The distribution of choline acetyltransferase- and acetylcholinesterase-like immunoreactivity in the palmar skin of patients with palmoplantar pustulosis

The distribution of choline acetyltransferase (ChAT) and acetylcholinestera se (AChE) in involved skin in patients with palmoplantar pustulosis (PPP) a nd in normal palmar skin in healthy nonsmokers and smokers has been studied by immunohistochemistry, especially in relation to the sweat gland apparat us. The sweat gland and its duct showed ChAT- and AChE-like immunoreactivit y (LT) of varying intensity in all three groups and with stronger reactivit y than in the epidermis. ChAT-LI was present in the coil and in the duct ex cept in the corneal layer. Smokers and patients with PPP displayed signific antly fewer ChAT+ acrosyringia than non-smokers. In the patients with PPP, the granulocytes in the pustules and in the papillary dermis displayed ChAT -LI. Western blot analysis of granulocytes from peripheral blood from healt hy donors confirmed the presence of ChAT-like proteins in large amounts in neutrophils and small amounts in eosinophils. AChE-LI of varying intensity was found in all parts of the sweat gland apparatus in all three groups. Th e strongest AChE-LI in the acrosyringia was seen in the lowest part of the stratum corneum, where the PPP pustules are located. No significant differe nces in staining pattern or intensity were found between the coils, nerve f ibres surrounding the coils or ducts. The number of mast cells in the papil lary dermis was about four times larger in the patients with PPP than in th e control subjects. AChE-LI was observed in about 25% of the mast cells in non-smoking control subjects and in patients with PPP, but only in 10% of t hose in the smoking control subjects. Our findings indicate that the (non-n euronal) cholinergic system may be involved in cutaneous inflammatory proce sses.