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Background: Chemotherapy-associated thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (C-TTP/HUS) is a condition involving thrombocytopenia, microangiopathic hemolytic anemia, and progressive renal dysfunction that develops in 2-10% of patients with a history of malignant neoplasms treated with certain chemotherapeutic agents. Pathogenesis of the disease may depend on the following: (1) generation of endothelial lesions in the kidney microvasculature, resulting from drug toxic effects and/or generation of small soluble circulating immune complexes (CIC), and (2) generation of autoantibodies and/or CIC that trigger aggregation and deposition of platelets around the lesions., Methods: Extracorporeal immunoadsorption treatment of plasma (PROSORBA columns, IMRE Corporation, Seattle, WA) to remove immunoglobulin G and CIC was evaluated in 55 patients for the potential to induce significant clinical benefits (increase in platelet count, decrease in hemolysis, stabilization of renal function) and longer survival., Results: Response to therapy was achieved in 25 of 55 patients examined. Response was associated with an estimated 1-year survival rate of 61%, as compared with an estimated survival rate of only 22% in those who did not respond (P = 0.0001). Patients whose malignant neoplasms were in complete or partial remission at the time of development of C-TTP/HUS had a significantly higher estimated 1-year survival rate (74%) as compared with a historic control group of patients receiving other treatments (22%, P = 0.0161). Clinical responses were correlated with normalization of serum levels of CIC and complement components C3c and C4. There were no side effects associated with 75% of treatments. Immunoadsorption therapy was associated with generally mild to moderate manageable side effects, such as fever, chills, nausea/vomiting, respiratory symptoms, pain, hypertension, and hypotension, which were reported in 25% of procedures., Conclusions: This multicenter study establishes protein A immunoadsorption as an effective and safe treatment for cancer chemotherapy-associated TTP/HUS, an otherwise fatal disease.

Ten thrombocytopenic patients (platelets < 10-24 x 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/- 11 x 10(9) per L as compared with counts of 16 +/- 7 x 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/- 810 and 10,010 +/- 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/- 9 and 13 +/- 10 x 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/- 1410 and 1520 +/- 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Two patients with paraprotein-associated peripheral polyneuropathy were treated successfully using immunoadsorption of patient's plasma with staphylococcal protein A. Both had previously been treated with immunosuppressive agents or plasma exchange, and were rapidly relapsing at the time of their protein A immunoadsorption therapy. One patient was treated "on-line" with a blood cell separator, and one was treated "off-line." Both responded well to therapy with minimal toxicity. Serum levels of circulating immune complexes were elevated in one patient and remained so during and after therapy. Immunoadsorption with protein A should be investigated as a therapeutic option for patients with paraprotein-associated peripheral polyneuropathy. The therapy is relatively easy to administer, particularly "off-line," and was well tolerated by our patients. More experience, including formal clinical trials, will be required to properly define the indications for, and mechanism of response to, this therapy.

Epicardial adhesions are believed to form secondarily to impaired pericardial fibrinolytic activity. This activity was reconstituted in a rabbit pericardial adhesion model with single doses of the fibrinolytic agents tissue plasminogen activator (t-PA), t-PA analog (Fb-Fb-CF), and streptokinase (SK), resulting in reductions in the extent and tenacity of adhesion formation. Adhesions of the median strip of the anterior cardiac surface were reduced in area from 89% (n = 22) in controls, to 28% (n = 5) by treatment with Fb-Fb-CF (0.94 mg), and to 49% (n = 7) by treatment with SK (93,750 IU). A modified fabric of oxidized regenerated cellulose (mTC7) used to deliver the agent to the cardiac surface did not interfere with the activity of these agents (Fb-Fb-CF 19%, n = 14; SK 33%, n = 7). t-PA (0.94 mg) was also found to reduce adhesion formation in combination with mTC7 (4%, n = 4), although the appearance of significant postoperative bruising and bleeding resulted in a decision to terminate the treatment of further animals with t-PA with and without mTC7. Postoperative bruising, bleeding, and swelling, to a lesser extent, were associated with SK and Fb-Fb-CF. Despite the efficacy of the these fibrinolytic drugs further work is required to assess their safety before they are used clinically.

Polyhydroxyethylmethacrylate (PHEMA) beads were prepared by phase separation polymerization. Hydroxyl groups on PHEMA beads were activated with CNBr at alkaline pH. Adsorption of heparin, blood proteins (i.e. albumin, fibrinogen and gamma-globulin), protein A, HIgG and DNA on these beads were studied. Preparation and activation procedures are given here. The preliminary results of these studies are also reported.

