC was decreased in all the biological SSc sources studied. TGF-beta1, IL10, and sCD30 were produced at a significantly lower level by SSc TCL. Serum IL6 and sCD30 levels were significantly increased in dc-SSc patients compared to lc-SSc as were levels of MCP-1 produced by PBMC and IL10 from TCL. We observed a strict relationship between pulmonary fibrosis and IL10, MCP-1 (both from TCL) and serum IL6. Kidney involvement was related to serum MCP-1 levels and IL18 production from PBMC. Oesophageal involvement correlated with MDC production from PBMC and IL10 synthesis by TCL. We showed that IL-6, IL-10, MDC and MCP-1 are variably associated with internal organ involvement and allow the discrimination between limited and diffuse forms of the disease.

Interleukin-16 expression and release in bullous pemphigoid.

Cutaneous infiltration of activated CD4(+) T cells and eosinophils is an early event in blister formation during bullous pemphigoid (BP), suggesting that the trafficking of circulating leucocytes through the sites of inflammation, their activation and cytokine release is crucial in the pathogenesis of the disease. IL-16 is a major chemotactic factor able to recruit CD4(+) cells in the skin during inflammation and to induce the expression of functional high-affinity interleukin (IL)-2 receptors, thus contributing to cellular activation and proliferation. We performed a study in order to evaluate the presence of IL-16 in skin samples and sera and blister fluids of patients affected with BP in active phase of the disease (n = 39), compared with healthy donors studied as control group. Ten patients were also evaluated before and after steroid therapy. Our results demonstrated that IL-16 was expressed strongly by keratinocytes and by dermal infiltrating CD4(+) T lymphocytes in lesional skin of BP patients. High levels of IL-16 were detected in sera and blisters of BP, significantly higher in respect to healthy donors. When patients were investigated for the presence of eosinophil cationic protein (ECP) and soluble CD30 (sCD30) to reveal signs of eosinophils and Th2-cells activation, we found a positive correlation between IL-16 serum levels and both ECP and sCD30, suggesting that IL-16 is involved in Th2 lymphocytes and eosinophils recruitment during BP.

The role of T lymphocytes and cytokines in the pathogenesis of pemphigoid gestationis.

BACKGROUND: Pemphigoid gestationis (PG), also known as herpes gestationis, is a rare autoantibody-mediated bullous disease, usually associated with pregnancy and the postpartum period. However, infiltrating cells have recently been suggested to also contribute to the pathogenesis of cutaneous lesions. OBJECTIVES: To evaluate the immunophenotype of T cells infiltrating the PG lesional skin and their prevalent cutaneous cytokine expression, as well as the presence and distribution of mast cells, eosinophils and neutrophils. Methods We performed an immunohistochemical study with a large panel of monoclonal antibodies to CD3, CD4, CD8, HLA-DR, CD25, myeloperoxidase, tryptase, eosinophil cationic protein EG2, human interleukin (IL)-2, -4, -5, -8, interferon (IFN)-gamma, and granulocyte-macrophage colony-stimulating factor using the alkaline phosphatase-antialkaline phosphatase procedure on lesional skin of seven patients with PG. Skin from four subjects with pruritic urticarial papules and plaques of pregnancy and three additional healthy donors were used as controls. RESULTS: The findings indicate that there is a T-cell population with a prevalent T-helper (Th) 2 phenotype in the lesional skin of PG subjects. We also found a number of eosinophils and neutrophils with clear signs of activation. CONCLUSIONS: These data suggest that an inflammatory infiltrate is involved in the production of PG bullous lesions. In particular, we assume that the Th2 cells might be implicated in the very early stages of autoimmune response and may exercise a broad influence in blister formation in this disease.

Distinct delayed T-cell response to beta-methasone and penicillin-G in the same patient.

