Ex vivo removal of serum IgG in a patient with colon carcinoma: some biochemical, immunological and histological observations

Rapid preparation of 1-vinylimidazole based non-affinity polymers for the highly-selective purification of antibodies from multiple biological sources

There is an urgent need for developing advanced purification techniques with the merits of low cost and satisfactory capacity in order to meet the challenges in the current downstream purification of monoclonal antibodies (mAbs). Herein, a simple and inexpensive nitrogen heterocycle molecule, 1-vinylimidazole (VIM), was proposed as the capture ligand of antibodies for the first time. The corresponding VIM-based non-affinity polymeric material (polyVIM) was then fabricated via a one-step polymerization for use in the highly selective purification of antibodies. Compared to the previously reported materials, this novel material exhibited many advantages without clearly sacrificing selectivity, such as a simpler and faster fabrication (within 1.5 h), comparable or even higher binding capacity (saturated static adsorption capacity > 190 mg/g polymer, dynamic binding capacity about 31.62 mg/g polymer), lower non-specific protein adsorption, and much lower cost. Notably, the polyVIM can effectively purify the antibodies from multiple biological sources with high purity (95.4% for mAbs in the cell culture medium, 93.3% for hIgG in the human serum), with an acceptable recovery (91.6% for mAbs, 77.0% for hIgG), and good reusability (> 10 times). Moreover, the target ELISA binding assay and NFAT-luc reporter gene assay demonstrated that the enriched antibodies can well maintain their binding activity and bioactivity during the whole purification process. The excellent performance of the polyVIM material may be attributed to the high recognition ability of VIM for antibodies, as well as the biocompatible and antifouling properties of the porous polymer. This study provides a promising alternative material for the purification of mAbs in downstream processes and the enrichment of hIgG in human serum.

Extracorporeal removal of immune complexes: Preparation and characterization of immobilized bovine conglutinin

The binding of immune complexes to immobilized bovine conglutinin (K) was studied in order to develop an ex vivo immunoadsorbent system for the removal of circulating immune complexes. K was immobilized to the surface of solid, polymeric beads of two different sizes (1–3 um and 38–63 um diameter) which were activated with N-hydroxysuccinimide ester groups. The binding of both a model immune complex, aggregated human globulin (AHG) and an actual immune complex, bovine serum albumin (BSA): anti-BSA, to the immobilized K were determined utilizing both batch and flow conditions. The binding of AHG occurred rapidly (within 15 min.) at 37°C and additional binding was attained by using a subsequent low temperature incubation (37°C, 30 min., followed by 4°C, 18 hrs.). Uptake of AHG from solution was 2.6 g/g immobilized K. The binding of the 125I-AHG to immobilized K was found to be linear with concentration over the range of 20-2,000 ug AHG/ml tested. Similarly, the binding of BSA:anti-BSA complexes in solution to immobilized K was 0.16 ug 125I-BSA:anti-BSA/ug immobilized K. Significant amounts of the bound AHG were found to be released nonspecifically in the presence of buffered protein solutions, including human serum albumin (HSA) and BSA, while bound BSA:anti-BSA complexes were not released by similar treatments. Effluents of solution perfused over immobilized K showed no toxicity upon intravenous infusion into mice. These studies suggest that K may be immobilized on a biocompatible solid support and in this state retains functional capacity to extract immune complexes from solution. Hence, this may represent a promising system for use as an extracorporeal immunoadsorbent to remove circulating immune complexes in vivo.

Study of imidazole performance as pseudo-affinity ligand in the purification of IgG from bovine milk

The spherical sepharose CL-6B beads were activated by epichlorohydrin in different epoxy contents (80, 120 and 160 μmol_epoxide/mL_gel) and, l-histidine and imidazole as pseudo-affinity ligands were covalently immobilized to them. Some linkers with different length, (1,2-ethanediol diglycidyl ether and 1,4-butanediol diglycidyl ether) were synthesized for activation of sepharose and the activated sepharose beads modified with imidazole and the performance of these adsorbents in the purification of immunoglobulin G from bovine milk were evaluated. Among the l-histidine bearing adsorbents, higher adsorption of IgG (0.28 mg/mL) was obtained by adsorbent with the lower concentration of l-histidine. The highest amount of IgG adsorption (0.53 mg/mL) was obtained by imidazole bearing adsorbent with the highest amount of imidazole and Among the adsorbents with synthesized linkers, the adsorbent with 1,2-ethanediol diglycidyl ether showed better performance and was able to purify 0.25 mg/mL IgG with high purity. The synthesized pseudo-affinity adsorbents represented the abbility to purify immunoglobulin G in one-step process with high purity and efficiency.