Protein A of Staphylococcus aureus Cowan I is a powerful immunostimulating agent. Female Swiss Portan rats fed 7,12-dimethylbenz(alpha)anthrancene (DMBA) exhibited increased serum alkaline phosphatase activity, which returned to normal levels following eight weeks of treatment with 12 micrograms protein A subcutaneously. Protein A reduced the potential of tumor induction by DMBA as observed by the noninduction of tumors until three months after discontinuation of protein A administration. The total leukocyte count was not affected. Protein A treatment for six weeks of DMBA-induced mammary adenocarcinoma-bearing rats caused the increased serum alkaline phosphatase activity to decrease but not to normal levels, indicating regression but no disappearance of the tumors. The total leukocyte count of the tumor bearers was stimulated by protein A and increased 24 hours after protein A administration; however, in the fourth week of treatment it returned to normal levels. The leukocytosis suggests that protein A could cause tumor necrosis by an inflammatory reaction, edema, and cell destruction and thus tumor regression.

Fibrinolytic therapy may be effective in the treatment of ischemic stroke, and clinical trials are under way. We evaluated two fibrinolytic agents, an analogue of tissue plasminogen activator (Fb-Fb-CF, the catalytic fragment of the tissue plasminogen activator molecule with a prolonged serum half-life, n = 10) and streptokinase (n = 7), in a rabbit model of embolic stroke. Both agents were given 3 hours after stroke onset, a time relevant to the clinical setting. Fb-Fb-CF was significantly better (p less than 0.04) than saline (n = 7) in restoring blood flow to previously occluded intracranial arteries, but streptokinase was ineffective. Neither fibrinolytic agent was associated with a substantial risk for intracerebral hemorrhagic side effects. Our study demonstrates that Fb-Fb-CF can safely and effectively reperfuse rabbit intracranial arteries 3 hours after occlusion, while streptokinase does not.

Biological effects of staphylococcal protein A (SPA) immunotherapy were studied in 5 viremic and 6 nonviremic cats with induced FeLV infection and in 6 control cats. The SPA therapy neither reversed FeLV viremia nor resulted in consistent improvement in humoral immune responses to FeLV antigens. However, SPA immunotherapy induced a proliferative response in bone marrow granulocytic lineage, possibly resulting in expression of FeLV-free mature neutrophils in the blood. Seemingly, viral burden and chemiluminescent responses were reversed in viremic cats during SPA immunotherapy.

ECI using protein A columns has been designed to selectively remove circulating CICs and IgG from the plasma of patients in whom these substances are associated with their disease. The use of protein A columns appears to be a reasonable alternative to plasmapheresis in many autoimmune disorders for which plasma exchange is indicated. Although preliminary evidence suggests efficacy of plasma exchange, there is a paucity of data indicating that ECI would indeed provide comparable efficacious results. Although the role of ECI using protein A columns for the treatment of ITP continues to be poorly defined, its use in urgent and life-threatening situations in both ITP and HUS appears reasonable. The results of any treatment for chronic refractory ITP continue to be unsatisfactory. However, favorable responses have been achieved using protein A columns, suggesting the need for further investigation. The role of ECI in the treatment of other disorders, including AIDS, TTP, and the treatment of malignancies, where clinical effects are transient, continues to be investigational. The true clinical response rates and duration of responses to ECI using protein A in treating any disorder requires definition in studies involving a larger number of patients with longer followup. The demonstration of the ultimate clinical value of this therapy will require clinical trials comparing its efficacy to other therapies. Although more serious reactions have been reported, toxicities associated with the use of protein A columns are generally transient and mild.