BACKGROUND: Multiple drug allergy syndrome is a clinical condition characterized by reactions against more than one different class of, both pharmacologically and structurally, unrelated drugs. Scanty data are available to date about a multiple drug delayed hypersensitivity syndrome. Our aim was to report the case of a delayed reaction to both beta-methasone (beta-MT) and penicillin-G (pen-G) occurring in the same patient, and analyse beta-MT- and pen-G-specific T-cell Lines (TCLs) with regard to their specificity, phenotype and cytokine profile. METHODS: We generated two drug-specific TCLs from biopsies at the site of positive intradermal reactions, and analysed their immunophenotype, T-cell receptor Vbeta (TCR-Vbeta) domains expression and cytokine profile. RESULTS: We demonstrated the specificity of the T cells isolated from positive intradermal test reactions to pen-G and beta-MT through the strict dose-dependent proliferation in response to drug-pulsed autologous antigen presenting cells. Fluorescence activated cell sorter (FACS) analysis revealed a predominance of CD4+ cells in the inflammatory cell infiltrate of intradermal test with beta-MT, while a predominance of CD8+ T cells in the site of delayed reaction to pen-G was found. The drug specific CD4+ and CD8+ T cells were heterogeneous, with regard to TCR-Vbeta usage. CD8+ pen-G-TCL displayed a preferential T helper 2 (Th2) profile, while a substantially heterogeneous pattern of cytokine production characterized specific beta-MT TCL. CONCLUSION: The study describes the coexistence in the same patient of a delayed hypersensitivity to both penicillin G and beta-MT, driven, respectively, by pen-G-specificTh2-skewed CD8+ and beta-MT specificTh0 CD4+ T cells. This case further support the existence of a multiple drug allergy syndrome also for delayed hypersensitivity.

Increased IL-18 in patients with systemic lupus erythematosus: relations with Th-1, Th-2, pro-inflammatory cytokines and disease activity. IL-18 is a marker of disease activity but does not correlate with pro-inflammatory cytokines.

OBJECTIVE: The aim of this study was to investigate the imbalance between Th-1 and Th-2 cytokines in systemic lupus erythematosus patients (SLE) and to asses if any of these cytokines could be related to disease activity. METHODS: Twenty SLE patients and 20 healthy individuals were investigated. Blood samples were collected to evaluate, using ELISA method, serum levels of a wide array of cytokines including: Th-1 type cytokines (Interleukin (IL)-12, Interferon (IFN)-gamma), Th-2 cytokines (IL-4, IL-10), pro-inflammatory cytokines (tumor necrosis factor (TNF)-alpha, IL-1beta and IL-18). Disease activity was assessed using the SLE Disease Activity Index (SLEDAI). Data were evaluated using the Mann-Whitney and Spearman's rank tests. RESULTS: The SLE patients group had a higher IL-4, IL-10, IL-12 and IL-18 serum concentration compared to the normal control group. IL-18 was negatively correlated with IL-4 and positively correlated with IFN-gamma. No serum cytokine level was correlated with disease activity except for IL-18, which was found strongly correlated with "active disease", defined as SLEDAI > 8 points. IL-18 showed no correlation with pro-inflammatory cytokines. CONCLUSIONS: Our results show that Th-1 as well Th-2 cytokines can be elevated in SLE patients suggesting that lupus is a complex disease that may be supported by different cytokine patterns in different time-points. Only IL-18 has been found to be disease-activity related. The role of IL-18 in the pathogenesis of SLE might be important through apoptosis-mediating properties.

Circulating interleukin 16 (IL-16) in children with atopic/eczema dermatitis syndrome (AEDS): a novel serological marker of disease activity.

