The biologic activity of mast cell granules in rat skin: effects of adrenocorticosteroids on late-phase inflammatory responses induced by mast cell granules

Photoperiodic variation in substance P induced plasma extravasation in the rat

Photoperiodic variation in plasma extravasation was examined following exogenous perfusion of substance P over a vacuum-induced blister base on the rat hind footpad. The results showed a generalised suppression of plasma extravasation during the dark or active phase of the light/dark cycle which appears to be independent of the circadian fluctuations in endogenous corticosterone. These findings emphasise the need to consider photoperiodic conditions as a possible source of variability in neurogenic inflammatory responses.

Effects of topical pre-treatment with dexamethasone on the immediate and late phases of topically induced ocular anaphylaxis in the rat

We tested the effects of pre-treatment with dexamethasone on topically induced ocular anaphylaxis in the rat. Rats were immunized with dinitrophenylated Ascaris suum extract and challenged with di-DNP-lysine. Dexamethasone was administered topically once (24, 6, or 1 h before challenge) or three times (6, 4, and 2 h before challenge). A single pre-treatment given at 24 or 6 h had no significant effect. A single pre-treatment 1 h before challenge reduced the extent of edema assessed histologically but not clinically, and had no significant effect on the eosinophil count in conjunctival tissue examined 6 h after challenge. Eyes pre-treated with dexamethasone 6, 4, and 2 h before challenge showed a significant reduction in conjunctival edema assessed histologically and clinically 1 h after challenge. In addition, 6 h after challenge the number of eosinophils was significantly reduced. We conclude that repeated pre-treatment with dexamethasone can suppress both the immediate phase and the cellular late phase of topically induced ocular anaphylaxis.

Prednisone inhibits late asthmatic reactions and airway inflammation induced by toluene diisocyanate in sensitized subjects

To determine the importance of airway inflammation for late asthmatic reactions induced by toluene diisocyanate (TDI), we investigated whether prednisone prevented them [corrected] by modifying the associated airway inflammatory reaction. We measured FEV1 before and at regular intervals after exposure to TDI and performed bronchoalveolar lavage at 8 hours after TDI in two groups of subjects with previously documented late asthmatic reactions, in one group, after no treatment, and in the other group, after treatment with prednisone (50 mg/day for 4 days). After no treatment, each subject developed a late asthmatic reaction, an increase in airway responsiveness, polymorphonuclear leukocytosis, and increased albumin in bronchoalveolar lavage. By contrast, after treatment with prednisone, no subject developed a late asthmatic reaction or an increase in airway responsiveness, and the number of leukocytes and the concentration of albumin were normal in bronchoalveolar lavage. These results suggest that late asthmatic reactions induced by TDI may be caused by airway inflammation and that prednisone may block them [corrected] by inhibiting the inflammatory reaction of the airway induced by TDI in sensitized subjects.

Inhibition of mediator release in allergic rhinitis by pretreatment with topical glucocorticosteroids

Patients with allergic rhinitis often have immediate symptoms after antigen challenge (the early-phase response), followed several hours later by a recurrence of symptoms (the late-phase response). Systemic glucocorticosteroids are known to inhibit the late-phase but not the early-phase response. We studied the effect of one week of pretreatment with topical (rather than systemic) glucocorticosteroids on the response to nasal challenge with antigen in a double-blind, randomized, placebo-controlled crossover study of 13 allergic patients who had previously had a dual response to nasal challenge. The patients were challenged with three 10-fold increments of allergen, producing an early response, and were then followed for 11 hours, encompassing the late response, before they were rechallenged with the lowest dose of allergen. We monitored their responses by means of symptom scores and measurements of the levels of histamine, tosyl-L-arginine methyl ester (TAME)-esterase activity, and kinins in nasal lavages. Topical glucocorticosteroids significantly reduced both the symptoms and the levels of histamine, TAME-esterase activity, and kinins in the early, late, and rechallenge allergic reactions. The fact that, in contrast to treatment with systemic glucocorticosteroids, prolonged pretreatment with topical glucocorticosteroids inhibited the early-phase response to antigen suggests that the route and duration of administration affect the mechanisms of action of the steroids. We conclude that inhibition of the early-phase as well as the late-phase response by topical glucocorticosteroids may provide an advantage over treatment with systemic glucocorticosteroids in patients with allergic rhinitis.

