Interferon-α in Serum and Carcinomatous Pleural Effusion after Repeated Intrapleural Injections of Antitumor Agents

: Pleural effusions and sera of two patients with lung cancer were tested after intrapleural injection of OK-432 as an anticancer drug for IFN-alpha activity by biological assay and for IFN-alpha as an antigen by radioimmunoassay. The titers by radioimmunoassay were fairly consistent with those by biological assay, but were usually higher. In Case 1, IFN-alpha was observed fairly early after administration of OK-432 and only in pleural effusions. In Case 2, induction of IFN-alpha at low level was observed late after the first administration of OK-432 both in the pleural effusion and serum and was detected only by radioimmunoassay.