Therapeutic Plasma Adsorption. A Review

Alternative techniques to the traditional plasma exchange are emerging in clinical practice for the treatment of different pathological conditions, particularly autoimmune diseases. Filtration is a technique used to separate blood cells from plasma, which may be further “treated” with other filters or columns. The case for cascade filtration and absorption onto a column is becoming stronger and stronger and the patient population is increasing. Alongside the “historical” techniques of adsorption onto a column, new systems (pairs of self-regenerating columns) and new products (columns with dextran sulphate, tryptophane, anti-human lipoprotein antibodies) are now available. Protein A in particular seems to open up new horizons; in therapeutic plasmapheresis, there are two versions, one Swedish and the other American, based on different theoretical premises and obtaining different results, with different biocompatibilities but good clinical results.

Changes in Circulating Immune Complexes in Tumour Patient Serum after in Vitro or ex Vivo Affinity Chromatography of Blood Plasma or whole Blood over Immunoglobulinbinding Staphylococcal Protein A-Sepharose

Circulating immune complexes (CIC) were determined in tumour patient sera using three methods. One is based on PEG-precipitation, one on C1q-reactivity, and one on protein A-reactivity. About 25-30% of the sera were positive in at least one of the tests. Incubation of serum with protein A-Sepharose in vitro removed PEG-precipitable CIC from most sera, whereas C1q-reactive CICs had a much lower affinity to protein A. The protein A-reactive complexes showed considerable variation in their binding to protein A-Sepharose, and in some sera the amount of these CICs was actually increased. Similar changes in protein A-reactive CIC were also found during ex vivo treatment of tumour patients with immune adsorption. It is proposed that the binding of immune complexes to protein A can result in remodelling of protein A itself. Results from ultracentrifugation and fractionated PEG-precipitation support this hypothesis.

The Efficacy of Large Volume Plasma Exchange in Chemotherapy Resistant Malignancies

Chemotherapy resistance in cancer patients may be due to serum blocking factors, which can be deminished or eliminated by large volume plasma exchange (PE). This procedure was performed with the IBM blood cell separator in 69 patients resistant to chemotherapy. Immediately after PE the chemotherapy was given but it failed to produce remission. The combined treatment was reinstituted, if clinical evaluation revealed partial remission, minor response or no change. 37 out of 69 patients (53.6%) responded again, 32 (46.4%) did not. Response duration ranged from 2 to 45 weeks. Best clinical results were obtained in patients with colorectal cancer, 15 out of 23 showed improvement between 4 to 45 weeks. Serum blocking activity was measured using a modified mixed lymphocyte culture assay (MLC). There was a 80% positive correlation between clinical course of patients and MLC levels, if basic activity before the first PE was compared to MLC inhibition before the following PE's.

Protein a Carrying Monosize PMMA Microbeads for the Removal of HlgG from Human Plasma

Protein A-incorporated polymethylmethacrylate (PMMA) microbeads were investigated for specific removal of HlgG from human plasma. The microbeads were prepared by a phase inversion polymerization, and activated by periodate oxidation. Protein A was then incorporated by covalent binding onto these microbeads through hydroxyl groups coming from the stabilizer. The amount of incorporated protein A was controlled by the initial concentrations of protein A in the immobilization medium and pH. The maximum protein A immobilization of 0.615 mg protein A/g PMMA, was observed at a pH of 9.5 corresponding to an initial protein A concentration of 0.1 mg/ml. There was no HlgG adsorption onto the plain PMMA microbeads, while high HlgG adsorptions of up to 32 mg HlgG/g PMMA were achieved with human plasma.

