[Carbohydrate antigens in pleural effusion from patients with lung cancer].

Sialosylated Lewisa (S-Lea) is an active antigen determinant of CA19-9 which is well known as a tumor maker. Sialosylated Lewisx (S-Lex) is a positional isomer of S-Lea. The positive percent of S-Lex and CA19-9 in pleural effusion from the patients with primary lung cancer was 49.1% and 40.0%, respectively. However, most S-Lea positive effusions showed a positive level of S-Lex. Therefore, S-Lex is considered to be more useful as a tumor marker than CA19-9. The studies on gel chromatography of the effusion obtained from a patients showed high levels of both antigens using sephacryl S-1000 revealed that the molecular weights of S-Lex and CA19-9 were more than 2 X 10(6) and the elution profile of S-Lex coincided with that of CA19-9 fractionated effusions using the monoclonal antibodies to the antigens showed the same pattern of elution profiles of these carbohydrates. From these results, we concluded that the carriers of S-Lex and CA19-9 in pleural effusion from lung cancer might be the same molecules with a high molecular weight more than 2 X 10(6).