Expression of mast cell tryptase and immunoglobulin E is increased in cutaneous photodamage: implications for carcinogenesis

Purpose: Mast cells, their serine proteinase tryptase, and immunoglobulin E (IgE) can be involved in cutaneous carcinogenesis.Materials and methods: To study the association of tryptase+ and IgE+ cells with photodamage and skin cancers 385 adult patients (201 males, 184 females, 75 with immunosuppression) at risk of any type of skin cancer were examined. Skin biopsies were taken from the sun-protected medial arm and from the photodamaged dorsal forearm skin followed by immunohistochemical staining for tryptase and IgE.Results: The results show that tryptase+ and IgE+ cells are significantly higher in number in the photodamaged than sun-protected skin, both in immunocompetent and -compromised subjects, and there is a strong correlation between tryptase+ and IgE+ cells. The numbers of forearm tryptase+ and especially IgE+ cells associated significantly with the forearm photodamage severity. In the logistic regression analysis, the forearm to upper arm ratio of IgE+ cells produced a univariate odds ratio of 1.521 (p = .010) and a multivariate one of 3.875 (p = .047) for the history of squamous cell carcinoma. The serum level of total IgE correlated significantly to the IgE to tryptase ratio in both skin sites.Conclusions: Therefore, IgE+ mast cells participate in photodamage and carcinogenesis, though it is unclear whether they are tumor-protective or -causative.

Increased expression of complement C3c, iC3b and cells containing CD11b or CD14 in experimentally induced psoriatic lesion

Psoriasis is a chronic inflammatory skin disease with a characteristic isomorphic reaction, i.e., the Köbner reaction, induced by slight epidermal trauma. In this study, the tape-stripping technique was used to induce the development of Köbner reaction in 18 subjects with psoriasis. Eight subjects developed the positive reaction. To study the early cellular changes, skin biopsies were taken at the baseline and subsequent time points of 2 hours, 1 day, 3 days and 7 days for the immunostaining of complement C3c, iC3b, and cells expressing complement receptor 3 (CD11b/CD18; a receptor of iC3b) or CD14. The results show that the positive Köbner reaction associated with rapid (2h-1d) and sustained (3-7d) increase in the expression of epidermal C3c and iC3b and dermal C3c. In addition, there was a positive correlation between CD11b+ and CD14+ cells in baseline and 2h-1d biopsies with a subsequent increase in CD11b+ and CD14+ cells in 3-7d biopsies in the Köbner-positive group. In the Köbner-negative group, only a transient increase in epidermal iC3b at 2h-1d, as well as rapid (2h-1d) and sustained increase (3-7d) in dermal iC3b and CD14+ cells, was observed. In experiments with cultured monolayer keratinocytes, a slight cell damage already at 30 mJ/cm2 ultraviolet B irradiation led to increased expression of C3c, but not iC3b. Therefore, there are marked differences between Köbner groups in respect to the expression of C3c, iC3b and cells expressing CD11b or CD14. Of note is the rapid and sustained increase in epidermal C3c and iC3b in the positive Köbner reaction.

FoxP3-Positive Cells and Their Contacts with Mast Cells Are Highly Increased in Basal Cell Carcinoma

INTRODUCTION

The cells of the immune system are thought to contribute to the development of skin cancers, such as basal cell carcinoma (BCC). One possible mechanism may be the interaction between mast cells and regulatory T cells (Tregs), resulting in immunosuppression.

METHODS

Fresh-frozen biopsies from the lesional and nonlesional skin of 16 patients with BCC were processed for the enzymehistochemical staining of mast cell tryptase, immunohistochemical staining of FoxP3 (a marker of Tregs) as well as for the double-staining method to label tryptase+ cells and FoxP3+ cells on the same cryosection. The cell numbers and apparent morphological contacts (AMCs) between these cell types were counted.

RESULTS

There was a high increase in the number of tryptase+ cells, FoxP3+ cells, and AMCs between them in the lesional compared to corresponding nonlesional skin (p < 0.0001) in all cases.

CONCLUSION

A morphological basis is theoretically present in BCC, suggesting an immune evasive microenvironment.

Survival from cutaneous malignant melanoma is improving, but is it because of a trend in decreasing melanoma thickness or the advent of new 'revolutionary' therapeutics?

Linked Article: Zamagni et al. Br J Dermatol 2022; 187:52–63 .

Case: Unexpected development of severe penicillin allergy and review of literature

A 54-year-old man developed a severe anaphylactic penicillin allergy after 16 years and 5 standard erysipelas treatments by intravenous benzylpenicillin and/or oral phenoxymethylpenicillin without any symptoms of allergy. It is recommended to analyze specific IgE antibodies for phenoxymethylpenicillin, benzylpenicillin, amoxicillin, and cefaclor to select an appropriate antibiotic.

Clinical, patient and estimated cost benefits of proactive management versus reactive management with calcipotriol/betamethasone dipropionate foam for the treatment of plaque psoriasis in Finland

BACKGROUND

Proactive management of plaque psoriasis with twice-weekly topical calcipotriol/betamethasone dipropionate (Cal/BD) foam has a demonstrated clinical benefit in preventing disease relapse compared to reactive management, where Cal/BD foam is only given as rescue therapy once-daily for four weeks after relapse. The impact of proactive management with Cal/BD foam on a wider range of clinical responses is not yet known, nor is its potential cost-effectiveness in the healthcare system of Finland.

METHODS

This study involved a post-hoc analysis exploring the clinical and patient-reported benefits of proactive versus reactive management with Cal/BD foam observed in the PSO-LONG trial (NCT02899962). A range of response criteria based on modified psoriasis area and severity index (mPASI) and dermatology life quality index (DLQI) were analyzed, and the cost-effectiveness of proactive versus reactive management was estimated in a Finnish healthcare setting.

RESULTS AND CONCLUSION

The analysis found a consistent clinical benefit of proactive management compared to reactive management on all response criteria, and a markedly lower cost-per-responder for the response criteria of mPASI 75, mPASI ≤ 2 and DLQ1 ≤ 1. The analysis was robust to sensitivity analyses on key inputs and demonstrates the cost and clinical benefits of proactive over reactive management of plaque psoriasis with Cal/BD foam in the Finnish healthcare setting.

Mast cell chymase is present in uterine cervical carcinoma and it detaches viable and growing cervical squamous carcinoma cells from substratum in vitro

Increased numbers of mast cells is a typical feature of a variety of human cancers. The major mediators in the secretory granules of the MC(TC) type of mast cells, serine proteinases tryptase and chymase, may be involved in squamous cell carcinoma (SCC) lesions by inducing matrix remodeling and epithelial cell detachment. The objective of this study was to analyze immunohistochemically whether MC(TC) mast cells as well as protease inhibitors, squamous cell carcinoma antigens (SCCAs), are present in the uterine cervical SCC. In addition, the effect of tryptase and chymase on uterine cervical SCC cell lines was studied in vitro. Here we report that tryptase- and chymase-positive mast cells are present in significant numbers in the peritumoral stroma of SCC lesions. Also, weak SCCA-2 immunoreactivity is observed in the SCC lesions, but only SCCA-1 in uterine cervical specimens with nonspecific inflammation. In cell cultures, especially chymase, but not tryptase, was shown to induce effective detachment of viable, growing and non-apoptotic SiHa SCC cells from substratum. Chymase also detached viable ME-180 SCC cells from substratum as well as degraded fibronectin. In contrast, normal keratinocytes underwent apoptotic cell death after similar prolonged chymase treatment. No inhibition of chymase was detected by SiHa cell sonicates nor did these cells express marked SCCA immunopositivity. MC(TC) mast cells containing tryptase and chymase are present in the peritumoral stroma of uterine cervical SCC and the malignant cells are only weakly immunoreactive for the chymase inhibitor SCCA-2. It is chymase that appears to be capable of inducing effective detachment of viable and growing SCC cells and therefore, it may release SCC cells from a tumor leading to spreading of malignant cells.