Protein A Immobilized Poly(Methylmethacrylate-Co-Hydroxyethylmethacrylate) Microbeads for IgG Adsorption

Poly(methylmethacrylate- co-2-hydroxyethylmethacrylate) microbeads in the size range of 1.5-2.0μm were prepared by a phase inversion polymerization. The hydroxyl groups were activated by periodate oxidation, and the active ligand, i.e., protein A was immobilized via a spacer-arm, i.e., hexamethylene diamine (HDMA) by using a cross-linker, i.e., glutaraldehyde and protein A. The optimal concentration obtained for modifications are as follows: sodium periodate concentration: 0.467 × 10−2mmol/mL; HMDA concentration: 3.5 × 10−2mmol/mL; and glutaraldehyde concentration: 0.7 × 10−6mmol/mL. Yields of immobilization of protein A onto the plain and periodate oxidized microbeads were found very close, and were in the range of 0.01-0.02 mg protein A/g microbeads. The optimal conditions for immobilization are as follows: the initial protein A concentration: 0.1 mg/mL; temperature: 25°C; pH: 9.5; and immobilization time:120 min. Incorporation of protein A at these conditions resulted in 0.825 mg protein A/g microbeads. The HIgG adsorption onto these protein A incorporated microbeads was 41 mg HIgG/g microbeads.

The gene for staphylococcal protein A

Protein A from Staphylococcus aureus has become an important tool in immunology and molecular biology due to its specific binding to the constant region of immunoglobulins (Igs) from most mammalian species(1). Many qualitative and quantitative techniques have been developed which take advantage of this 'pseudo-immune' reaction(2). In addition, solid state protein A has recently been introduced in medical therapy to decrease the amount of circulating immune complexes in sera(3). In this article Mathias Uhlén, Martin Lindberg and Lennart Philipson describe the structure of the protein A molecule and its gene. They also discuss the possibilities for fusing the protein A gene to other genes.

Affinity-recognition-based polymeric cryogels for protein depletion studies

Supermacroporous cryogels can be used for the depletion of highly abundant proteins prior to proteome investigations.

Immunoglobulin mRNA and protein expression in human oral epithelial tumor cells

In our previous work, we have reported the expression of immunoglobulin (Ig) molecules by numerous epithelial cancer cells and hyperplastic epithelial cells. In the present study, we extended our investigation to study the frequencies of expression of IgG and IgA in some types of oral epithelial tumor cells, and analyzed the oral tumor-derived V regions characteristic of Ig gamma chain gene transcripts by immunohistochemistry, in situ hybridization, laser capture microdissection-correlated reverse-transcription polymerase chain reaction, and sequencing. IgG and IgA immunoreactivity was prominent in the cytoplasmic or plasma membrane or secretion of malignant cells, pleomorphic adenoma tumor cells, and some normal glandular epithelial cells or squamous cells adjacent to tumors. More importantly, rearranged Ig gene transcripts were identified in these tumor cells, and in some normal glandular epithelial cells, the V-D-J region sequences revealed that IgG transcripts in 2 tested oral tumors were oligoclonal. These results support that the phenomenon of Ig could also be expressed in oral cavity epithelial tumor cells.

Immune cells as anti-cancer therapeutic targets and tools

Chronic inflammation is a contributing factor to overall cancer risk as well as cancer promotion and progression; however, pathways regulating onset of cancer-promoting inflammatory responses are still poorly understood. Clinical data suggest that deficient anti-tumor cell-mediated immunity, in combination with enhanced pro-tumor humoral and/or innate immunity (inflammation), are significant factors influencing malignant outcome. Here, we discuss therapeutic implications from clinical data and experimental studies using de novo immune-competent mouse models of cancer development that together are revealing molecular and cellular mechanisms underlying interactions between immune cells and evolving neoplastic cells that regulate cancer outcome. Understanding the functionally significant links between adaptive and innate immunity that regulate cancer development will open new therapeutic opportunities to manipulate aspects of immunobiology and minimize lethal effects of cancer development.