Protein A (SpA) alone or immobilized on bacteria (e.g., Cowan strain I), collodion charcoal, or on Sepharose have been used in serotherapy of cancer in humans and experimental animals. Because SpA forms complexes with IgG that can activate complement, and the physiologic response during treatment often involves hypocomplementemia and reactions that are similar to those induced by anaphylatoxins, we used sensitive and specific radioimmunoassays to test the ability of SpA reagents to generate C3a, C4a, and C5a from human serum. The yield of anaphylatoxins depended on the dose of SpA, with the maximum generation of C3a (47 to 55 micrograms/ml) and C5a (1.4 to 1.9 micrograms/ml) being produced with levels of SpA that were maximally precipitated from serum. Maximum C4a levels (up to 15 micrograms/ml) were obtained at concentrations of SpA equal to or greater than the dose required to give optimal precipitation. The maximum concentrations of anaphylatoxins correspond to essentially quantitative conversions of C3 to C3a, C4 to C4a, and 40% of C5 to C5a after correction for levels found in serum incubated in pyrogen-free saline. Preformed insoluble complexes prepared from either serum or monomeric IgG also were capable of generating anaphylatoxins in fresh whole serum up to levels approximately equal to those observed in serum treated directly with an optimal amount of SpA. The preformed complexes from serum or IgG generated similar high concentrations of anaphylatoxins when carried through four sequential incubations with fresh serum, and complexes that contained approximately 1 microgram SpA were still active. Preincubating the insoluble complexes with chicken anti-SpA serum did not alter their activity. Incubation of serum with collodion charcoal coated with SpA, in a system that models the perfusion technique used to treat cancer, produced complexes that generated significant levels of C3a compared with levels found in serum passaged over albumin charcoal or in untreated serum. The C3a levels in serum from the albumin collodion charcoal were not significantly different from those found in untreated serum. Similar amounts of C3a, C4a, or C5a were observed in serum incubated with differing numbers of bacteria representing a strain of S. aureus rich in cell bound SpA (Cowan strain I) or a strain (Wood 46) deficient in SpA. This suggests that in intact bacteria, cell wall factors other than SpA (e.g., peptidoglycan) are predominantly responsible for generating anaphylatoxins.(ABSTRACT TRUNCATED AT 400 WORDS)

Fischer F 344/CRBL female rats were injected intravenously with 10(6) syngeneic 13,762 adenocarcinoma cells, and daily doses of either 10 micrograms, 100 micrograms or 1 mg Staphylococcus aureus protein A were administered intraperitoneally on days 1 through 11. The animals were sacrificed on day 12, their lungs infused with Bouin's solution, and lung metastases counted. A significant reduction in the number of visible metastatic nodules was observed in the animals given 100 micrograms and 1 mg of Staphylococcus aureus protein A daily.

Adsorption of the plasma of Sprague-Dawley rats having 7, 12-dimethylbenzanthracene (DMBA)-induced primary mammary adenocarcinomas with protein A-containing Staphylococcus aureus Cowan I (SAC) and reinfusion of the adsorbed plasma caused significant (p less than 0.05) regression of mammary adenocarcinomas. Adsorption of plasma was done at different intervals--weekly, biweekly, and on alternate days. Of these protocols, alternate-day adsorptions induced very fast (within a week) tumor regression (p less than 0.001). Other protocols also produced tumor regression; however, the effect was delayed. In long-term studies, the responding animals showed fewer tumor nodules than did the untreated controls. The plasma of the treated animals showed (a) a reduction in blocking activity, (b) an increase in antibody- and complement-mediated cytotoxicity, and (c) potentiation of the cytotoxic activity of peripheral blood mononuclear cells (PBMCs). Histopathological analyses of biopsied sections of tumors from treated animals showed (a) disruption of tumor cell architecture, (b) loss of glandular structure, (c) shrinkage of epithelial cells, and (d) moderate mononuclear cell infiltration. Thus, adsorption of the plasma of DMBA tumor-bearing rats with SAC allows an indigenous immune mechanism to function against autochthonous tumors to control their growth and cause regression.

Tumoricidal responses and tumor regressions have been observed after plasma perfusion over Staphylococcus aureus Cowan I (SAC), or purified protein A immobilized on solid supports. This system was initially studied in a single human patient and then extended to dogs with spontaneous mammary carcinoma, an excellent model of human breast cancer. In the single patient and dogs with mammary tumors, perfusion of plasma over protein A bearing staphylococcus resulted in tumor necrosis and tumor regression. Tumor reduction or growth retardation with similar perfusion systems has been noted in various feline and rodent tumor models. Tumoricidal responses were also observed in canine tumors after perfusion over commercial protein A which was immobilized in a collodion charcoal matrix (PACC). These responses were amplified when a subtherapeutic and nontoxic dose of cytarabine was given after perfusion. Similar tumor reduction in murine and feline tumor models has been noted after perfusion of autologous serum over protein A immobilized on various other solid supports. The PACC perfusion system was extended to five consecutive patients with advanced breast adenocarcinoma. Four of five patients showed tumor regression after perfusion of small volumes of autologous or homologous plasma over PACC. Patients also experienced pyrexia, nausea, vomiting, and significant cardiopulmonary toxicity. Detailed hemodynamic studies of these effects showed that the major pathophysiology involved a decline in total peripheral resistance associated with an increase in cardiac output. With reduction of immobilized protein A quantity and diminution in plasma perfusion rate, the cardiopulmonary toxicity associated with treatments was diminished. Chemotherapy given as FAC to a single patient shortly after concluding perfusion therapy resulted in rapid regression of residual large tumor masses. Studies focusing on the mechanism of the tumoricidal responses have examined changes in sera after incubation or perfusion over immobilized SAC or PACC. Major findings include (1) the identification of protein A leaching from PACC and SAC after serum perfusion and appearing in the effluent as Clq binding oligomers composed predominantly of IgG and protein A but also containing IgA, IgM and C3 with a molecular weight range of 600,000 to 2,000,000; (2) the identification of C3a anaphylatoxins in serum perfused over PACC or SAC; (3) the recognition that several enterotoxins, in particular enterotoxin B are present in commercial protein A preparation.(ABSTRACT TRUNCATED AT 400 WORDS)