Cervical squamous carcinoma cells are resistant to the combined action of tumor necrosis factor-alpha and histamine whereas normal keratinocytes undergo cytolysis

BACKGROUND

Previous reports showed that mast cells can typically be found in the peritumoral stroma of cervix carcinomas as well as in many other cancers. Both histamine and TNF-alpha are potent preformed mast cell mediators and they can act simultaneously after release from mast cells. Thus, the effect of TNF-alpha and histamine on cervical carcinoma cell lines was studied.

METHODS AND RESULTS

TNF-alpha alone induced slight growth inhibition and cell cycle arrest at G0/G1 phase in SiHa cells, but increased their migration. Histamine alone had no effect on cells. In addition, TNF-alpha and histamine in combination showed no additional effect over that by TNF-alpha alone, although SiHa cells were even pretreated with a protein synthesis inhibitor. Furthermore, TNF-alpha-sensitive ME-180 carcinoma cells were also resistant to the combination effect of TNF-alpha and histamine. In comparison, TNF-alpha or histamine alone induced growth inhibition in a non-cytolytic manner in normal keratinocytes, an effect that was further enhanced to cell cytolysis when both mediators acted in combination. Keratinocytes displayed strong TNF receptor (TNFR) I and II immunoreactivity, whereas SiHa and ME-180 cells did not. Furthermore, cervix carcinoma specimens revealed TNF-alpha immunoreactivity in peritumoral cells and carcinoma cells. However, the immunoreactivity of both TNFRs was less intense in carcinoma cells than that in epithelial cells in cervical specimens with non-specific inflammatory changes.

CONCLUSION

SiHa and ME-180 cells are resistant to the cytolytic effect of TNF-alpha and histamine whereas normal keratinocytes undergo cytolysis, possibly due to the smaller amount of TNFRs in SiHa and ME-180 cells. In the cervix carcinoma, the malignant cells may resist this endogenous cytolytic action and TNF-alpha could even enhance carcinoma cell migration.

Increase in CD30 ligand/CD153 and TNF-alpha expressing mast cells in basal cell carcinoma

Mast cells are a significant source of tumor necrosis factor (TNF) superfamily members, such as TNF-alpha, CD30 ligand/CD153 (CD30L) and CD40L/CD154. Furthermore, the expression of some of these proteins in mast cells has been associated with tumorigenesis, and mast cells have been found to be increased in number in the basal cell carcinoma (BCC) lesion. In this study, we have examined the expression of TNF-alpha, CD30L and CD40L immunoreactivity in mast cells in the healthy-looking skin and lesional skin of ten patients with superficial spreading BCC. Also, the counterparts of these molecules, TNF receptor (TNFR) I and II as well as CD30 and CD40, were analysed immunohistochemically. We found that numbers of mast cells and Kit-positive cells were significantly increased in the dermal BCC lesion. The percentage of CD30L-positive mast cells and the number of CD30-positive cells were significantly increased in the upper dermis of the BCC lesion as well. In addition, the numbers of TNF-alpha-positive mast cells and cells with TNFRI and TNFRII were markedly increased in the upper lesional dermis. In contrast, no mast cells positive for CD40L could be detected, even though the lesional dermis contained increased numbers of CD40 positive cells. The BCC epithelium was positive for TNFRI, TNFRII and CD40, but not for CD30, though the larger basal buds appeared to be less intensely stained for TNFRI and CD40. In conclusion, mast cells positive for CD30L and TNF-alpha, but not CD40L, are increased in number in the lesional dermis in BCC. These data suggest plausible pathways whereby mast cells can be activated and to interact with other cells and thereby contribute to the tumorigenesis in BCC.

The increase in tryptase- and chymase-positive mast cells is associated with partial inactivation of chymase and increase in protease inhibitors in basal cell carcinoma

BACKGROUND

In basal cell carcinoma (BCC), mast cells accumulate in the peritumoral stroma. The serine proteinases tryptase and chymase are the major mediators in mast cell granules and they may exert their enzymatic activity in the BCC lesion by inducing matrix remodeling and epithelial cell detachment.

OBJECTIVE

To analyse the numbers of mast cells showing tryptase enzyme activity, chymase enzyme activity and chymase immunoreactivity as well as the presence of chymase inhibitors alpha(1)-antichymotrypsin (alpha(1)-AC), alpha(1)-proteinase inhibitor (alpha(1)-PI) and squamous cell carcinoma antigen-2 (SCCA-2) in BCC.

METHODS

Eleven biopsies were taken from the lesion and healthy-looking skin of 10 patients with superficial spreading BCC. The frozen biopsies were analysed enzyme- and immunohistochemically, and a sequential double-staining method was applied.

RESULTS

In the BCC lesion, the number of mast cells with tryptase activity and chymase immunoreactivity was significantly increased by 2.2- to 2.3-fold. Practically all tryptase-immunopositive cells contained tryptase activity although occasional tryptase-immunopositive cells (about 1% of total) revealed no activity. However, the ratio of cells with chymase activity to those with chymase immunoreactivity was significantly decreased from 49 +/- 19% in the healthy skin to 33 +/- 19% in the BCC lesion. Instead, the percentage of mast cells displaying alpha(1)-AC or alpha(1)-PI immunoreactivity was significantly increased by 1.7-fold in the BCC lesion. SCCA-2 expression was strongly increased in the malignant BCC epithelium but mostly in the suprabasal layers.

CONCLUSIONS

Tryptase- and chymase-positive mast cells (MC(TC)) increased in the BCC lesion. However, chymase is partially inactivated, possibly by the effective chymase inhibitors alpha(1)-AC and alpha(1)-PI. SCCA-2 increased in BCC, but was localized mostly to the suprabasal layers, and thus it seems not to be crucial in inhibiting chymase.

Patch test reactions to cosmetic allergens in 1995-1997 and 2000-2002 in Finland - a multicentre study

Contact sensitivity to cosmetics is common, but the sensitizing chemicals vary between countries and study periods. The present survey aimed at revealing the recent trends in patch test sensitivity with cosmetic chemicals in Finland. We report a retrospective multicentre survey of patch test reactions focusing on cosmetic-related substances and comparing the test results in 1995-97 with those in 2000-02. The most striking increases in the frequency of the patch test sensitivity were found with balsam of Peru and propolis from 4.0% to 6.2% (P < 0.001) and from 0.5% to 1.4% (P < 0.001), respectively, whereas the most prominent decreases were found with methylchloro/methylisothiazolinone and chlorhexidine diglugonate from 2.4% to 1.3% (P < 0.001) and from 1.2% to 0.5% (P < 0.001), respectively. The level of patch test sensitivity to methyldibromo glutaronitrile increased, although not significantly, from 1.0% to 1.5%. An increasing tendency was also found with hair dye chemicals 4-aminophenol and toluene-2,5-diamine or toluene-2,5-diamine sulfate from 1.3% to 3.8% and from 1.4% to 5.2%, respectively, while such a tendency was not found among permanent wave chemicals. The sensitivity level of fragrance mix remained the same (6% - 7%). We conclude that surveys revealing the state of sensitivity to cosmetic chemicals should be performed periodically in different countries.

Early onset of action and efficacy of a combination of calcipotriene and betamethasone dipropionate in the treatment of psoriasis

BACKGROUND

Calcipotriene and betamethasone dipropionate are topical treatments for psoriasis vulgaris. Their mode of action is different. Improved risk/benefit may result with concomitant use of the two compounds together. A new vehicle has been created with the objective of obtaining optimal stability of both calcipotriene and betamethasone dipropionate in the combination product.

OBJECTIVE

We compared the clinical efficacy of a fixed combination of calcipotriene and betamethasone dipropionate in a new vehicle to calcipotriene in the new vehicle, betamethasone in the new vehicle, and the new vehicle alone.