Immunoglobulin G depletion from human serum with metal-chelated beads under magnetic field

Magnetic poly(ethylene glycol dimethacrylate-N-methacryloyl-(L)-histidine methyl ester) [mag-poly(EGDMA-MAH) beads, 50-100 microm in diameter, were produced by suspension polymerization for affinity depletion of immunoglobulin G (IgG) from human serum. Cu2+ ions were complexed directly via MAH groups (Cu2+ loading: 4.1 micromol/g). IgG depletion studies were performed by magnetically stabilized fluidized bed column. Acetate, Tris-HCl, MES and phosphate buffers all allow adsorption of similar quantities of IgG (27.3-45.6 mg/g). MOPS and HEPES allow higher adsorption quantities (79.6 mg/g and 74.1mg/g, respectively). Maximum adsorption capacities in MOPS buffer were 46.8 mg/g for mag-poly(EGDMA-MAH) and 102.1mg/g for Cu2+ chelated mag-poly(EGDMA-MAH) beads. The adsorption capacity decreased drastically from 102.1mg/g to 30.7 mg/g with the increase of the flow rate from 0.2 ml/min to 3.5 ml/min. The elution studies were performed by 1.0M NaCl. The elution results demonstrated that the adsorption of IgG to the adsorbent was reversible. To test the efficiency of IgG depletion from human serum, proteins in the serum and eluted portion were analyzed by two-dimensional gel electrophoresis. The depletion efficiency for IgG was above 99.4%. Eluted proteins include mainly IgG, and a small number of non-albumin proteins such as apo-lipoprotein A1, sero-transferrin, haptoglobulin and alpha1-antitrypsin. When anti-HSA-sepharose adsorbent is used together with our metal-chelated mag-beads, IgG and HSA can be depleted in a single step.

Novel metal-chelate affinity adsorbent for purification of immunoglobulin-G from human plasma

Metal-chelating ligand and/or comonomer 2-methacrylolyamidohistidine (MAH) was synthesized by using methacryloyl chloride and L-histidine methyl ester. MAH was characterized by NMR and FTIR. Spherical beads with an average diameter of 75-125 microm were produced by suspension polymerization of methylmethacrylate (MMA) and MAH carried out in an aqueous dispersion medium. Poly(MMA-MAH) beads had a specific surface area of 37.5 m(2)/g. Poly(MMA-MAH) beads were characterized by water uptake studies, FTIR, SEM and elemental analysis. Elemental analysis of MAH for nitrogen was estimated as 34.7 microM/g of polymer. Then, Cu(2+) ions were chelated on the beads. Cu(2+)-chelated beads with a swelling ratio of 38% were used in the adsorption of human-immunoglobulin G (HIgG) from both aqueous solutions and human plasma. The maximum adsorption capacities of the Cu(2+)-chelated beads were found to be 12.2 mg/g at pH 6.5 in phosphate buffer and 15.7 mg/g at pH 7.0 in MOPS. Higher adsorption value was obtained from human plasma (up to 54.3 mg/g) with a purity of 90.7%. The metal-chelate affinity beads allowed one-step separation of HIgG from human plasma. The adsorption-desorption cycle was repeated 10 times using the same beads without noticeable loss in their HIgG adsorption capacity.

Correcting immune imbalance: the use of Prosorba column treatment for immune disorders

The treatment of selected refractory autoimmune diseases has been complemented by the use of Protein A (Prosorba column) immunoadsorption. US Food and Drug Administration-approved clinical applications include idiopathic thrombocytopenia purpura (ITP) and rheumatoid arthritis (RA). Other common off label uses include thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). Less common experimental uses in diseases in which efficacy has been reported include autoimmune CNS syndromes, peripheral neuropathies, autoimmune pancytopenia, hemolytic anemia and solid organ transplant rejection. Prosorba column treatment is generally well tolerated but a small proportion of treated patients experience chills, fever, tremor, hypotension and rash. The mechanism of action suggested for the efficacy of the column is the restoration of normal immune balance and normal tolerance. Observations in ITP has suggested that column treatment stimulates a rise in anti-idiotype antibody directed against antiplatelet antibodies, effecting a decrease in pathogenic antiplatelet antibodies and immune complexes.

