Allergy to nickel or cobalt: tolerance to nickel and cobalt samples in man and in the guinea pig allergic or sensitized to these metals

The aim of this study was to evaluate, in animals and humans sensitive to nickel or cobalt, the tolerance to manufactured metal samples of nickel and cobalt of a defined metallographic structure, plated or not with a layer of chrome or copper/chrome of a determined thickness. Under the defined experimental conditions, a guinea pig sensitized to one metal (nickel or cobalt) was intolerant to both metals (nickel and cobalt). A plating of chrome or copper/chrome did not act as a protection. In the human, it was not the same: the tolerance to metal samples was determined by the specific sensitivity. A plating of chrome or copper/chrome did not act as protection.

Local suppression of contact hypersensitivity in mice by a monofunctional psoralen plus UVA radiation

Monofunctional psoralens, plus UVA radiation are not erythemogenic and are less mutagenic than bifunctional psoralens plus UVA radiation. Thus, they have received considerable attention in recent years as potential therapeutic agents for various skin diseases. The purpose of this study was to examine the immunologic side effects following treatment of mice with a monofunctional psoralen plus UVA radiation. We report that angelicin plus UVA radiation suppressed the induction of contact hypersensitivity to dinitrofluorobenzene. This decreased immune response was associated with the presence of splenic suppressor cells that transferred suppression to normal recipients. Treatment with angelicin and UVA radiation also decreased the number of Thy-1+ and Ia+ dendritic epidermal cells in the treated site. We conclude that although this monofunctional psoralen is not phototoxic, it has immunosuppressive activity in mice.

Identification of cross-reaction patterns in allergic contact dermatitis from topical corticosteroids

Contact allergy to topical corticosteroids occurs more frequently than previously supposed. Cross-allergic phenomena are common. On the basis of a review of the literature and our own patch test data on 15 patients, we conclude that positive patchtests to corticosteroids occur approximately six to seven times more frequently in well-defined groups of structurally-related substances than between corticosteroids of different groups. An analogous substitution pattern on the steroid D-ring or the carbon side chain (C20, C21) seems to have a significant influence on the association of positive patchtest results. This is not the case for other structural variables, such as the presence of a double bond in the steroid A-ring or fluoride substitutions on the B-ring. The effect of other factors such as concomitant sensitization and steroid metabolism in the skin on the development of a corticosteroid polyallergy are analysed, and the specificity and sensitivity of cross-allergy phenomena are evaluated. These are important in the selection of a topical steroid in the future treatment of a corticosteroid sensitive patient.

A murine local lymph node assay for the identification of contact allergens. Assay development and results of an initial validation study

The development of an alternative predictive test for the identification of contact sensitizing chemicals is described. The method is based upon the fact that, following epicutaneous application, sensitizing chemicals initiate a primary immunological response in the draining lymph node(s) which is characterized by lymphocyte proliferation. Experimental conditions for the measurement in vitro of the induced lymph node cell proliferative response have been optimized. On the basis of the data presented a local lymph node assay was developed in which CBA/Ca strain mice were exposed daily, for 3 consecutive days, to various concentrations of the test chemical, or to vehicle alone, on the dorsum of the ear. Lymph node activation was measured subsequently as a function of increased node weight, the frequency of large pyroninophilic cells and lymphocyte proliferation in the presence or absence of an exogenous source of interleukin 2 (IL-2). The results of a validation study are reported in which 22 well-characterized sensitizing chemicals of varying potency were examined. With the exception of three chemicals where water was used as the application vehicle, positive responses, defined as a substantial increase in lymphocyte proliferative activity, were recorded with all these test materials. Under the conditions employed non-sensitizing chemicals, including non-sensitizing irritant chemicals, failed to influence the immunological status of the draining lymph node. Taken together, the data suggest that the local lymph node assay provides the basis for a rapid and cost-effective alternative to the currently available guinea pig predictive test methods. The local lymph node assay may be of particular value for the evaluation of coloured or irritant chemicals.