METHODS

This was an international, multicenter, prospective, randomized, double-blind, parallel-group, 4-week study in patients with psoriasis vulgaris amenable to topical treatment.

RESULTS

The mean percentage reduction in PASI from baseline to end of treatment was 73.2% in the combination group (n = 301), 48.8% in the calcipotriene group (n = 308), 63.1% in the betamethasone dipropionate group (n = 312) and 28.8% in the new vehicle group (n = 107), (P < .001). The mean percentage reduction in PASI during the first week was 48.1%, 28.4%, 41.4%, and 21.5%, respectively (P < .001).

CONCLUSION

A combination product of calcipotriene 50 microg/g and betamethasone dipropionate 0.5 mg/g in the new vehicle shows superior efficacy with a more rapid onset of action than the new vehicle containing either constituent alone in the treatment of psoriasis vulgaris.

The release of histamine is associated with the inactivation of mast cell chymase during immediate allergic wheal reaction in the skin

BACKGROUND

Chymase released by mast cells can participate in the immediate allergic wheal. However, chymase may be susceptible to inactivation by protease inhibitors during degranulation.

OBJECTIVE

To study the inactivation of chymase and the release of histamine in the immediate allergic wheal reaction.

METHODS

Ten sensitive atopic subjects were prick-tested with the cow dander allergen, and skin biopsies were taken from the control skin and from the challenge site at 30 and 120 min. Tryptase (Tact) and chymase (Cact) activities in mast cells were measured enzyme-histochemically. Sequential double-staining was used to demonstrate the activity and immunoreactivity (Cprot) of chymase in the same mast cell as well as alpha1-proteinase inhibitor (alpha1-PI) and alpha1-antichymotrypsin (alpha1-AC) in Tact+ cells. Skin microdialysis was used to monitor histamine release after the allergen challenge for up to 120 min

RESULTS

The numbers of Tact+ and Cact+ cells were already maximally decreased at 30 min by 37 +/- 17% and 61 +/- 31%, respectively (mean +/- SD, P < 0.0001). At the same time the Cact+/Cprot+ ratio decreased from 82 +/- 15% to 43 +/- 16% (P < 0.0001). The cumulative histamine release at 30 min correlated negatively with the Cact+/Tact+ (P = 0.047) and Cact+/Cprot+ (P = 0.024) ratios, but positively with the decrease in the number of Cact+ cells (P = 0.024). These data indicate that the higher the histamine release the lower the chymase activity. Also the number of Tact+ cells in the control skin correlated positively with the cumulative histamine release at 120 min (P = 0.043). In the control skin, 95 +/- 6% and 76 +/- 8% of the Tact+ cells displayed alpha1-AC and alpha1-PI, respectively.

CONCLUSION

In addition to extensive degranulation of mast cells, chymase is also rapidly inactivated after the allergen challenge, possibly by pre-existing chymase inhibitors in the mast cells. This inactivation is associated with the release of histamine.

Release of soluble tryptase but only minor amounts of chymase activity from cutaneous mast cells

Tryptase and chymase are the major serine proteinases of skin mast cells but their biologic significance depends on their activity. In this study, we demonstrate the release of soluble activity of tryptase, but not markedly that of chymase, into skin blister fluids induced by freezing with liquid nitrogen as well as into supernatant during incubation of 8 whole skin specimens with compound 48/80 for up to 2 days followed by sonication. Incubation of 3 other skin specimens in compound 48/80 for up to 2 days revealed that the number of mast cells displaying tryptase activity decreased significantly on day 2, and the number of mast cells showing chymase activity (but not those showing chymase immunoreactivity) decreased significantly on day 1 but not thereafter on day 2. The results of 3 skin organ cultures for up to 14 days showed steady decrease in the number of tryptase-positive cells but persistence of mast cells containing chymase activity. Chymase in solution was sensitively inhibited by 0.01 mg/ml alpha1-antichymotrypsin but higher concentrations (0.3-3.0 mg/ml) were needed for inhibiting chymase on skin sections. In conclusion, after mast cell degranulation tryptase activity is substantially solubilized and it may potentially affect both local and distant skin structures. Instead, chymase is partially inactivated and the remaining chymase activity persists at the site of degranulation having only local effects.

A multicenter study of patch test reactions with dental screening series

BACKGROUND

Dental products contain many allergens, and may cause problems both for patients undergoing dental treatment and for dental personnel because of occupational exposure. Individual patch test clinics may not study sufficient numbers of patients to collect reliable data on uncommon allergens.

OBJECTIVE

To collect information on dental allergens based on a multicenter study.

MATERIALS AND METHODS

The Finnish Contact Dermatitis Group tested more than 4,000 patients (for most allergens, 2,300 to 2,600 patients) with dental screening series. Conventional patch testing was performed. The total number and percentage of irritant (scored as irritant [IR] or doubtful [?]) and allergic (scored as +, ++, or +++) patch test reactions, respectively, were calculated, as well as the highest and lowest percentage of allergic patch test reactions recorded by the different patch test clinics. A reaction index (RI) was calculated, giving information on the irritancy of the patch test substances.

RESULTS

The most frequent allergic patch test reactions were caused by nickel (14.6%), ammoniated mercury (13%), mercury (10.3%), gold (7.7%), benzoic acid (4.3%), palladium (4.2%) and cobalt (4.1%). 2-hydroxyethyl methacrylate (2.8%) provoked most of the reactions caused by (meth)acrylates. Menthol, peppermint oil, ammonium tetrachloroplatinate, and amalgam alloying metals provoked no (neither allergic nor irritant) patch test reactions.

CONCLUSION

Patch testing with allergens in the dental screening series, including (meth)acrylates and mercury, needs to be performed to detect contact allergy to dental products.

Modulation of the immediate allergic wheal reaction in the skin by drugs inhibiting the effects of leukotriene C4 and prostaglandin D2

OBJECTIVE

To study the effect of nordihydroguaiaretic acid (NDGA), zafirlukast and indomethacin on the size of the size of the allergic prick-test wheal.

METHOD

In the first part of the study, NDGA and indomethacin, as well as the mepyramine control (10 micrograms/ml and 100 micrograms/ml), were injected intracutaneously 10 min before prick-testing with the cow dander allergen in 51 sensitised atopic subjects. In the second part, five other subjects were prick-tested with several allergens followed by administration of 40 mg zafirlukast or 100 mg indomethacin and re-prick-testing 2 h or 4 h later.

RESULTS

The intracutaneous indomethacin at both concentrations enlarged the wheal by 27 +/- 50% and 29 +/- 51% (P < 0.02, n = 51), respectively. Likewise, the peroral indomethacin significantly increased the wheal area by 17 +/- 30% (P = 0.035, n = 5). Neither intracutaneous NDGA in 51 subjects nor peroral zafirlukast in 5 subjects had marked effects on the size of the prick-test wheal. As expected, mepyramine (10 micrograms/ml) decreased the wheal area by 33 +/- 32% (P < 0.001, n = 51), but 14 subjects did not show any decrease after administration of this H1-antihistamine.

CONCLUSION

The prostaglandin synthesis inhibitor (indomethacin) augments the prick-test wheal, but the leukotriene synthesis inhibitor (NDGA) and leukotriene C4 antagonist (zafirlukast) have no marked effects on the size of the prick-test wheal.

Interleukin-4-positive mast cells are highly associated with the extent of immediate allergic wheal reaction in the skin

BACKGROUND

In addition to histamine, mast cells contain other potent mediators which can contribute to the allergic wheal reaction in the skin.

METHODS

To study the association of tryptase-, chymase-, and interleukin-4 (IL-4)-positive mast cells with the size of the prick-test wheal reaction, 50 sensitive atopic subjects were prick-tested with the cow-dander allergen on the forearm skin, and the wheal area was measured. A corresponding site of intact healthy-looking skin was biopsied and examined enzyme-histochemically for tryptase and chymase. A double-staining method was used to demonstrate the immunoreactivity of IL-4 and chymase inhibitors (alpha1-proteinase inhibitor and alpha1-antichymotrypsin) in mast cells. The levels of total and cow-specific immunoglobulin E (IgE) were measured in serum.

