Quantitative detection of FAS/FAS ligand in Mycosis fungoides and Psoriasis

Background. Apoptosis is a physiological form of cell death that is responsible for the deletion of cells.Psoriatic skin shows marked thickening of the epidermis which might be related to abnormal apoptotic process. The usually protracted and indolent course of cutaneous T cell lymphoma is consistent with anaccumulation rather than being a true proliferative disorder, perhaps as the result of defective lymphocyteapoptosis. FasFas ligand signaling is an important inducer of apoptosis. Aim of work. is to evaluate the expression of Fas and Fas Ligand in patients with mycosis fungoides in different stages of the disease and inpatients with psoriasis in an attempt to correlate their expression with the clinical behavior of both diseases and to compare the role of Fas and Fas L system in progression of malignancies and in inflammatory conditions. Patients and Methods. Forty patients were included in this study (20 with mycosis fungoidesand 20 with psoriasis) and 10 controls. One skin biopsy was taken from each patient and control and was fixed in formalin. The levels of Fas and Fas ligand were measured by polymerase chain reaction. Results.Fas was only detected in the patch stage while it was lost in plaque and tumor stage mycosis fungoides indicating tumor progression. Fas ligand was detected in 90% of cases of mycosis fungoides being higher inpatch than plaque and tumor stage. As for psoriasis, Fas was detected in all biopsies. Fas ligand was only detected in 40% of cases of psoriasis.Conclusion. Absence of Fas in the tumor stage MF indicates disease progression and unfavorable prognosis,while in psoriasis, prevalence of Fas with defective apoptosis indicates that it has a role in the pathogenesis of psoriasis other than apoptosis.