A study on late allergic reactions to house dust mite in bronchial asthmatics

Patterns of skin and bronchial reactions to the allergen were examined in thirty perennial asthmatics who showed a positive early cutaneous reaction (ECR) to the skin prick test with Dermatophagoides farinael. A dualcutaneous reaction (DCR) was elicited in nine subjects by the skin prick test and in twenty-four by the intradermal test. The size of the late cutaneous reaction (LCR) to the intradermal test was found to correlate with that of the preceding ECR. A bronchial provocation test resulted in no reaction in six, and isloated early asthmatic reaction (EAR) in three, and a dual asthmatic reaction (DAR) in twenty-one. A large LCR was associated with the occurrence of DAR and the patients with a large LCR required a lower allergen concentration to elicit an EAR.

Should corticosteroids be used in the treatment of acute, severe asthma? I. A case for the use of corticosteroids in acute, severe asthma

Corticosteroids have been used for over 3 decades in the treatment of asthma. There are theoretic reasons and long-standing clinical support for their use, but little in the way of good objective data on their efficacy. I have reviewed this information and concluded that notwithstanding rare side effects, corticosteroids should be used in acute asthma, and objective data exist to support this premise.

Late-phase reactions in ocular anaphylaxis in the rat

We assessed whether anaphylactic stimulation of rat ocular tissue produces a late-phase reaction at the histologic level. Clinical changes of swelling and redness started within minutes, peaked at about 20 min, and then subsided. Neutrophils increased at 1/2 hr after stimulation, peaked at 6 hr, and subsided to normal at 24 hr. Eosinophils reached a significant increase at 6 hr. Compaction of vessel contents was present at 1/2 hr; vessels were normal thereafter. Extravasated red blood cells and debris in the tissue were prominent at 6 hr. Macrophages had accumulated significantly at 6 hr and maintained that level at 24 hr. Any effect of anaphylaxis on macrophage accumulation was masked because control-injected ocular tissue also showed an accumulation of macrophages at 24 hr. Our results demonstrate that in ocular tissue, as in skin, the early acute phase of immediate hypersensitivity is but one stage of a multiphasic reaction.

Delayed pressure urticaria

Delayed pressure urticaria (DPU) is a poorly understood syndrome. We describe 17 patients with DPU. Chronic urticaria was present in 94%. All had negative challenges for immediate demographism and cold urticaria. DPU was induced with a pressure challenge on the shoulder of 15 pounds for 15 min. Average onset of pressure lesions after challenge was 6.5. Lesions were painful, not pruritic, peaked at 9 hr, and disappeared by 24 to 48 hr. Fever, chills, and/or arthralgias occurred in 78%. Positive laboratory abnormalities included leukocytosis in 20% and elevated erythrocyte sedimentation rate in 37.5%. Skin biopsies of lesions showed perivascular round cell infiltrates and negative immunofluorescence. Urticaria responded to antihistamines, but not aspirin, in 100% of patients, while pressure lesions improved with nonsteroidal anti-inflammatory drugs (NSAID), but not antihistamines, in 80% of patients. Both urticaria and DPU were controlled with prednisone, which was necessary in 87.5% of patients. A severe nonremitting course was noted in 7%, 40% had a moderate remitting course requiring intermittent prednisone, and 53% had a mild remitting disease requiring no medication or antihistamines and/or NSAID only. We conclude that DPU is more common than previously appreciated and likely involves mediators other than histamine, possibly the prostaglandin system.