Retinoic acid protects Langerhans' cells from the effects of the tumour promotor 12-O-tetradecanoylphorbol 13-acetate

Retinoic acid prevents the decrease in epidermal Langerhans' cell (LC) density which occurs upon application of the tumour promotor 12-O-tetradecanoylphorbol 13-acetate (TPA) to murine skin. This occurred very rapidly, after only 1 week, and was still observed after 4 weeks of treatment. Retinoic acid alone increased the LC density, indicating that it could affect LC density independently of TPA. The induction of a contact sensitivity response which was inhibited by prior treatment with TPA due to the low LC density was also protected by retinoic acid. The anti-carcinogenic activity of retinoic acid is partially the result of its ability to inhibit tumour promotion. The loss of LC may be one of the important steps in tumour promotion as this would allow developing tumours to escape immune destruction. Our studies suggest that the ability of retinoic acid to suppress tumour promotion may be in part by protecting local antigen-presenting cells, thus allowing an immune response to be generated against tumours.

Guinea pig maximization test for skin sensitisation: the use of fewer test animals

Current European Community (Annex V) guidelines recommend the use of 20 test animals in the guinea pig maximisation test for skin sensitization. The suitability, for classification and labelling purposes, of reducing the number of test animals has been examined by analysing the results of 40 studies submitted to the Health and Safety Executive, and by the use of a mathematical model. Our results suggest that in most cases an experiment with ten test animals can be used to determine satisfactorily whether a substance should be labelled with the risk phrase "may cause sensitisation by skin contact". However, serious consideration should be given to the need for additional investigation if two or three of the ten test animals show a sensitisation response. The highest non-irritant concentration of a substance should be used at challenge. Clearer guidance in Annex V on evaluating challenge responses would be beneficial.

Common inflammatory skin diseases of the elderly

Elderly patients are more likely than the general population to have significant cutaneous diseases due to structural changes, alteration of immunologic response, and different environmental influences. This review focuses on the pathogenesis, diagnosis, and management of the most common inflammatory dermatoses likely to be encountered in the geriatric population.

Flare-up reaction on murine contact hypersensitivity. I. Description of an experimental model: rechallenge system

In this experiment, a 'rechallenge system' was established in BALB/c mice to study a local immunological reaction of contact hypersensitivity (CH). Briefly, mice were sensitized by a single painting with 25 microliters of 0.5% dinitrofluorobenzene (DNFB) on the shaved back skin on Day 0. On Day 5, they were challenged with 20 microliters of 0.2% DNFB on each left ear, and on Day 33 challenged again with either painting 20 microliters of 0.2% DNFB on their both ears or intravenous administration of 15 mg of dinitrobenzene sulphonic acid (DNBS). As the result, marked ear swelling was observed by the second challenge only on the first challenged site and these responses were clarified to be antigen specific. In in vitro experiments, it was shown that only the cells from the regional lymph node of the skin, which were previously elicited on challenge, were enhanced to proliferate by DNBS, which was added into the culture medium. These results suggest that there is a local immunological mechanism to respond to the specific antigen only on the site in which CH reaction has been elicited previously. The results from this 'rechallenge system' may help to explain some pathological mechanisms of such chronic diseases as fixed drug eruption or chronic contact dermatitis, which recur easily in skin lesions involved previously.

Ultrasensitive enzyme-linked immunosorbent assay (ELISA) for the detection of picogram quantities of IgE

Existing methods of measuring IgE in in vitro peripheral blood lymphocyte (PBL) cultures are not sufficiently sensitive to detect IgE when it is present in small amounts. This paper describes a modification of a two-site ELISA which increases the sensitivity of the assay 10-20-fold. By using the Fab' fragment of either rabbit or mouse monoclonal anti-IgE conjugated to alkaline phosphatase (AP) as the detector, the background of the assay was reduced sufficiently to permit signal amplification, using a commercially available amplified AP substrate. With this assay as little as 10 pg/ml of IgE could be detected. The interassay coefficient of variation was 15-18% between 1200 and 100 pg/ml IgE (n = 14) and there was a good correlation with a commercial IgE radioimmunoassay (RIA) (r = 0.98, n = 38).

