benzofurans and Dermatitis--Contact

Regulatory T (Treg) cells suppress contact hypersensitivity (CHS) responses, but the dynamics, mode, and site of their action is not well characterized. We studied forkhead box P3+ (Foxp3+) Treg cells during the CHS response in conditional Foxp3 knockout depletion of regulatory T cell (DEREG) mice, where Foxp3+ cells can be transiently deleted by diphtheria toxin. The mice were sensitized and challenged with oxazolone, and Foxp3+ cells were depleted either during sensitization or elicitation. Treg cell depletion before sensitization led to significantly exacerbated and prolonged CHS responses. In contrast, depleting Treg cells during elicitation had no effect on the 24-hour response, but the response was significantly prolonged. In wild-type mice, the gradual resolution of the CHS response was accompanied by a similarly gradual accumulation of Foxp3+ Treg cells relative to T effector cells in the skin. This effect was not as marked in the Treg cell-depleted mice, suggesting that the skin is an important site of Treg cell activities during the resolution phase. Together, our results show that endogenous Foxp3+ Treg cell function is important during the sensitization and resolution phases, but their depletion just before elicitation does not have an effect on the CHS response during the first 24 hours after elicitation.

Topics: Animals; B7-1 Antigen; B7-2 Antigen; Benzofurans; Biomarkers; CD11c Antigen; Cell Proliferation; Dendritic Cells; Dermatitis, Contact; Diphtheria Toxin; Disease Models, Animal; Forkhead Transcription Factors; Immune Tolerance; Immunophenotyping; Lymphocyte Depletion; Mice; Quinolines; RNA, Messenger; T-Lymphocytes, Regulatory

1-methylnicotinamide (MNA) displays anti-inflammatory effects in patients with contact dermatitis, though the mechanisms involved remain unknown. Herein, we examined the anti-inflammatory effects of MNA and its parent molecule, nicotinamide, in the contact hypersensitivity reaction to oxazolone in CBA/J inbred mice. Feeding mice with MNA or nicotinamide (100 mg/kg, 10 days) resulted in the inhibition of the development of contact hypersensitivity reaction by 37% and 35%, respectively, as assessed by the magnitude of ear swelling. This effect was not associated with changes in the expression of adhesion molecules (CD49d(+) and CD54(+)) on CD4(+) and CD8(+) oxazolone-specific T lymphocytes, the major cell component of an inflammatory infiltrate in contact hypersensitivity reaction. Furthermore, in the adoptive transfer model of contact hypersensitivity reaction, pretreatment of mice (recipients of oxazolone-specific T cells), with MNA, resulted in a remarkable anti-inflammatory effect (inhibition of contact hypersensitivity reaction by 66%). Interestingly, in the presence of prostanoid IP receptor antagonist R-3-(4-fluoro-phenyl)-2-[5-(4-fluoro-phenyl)-benzofuran-2-ylmethoxycarbonylamino]-propionic acid (RO-3244794) (10 mg/kg) the MNA was inactive. In summary, pretreatment with MNA profoundly attenuated contact hypersensitivity reaction in vivo. In particular, the vessel dependent phase of contact hypersensitivity reaction was affected, in spite of the fact that MNA did not alter the expression of adhesive molecules on oxazolone-specific T lymphocytes. However, the anti-inflammatory action of MNA was completely reversed by the antagonist of prostanoid IP receptor. Accordingly, our results demonstrate for the first time that anti-inflammatory properties of MNA are linked to endothelial, PGI(2)-mediated mechanisms.

Topics: Adoptive Transfer; Animals; Anti-Inflammatory Agents; Benzofurans; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Dermatitis, Contact; Dermatologic Agents; Disease Models, Animal; Endothelium, Vascular; Epoprostenol; Integrin alpha4; Intercellular Adhesion Molecule-1; Male; Mice; Niacinamide; Oxazolone; Propionates; Receptors, Epoprostenol; Receptors, Prostaglandin; Skin

A 30-year-old pharmacist suffered from acute allergic contact dermatitis due to 4-chloro-7-nitrobenzofurazan (NBD-Cl). Contact allergy towards this reagent and 2 of its reaction products was proven by patch tests. As NBD-Cl has not been reported as an allergen before, the characteristics of this chemical and its use as an analytical reagent are briefly surveyed. Similarities to dinitrochlorobenzene (DNCB) are pointed out.

Topics: Acute Disease; Adult; Benzofurans; Dermatitis, Contact; Dermatitis, Occupational; Female; Humans; Praziquantel

Topics: Benzofurans; Deodorants; Dermatitis, Contact; Female; Humans; Patch Tests

Topics: Adult; Benzofurans; Dermatitis, Contact; Female; Flavonoids; Hand Dermatoses; Humans; Inula; Lactones; Patch Tests; Plant Extracts; Sesquiterpenes; Sesquiterpenes, Eudesmane; Skin Diseases, Vesiculobullous

Allergic contact dermatitis is essentially enantiospecific: sensitization to one enantiomer generally does not imply elicitation to the mirror-image allergens. Examples from patients allergic to Frullania, and from the literature (usnic acids, 4-methoxydalbergiones, gamma-methyl-alpha-methylene-gamma-butyrolactones, frullanolides) are discussed.