Use of a modified zirconia support in the separation of immunoproteins

Zirconia beads (25-38 microm in diameter) were modified with N,N,N',N'-ethylenediaminetetramethylenephosphonic acid to generate a zirconia based pseudoaffinity support, further referred to as r_PEZ. The influence of pH, salt concentration and temperature on the binding of human immunoglobulin G (hIgG) to r_PEZ was studied. Temperature had no significant impact on the maximum binding capacity (Qmax), and the equilibrium-binding constant (Kd), whereas pH and the salt concentration had a noticeable impact on both Qmax and Kd. The Qmax value of 55 mg hIgG/ml of bead was obtained at a pH of 5.5 and found to decrease with an increase of pH. The modified zirconia support allowed the separation of immunoglobulins (IgG, IgA and IgM) from untreated human serum. Elution was possible under mild conditions with a step salt gradient. Overall protein recoveries in the range of 109-125% were obtained with human serum. Human IgG, human IgA, and human IgM yields of 29.50+/-6.3, 3.22+/-0.7, and 6.84+/-0.7%, respectively, were obtained at a linear velocity of 4.32 cm/min. Purity of products, obtained from a single chromatographic step was estimated to be greater than 89.0+/-2.6%. The utility of r_PEZ in the selective removal of immunoglobulins, as in immunoadsorption was discussed.

Background and indications for protein A-based extracorporeal immunoadsorption

Protein A (SPA), a major cell wall component of Staphylococcus aureus, has occupied numerous investigators from its discovery in the late fifties. Its availability and avid binding to human immunoglobulins have led to extensive usage for diagnostic and research purposes. Today, SPA-based extracorporeal immunoadsorption relies on two rather different systems, namely, SPA-silica (Prosorba), and SPA-Sepharose (Immunosorba). Both systems are approved by the Food and Drug Administration for the core indications of rheumatoid arthritis and idiopathic thrombocytopenic purpura (SPA-silica) or hemophilia with inhibitors (SPA-Sepharose). Off label indications include immune disorders with a conceivable connection between autoantibody titers and disease activity, like forms of glomerulonephritis, systemic lupus erythematodes, myasthenia, and the Guillain-Barré syndrome as well as alloantibody formation in the context of e.g., transplantation. This review summarizes historical developments and important properties of SPA. Indications for extracorporeal therapy are discussed on the basis of available information and personal experience.

How Prosorba Apheresis Came to Be Used for Rheumatoid Arthritis: A Personal Historical Perspective

The Prosorba column is an effective treatment for refractory rheumatoid arthritis. In this article, I review how membrane methodologies evolved with regard to the management of the disorder through a focused review of rarely cited key references and personal experience.

Protein A-immobilized microporous polyhydroxyethylmethacrylate affinity membranes for selective sorption of human-immunoglobulin-G from human plasma

Microporous membranes made of poly(2-hydroxyethylmethacrylate) [poly(HEMA)] carrying protein A were used for selective sorption of human-IgG from human plasma. Poly(HEMA) membranes were prepared by a photo-polymerization technique, and activated by cyanogen bromide (CNBr) in an alkaline medium (pH 11.5). Bioligand protein A was then immobilized by covalent binding onto these CNBr-activated membranes. The amount of immobilized protein A was controlled by changing pH and the initial concentrations of CNBr and protein A. The non-specific adsorption of protein A on the plain poly(HEMA) membranes was 2.9 microg cm(-2). Maximum protein A immobilization was observed at pH 9.5. Up to 186 microg cm(-2) was immobilized on the CNBr-activated poly(HEMA) membranes. The maximum adsorption of human-IgG on the protein A-immobilized poly(HEMA) membranes was observed at pH 8.0. The non-specific adsorption of human-IgG onto the plain poly(HEMA) membranes was low (about 4.4 microg cm(-2)). Higher human-IgG adsorption values (up to 394 microg cm(-2)) were obtained in which the protein A-immobilized poly(HEMA) membranes were used. Much higher amounts of human-IgG (up to 489 microg cm(-2)) were adsorbed from human plasma. Up to 91% of the adsorbed human-IgG was desorbed by using 0.1 M aminoacetic acid as elution agent. The adsorption-desorption cycle was repeated ten times using the same polymeric membranes. There was no remarkable reduction in the adsorption capacity of the protein A-immobilized poly(HEMA) membranes.