Mice (C57BL) succumbed to cultured B16 melanoma cells i.p. with reproducible kinetics and an MST2 of about 26 days. Serum from tumour-bearing or normal mice was treated at 0 degree C with fixed SAC cells and injected i.p. into fresh tumour-bearing mice. If serum was given 7 days or less after B16 inoculation, the MST of the mice was highly significantly increased by up to 32%. Similar activity has been generated in normal human, rabbit and guinea-pig serum, while untreated sera were ineffective. Apparently the sera contained an inactive native precursor that was activated by the SAC to produce an anti-tumour agent. Precursor and product were both relatively labile at 0 degree C. Anti-tumour activity was eluted at pH 2.5 from SAC or Sepharose-protein-A pretreated with serum, thus implicating the protein A component of SAC. The eluates contained haemolytically active C1, the first component of complement, and five crude C1 preparations made by standard methods showed good anti-tumour activity. However, seven other highly haemolytic C1 preparations had no anti-tumour effect. Similarly, two crude preparations of the subcomponent C1q had good anti-tumour activity, but eight other, more pure and highly haemolytic C1q preparations were inactive in mice. Thus the anti-tumour principle was not C1 or C1q alone, although it had some chemical properties in common with these substances. It remains unidentified, but has potential interest for cancer therapy.

Sixteen feline leukemia virus (FeLV)-infected cats with lymphosarcoma (LSA) were treated by extracorporeal immunoadsorption using staphylococcal protein A columns in order to remove immunoglobulin G (IgG) and circulating immune complexes (CIC) from plasma. Complete viral clearance and long-lasting tumor regression were achieved in nine of the cats and tumor regression without virus clearance was observed in two other cats. Since LSA cats rarely go into spontaneous remission, and since other forms of therapy are ineffective, these cats offered a unique system for analyzing details of the immune response to LSA and FeLV as they are cleared. Immunological parameters associated with the FeLV and LSA responses were assessed in detail in three responder cats and three nonresponders during the treatment and follow-up periods. Two serological parameters that always correlated with complete clearance of LSA were development of precipitating antibodies against FeLV-C gp70 and development of cytotoxic antibodies that kill cultured FL74 LSA cells in the presence of complement. The precipitating antibodies were detected prior to the clearance of LSA and prior to the detection of free cytotoxic antibodies. One serological parameter that always correlated with complete clearance of. FeLV was development of free antibodies to FeLV-AB gp70. Quantitative levels of FeLV-specific CIC and feline oncornavirus-associated cell membrane antigen (FOCMA)-specific CIC correlated well with fluctuating levels of the corresponding antigens and antibodies. These results suggest that the staphylococcal protein A treatment columns remove CIC "blocking factors" directly or indirectly and thereby stimulate existing antibody responses. These antibodies mediate clearance of FeLV and LSA.

Staphylococcus aureus Cowan I has shown antitumor activity in in vitro and in animal tumor models. It is hypothesized that this antineoplastic effect results from the interaction of protein A on the cell surface of Cowan I strain S. aureus and immunosuppressive circulating immune complexes. Therefore, we treated five patients with ex vivo plasma immuno-perfusion over killed and fixed S. aureus Cowan I. Toxic effects were marked in all patients and appeared to be related to the plasma volume infused and rate of infusion. Toxic reactions occurred in the cardiovascular, respiratory, and hematopoietic systems. No responses even minimal or transient, were observed in this phase I trial. This toxicity may be reduced if the rate of plasma infusion decreases.