BACKGROUND: Chemokines play a central role in atopic eczema/dermatitis syndrome (AEDS). Interleukin 16 (IL-16) has been described as a main cytokine involved in CD4+ cell recruitment during inflammation. Recently the influx of CD4+ lymphocytes has been related to the up-regulation of IL-16 in AEDS skin lesions. Circulating beta-chemokines (Eotaxin and RANTES) and IL-16 were investigated in children with AEDS to correlate their presence with the severity of the disease. We also measured serum levels of soluble CD30 (sCD30), a marker of Th2 immune responses related to AEDS disease activity. METHODS: Serum levels of eotaxin, RANTES, IL-16 and sCD30 were measured by immunoenzymatic assay in paediatric patients with pure AEDS (pAEDS, n = 39); the severity of the disease was graded by SCORAD. Fifteen children with AEDS in presence of respiratory allergy (AEDS+A), 15 with allergic asthma (A) and 20 age-matched healthy donors were investigated as control groups. RESULTS: When compared to normals, high amounts of Eotaxin and IL-16 were detected in sera of pAEDS (P = 0.002; P < 0.0001), AEDS+A (P = 0.02; P = 0.01) and A patients (P = 0.004; P = 0.03) with respect to normals. Serum levels of RANTES were also elevated in pAEDS patients, significantly higher than normals (P = 0.009), whereas no statistically significant differences could be detected between pAEDS and AEDS+A or A groups. IL-16 was progressively increased in the different stages of pAEDS, with a positive correlation between IL-16 and both SCORAD and sCD30 (P < 0.0001). CONCLUSION: We suggest that IL-16 could serve as a useful marker of disease activity in childhood pAEDS.

Keratinocytes from patients with atopic dermatitis and psoriasis show a distinct chemokine production profile in response to T cell-derived cytokines.

BACKGROUND: Atopic dermatitis (AD) and psoriasis are genetically determined inflammatory skin disorders. Keratinocytes actively participate in cutaneous inflammatory responses by elaborating various chemokines. OBJECTIVE: We investigated the capacity of IL-4, IFN-gamma, and TNF-alpha to modulate the expression of CCL and CXCL chemokines in cultured keratinocytes from patients and healthy individuals, as well as chemokine expression in situ. METHODS: Keratinocyte cultures were established from normal-looking skin of adult patients with AD or psoriasis vulgaris and from healthy subjects. Monocyte chemoattractant protein 1 (MCP-1)/CCL2, RANTES/CCL5, IL-8/CXCL8, and IFN-gamma-induced protein of 10 kd (IP-10)/CXCL10 production was evaluated at the mRNA and protein levels by using RNase protection assay and ELISA, respectively. The expression of the same chemokines was studied in chronic lesional skin by means of immunohistochemistry or in situ hybridization. RESULTS: Only IL-8 mRNA was detected in unstimulated ke-ratinocyte cultures. MCP-1 and IP-10 were potently induced by IFN-gamma, whereas IL-8 and RANTES were preferentially upregulated by TNF-alpha and, to a lesser extent, by IFN-gamma. IL-4 weakly induced IP-10, RANTES, and IL-8 but not MCP-1. Keratinocytes of patients with AD invariably responded with significantly earlier and higher RANTES expression. By contrast, keratinocytes of patients with psoriasis displayed much higher levels of both constitutive and induced IL-8 and a stronger induction of MCP-1 and IP-10. RANTES and MCP-1 mRNA(+) keratinocytes were detected in the basal layer of lesions of patients with AD and psoriasis. IP-10 and IL-8 were consistently upregulated in the epidermis of patients with psoriasis but not in lesions of patients with AD. CONCLUSIONS: Keratinocytes of patients with AD and psoriasis show an intrinsically abnormal and different chemokine production profile and may thus favor the recruitment of distinct leukocyte subsets into the skin.

Cyclosporin A (CyA) reduces sCD30 serum levels in atopic dermatitis: a possible new immune intervention.

