To provide a novel phospholipase A2 (PLA2) associated with psoriasis, a nucleic acid encoding the same, a method for characterizing, identifying or screening an inhibitor for the PLA2 or a medicament; and a novel method for diagnosis or examination of psoriasis or the like. A polypeptide having the amino acid sequence shown in SEQ ID NO: 9, a conservative substitution variant thereof, a naturally occurring allelic variant thereof, or the like. A nucleic acid encoding the above-mentioned polypeptide, a complement thereof or the like. A method for characterizing, identifying or screening an inhibitor for the PLA2 or a medicament, using the above-mentioned polypeptide. An examination method for psoriasis, characterized by assaying an expression level of a gene consisting of the above-mentioned nucleic acid or the like.