Hapten-specific cellular immune response producing glomerular injury

A new model of experimental glomerulonephritis (GN) in which a cell-mediated (delayed-type) reaction predominated was established. Cationized TNP-BSA conjugates were planted in the kidney of rats by perfusion via the renal artery. Rats which had been sensitized with the TNP hapten 7 days previously revealed marked exudative and proliferative changes in their glomeruli, accompanied by transient proteinuria. A cellular influx was seen without deposition of any autologous antibody. The resulting data are compatible with the idea that cell-mediated immune reactions can participate in tissue damage in glomerular disease.

The role of suppressor factors in the regulation of immune responses by ultraviolet radiation-induced suppressor T lymphocytes. I. Activity of suppressor cell culture supernatants

The purpose of this study was to determine whether soluble suppressor factors are involved in the regulation of immune responses by ultraviolet radiation-induced suppressor T lymphocytes (UV Ts). The UV Ts were induced by applying contact allergens to the ventral, unirradiated skin of mice that had been exposed 5 days earlier to UVB radiation. Supernatants from cultures that contained a mixture of UV Ts, normal responder lymphocytes, and hapten-modified stimulator cells were injected iv into normal recipients at the time of sensitization; they inhibited the induction of contact hypersensitivity (CHS) in vivo in an hapten-specific manner. The supernatants similarly suppressed the generation of specific cytotoxic T lymphocytes (CTL) in vitro. Moreover, supernatants from cultures that contained either UV Ts alone or UV Ts in combination with either the responder or the stimulator cells failed to suppress the CHS and CTL responses. These results suggest that hapten-specific inhibitory factors may participate in the regulation of immune responses by suppressor cells generated by epicutaneous sensitization of UV-irradiated mice.

The role of suppressor factors in the regulation of immune responses by ultraviolet radiation-induced suppressor T lymphocytes. II. Activity of suppressor cell culture sonicates

The purpose of this study was to determine whether multiple types of suppressor factors play a role in the regulation of immune responses by ultraviolet radiation-induced suppressor T lymphocytes (UV Ts). The UV Ts were induced by applying contact allergens to the ventral, unirradiated skin of mice exposed 5 days earlier to UVB radiation. Previous studies indicated that supernatants from cultures containing UV Ts, normal lymphocytes, and hapten-modified cells suppressed contact hypersensitivity (CHS) in vivo and cytotoxic T lymphocyte (CTL) generation in vitro in a hapten-specific manner. In this report, cell-free lysates from sonically disrupted UV Ts were examined for their ability to suppress these responses. When lysates were injected into normal animals at the time of sensitization, they inhibited CHS in a hapten-nonspecific manner. In addition, the lysates suppressed not only the induction but also the elicitation of CHS, and they suppressed the generation of CTL. Lysates prepared from spleen cells obtained from non-UV-irradiated mice or UV-irradiated, unsensitized mice failed to inhibit either response. Moreover, in contrast to the lysates, the hapten-specific UV Ts culture supernatants inhibited the induction but not the elicitation of CHS. These results suggest that both hapten-specific and nonspecific inhibitory factors may participate in the regulation of immune responses by UV Ts.

Optimization of an in vitro lymphocyte blastogenesis assay for predictive assessment of immunologic responsiveness to contact sensitizers

