Elimination of anemia-inducing substance by cyclic plasma perfusion of tumor-bearing rabbits

We carried out a fundamental study to search for a therapeutic modality tha t mould remove the anemia-inducing substance (AIS) from the plasma of cance r patients because it is thought to be one of the substances responsible fo r anemia and immunodeficiency in advanced cancer patients. Using AIS isolat ed from the plasma of patients with advanced ovarian carcinoma, we confirme d that adsorption of AIS to noncoated charcoal was nonspecific and high. Mo reover, it was verified that VX2 carcinoma-bearing rabbits are an optimal e xperimental model for plasma perfusion. The data obtained on day 40 after t ransplantation (hemoglobin, 9.1 +/- 2.1 g/dl; osmotic pressure inducing RBC lysis, 137 +/- 11 mosmol/kg; lymphocyte stimulation index, 8.8 +/- 8.6; an d RBC fragility-inducing activity, 40 +/- 9 mosmol/kg) proved similar to th e hematological findings in patients with cancer cachexia, A 1-h plasma per fusion (3 ml/min) through noncoated charcoal was performed in tumor-bearing rabbits, and it resulted in the restoration of RBC fragility-inducing acti vity and suppression of lymphocyte blast formation to pretransplantation va lues. When plasma perfusion was performed every 3 days, RBC fragility-induc ing activity, which increased again 3 days after perfusion, was diminished, and RBC osmotic resistance was within the normal range from the fourth per fusion onward, These results showed that cyclic plasma perfusion is effecti ve in sustained removal of RBC fragility-inducing factor from plasma, sugge sting that it might have the potential for clinical application.