RESULTS

The number of tryptase- and chymase-positive mast cells or those containing chymase inhibitors revealed no correlation with the wheal reaction. In contrast, both the percentage and the number of IL-4-positive mast cells showed significant positive correlation with the wheal size per se (P<0.0001), as well as with the ratio of the wheal size by cow allergen to that by histamine control (P<0.003). In addition, tryptase-, chymase-, and IL-4-positive mast cells correlated with total IgE, but not with specific IgE, levels, and they showed no relation to the clinical manifestation of atopic disease, asthma or atopic dermatitis.

CONCLUSIONS

The novel finding was that IL-4-positive, but not tryptase- and chymase-positive, mast cells are intimately associated with the extent of the prick-test wheal.

Is Helicobacter pylori infection associated with chronic urticaria?

There have been controversial reports of an elevated prevalence rate of Helicobacter pylori infection in chronic urticaria patients. Furthermore, in some studies remission of chronic urticaria has been reported after eradication of H. pylori. The aim of this investigation was to evaluate the prevalence of H. pylori infection among chronic urticaria patients and to study the effect of eradication therapy on urticaria symptoms. Chronic urticaria patients (n=235) were enrolled and H. pylori status was determined serologically. Thirty-five patients received antimicrobial triple therapy. 25% of the patients were positive for H. pylori. The prevalence of H. pylori infection was not significantly higher among urticaria patients compared with the normal Finnish population in any of the age groups studied. Of the successfully treated patients, 27% showed remission of urticaria. Our data suggest that the prevalence of H. pylori infection is not elevated among chronic urticaria patients and that H. pylori eradication does not appear to influence the course of chronic urticaria.

Alterations in mast cells showing tryptase and chymase activity in epithelializating and chronic wounds

Mast cells can be found in contact with epidermis in certain circumstances; especially in chronic inflammatory skin diseases and chronic ulcers, but the significance of this association is obscure. In this study, the association of mast cells with wound healing was studied by counting mast cells in the wound edges at different stages after wounding the donor site skin for pinch-grafting. Chronic venous leg ulcers were biopsed for comparison. Tryptase- and chymase-positive mast cells were stained enzyme-histochemically for active proteinases. Both the number of tryptase-positive, i.e. total mast cells, and chymase-positive mast cells decreased during wound healing, but only the change in chymase-positive mast cells was statistically significant (P< or =0.03) the maximal decrease being 63% on day 7. No mast cells could be found in the vicinity of epithelialization margin. In venous leg ulcers, significantly more mast cells were present in the perilesional skin near the epithelium margin than in the wound bed (P=0.03), and mast cells were also seen in close contact with the basement membrane. Immunoreactivity for IL-4 and TNF-alpha in mast cells was studied to see if either of these molecules was associated with wound healing. In normally healing wounds, only a minority of mast cells were immunoreactive for these cytokines and no change in positive mast cell numbers could be seen during wound healing. In chronic wounds, IL-4 was absent in mast cells, and TNF-alpha positive mast cells were present only in perilesional skin and in small numbers. These results show that mast cells especially chymase-positive - decrease in number and can not be found in the epithelialization zone in normal wound healing, whereas tryptase-positive mast cells are associated with delayed wound healing and epithelialization in chronic wounds. Thus it seems, that mast cells attempt to control hyperproliferation of epidermis in chronic wounds.

Release of histamine and leukotriene C4 in immediate allergic wheal reaction as measured with the microdialysis technique

Other mediators as well as histamine can contribute to the allergic wheal reaction. In this study, the microdialysis technique was used to monitor the release of histamine, leukotriene C4 (LTC4) and prostaglandin D2 (PGD2) in prick-test wheal reactions induced by cow dander allergen. Of 31 atopic subjects, 25 showed detectable histamine release that correlated significantly with the number of tryptase-positive mast cells and serum cow-specific IgE but not with the wheal size. Detectable LTC4 release was shown by 16 of 18 subjects, but PGD2 release was shown by only 7 of 17 subjects, and neither mediator was associated with tryptase-positive mast cells, IgE levels or wheal size. An inverse association between histamine release and LTC4 release in these 18 subjects was found rather than a direct correlation. With advancing age of the subject histamine release (n = 31) tended to decrease, although insignificantly, but LTC4 release (n = 18) and sensitivity to histamine prick increased significantly, which seemed to parallel the changes in the wheal size induced by cow allergen. In conclusion, the results showed that the release of histamine, LTC4 or PGD2 alone cannot explain the extent of the wheal reaction. In addition, the amount of histamine released was not related to the amount of LTC4 released, but rather an inverse association existed between these mediators.

Focal dermal-epidermal separation and fibronectin cleavage in basement membrane by human mast cell tryptase

Mast cell proteases are believed to participate in the basement membrane destruction in blistering diseases. Thus, normal human skin specimens were incubated with purified human skin tryptase or compound 48/80 (a mast cell degranulator) for up to 24 h. Thereafter, the specimens were studied immunohistochemically. Tryptase caused, in the presence and absence of 1,10-phenanthroline, focal dermal-epidermal separation above laminin and almost complete disappearance of the staining of the extra domain A region of cellular fibronectin in and beneath the basement membrane. The immunopositivity of the cell-binding region of fibronectin, laminin, and collagens IV and VII, however, was unaltered. Compound 48/80 induced almost complete dermal-epidermal separation above intact laminin and only focal reduction in the extra domain A region of cellular fibronectin staining. These alterations by compound 48/80 were prevented partially by Nalpha-p-tosyl-L-lysine chloromethyl ketone or 1,10-phenanthroline alone but completely when both inhibitors were present suggesting the involvement of tryptic serine proteinases, probably also tryptase, and metalloproteinases. Preventive effect of N-tosyl-L-phenylalanine chloromethyl ketone was weak suggesting minor function of chymotryptic serine proteinases. When tryptase was incubated with heparin and pure plasma fibronectin, an abrupt decrease in the adherence of cultured keratinocytes on to plastic surface coated with these substances and a gradual plasma fibronectin cleavage to 173, 161, and 28 kDa fragments in sodium dodecyl sulfate-polyacrylamide gel electrophoresis were found. In conclusion, tryptase can cause focal dermal-epidermal separation above laminin in skin specimens but it is not known to what extent the decreased keratinocyte adherence in vitro and fibronectin cleavage are related to this dermal-epidermal separation.

Mast cells in psoriatic skin are strongly positive for interferon-gamma

The increased number and early activation of cutaneous mast cells is a typical feature of psoriatic inflammation. Interferon-gamma (IFN-gamma) is believed to be one of the important mediators in the cytokine cascade of psoriasis. Human mast cells have been previously reported to release various cytokines upon stimulation including interleukin (IL) -4, IL-5, IL-6, IL-8, IL-13 and tumour necrosis factor-alpha. Here we report that human mast cells synthesize also IFN-gamma at mRNA and protein level and that the number of IFN-gamma producing mast cells is significantly increased in the psoriatic skin. IFN-gamma immunoreactivity in mast cells was demonstrated by staining non-lesional and lesional skin sections from 21 patients with psoriasis. Ten patients with atopic dermatitis (AD) and five healthy persons served as control groups. The percentage (mean +/- SD) of IFN-gamma + mast cells in lesional compared with non-lesional psoriatic skin was 67 +/- 18% vs. 44 +/- 17% (P < 0.0001, paired t-test), respectively, but only 9 +/- 6% vs. 10 +/- 7% in corresponding skin samples of AD. In the skin of healthy controls, only 12 +/- 12% of the mast cells were IFN-gamma +. Using immunoelectron microscopy, we confirmed the ultrastructural localization of IFN-gamma within the granules of mast cells in psoriatic skin. In addition, stimulation of a human mast cell line HMC-1 with phorbol myristate acetate (PMA) (100 nmol/L) for periods of 2-24 h induced expression of IFN-gamma mRNA, which peaked at 24 h. When HMC-1 cells were stimulated with PMA (100 nmol/L) for periods of 0-3 days, the cells released IFN-gamma protein, peaking on day 1. These results provide further evidence for the important role of mast cells in the pathogenesis of psoriasis.

