LATE SKIN-PRICK-TEST REACTIONS TO MALTED WHEAT - CLINICAL OBSERVATIONS AND IMMUNOHISTOCHEMICAL CHARACTERIZATION

This study reports late skin-prick-test (SPT) reactions in seven baker s and seven control subjects to malted wheat appearing after 6-10 h, a nd not preceded by an immediate-phase reaction. Two subjects in each g roup had a history of atopic symptoms and were Phadiatope(TM) positive . Serologic IgE analysis (RAST) of normal wheat flour and of malted wh eat grain was negative in all subjects. Skin biopsy specimens were obt ained 16-18 h after SPT to malted wheat grain and to histamine and fro m untested skin. The late SPT reactions in all participants had an urt icarial appearance, clinically and in routine histology. Immunohistolo gically mild to moderate perivascular dermal cell infiltrates were obs erved in both groups, consisting mainly of CD4(+) and HLA-DR+ cells. T he number of CD1a(+) epidermal cells was statistically significantly h igher (P<0.01) in the bakers' prick-tested skin compared to that of th e controls, a fact which might reflect preparedness to react upon chal lenge. There were no statistical differences between the two groups in IgE(+) epidermal cells or epidermal cells expressing the high-affinit y IgE receptor (Fc(epsilon)RI). However, there was a correlation betwe en serum-IgE levels and the number of IgE(+) epidermal cells. The late skin reactions observed in both bakers and controls were probably mor e of an irritant or toxic than immune-mediated nature, but they raise the question of whether skin contact with malted flour contributes to an unfavorable prognosis of hand eczema in bakers.