EXPRESSION OF CD30 ON T-HELPER CELLS IN THE INFLAMMATORY INFILTRATE OF ACUTE ATOPIC-DERMATITIS BUT NOT OF ALLERGIC CONTACT-DERMATITIS

The CD30 molecule has been proposed as a marker for a subset of CD4(+) CD35RO(+) (memory) T cells with potent B cell helper activity producin g IL-5 and IFN-gamma and as a specific marker for Th2 cells. Recently, an association has been demonstrated between elevated serum levels of soluble CD30, which is shed by CD30(+) cells in vitro and in vivo, an d atopic dermatitis but not respiratory atopic disorders or allergic c ontact dermatitis. We studied the expression of CD30 in the inflammato ry infiltrate of atopic dermatitis compared with that of allergic cont act dermatitis, with special regard to skin disease activity (acute vs subacute/chronic). Biopsies were obtained from 16 patients suffering from atopic dermatitis (acute n = 6, subacute/chronic n = 10), from 7 patients with acute allergic contact dermatitis and from 5 positive pa tch-test reactions. Paraffin-embedded as well as snap-frozen material was stained with anti-CD30 and anti-CD45RO mAbs according to standard procedures. Double-staining procedures for CD30CD3, CD30CD4, CD30CD45R O and CD30CD68 were also performed. Abundant CD45RO(+) cells were dete cted both in atopic dermatitis and in allergic contact dermatitis lesi ons. We found scattered CD30(+) cells in only one of six formalin-fixe d paraffin-embedded acute atopic dermatitis biopsies, but in all of th e respective snap-frozen specimens, possibly because CD30 expression o n atopic dermatitis infiltrating cells is weak and sensitive to formal in fixation and paraffin embedding. CD30CD3 and CD30CD4 double stainin g identified CD30(+) cells to be helper T lymphocytes. No significant CD30 expression (either in paraffin-embedded or in frozen material) co uld be found in subacute/chronic atopic dermatitis lesions or in any o f the specimens of allergic contact dermatitis. The results suggest a specific regulatory function of CD30(+) T cells in acute atopic dermat itis. With respect to the view that CD30 is a marker for Th2 cells, ou r observations confirm previous findings that Th2 cells predominate in the infiltrate particularly of acute atopic dermatitis. CD30 expressi on in acute atopic dermatitis but not in acute allergic contact dermat itis might be helpful in the histological differentiation of these dis orders and in the further characterization of atopy patch testing.