Atopic dermatitis (AD) is a chronic inflammatory skin disease frequently associated with asthma, rhinitis, and food allergy. Lymphocytes producing Th2-type cytokines (such as interleukin [IL]-3, IL-4, and IL-5) have been thought to have a key role in the pathogenesis of the disease. We have recently demonstrated that elevated serum levels of the soluble form of CD30 (sCD30), an activation marker of Th2-cell clones, correlates with disease activity in pediatric patients suffering from AD. Clinical trials have demonstrated that cyclosporin A (CyA) treatment resulted in significant improvement of clinical symptoms in patients affected with AD. In this study, we evaluated the role of CyA in modulating sCD30 release in a group of adult patients affected by severe AD treated with CyA at the dosage of 3.5 mg/kg body weight for 12 weeks. Our results demonstrated, in parallel with an improvement of clinical symptoms, a significant reduction of serum levels of both IL-4 and sCD30, thus suggesting that CyA can prevent the activation of Th2 cells observed in AD.

Squamous cell carcinoma-related antigen (SCCr-Ag), sICAM-1 and beta 2-microglobulin are useful markers of disease activity in psoriasis.

Several published studies suggest the involvement of immune and inflammatory factors in psoriasis. We recently demonstrated that the number of circulating ICAM-1 + lymphocytes and the levels beta 2-microglobulin are useful parameters in monitoring the activity of the disease. In this study we investigated serum levels of SCCr-Ag in 24 patients with psoriasis in order to determine whether this antigen is a marker of disease activity. Our results demonstrated high serum levels of SCCr-Ag, IL-2, sIL-2R, sCD4, sCD8, sICAM-1 and beta 2-microglobulin in the acute phase of psoriasis. Furthermore, we found a positive correlation of SCC with TBSA, PASI score, sICAM-1 and beta 2-microglobulin. These data demonstrate that serum levels of SCCr-Ag depend on the severity of the disease and correlate with both immunological and inflammatory markers of disease activity. We suggest that expression of SCCr-Ag may be induced by cytokines in the microenvironment of psoriatic lesions, suggesting that SCC-Ag may play a role in the inflammatory process.

Pigmented purpura-like eruption as cutaneous sign of mycosis fungoides with autoimmune purpura.

We describe the clinical and laboratory findings of a young man with mycosis fungoides. The disease was associated, since the early stages, with autoimmune purpura. Interferon alfa (IFN-alpha) administration improved this patient's condition, both the purpuric eruption and patchy cutaneous lesions, thus suggesting T-cell abnormalities may be responsible for the development of the disease.

The role of proopiomelanocortin-derived peptides in skin fibroblast and mast cell functions.

We have previously described proopiomelanocortin (POMC) gene-expression in human normal cultured dermal fibroblasts, and its dose- and time-dependent modulation by transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha). The aim of the work described here was to investigate POMC-derived peptide release in vitro by cultured fibroblasts following incubation with different concentrations of both TNF-alpha and TGF-beta for 24 hours (1, 5, and 10 ng/ml). The effect of simultaneous addition of both TNF-alpha and TGF-beta (10 ng/ml) was also evaluated. Culture supernatants of human skin fibroblasts were collected to detect adrenocorticotropin hormone (ACTH), alpha-melanotropin (alpha-MSH), and beta-endorphin (beta-EP) levels by specific immunoenzymatic assay. We investigated the in vitro histamine-releasing activity of the POMC-derived peptides, alpha-MSH and beta-EP, on human foreskin mast cells. Detection of cleavage products in supernatants from cultured normal human dermal fibroblasts indicated intracellular processing by POMC protein. We were able to measure detectable levels of all peptides in basal conditions. TNF-alpha addition resulted in an increase in beta-EP and ACTH levels. TGF-beta-stimulated fibroblasts showed no alteration in beta-EP and alpha-MSH levels, whereas ACTH release was significantly enhanced. Both alpha-MSH and beta-EP induced histamine release from human foreskin mast cells in vitro with beta-EP-induced histamine levels as high as those observed with the calcium ionophore, ionomycin. Our data document fibroblast POMC-derived peptide release and modulation by cytokines, suggesting that they have a possible role in extracellular matrix deposit regulation and skin inflammation.