Immunoadsorption therapy employing protein A columns (PROSORBA columns) was used for the treatment of patients with naturally occurring or transfusion-induced immune thrombocytopenia purpura (ITP). Plasma from one unit of blood was perfused through the columns and returned to each patient. This procedure was performed once or twice weekly. In two cases of acute ITP, platelets markedly increased, and platelet-associated IgG (Pa-IgG) and circulating immune complexes (CIC) were decreased following the treatments. A transient increase in platelets was achieved in one patient with chronic ITP. Some improved response to platelet transfusions was noticed in one patient with aplastic anemia and platelet alloimmunization. Two mechanisms are suggested for the effect of protein A column therapy: one is the stimulation of the production of anti-idiotype antibody that neutralizes platelet auto-antibody and the other is activation of complement that induces solubilization and removal of CIC containing platelet autoantibodies. Immunoadsorption by protein A column is a useful therapy for some ITP cases, especially those that are acute.

Extracorporeal immunoadsorption with protein A (SpA) containing Staphylococcus aureus Cowan I (SAC) has previously been shown to induce an antitumor and antiviral response in some feline leukemia virus (FeLV)-infected, lymphosarcoma (LSA) cats. However, the mechanism by which this response is induced is unknown. Since it is possible that SpA dissociates from the SAC column during treatment, and that intravenous infusion of SpA could be a more efficacious form of treatment than extracorporeal immunoadsorption therapy, 6 normal cats and 15 FeLV-infected pet cats with naturally occurring leukemia or LSA were infused with SpA. No toxic effects resulting from SpA infusion were observed in the normal cats. Antitumor effects were observed in one of the eight cats with LSA and in three of the six cats with leukemia, but there were no antiviral responses. The antitumor responses were objective regressions; however, all tumors recurred. These results demonstrate that infusion of SpA into FeLV-infected LSA or leukemic cats can result in an antitumor but apparently not in an antiviral response.

Administration of plasma perfused over Protein A immobilized in collodion-charcoal produced focal acute tumor necrolytic reactions in breast adenocarcinomas. With repeated procedures, objective tumor regressions were observed in four of the first five consecutive patients treated. Within 4 to 48 hr after treatments, tumors became hyperemic and edematous, often with the appearance of focal vesicles. Microscopic and ultrastructural evaluation demonstrated a spectrum of lesions in cytoplasm and nucleus of tumor cells indicative of lethal and sublethal changes. With further treatments, more pronounced degenerative changes in individual tumor cells, tumor nodules, and intervening stroma were apparent. Furthermore, increased luminal and abluminal vesiculation of endothelial cells of postcapillary venules adjacent to tumor nodules was noted. With continued treatments at intervals of 2 to 3 days, some tumor sites showed focal mononuclear cell infiltration, and at the conclusion of plasma perfusion treatments previously ulcerated tumor foci were replaced by granulation tissue. These data suggest that several cytotoxic and inflammatory mechanisms are activated simultaneously or in succession and may account for the tumoricidal effects noted following repeated plasma perfusions.

Circulating immune complexes, autoantibodies, and suppressor factors to normal lymphoproliferation may play an important role in the induction and maintenance of the cellular immunodeficiency characteristic for the acquired immunodeficiency syndrome (AIDS) and its related conditions. In order to explore the possibility that the removal of circulating humoral factors may have an immunomodulatory effect in patients with AIDS and AIDS-related conditions (ARC), we used apheresis procedures to treat patients with different clinical presentations of AIDS and ARC. Five patients with AIDS and opportunistic infections were treated with plasmapheresis. Four patients with AIDS and Kaposi's sarcoma without opportunistic infections were treated with staph protein-A immunoadsorption and two patients with ARC and peripheral neuropathy were treated with lymphoplasmapheresis. The treatments were tolerated well by all patients. Effective removal of circulating humoral immune factors was observed in all three groups. No significant clinical benefit was seen in the patients with AIDS and opportunistic infections treated with plasmapheresis. Partial tumor responses were observed in three of the four patients with AIDS related Kaposi's sarcoma treated with staph protein-A plasma perfusion, and resolution of neurologic symptoms was seen in both patients with ARC and peripheral neuropathy treated with lymphoplasmapheresis. Our preliminary results suggest that lymphoplasmapheresis may be an effective treatment modality for patients with ARC related peripheral neuropathy, that protein-A immunoadsorption is well tolerated by patients with AIDS-related Kaposi's sarcoma, and that this treatment has antitumor and immunomodulatory effects in these patients.

