Photodynamic therapy upregulates expression of Mac-1 and generation of leukotriene B(4) by human polymorphonuclear leukocytes.

This study investigated the expression of Mac-1 (CD11b/CD18) and generation of leukotriene B(4) (LTB(4)) by polymorphonuclear leukocytes (PMNs) in response to Mono-L-aspartyl chlorine 6 (NPe6) mediated photodynamic therapy (PDT). PDT was carried out using a laser diode at a light dose of 10 J/cm(2) and wavelength of 664 nm. Expression of Mac-1 was significantly increased about 3-fold by PDT compared with that of Npe6 exposure. The increase in the expression of Mac-1 was not inhibited by 5-lipoxygenase inhibitor (AA861). On the other hand, generation of LTB(4) by PMNs was increased by incubation with NPe6 alone and further promoted by PDT and that was significantly inhibited by AA861. These results suggest that PDT can induce PMNs to express extensively Mac-1 and generate a certain amount of LTB(4) that may play an important cytocidal role in the treatment of oral cancer.