Repeated hand urticaria due to contact with fishfood

BACKGROUND

The etiology of urticaria is often difficult to determine. However, in case of repeated circumstance-connected urticaria, the reason may be easily clarifyable.

CASE

A 51-year-old healthy woman repeatedly experienced occupational hand urticaria when handling fish food. An unexpected reason for the urticaria was found in that the fishfood contained histamine as a "contaminant".

CONCLUSIONS

In fishfood batches, biological degradation can produce histamine and possibly other toxic substances that can lead to occupational health problems.

Quantitative digital image analysis applied to demonstrate the stratified distribution of involucrin in organ cultured human skin

In this study, quantitative digital image analysis was utilized to measure the optical density of immunostains of involucrin at different depths in the epidermis to obtain reliable ordinal-scaled interpretations of the staining intensity. The distribution of involucrin within the epidermis was investigated in air-liquid interface and submerged skin organ cultures at different time-points. A greyscale calibration procedure to standardize the optical units was used. By the 2nd day of culture, staining of involucrin had shifted markedly towards the mid or basal epidermis. Air-liquid interface cultures showed a less intensive shift than the submerged cultures. Up to the 7th day, involucrin staining remained in the upper epidermis in the air-liquid interface cultures, though weak staining was already observed in the basal epidermis. The results suggest that air-liquid interface conditions maintained physiological conditions better than submerged conditions which result in cultures that may have to increase their involucrin synthesis to improve the barrier function against the surrounding liquid during culture. Alternatively, changes in involucrin synthesis could reflect disturbed homeostasis. Concentrating measurements on certain cell layers might give more detailed information about changes in involucrin expression. Although the detection method was used to study the histochemistry of skin, it could easily be applied to other tissues as well.

Decreased chymase activity is associated with increased levels of protease inhibitors in mast cells of psoriatic lesions

Mast cells contain large amounts of the powerful serine proteinases, tryptase and chymase, of which only chymase can be inactivated by serum protease inhibitors. In this study, 20 patients with psoriasis and a control group of 13 with atopic dermatitis were biopsied for lesional and non-lesional skin specimens. The presence of chymase inhibitor alpha 1-proteinase inhibitor (alpha 1-PI), alpha 1-antichymotrypsin (alpha 1-AC), alpha 2-macroglobulin (alpha 2-MG) and C1-esterase inhibitor (C1-Inh) immunoreactivity in mast cells was verified using the sequential double-staining method. Tryptase- and chymase-positive mast cells were stained enzyme-histochemically. Tryptase-positive mast cells were increased in number in the upper dermis of the psoriatic lesion compared with lesion-free psoriatic skin (308 +/- 109 vs. 100 +/- 29 cells/mm2, respectively, mean +/- SD, p < 0.0005, t-test) while the percentage of mast cells showing chymase activity was decreased (76.8 +/- 22.1% vs. 28.6 +/- 14.4%, p < 0.0005). These findings are consistent with our previous ones. In contrast to the decreased percentage of chymase-positive mast cells, a novel finding was that the percentages of alpha 1-AC+ (86.9 +/- 7.2% vs. 59.5 +/- 12.6%, p < 0.0005), alpha 1-PI+ (72.2 +/- 14.9% vs. 33.4 +/- 18.6%, p < 0.0005) and alpha 2-MG+ (16.8 +/- 7.0% vs. 6.2 +/- 3.5%, p < 0.002) mast cells were significantly higher in the psoriatic lesion with the exception of the percentage of C1-Inh+ mast cells (13.7 +/- 10.0% vs. 11.0 +/- 6.1%, p < 0.7). The localization of these inhibitors in mast cells is not a characteristic feature of psoriasis, since mast cells in atopic dermatitis skin also showed immunoreactivity though in slightly lower percentages. Previously, we have shown that MCTC (tryptase+, chymase+) mast cells increase in number in the psoriatic lesion but chymase becomes inactive. The results of this study show again the decreased chymase activity, which could be due to increased levels of its inhibitors (alpha 1-AC, alpha 1-PI and alpha 2-MG) in the same mast cells. Thus, active tryptase could promote inflammation but chymase seems not to be an important mediator in the pathomechanism of psoriasis.

Identification and characterization of multiple forms of tryptase from human mast cells

Mast cell tryptase purified from human adult skin (AS), adult lung (AL) and newborn foreskin (NS) with a monoclonal antitryptase B2 immunoaffinity Sepharose column was further fractionated by HPLC using a Mono-S cation exchange column at pH 6.5. Tryptases exhibited two clearly separated major fractions, both of which also revealed at least two overlapping peaks. Native tryptase molecules from skin consisted of two diffuse protein bands in SDS-PAGE at about 31 and 35 kDa, whereas those from lung usually exhibited a predominant diffuse band at about 29 kDa. The forms of tryptases separated by Mono-S HPLC gave a different banding pattern in SDS-PAGE. Tryptase from NS exhibited chromatographic peaks that each showed Mr values approximately 1-3 kDa higher than those of tryptase from AS. By gel filtration, the Mr values for native major fractions of tryptases derived from AS and AL were 178 kDa and 141 kDa, respectively. After carbohydrate removal by glycanase, the observed differences in Mr values in SDS-PAGE reduced to two similar sharp bands of Mr approximately 28 kDa and 30 kDa for all tryptase preparations. AS and AL tryptases and their subfractions exhibited similar enzyme kinetic values and similar immunoreactivities in a tryptase immunoassay. Inactivation rates at physiologic ionic strength were similar for both AL and AS tryptases. The results show the enzymatic and antigenic similarity between lung and skin tryptases, and suggest that tryptase is stored mainly as beta-tryptase in human mast cells. Tryptase immunoassay measures similarly both lung and skin tryptases and, thus, this assay is suitable for detection of mast cell activation, in contrast to assays for other proteinases of mast cells, e.g. chymase, cathepsin G and carboxypeptidase, that are present in MC(TC) cells mainly in skin only.

Association of psychic stress with clinical severity and symptoms of psoriatic patients

The association of stress with psoriatic skin and joint symptoms was studied in 38 patients with psoriasis by dividing the patients into low-stress and high-stress groups based on their answers to four questionnaires (General health questionnaire, Somatization questionnaire, Depression questionnaire, and Life change questionnaire), measuring minor psychiatric disorder, psychosomatic reactivity, depression and life changes, respectively. Compared to the low-stress group (n = 21), the patients in the high-stress group (n = 17) had more severe skin and joint symptoms and a higher score, which in established psoriatic General severity score that was calculated by judging Psoriasis Area and Severity Index, activity of psoriasis and the presence of joint symptoms. All the four questionnaires showed higher morbidity frequency and higher score points. Actively spreading psoriasis was significantly associated with stressful life events for men but not for women. However, in the low-stress group, men had experienced significantly fewer stressful events than women. Psoriasis Area and Severity Index showed strong correlation with the Somatization score, but no differences between men and women. The General severity score correlated with the Somatization score, and the higher the General severity score (score > or = 6) the higher were all the four questionnaire scores. Also, patients having joint symptoms had higher scores in all of the four psychic questionnaires than patients without joint symptoms. By the chi-test, female patients with joint symptoms showed a significant correlation with the high General health questionnaire. The presence of joint symptoms showed a tendency for correlation in women with high depression level and in men with high somatization level. This study suggests that psychic stress is associated with exacerbation of psoriasis, and more attention to mental well-being should be paid at least in the case of those psoriatic patients seeking actively for medical care.