In dogs with spontaneous mammary adenocarcinomas, a single nontoxic infusion of cytosine arabinoside after extracorporeal perfusion of plasms over immobilized protein A resulted in a necrotizing response rapid in onset and specific for tumorous tissue. Gross tumoricidal reactions 12 hours after this combined treatment exceeded the algebraic sum of responses to cytosine arabinoside and protein A perfusion treatments alone in the same dogs, implying a synergistic effect between the two. The magnitude, rapidity, and specificity of the tumoricidal response after the combined treatment suggests that it may be an effective chemimmunotherapeutic approach to breast adenocarcinoma.

I describe morphologic, histologic, immunohistochemical, and serologic changes in dogs with spontaneous breast adenocarcinoma, squamous cell carcinoma, hemangiopericytoma, and fibrosarcoma after extracorporeal perfusion of plasma over heat-killed and formalin-stabilized Staphylococcus aureus Cowans I (SAC), which was embedded in a membrane filtration system. In 12 dogs with breast adenocarcinoma, tumor necrosis was observed within 12 hours after perfusion; 24 hours after perfusion, multiple visible lesions in 6 of 6 dogs exhibited necrosis, but there was no reaction in uninvolved normal mammary tissue. In 8 dogs, healing of large ulcerated areas of cutaneous tumor was observed within 8 to 18 days after perfusion. Similar tumoricidal responses were observed in dogs with other neoplasms after SAC perfusion. Tumor cell necrosis oserved within 4 hours after extracorporeal perfusion was associated with immunohistochemical deposits of IgG and C'3 and ultrastructural evidence of lytic lesions on tumor cell membranes. No tumoricidal effects were observed after perfusion over Staphylococcus aureus Woods (SAW) (non-protein A bearing) in 3 dogs that previously or subsequently responded to SAC perfusion. No tumoricidal reactions were noted after phlebotomy of up to 50% of plasma volume in 6 tumor-bearing dogs that subsequently responded to SAC perfusion. SAC but not SAW perfusion was followed by increases in circulating tumor associated antibodies (TAA) for up to 48 hours after perfusion. Immune complexes increased after perfusion and remained elevated fo 72 hours. Findings suggest that the acute tumoricial responses are not due to mere removal of circulating immune reactants and may be initiated by TAA that are rendered operational after extracorporeal perfusion over SAC. The rapidity, specificity, and magnitude of the observed tumoricidal effects in various canine neoplastic diseases suggests that this may have potentially broad-based therapeutic and biologic implications for canine neoplasia.

We have injected purified Staphylococcus aureus protein A intraperitoneally into leukemic cats infected with feline leukemia virus, into cats persistently infected with feline leukemia virus but without hematologic or cytologic abnormalities, and into healthy cats without feline leukemia virus infection. Pre- and post-treatment serum samples were evaluated sequentially for interferon activity and for complement-dependent cytotoxic antibody. Our results indicate that serum interferon increased dramatically (less than 3 to 324 units/ml) during treatment only in cats that responded to staphylococcal protein A therapy. Increase of interferon preceded or was closely associated with increasing levels of cytotoxic antibody, loss of viremia, and correction of cytological and hematological abnormalities of three leukemic cats. The cytotoxic antibody was shown to be specific for envelope glycoprotein gp70 of the feline leukemia virus. One persistently feline leukemia virus-infected cat without leukemia that became nonviremic also developed high levels of interferon and specific cytotoxic antibody. By contrast, interferon levels of cats not responding to treatment had levels of less than 3 to 27 units/ml. Normal healthy cats injected with staphylococcal protein A showed moderate transient increases of interferon but no detectable cytotoxic antibodies to FL-74 cells. These data suggest that interferon and cytotoxic antibody may play important, possibly complementary roles in inducing remission of leukemia and loss of viremia in cats treated with staphylococcal protein A.

Nineteen patients with metastatic breast cancer refractory to conventional therapy were treated with plasma perfusion over 200 mg of staphylococcal Protein A immobilized on a silica matrix. Fever and chills (33%), pain at the site of tumor (18%), and dyspnea (16%) were the most frequent toxic effects encountered. Four patients (21%) developed a disseminated rash which necessitated cessation of treatment. Of 16 patients evaluable for response, one achieved a minor response of chest wall disease and two had no change in hepatic metastases for 4 and 5 months' duration. Potential mechanisms of antitumor effect are discussed.

