Prognostic indicators of tumor response to Staphylococcus aureus Cowan strain I plasma perfusion

Ten tumor-bearing dogs were treated with passage of autologous plasma over fixed Staphylococcus aureus Cowan strain I. Five similar dogs were treated identically except for the exposure to S. aureus. These animals have been assessed to identify positive and negative prognostic variables for response. Nonresponder treated animals had significantly larger chest wall tumor bulk than did the responder and control groups (P less than .01). Responder animals had fewer initial circulating immune complexes than did the nonresponders, though each group had similar reductions in immune complexes with therapy. Nonresponder animals had smaller volumes of plasma processed per kilogram of body weight per procedure than did controls (P = .016), whereas responder and control animals had similar volumes processed per kilogram of body weight per procedure (P = .84). These data suggest that the response observed in our original series was significantly related to the larger amount of plasma treated per procedure and suggest that a factor may be eluted from the S. aureus cartridge that mediates this response.