Quantitative histochemical analysis of mast cells and sensory nerves in psoriatic skin

To study the elements of neurogenic inflammation in psoriatic skin, morphological contacts were examined between mast cells and sensory nerves containing the neuropeptides substance P (SP), calcitonin gene-related peptide (CGRP) or vasoactive intestinal polypeptide (VIP). Because mast cells in psoriatic lesions appear in great numbers at the basement membrane (BM) zone, neuropeptide-mast cell contacts with the BM were also counted. A double stain for active mast cell tryptase and the neuropeptides was applied and the contacts were quantitated morphometrically. Sensory nerve-mast cell contacts were also studied three-dimensionally with a confocal laser scanning microscope. Increases in the contact values of SP and CGRP with mast cells, as well as with the BM, were obtained in developing (1-3 weeks) lesions when compared with their non-lesional controls. This increase reached statistical significance in mature lesions. In contrast, the corresponding contact values for VIP were decreased. By confocal microscopy, a close association between mast cells and sensory nerves was observed in the lesional dermis. Since tryptase is known to degrade CGRP but not SP, neurogenic stimuli, mainly via SP, can result in degranulation of mast cells, which release substances to enhance inflammation. At the BM zone in psoriatic lesions, the numerous mast cells loaded with tryptase can promote degradation of BM components and allow entry of various mediators to interact with keratinocytes.

Histamine and leukotriene C4 release in cutaneous mosquito-bite reactions

BACKGROUND

Mosquito bites are known to sensitize persons, and the most common cutaneous reactions are immediate wheals and delayed bite papules. Anti-saliva IgE and IgG4 antibodies are common in mosquito-sensitive subjects, but mediator release in bite reactions is not known.

METHODS

We used the microdialysis technique to measure in vivo histamine and leukotriene C4 release after bite challenges in six mosquito-sensitive subjects. One individual who was not sensitive to bites volunteered as a control subject.

RESULTS

Three of the six mosquito-sensitive subjects had large wheals and showed clearly increased histamine concentrations 30 to 45 minutes after the bites. The histamine levels declined to baseline value within 2 hours; thereafter, one subject showed a second increase in histamine concentration. Four of the six mosquito-sensitive subjects showed increased leukotriene C4 concentrations, and this mediator seemed to be released somewhat later than histamine.

CONCLUSIONS

The increased histamine and leukotriene C4 release observed in this study suggests that both mediators are involved in the early allergic response caused by mosquito bites.

Neuropeptide- and capsaicin-induced histamine release in skin monitored with the microdialysis technique

Mast cells are thought to be involved in neurogenic inflammation in skin, and numerous neuropeptides are known to degranulate mast cells. We monitored histamine release in skin in situ with the microdialysis method after skin challenge with neuropeptide injections (10 microM substance P, vasoactive intestinal peptide and calcitonin gene-related peptide), capsaicin injection (30 microM) and 0.1% capsaicin cream with a moist compress. Fractions were collected for 15 min each at 3.0 microliter/min. One hour after insertion of the probe, the baseline histamine level was 4.5 +/- 4.5 nM (mean +/- SD, n = 20). Substance P (250 pmol) induced histamine release peak (66.1 +/- 52.5 nM, n = 8) in the 0-15 or 15-30 min fraction. Thereafter, the histamine concentration declined steadily and rapidly and no second rise was observed. A single substance P injection was sufficient to induce major histamine release in three out of four experiments; and the release kinetics of the second injection (1 h later) mimicked that of the first injection. Vasoactive intestinal peptide (100 and 250 pmol) induced a rapid release of histamine in 4 subjects comparable to substance P, whereas calcitonin gene-related peptide (250 pmol) did not release detectable amounts of histamine in 2 subjects tested. Capsaicin induced a low and rather non-significant release of histamine in 4 out of 5 patients who received capsaicin injection and in 2 out of 5 who were treated with capsaicin cream. The present study shows that neuropeptides substance P and vasoactive intestinal peptide, but not calcitonin gene-related peptide, can induce activation of mast cells and release of histamine into the extracellular space. The low release of histamine by capsaicin suggests low levels of neuropeptides or infrequent morphological contacts between mast cells and sensory nerves in normal human skin. The microdialysis method can be used for studying skin inflammatory reactions involving mast cells.

Histamine release in skin monitored with the microdialysis technique does not correlate with the weal size induced by cow allergen

The purpose of this study was to monitor histamine release in immediate-type hypersensitivity reactions in the skin of 10 atopic patients, sensitive to cow, by using the microdialysis technique. Three healthy subjects, without any atopic features or background, served as the control group. The probe inserted into the forearm dermal skin was perfused with isotonic saline solution. Samples were collected at 15-min intervals. After the first allergen challenge of four prick tests close to the probe with cow allergen extract, the skin was similarly repricked again in five patients and three healthy subjects, and in five other patients, 25 microliters of 10 mumol/l substance P (SP) was injected intracutaneously. The samples were analysed for histamine by radioenzyme assay. The patients were clinically evaluated for allergic symptoms, prick- and scratch-patch test reactivity and for serum cow-specific, and total, IgE levels. The baseline histamine concentration was 7.5 +/- 4.0 nmol/l (mean +/- standard deviation: SD; n = 10). After the allergen challenge, the histamine concentration in the consecutive samples was 11.9 +/- 11.0 nmol/l, 91.1 +/- 127.3 nmol/l, 61.0 +/- 94.2 nmol/l and 33.7 +/- 53.7 nmol/l. The peak concentration was detected in the 15-30 min fraction, and it varied between 0 and 406 nmol/l regardless of the weal size. The second allergen challenge was unable to induce marked additional histamine release, but SP induced extensive histamine liberation in those patients who did not exhibit histamine release during the preceding prick tests. In three healthy subjects, the baseline histamine concentration was 6.2 +/- 3.9 nmol/l. After the allergen challenge, no additional histamine liberation could be measured. Surprisingly, the histamine release was not related to the size of the cow-induced weal nor was it related to any specific allergic symptoms or IgE levels. The results suggest that, in some patients, mast cell mediators other than histamine play a significant part in immediate-type allergic reactions of skin.

Mast cells are one major source of interleukin-4 in atopic dermatitis

Several reports have shown the presence of T-helper lymphocytes with Th2 characteristics in the skin lesions of atopic dermatitis (AD). However, Th2 cells themselves require an exogenous pulse of IL-4 to initiate their differentiation and synthesis of IL-4. As mast cells have recently been shown to contain IL-4, this finding prompted us to investigate IL-4 in mast cells of AD lesions, to determine if they might provide the IL-4 pulse needed by the Th2 cells. In this study, we measured IL-4 immunoreactivity in mast cells of non-lesional and lesional skin sections from 20 patients with AD. Ten patients with nummular eczema (NE) without any atopic features or background, and five healthy subjects, served as the control groups. Mast cells were first identified using an enzyme--histochemical staining method for tryptase. Subsequently, the sections were photographed, the tryptase stain was removed, and IL-4 was demonstrated with a polyclonal antibody. The sections were photographed again, and the percentage of IL-4 positive mast cells was calculated. The percentage of mast cells exhibiting IL-4 immunoreactivity in the upper dermis in lesional vs. non-lesional skin was 66 +/- 18% vs. 37 +/- 18% in AD (P < 0.0001, paired t-test), but only 46 +/- 19% vs. 31 +/- 22% in NE. In the skin of healthy controls, only 23 +/- 25% of the mast cells were positive for IL-4. In addition, a significant difference was found between lesional skin of AD vs. NE patients (P < 0.008, unpaired t-test).(ABSTRACT TRUNCATED AT 250 WORDS)

Separation and partial characterization of proteinases with substrate specificity for basic amino acids from human MOLT-4 T lymphocytes: identification of those inhibited by variable-loop-V3 peptides of HIV-1 (human immunodeficiency virus-1) envelope glycoprotein

