Abstract: We used the method of aggregation of washed rabbit platelet to study the effect of nitrogen mustard and dexamethasone on the synthesis of PAF from calcimycin (A23187) sitmulated human primary cultured keratinocytes and found that both nitrogen mustard and dexamcthasone could does- and timedependently inhibit PAF synthesis. The ICSO of nitrogen mustard and dexamethasone are 6.34×10^-9 mol/L and 1.005×10^-8 mol/L respectively. The results indicate that the inhibition of PAF synthesis might be part of tile mechanism of action of nitrogen mustard and dexamethasone therapy in psoriasis.

Key words: Mechlorethamine, Dexamethasone, Platelet activating, factor Keratinocyte