The effect of Dermatophagoides pteronyssinus allergens on proliferation and CD23 antigen expression of peripheral blood lymphocytes from atopic patients

Rebound phenomenon to systemic corticosteroid in atopic dermatitis

Three patients with atopic dermatitis, one boy and two girls, aged between 6 and 17 years, presented eczematous skin, pruritus, scarifications, lichenification and a family history of atopy. During exacerbations, the patients sought emergency care and were prescribed oral corticosteroids for a period of approximately 15 days. Initially, the patients improved but after cessation of therapy or dose reduction, marked worsening occurred with the development of lesions with extreme pruritus, several confluent lesions, scarification and intense exudates, as well as fever and dehydration. The patients' condition was so severe that two were admitted to the allergy unit. The medication was withdrawn and intravenous hydration was administered, together with hydrating skin creams and antihistamine therapy. In addition, weak topical corticosteroids were applied on the most severely affected areas. All three patients progressively improved. We conclude that the patients with atopic dermatitis described herein presented a rebound phenomenon after the use of corticosteroids. We believe that systemic corticosteroids may exacerbate the acute phase of atopic dermatitis, mediated by IgE, accentuating the Th2 pattern in these patients.

Hydrocortisone enhances allergen-specific IgE production by peripheral blood mononuclear cells from atopic patients with high serum allergen-specific IgE levels

BACKGROUND

Although there is convincing evidence that human B cells can be induced to produce IgE by a combination of interleukin 4 (IL-4) and hydrocortisone (HC) in atopic subjects, it is still uncertain if this performs the same functions in allergen-specific IgE synthesis.

OBJECTIVE

This study was designed to investigate the differences of IgE regulation between atopics and nonatopics, interactions of HC with IL-4, and the correlation between in vitro total IgE, allergen-specific IgE synthesis and serum IgE levels.

METHODS

Peripheral blood mononuclear cells (PBMCs) from 16 atopic asthma patients sensitive to Dermatophagoides farinae and seven nonatopic controls were cultured with IL-4 and/or HC. Total IgE and D. farinae-specific IgE in culture supernatant were measured by ELISA and FAST.

RESULTS

IL-4 increased total IgE synthesis in PBMCs from both atopics and nonatopics, whereas, HC had this effect only in some atopics who showed spontaneous IgE production in vitro. HC acted synergistically with IL-4 in total IgE synthesis. Their effects were more remarkable in cases with lower total serum IgE levels. PBMCs from eight of 16 atopics produced D. farinae-specific IgE in vitro either spontaneously or by IL-4 and/or HC. HC had more profound effects than IL-4 in these patients. They also showed higher total IgE synthesis by HC, and higher specific serum IgE levels than the others. IL-4 and/or HC did not induce any D. farinae-specific IgE synthesis by PBMCs from nonatopics.

CONCLUSION

HC had a more profound effect than IL-4 on the induction of D. farinae-specific IgE synthesis in atopic patients with high serum allergen specific IgE levels. Further studies to determine the causes of these effects, such as the presence of long lived allergen specific B cells as the result of the priming effect of IL-4 in vivo, may be needed.