The V3 loop of the HIV (human immunodeficiency virus)-1 envelope glycoprotein gp120 likely plays a role in HIV-1 infectivity. Although the amino acid sequence of the V3 loop is hypervariable, it contains a conserved region, Gly-Pro-Gly-Arg, that shows similarity to the active-site Gly-Pro-Cys-Arg sequence of inter-alpha-trypsin and trypstatin proteinase inhibitors. The purpose of the present work was to identify proteinases recognizing substrates with basic amino acids in the P1 substrate site that are present in MOLT-4 cells, a human CD4-positive T helper lymphocyte cell line, and to characterize these enzymes in terms of substrate, pH and ionic-strength preferences, size and susceptibility to various inhibitors, including 24- and 36-amino-acid-long V3 loop peptides. Extraction of MOLT-4 cells at low ionic strength solubilized nearly all of the trypsin-like activity, which was separable into five peaks of activity by chromatography on Mono-Q: Peaks 1, 2a, 2b, 3 and 4. All showed a neutral pH optimum, and all except Peak 4 showed optimal activity at high ionic strength. Peak 1 preferred Tos-Gly-Pro-Arg, p-nitroanilide (-pNA) substrate; Peaks 2-4 preferred benzyloxycarbonyl-Val-Leu-Gly-Arg-pNA. Peak 1, a zinc-dependent enzyme with serine and histidine in the active site, exhibited an M(r) of 75,000 on Superose 12 and was poorly inhibited by V3 loop peptides. Peak 2 contained two overlapping peaks, called 2a and 2b, that exhibited properties of zinc-dependent metalloproteinases. Gel filtration of Peak 2 activities revealed a major peak of activity at 81 kDa and a shoulder centred at 240 kDa. Each was modestly inhibited by V3 loop peptides. Peak 3, a zinc-dependent proteinase, exhibited a molecular mass of 100 kDa by gel filtration and was particularly sensitive to inhibition by V3 loop peptides. Peak 4 exhibited a molecular mass of 1100 kDa by gel filtration and was not inhibited by V3 loop peptides. None of these enzymes could be classified as mast-cell tryptase, and material in MOLT-4 cells cross-reactive with anti-(human tryptase) antibodies was not detected. Whether any of the MOLT-4 proteinases described in this study play a role in HIV-1 infectivity remains to be examined.

Mast cell tryptase and chymase in developing and mature psoriatic lesions

The number and distribution of mast cells in non-lesional and lesional skin samples from 13 psoriatic patients were analyzed enzyme- and immunohistochemically. Mast cell tryptase was stained with the sensitive substrate Z-Gly-Pro-Arg-4-methoxy-2-naphthylamide, and chymase with Suc-Val-Pro-Phe-MNA and monoclonal B7 anti-chymase antibody. In addition, healthy-looking skin from 27 psoriatic patients was tape-stripped resulting in induction of the Köbner response in 9 patients. Sequential biopsies were taken before and after (7, 14 and 21 days) tape-stripping, and both tryptase and chymase were stained enzyme-histochemically. In non-lesional psoriatic skin, 70 +/- 24% (mean +/- SD) of the mast cells contained chymase enzyme activity, and 78 +/- 18% chymase immunoreactivity. About 10% of the chymase-immunoreactive cells lacked chymase activity. In lesional psoriatic skin, tryptase-positive cells were increased in number throughout the dermis but especially beneath the epidermis. Chymase immunoreactivity paralleled the tryptase activity, whereas chymase activity was strongly diminished both in terms of mast cell numbers and in staining intensity in the papillary dermis. The apparent inactivation of chymase may be due to the action of the chymase inhibitors, alpha 1-antitrypsin and alpha 1-antichymotrypsin, localized immunohistochemically in mast cells of lesional and non-lesional psoriatic skin. In the developing psoriatic lesion, mast cells displaying chymase activity were already 27-38% decreased in number in the upper dermis on day 7 after tape-stripping, along with the first clinical signs of psoriasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Screening of effects of selenomethionine-enriched yeast supplementation on various immunological and chemical parameters of skin and blood in psoriatic patients

Selenium (Se) is known to affect the immune system, and decreased Se-levels in blood of patients with moderate or severe psoriasis have been reported. In this study, the effect of Se-supplementation (400 micrograms/day for 6 weeks as Se-yeast, containing about 70% selenomethionine, SeMet) on skin and blood Se-content, on skin glutathione peroxidase activity and on various chemical and immunological parameters of blood and skin was investigated in 7 psoriatic patients. Before the SeMet-supplementation, serum and blood Se-levels were at the normal range, but they increased 42-45% during the Se-dosage, while zinc levels remained unchanged. Se-dependent glutathione peroxidase activity in both normal and lesional psoriatic skin remained unchanged during the trial, although a small net Se-uptake was detected. At the same time, a slight but statistically significant increase in the number of CD4+ T-cells was observed in the reticular dermis of the psoriatic lesions whereas the numbers of CD8+, CD11c+, and CD1+ cells were not significantly altered. Also, a relatively high number of patients (3 out of 7) showed a strongly reduced number of gamma/delta T-lymphocytes or increased CD8+ T-cells (2 patients) in peripheral blood. However, SeMet-supplementation was not related to these abnormalities or to the number of other peripheral blood immunocytes or to serum immunoglobulin levels. In addition, no marked effect on the clinical condition of the patients was observed. This pilot study suggests that SeMet may be able to modulate the immunological mechanism of psoriatic lesions by increasing the number of CD4+ T-cells.

Association of cutaneous mast cells and sensory nerves with psychic stress in psoriasis

Association of stress with psoriatic skin symptoms was studied in 13 patients with psoriasis by dividing the patients into low- and high-stress groups based on their clinical examination and answers to three questionnaires (General Health Questionnaire, a somatization scale, and a life change questionnaire). This study focused on skin mast cells and sensory nerves which are the principal components in neurogenic inflammation. Mast cells were stained enzyme-histochemically for tryptase and chymase, and neuropeptides substance P (SP), vasoactive intestinal peptide (VIP), and calcitonin gene-related peptide (CGRP) were demonstrated immunohistochemically. Compared to the low-stress group (n = 7), the patients in the high-stress group (n = 6) had more severe skin and joint symptoms. Furthermore, mast cells positive for chymase activity were prominently reduced, but tryptase-positive mast cells only slightly decreased in the lesional skin of the high-stress group. A similar tendency was also observed in the nonlesional skin. In the papillary dermis of the lesional skin, both VIP- and CGRP-immunoreactive nerves could be observed in the high-stress group whereas in the low-stress group these nerve fibers were hardly visible in the corresponding area. No association of SP with stress was observed. This study suggests that psychic stress is associated with exacerbation of psoriasis, and stress may induce alterations in the psoriatic lesions by increasing the neuropeptide content with a concomitant decrease in the activity of neuropeptide-degrading enzymes, especially mast cell chymase.

Quantitative analysis of contact sites between mast cells and sensory nerves in cutaneous psoriasis and lichen planus based on a histochemical double staining technique

The aim of the present study was to test further our previous hypothesis that the inflammatory reaction in psoriasis is neurogenic. For this purpose, contact sites between mast cells and sensory nerves were morphometrically analysed in the basement membrane zone, papillary dermis and three dermal zones of lesional/non-lesional psoriatic and lichen planus skin as well as in healthy control skin. The analyses were made on sections stained with a histochemical double stain developed for this study. With the double stain, active mast cell tryptase was stained blue enzyme histochemically, and the sensory nerves black using specific monoclonal anti-neurofilament antibodies with immunogold. In psoriatic lesions, both mast cells and mast cell--nerve contacts were markedly more frequent in the basement membrane zone and in the papillary dermis when compared with the corresponding areas in the other groups. Mast cell numbers were increased in both lesional and symptom-free skin in lichen planus, but no increase was found in the mast cell--nerve contacts. Increased contacts between mast cells and sensory nerves indicate that the elements exist for neurogenic inflammation in psoriatic lesions. These increased contacts are not due to the extensive inflammatory reaction only, because they were not observed in lichen planus lesions.