Current methods for the predictive and diagnostic assessment of contact sensitization rely on the visual scoring of skin reactions. Predictive animal tests, generally using guinea pigs, require a relatively large number of animals to produce a sufficient database for interpreting skin reaction scores. In vitro assays have the potential of being more quantitative than skin testing and, if so, would require fewer animals. However, although in vitro assays are commonly used to study the cellular immune response to strong contact sensitizers, there has been little effort to validate them for predictive assessment purposes. We have optimized an in vitro lymphocyte blastogenesis assay for detecting the response of mouse lymphocytes to strong contact sensitizers with the eventual objective of applying this assay to moderate and weak sensitizers as well. Lymph node lymphocytes from mice sensitized to the strong contact allergens, dinitrochlorobenzene (DNCB), dinitrofluorobenzene (DNFB), or trinitrochlorobenzene (TNCB), responded [greater than or equal to 12,000 counts per minute (CPM) above background] when cultured with water soluble chemical analogues, di- or trinitrobenzene sulfonic acid (DNBS or TNBS). However, the strong sensitizer, oxazolone (OXAZ), has no water soluble analogue and lymphocytes from mice sensitized to OXAZ responded poorly in vitro (less than 2000 CPM) to an ethanol-solubilized OXAZ preparation in spite of very strong in vivo sensitization (ear swelling assay). To increase the assay sensitivity, for OXAZ, we modified the antigen presentation conditions by using 1) solubilized antigen-modified adherent spleen cells, 2) dendritic cells from the draining lymph nodes of antigen painted mice, and 3) antigen-modified Langerhans cell-enriched cultured epidermal cells (EC). These approaches increased OXAZ-directed responses to greater than 7000, greater than 20,000, and greater than 100,000 CPM, respectively, under culture conditions optimized for cell density, responder: stimulator cell ratio, culture duration, and responder cell type. Our results represent a first attempt to directly modify cultured epidermal cells with OXAZ and use these cells to stimulate OXAZ-directed blastogenesis in microtiter plate cultures. This optimized assay is now under evaluation for predictive assessment of contact sensitizers relevant to occupational and consumer exposures.

Cutting fluid dermatitis

174 consecutive patients with suspected cutting fluid dermatitis were investigated in 2 occupational dermatology clinics. 43% showed allergic reactions which were thought to be relevant to their dermatitis. Irritant contact dermatitis occurred in 63%, but only in 21% was it thought to be the sole diagnosis. Biocides, especially formaldehyde releasers, were the commonest cause of allergic reactions in a cutting fluid patch test series.

Patch testing in prurigo nodularis

32 patients with prurigo nodularis evaluated at the Mayo Clinic from 1975 to 1987 have been patch tested for sensitivity to appropriate allergen series; 25 of these had relevant positive reactions and subsequent follow-up to 5 to 14 years was available for 11. 6 patients had persistent disease and 5 had resolution or marked improvement. 3 of these latter patients noted a strong positive correlation between improvement and avoidance of contact allergens. Screening for contact sensitivity may be helpful in the management of this refractory dermatosis, particularly if there is a coexistent dermatitis.

Effect of acute propanil exposure on the immune response of C57Bl/6 mice

Propanil is a herbicide that is used extensively in rice farming to kill weeds without damaging the rice plant. The immunotoxic effects of acute exposure to propanil were determined in adult C57Bl/6 female mice exposed intraperitoneally to propanil at doses of 0, 10, 25, 50, 100, 200, or 400 mg/kg body wt. One week following exposure, the immune competency of the animals was assessed. Contact hypersensitivity response (CHR), blastogenic response to T- and B-cell-specific mitogens, and mixed lymphocyte reaction (MLR) were significantly depressed only in propanil-treated animals at 400 mg/kg. However, the number of splenic antibody-producing cells was also significantly depressed in a dose-dependent manner at the lower doses of 50, 100, and 200 mg/kg. In addition, a significant reduction in the thymus weight and an increase in absolute and relative spleen weight were also measured in animals treated with 200 and 400 mg/kg. The increase in spleen weight also showed a concomitant rise in spleen cellularity. These data indicate that propanil has a dose-dependent immunotoxic effect on the adult mouse that affects primarily the humoral response.

Allergic contact dermatitis from 3-(aminomethyl)-pyridyl salicylate

2 patients with acute allergic contact dermatitis from 3-(aminomethyl)-pyridyl salicylate are described. Both patients were females with histories of urticaria and showed cross-sensitization to substances of the para group. Clinical manifestations included eczema, angioedema and respiratory effects. In 1 patient, airborne elicitation was suspected. A lymphocyte transformation test confirmed the allergy, with an extremely high response index. 35 normal controls were negative.