Adsorption of autologous plasma over nonviable Staphylococcus aureus Cowan I (SAC) followed by reinfusion of the plasma causes regression of (a) chemically induced rat mammary adenocarcinomas (MA), and (b) canine transmissible venereal tumors (TVT) and spontaneously occurring dog tumors. Animal data are more impressive than that from trials in humans. Nine of 41 patients receiving perfusions of adsorbed plasma showed some partial objective response. Eight of these nine patients received multiple perfusions over a period of time. Twenty-one of 41 patients showed subjective responses. Adsorption of autologous plasma over non-protein A--containing S. aureus Wood 46 caused regression of MA. Adsorption of normal rat plasma with SAC, and infusion of this adsorbed plasma into mammary tumor--bearing rats, caused regression of MA. Intravenous infusion of purified protein A alone caused regression of both rat MA and canine TVT. Superimposed on this observation is the finding that, during plasma adsorption, bacterial moieties leach from SAC. It is possible that the immunostimulation observed in plasma-perfused hosts is due to the removal of plasma blocking agents on one hand, and introduction of the bacterial agents on the other.

Idiopathic thrombocytopenia purpura (ITP) is a primary immune thrombocytopenia that is typically manifested in adults by acute bleeding, severe thrombocytopenia, and normal to increased megakaryocytes in the bone marrow. Labeling studies suggest that most patients with ITP have an IgG antibody directed against the platelet membrane resulting in sequestration in the spleen. Splenectomy and/or corticosteroids remain the mainstay of therapy, with permanent remissions induced in 75% of patients. Despite the use of cyclophosphamide, azathioprine, vincristine, high-dose gamma globulin, and other forms of therapy, less than 50% of refractory patients achieve long-term satisfactory platelet counts. In view of these facts, ten consecutive patients with immune thrombocytopenia, unrelated to human immunodeficiency virus (HIV), received plasma perfusion over a staphylococcal protein A column (PROSORBA column) to evaluate efficacy and toxicity. All patients had an initial platelet count less than 50,000 and had failed corticosteroids. Five patients had also failed splenectomy. Two patients were not splenectomized due to pediatric age, two due to severe coexisting medical conditions, and one due to refusal of operation. Multiple other forms of therapy had also failed in this cohort of patients. Patients received two to ten treatments with the protein A column. All patients are evaluable for response and toxicities. Of the ten patients, results were as follows: complete response in one (platelet count greater than 150,000); partial response in four (platelet count greater than 50,000 and less than 150,000); and no response in five. Duration of responses ranged from 1 to 6 or more months.(ABSTRACT TRUNCATED AT 250 WORDS)

Purified protein A from Staphylococcus aureus Cowan I was injected intraperitoneally or was incorporated in filters ex vivo through which plasma from cats with feline leukemia virus (FeLV)-associated leukemia-lymphoma was passed. Before treatment, 65% of the FeLV-infected cats were anemic, and 70% were thrombocytopenic. Concomitant infections, or immune-mediated disease, was common. During treatment 50% of the cats with FeLV-associated disease improved objectively with normal posttreatment hematocrits, thrombocyte and leukocyte counts, disappearance of dysplastic hematologic elements, and correction of marrow dyscrasias. A 33% response to treatment occurred in cats with unequivocal manifestations of malignant disease and was characterized by reductions in tumor size and marrow and peripheral blood neoplastic cell populations. Clearance of FeLV viremia was documented in 28% of the treated cats. The several possible mechanisms by which treatment with staphylococcal protein A causes reduction in the extent of malignant disease are considered.

Staphylococcus aureus organisms and immobilized Staphylococcal protein A have been used as extracorporeal immunoadsorbents for the treatment of neoplastic disease. In a significant number of cases, a biologic response has been documented. This review analyzes the experimental results to date, correlates experimental design parameters with response to treatment, and discusses possible mechanisms of action. The evidence implicates protein A as the tumoricidal agent, although bacterial or complement components may act independently or synergistically. A more quantitative and fundamental approach is needed to exploit the potential for protein A immunoadsorption in treating neoplastic disease.

Several reports have indicated antitumor effects from the immunoadsorption of plasma from tumor-bearing animals and humans with protein A-containing Staphylococcus aureus. The columns used for these treatments have varied widely in design. In a Phase I trial at the University of Washington, we used protein A chemically linked to crystalline silica for continuous immunoadsorption of plasma in 20 patients with advanced malignancies. Separated blood was perfused continuously over columns containing 50-100 g of immunoadsorbent with 100-200 mg protein A. One calculated plasma volume was perfused over the columns for each treatment. Patients received between 1 and 22 treatments, in total, at one to three treatments per week. Two patients had in vitro treatment of plasma separated from a unit of whole blood obtained by phlebotomy. Side effects were common, were usually manageable, and included chills and fever, nausea, tumor pain, hypotension, and respiratory symptoms. The observed antitumor responses were modest. Three of seven patients with melanoma had indications of responses less than 50%. One of three patients with breast cancer had a response less than 50%. The above studies demonstrate the feasibility of using staphylococcal protein A immunoadsorption in a larger group of patients with a more favorable disease stage.

