Humoral manifestations of bioincompatibility were studied at early stages (during several hours and days) after operations using non-peculiar to heart trans- and implants: aortocoronary bypass at 102 patients with coronarosclerosis and implantation of artificial cardiac valves at 145 patients with endocarditis. In the various postoperation stages the formation of the structurally and functionally different types of the nonclonal specific autoprecipitins to autological membranocellular components was revealed at recipients by methods of double immunodiffusion and immunoelectrophoresis. These autoprecipitins such as: early, activated and tardly, synthesized under effect of alien agent--may be useful as diagnostic and prognostic indicators of bioincompatibility and its clinical consequences at the earliest period after cardiac operations using trans- and implants.