LOS ANGELES -- A class action lawsuit was filed in a San Francisco federal court Monday on behalf of 15 European hemophiliacs suing seven firms, including a subsidiary of Mitsubishi Pharma Corp., for selling contaminated blood products that exposed them to HIV and hepatitis C, their lawyer said Tuesday.

Attorney Robert Nelson said thousands of Japanese could also be named as potential plaintiffs because they contracted hepatitis C from unheated blood-clotting agents for hemophiliacs sold by Mitsubishi Pharma subsidiary Alpha Therapeutic Corp. as well as Bayer Corp., Baxter Healthcare Corp. and its subsidiary.

"This is a worldwide tragedy," Nelson said. "Thousands of hemophiliacs have unnecessarily died from AIDS and many thousands more are infected with HIV or hepatitis C."