Metabolism, cellular actions, and cytotoxicity of selenomethionine in cultured cells

Selenomethionine metabolism and the biochemical basis for its cytotoxicity were analyzed in cultured human and murine lymphoid cells. The metabolic pathways were also addressed, using purified mammalian enzymes and crude tissue extracts. Selenomethionine was found to be effectively metabolized to S-adenosylmethionine analog, and that analog was further metabolized in transmethylation reactions and in polyamine synthesis, similarly to the corresponding sulphur metabolites of methionine. Selenomethionine did not block these pathways, nor was there a specific block on the synthesis of DNA, RNA, or proteins when added to the culture medium. Selenomethionine showed cytotoxicity at above 40 microM levels. Yet, low selenomethionine levels (10 microM) could replace methionine and support cell growth in the absence of methionine. Selenomethionine toxicity took place concomitantly with changes in S-adenosylmethionine pools. D-form was less cytotoxic than L-form. Methionine concentration modified the cytotoxicity. Together, this indicates that selenomethionine uptake and enzymic metabolism are involved in the cytotoxicity in a yet unknown way.

Quantitative enzyme-histochemical analysis of tryptase- and chymase-containing mast cells in psoriatic skin

Tryptase-containing mast cells have recently been found to be increased in the upper dermis of psoriatic lesions. In the present study, the distribution of chymase- and tryptase-containing mast cells was morphometrically analysed at different dermal levels of lesional and non-lesional psoriatic skin (12 patients) as well as normal human skin. Mast cell tryptase was identified enzyme-histochemically, using Z-Gly-Pro-Arg-MNA as the substrate. For demonstrating mast cell chymase, a simple and specific enzyme-histochemical staining method was developed, using Suc-Val-Pro-Phe-MNA as the substrate. All mast cells positive for chymase were also positive for tryptase and Giemsa stain. Although the number of tryptase-positive mast cells was slightly increased throughout the dermis of lesional psoriatic skin, this increase was most pronounced in the upper dermis immediately beneath, and in close contact with, the epidermis. In contrast, the number of chymase-positive mast cells was clearly decreased in the upper dermis of psoriatic lesions, but not in the deeper dermis, as compared with non-lesional psoriatic skin. In addition, all chymase-positive mast cells observed in the upper dermis were very weakly stained when compared with those in the deeper dermis. No differences were found between non-lesional psoriatic skin and normal skin in which the number of mast cells containing chymase was 72-73% of the number containing tryptase. The present results suggest that T mast cells particularly, containing tryptase but no chymase, proliferate in psoriatic lesions, and that the increase in tryptase activity and the decrease in chymase activity in the upper dermis may lead to an imbalance in the biochemical regulatory systems.

Effects of selenomethionine on cell growth and on S-adenosylmethionine metabolism in cultured malignant cells

The effects of selenomethionine (SeMet) on the growth of 17 cultured cell lines were studied. SeMet in the culture medium of three hepatoma cell lines promoted cell growth at subcytotoxic levels (1-20 microM), but the growth of malignant lymphoid and myeloid cells was not stimulated. L-SeMet was cytotoxic to all 17 cell lines when assayed after culture for 3-10 days. A 50% growth inhibition was observed by 30-160 microM-SeMet in a culture medium containing 100 microM-methionine. SeMet cytotoxicity to normal (fibroblasts) and malignant cells was rather similar, excluding specific antineoplastic cytotoxicity. Cytotoxicity was increased by decreasing concentrations of methionine. The DL form of SeMet was less cytotoxic than the L form. L-SeMet was metabolized to a selenium analogue of S-adenosylmethionine approximately as effectively as the natural sulphur analogue methionine in malignant R1.1 lymphoblasts. Concomitantly, S-adenosylmethionine pools were decreased. This occurred early and at cytotoxic SeMet levels. Methionine adenosyltransferase activity was not altered by SeMet treatment. ATP pools were not affected early, and decreases in the synthesis of DNA and protein took place late and were apparently related to cell death. RNA synthesis was slightly stimulated at low cytotoxic SeMet levels by 24 h, but was markedly inhibited after 48 h. The SeMet analogue of S-adenosylmethionine could be effectively utilized in a specific enzymic transmethylation. Neither S-adenosylhomocysteine nor its selenium analogue accumulated in the treated cells. These findings together suggest a direct or indirect involvement of S-adenosylmethionine metabolism in SeMet cytotoxicity, but exclude a gross blockage of transmethylations.

Enzyme- and immunohistochemical localization of mast cell tryptase in psoriatic skin

The localization of mast cell tryptase in involved and noninvolved skin sections from 12 psoriatic patients was investigated using both enzyme- and immunohistochemical staining techniques. Each involved skin section contained an increased number of tryptase-positive mast cells in the superficial dermis as compared with corresponding noninvolved skin sections. The substrate-hydrolyzing and inhibition properties for tryptase activity in involved and non-involved psoriatic skin sections were identical with each other as well as with those previously described in normal human skin or mastocytoma skin sections. In four patients, epidermal enzyme activity was observed, but only in the involved skin. None of the uninvolved sections showed tryptase activity in the epidermis. This activity was not inhibited by alpha 1-antitrypsin, and after removing the enzyme-histochemical stain with Tween 20, positive results obtained with tryptase-specific antibody were found in the same locations. In addition, tryptase-positive cells were detected in close contact to lesional epidermis, but without epidermal staining in four patients. In the epidermis, the positive staining was granular, and active tryptase was detected as far as the stratum corneum. This study is the first description of the presence of active mast cell tryptase in psoriatic epidermis, where this enzyme may have a role in increased cell division.

Biochemical and histochemical evaluation of tryptase in various human tissues

The distribution of tryptase in various human tissue high-salt extracts (skin, lung, pancreas, liver, kidney, and spleen) was studied. Tryptase activity was compared with tissue histamine concentration, chymase activity, and cathepsin D, and histamine-N-methyltransferase (HMT) activities. Tryptase activity, found biochemically in tissue extracts, was localized in tissue sections by an enzyme-histochemical method using peptide 4-methoxy-2-naphthylamide substrates and Fast Garnet GBC as the chromogen. The highest levels of tryptase activity were found in lung and skin extracts. Liver, kidney, and spleen extracts displayed only a little activity. The distribution of histamine was similar to that of tryptase, whereas distributions of cathepsin D and HMT were quite different from that of tryptase. High-salt extracts of lung contained no detectable chymase activity, but in skin extracts this activity was high. Using an enzyme-histochemical method, the tryptase activity in tissue sections seemed solely to be confined to cells, which were granular and Giemsa positive after the red azo dye had been removed with Tween 20. Skin and lung sections contained the highest number of positively stained cells. The inhibition properties of tryptase, found in both tissue extracts and sections, and the substrate profile in tissue sections were identical. Human leukocyte preparation was negative for tryptase when stained enzyme-histochemically. The present results suggest that tryptase in human tissues is found only in the mast cells. The enzyme seems to be identical in the various human tissues studied because the different high-salt extracts were immunologically cross-reactive when tested with a rabbit polyclonal antibody against skin tryptase.

Synthesis and analysis of selenomethionine metabolites

This paper describes the enzymatic synthesis of selenomethionine metabolites of the transmethylation and polyamine synthesis pathways: adenosylselenomethionine, adenosylselenohomocysteine, decarboxylated adenosylselenomethionine, and methylselenoadenosine. These compounds and the corresponding methionine metabolites were simultaneously separated by a single HPLC run. The sensitivity of the HPLC method is about 20 pmol per compound. The method may be used for direct analysis of the metabolite levels in tissues or cells treated with selenomethionine and it provides an assay method for the pulse-chase type of analysis of relative flows for both selenium- and sulfur-containing compounds in transmethylation and polyamine pathways.