Protein A, a naturally occurring Staphylococcus aureus cell surface protein, has the unusual property of binding circulating immune complexes and immunoglobulin G with high avidity. CIC have played a major role in cancer-associated immunosuppression. Thus, removal of the immunosuppressive agents, ie, the CIC, may lead to a modulation of the immunosuppression and a liberation of the immune system to perform an antitumor effect. In animal studies, protein A has been used in extracorporeal immunoadsorption columns and treatments have resulted in tumor shrinkage and antiviral responses. Our group developed a multicenter clinical trial to assess toxicity and antitumor responses with this biologic response modifier alone. This is an update of our original trial. We have now treated 142 patients for a total of 1,306 treatments. The patients consisted of 74 males and 68 females. Their age ranged from 7 to 83 years, with a mean of 50 years. The Karnofsky performance index values ranged from 40 to 95, with a mean of 80. Patients who received seven or more treatments were considered eligible for tumor response assessment, and all patients with one or more treatments were eligible for toxicity assessment. Thus, there were 101 patients eligible for tumor response and 142 eligible for toxicity response. The total response rate was 22 patients or 21.8% (partial remission [PR], 12 patients, 12%; less than PR, 10 patients, 10%). Response rates were similar in the 13 treatment centers. Toxicity was assessed in 142 patients. One thousand three hundred six treatments were assessed for treatment toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Perfusion of plasma from tumor-bearing animals over Staphylococcus aureus with membrane-bound protein A has resulted in significant tumor shrinkage. Similar therapy has now been given to 16 patients by three methods. No tumor responses have been observed. Five patients were treated with perfusion over fixed and killed S. aureus Cowan I. Cardiovascular and respiratory toxicity was excessive and appeared to be related to volume and rate of plasma infused. Eight patients were treated with perfusion of autologous plasmas over protein A-collodion-charcoal. Doses of plasma ranged from 50 to 450 ml. No toxicity was noted. Three patients have been treated with perfusion over protein A-silica. Toxicity in two resembled that seen in the S. aureus trials, although it was not as severe. We conclude that the toxicity of this therapy can be life-threatening, and human trials should be undertaken with caution.

This report confirms our previous observation that IV inoculation of purified protein A causes regression of rat mammary adenocarcinomas. In treated tumors, we have obtained histological evidence of changes indicating tumor cell destruction. Protein A treatment does not cause reduction in the body weight or organ weights of rats; nor does it cause any decrease in activity of the enzymes of the microsomal mixed function oxidase system in the liver. Protein A stimulates peripheral white cell counts in normal rats, but not in tumor-bearing rats. We found that protein A infusion reduced (P less than 0.0005) the level of circulating plasma immune complex concentration. A homing study with 125I-labeled protein A indicated that liver, spleen, and kidney tissues are the major sites of protein A accumulation. Therefore, protein A seemed to exert its antitumor effects without causing any generalized toxicity to the system. It is postulated that the action of protein A may be related to its ability to cause a drastic reduction in circulating plasma immune complex concentration, thus potentiating the immune reactivity of the host observed earlier.

Protection from carbon tetrachloride (CCL4)-induced hepatotoxicity by protein A was assessed histologically in rats. Carbon tetrachloride exposure produced swollen, vacuolated and necrotic cells in the centrilobular region of the hepatocyte in rats. Animals given protein A prior to and during CCL1 treatment showed a complete absence of hepatic lesions. Our study showed that protein A, a potent immunomodulator, has the potential to reduce liver injury caused by carbon tetrachloride, a known hepatotoxin in the rat.

Systemic lupus erythematosus was diagnosed in a 3-year-old, male German Shepherd Dog. Clinical signs included lethargy, partial anorexia, fever, joint swelling, and skin and oral ulceration. The diagnosis was confirmed on the basis of an antinuclear antibody titer of 1:640 and immunofluorescence for immunoglobulin G at the dermal-epidermal junction in skin biopsy specimens. Treatment with prednisone and cyclophosphamide failed to induce remission. Intensive plasmapheresis-immunoadsorption, using purified Staphylococcus protein A in combination with low-dose prednisone therapy, resulted in sustained remission.