Evidence for a role for IL-5 and eotaxin in activating and recruiting eosinophils in drug-induced cutaneous eruptions

Background: Cutaneous drug reactions may be associated with increased numbe rs of eosinophils in the blood and tissue. However, the factors leading to the generation of eosinophilia have not been fully delineated. Objective: The aim of this study was to investigate the in situ expression of IL-5, eotaxin, RANTES, monocyte chemoattractant protein 3, and IL-8 toge ther with the appearance of eosinophils in acute cutaneous drug reactions. Methods: Skin biopsy specimens were obtained from drug-induced maculopapula r exanthems (n = 9), from normal skin of control subjects (n = 9), and from the skin of patients with psoriasis (n = 8). The in situ expression of IL- 5, eotaxin, RANTES, monocyte chemoattractant protein 3, and IL-8 was analyz ed by using immunohistochemistry. Furthermore, the corresponding numbers of eosinophils were determined in the blood and skin sections. Results: Compared with normal skin and psoriatic skin, a significantly high er number of eosinophils was found both in the blood and tissue of patients with a drug-induced exanthem. In comparison with normal skin, immunoreacti vity for IL-5 and all the chemokines was also significantly enhanced in dru g-induced exanthem, whereas significant differences in psoriatic were only observed for IL-5 and eotaxin. Conclusion: Our data indicate that IL-5 and eotaxin may particularly contri bute to the activation and recruitment of eosinophils and thereby play an i mportant pathogenic part in the development of skin inflammation in drug-in duced maculopapular exanthems.