Topics: 4-Butyrolactone; Animals; Benzofurans; Benzoquinones; Dermatitis, Contact; Guinea Pigs; Humans; Plants; Quinones; Sesquiterpenes; Skin Tests; Stereoisomerism; Structure-Activity Relationship

Topics: Benzbromarone; Benzofurans; Chemical Phenomena; Chemistry; Dermatitis, Contact; Female; Humans; Middle Aged

Australian blackwood (Acacia melanoxylon RBR) is a valuable commercial timber that since 1925 has been incriminated as being injurious to health. In addition to toxic effects numerous cases of allergic contact dermatitis and bronchial asthma have been observed in woodworkers. Several constituents have been identified in recent years, but none of them could be considered as aetiological factors. Sensitizing experiments performed with blackwood heartwood extracts corroborated the described sensitising properties. Chemical studies showed the occurrence of two or possibly three quinones that produced positive skin responses in the sensitised guinea pigs. The main contact allergens were isolated and identified by x-ray analysis. The first, a yellow quinone, was identified as 2,6-dimethoxy-1,4-benzoquinone while the second, a red quinone, has the structure of 6-methoxy-2-methyl-3,5-dihydrobenzofurano-4,7-dion and was named acamelin. Whereas 2, 6-dimethoxy-p-benzoquinone is already known from natural sources, acamelin is new and belongs to the rate group of naturally occurring furanoquinones. Though the obtained sensitising capacity of A melanoxylon RBR in respect of its quinones is not high, it should be considered as a possible source of allergic contact dermatitis, especially as greater amounts of Australian blackwood may enter European countries in the near future.

Topics: Acacia; Allergens; Animals; Benzofurans; Benzoquinones; Chemical Phenomena; Chemistry; Chromatography, Thin Layer; Dermatitis, Contact; Female; Guinea Pigs; Quinones; Skin Tests

Topics: Adult; Allergens; Benzofurans; Catechols; Child; Dermatitis, Contact; Female; Humans; Lactones; Male; Patch Tests; Plants, Toxic; Quinones; Sesquiterpenes; Thiocyanates

Experimental studies on allergic contact dermatitis due to Chrysanthemum indicum 1. (Chrysanthemum x-morifolium) (chrysanthemum of the florists) have indicated the following results: 1. In 5 patients with allergic contact dermatitis from chrysanthemum oil of turpentine and its sensitizing compounds gave no patch test responses. No relationship between contact allergy due to chrysanthemus and to turpentine oil could be determined. 2. The pyrethrins, constituents with insecticidal activity, derived from certain Chrysanthemum species and often suspected as the causative agents, play no role in chrysanthemum allergy. 3. Tests on sensitized guinea pigs (pirl bright white strain) with flowers of chrysanthemum as well as with the two sesquiterpene lactones parthenolide and alantolactone, derived from different Composite species, gave positive patch test reactions. The results showed that parthenolide produced stronger reactions than alantolactone. 4. By thin layer chromatography neither parthenolide, nor alantolactone or pyrethrosin could be detected in extracts of chrysanthemum flowers of the florists. But the investigations indicated that several other terpenic compounds are present, which gave positive color reactions to certain lactone reagents. Five of them showed strong positive patch test reactions in our patients as well as in sensitized guinea pigs. Further studies are required to identify these compounds.

Topics: Adjuvants, Immunologic; Allergens; Animals; Benzofurans; Chromatography, Thin Layer; Chrysanthemum cinerariifolium; Dermatitis, Contact; Guinea Pigs; Humans; Immunologic Techniques; Injections, Intradermal; Insecticides; Lactones; Male; Plant Extracts; Plants; Sesquiterpenes; Skin Tests; Turpentine

Topics: Anilides; Animals; Benzofurans; Carbanilides; Dermatitis, Contact; Dioxins; Edema; Food Contamination; Gastrointestinal Diseases; Hexachlorophene; Hydrocarbons, Chlorinated; Immunosuppression Therapy; Naphthalenes; Neurologic Manifestations; Pesticide Residues; Photolysis; Polychlorinated Biphenyls; Polycyclic Compounds; Rats; Skin

Topics: Aged; Allergens; Benzofurans; Dermatitis, Contact; Eczema; Humans; Lactones; Male; Plants; Terpenes

Topics: Aged; Allergens; Benzofurans; Chemical Phenomena; Chemistry; Dermatitis, Contact; Humans; Lactones; Male; Middle Aged; Occupational Diseases; Plants; Skin Tests; Terpenes; Trees

Topics: Adult; Animals; Benzofurans; Dermatitis, Contact; Freund's Adjuvant; Guinea Pigs; Humans; Injections, Intradermal; Lichens; Male; Skin Tests

Topics: Benzofurans; Dermatitis, Contact; Humans; Lichens; Male; Salicylates; Skin Tests

Topics: Benzofurans; Dermatitis, Contact; Drug Hypersensitivity; Humans; Hypersensitivity, Delayed

Topics: Benzofurans; Dermatitis, Allergic Contact; Dermatitis, Contact; Fungi; Humans; Hypersensitivity; Lichens; Occupational Diseases; Pathology

Two forest workers affected with allergic contact dermatitis, which occurred only during work in forest areas, showed positive patch test reactions to lichens containing usnic acid and to isolated usnic acid. Lichens are plants composed of fungi living in symbiosis with algae. Usnic acid, one of the lichenic acids which accumulates in lichenized fungi, is a monobasic acid with dibenzofuran structure and antibiotic properties. Dibenzofuran is chemically related to furocoumarans. Lichens are plentiful in temperate zone forests and allergy to usnic acid represents some part of the "cedar-poisoning" problem in British Columbia. Geographical distribution of lichens containing usnic acid suggests that allergy to usnic acid will be found to be more common than presently recognized.

Topics: Adult; Benzofurans; Dermatitis, Contact; Dermatitis, Occupational; Forestry; Humans; Lichens; Male

Topics: Benzofurans; Chemical Phenomena; Chemistry; Dermatitis, Contact; Humans; Hypersensitivity; Lichens; Occupational Diseases