Low-speed centrifugation of retroviral vectors absorbed to a particulate substrate: a highly effective means of enhancing retroviral titre

For many gene therapy applications the effective titre of retroviral vectors is a limiting factor both in vitro and in vivo. Purification and concentration of retrovirus from packaging cell supernatant can overcome this problem. To this end we have investigated a novel procedure which involves complexing retrovirus to a dense and particulate substrate followed by a short low-speed centrifugation. The study reported here uses heat-killed, formaldehyde fixed Staphylococcus aureus (Pansorbin) absorbed to PG13 derived retrovirus. This complex was then used to harvest retrovirus from packaging cell supernatant: centrifugation and washing of this complex allows the retrovirus to be both purified and concentrated. This procedure increases the effective titre of retrovirus by up to 7500-fold after an only 200-fold reduction in volume. The affinity of Pansorbin for retrovirus allows concentration regardless of its encoded genes and makes this protocol applicable to other popular packaging cells and envelope proteins. Possible explanations for the marked increase in titre of concentrated virus and the mechanism governing the complexing of retrovirus to Pansorbin are discussed.

Protein A immobilization and HIgG adsorption onto porous/nonporous and swellable HEMA-incorporated polyEGDMA microspheres

Both non swellable and swellable poly(EGDMA/HEMA) microbeads were produced by suspension copolymerization. These microbeads were modified by immobilization of a spacer-arm (hexamethylene diamine (HMDA)) and protein A. The optimal values for modifications were as follows: sodium periodate concentration, 1.0 mgml(-1); HMDA concentration, 4 mgml(-1); and glutaraldehyde concentration, 0.070 microgml(-1). Adsorption of protein A onto the plain and periodate oxidized poly(EGDMA/HEMA) microbeads were very close to each other, and were 0.01-0.02 mg protein A on the 1-g Microbeads I and II, respectively. Protein A immobilization on poly(EGDMA/HEMA) microbeads were studied at different temperatures, times, and pHs using single protein solution containing different amounts of proteins. The optimal values for immobilization were as follows: the initial protein A concentration, 0.1 mgml(-1); temperature, 25 degrees C; pH, 9.5; and immobilization time, 120 min. Incorporation of protein A resulted in 1.420 and 1.825 mg protein A on the 1-g Microbeads I and II, respectively. HIgG adsorption capacity on the protein A-incorporated poly(EGDMA/HEMA) microbeads is 27 and 35 mg HIgGg(-1) polymer for Microbeads I and II, respectively.

Promotion of tumor invasion by cooperation of granulocytes and macrophages activated by anti-tumor antibodies

We investigated the potential role of anti-tumor antibodies and tumor antigens in the formation of immune complexes which promote matrix degradation and angiogenesis. B-cell deficient or B-cell depleted mice showed a reduction in tumor invasion and metastasis. In vitro invasion assays and in vivo models of metastasis showed that anti-sTn antibodies and sTn tumor antigens form complexes which induce granulocytes and macrophages together to mediate tumor invasion and metastasis by processes including extracellular matrix degradation and angiogenesis. These results suggest the existence of a tumor promoting role of a B-cell immune response induced by shed tumor associated antigens of solid, nonlymphoid tumors.

First results for resetting the antitumor immune response by immune corrective surgery in colon cancer

BACKGROUND

A critical step for cancer recurrence is the failure of the cellular immune response. It is suspected that chronic humoral immune responses against some tumor-associated antigens (TAA) can contribute to that failure.

METHODS

In this study, we tested the ability of an immune corrective surgical procedure to prevent recurrences of colon cancer in stages I, II, and III. Radiolabeled anti-TAG antibodies injected intravenously become concentrated on TAG-72 immune complexes presented by follicular dendritic cells, which are responsible for the persistent humoral response against TAG-72 TAA. Using a hand-held gamma probe, we can intraoperatively detect and remove lymph nodes involved in TAG-72 presentation. By removing these lymph nodes, together with the tumor tissue, presentation and source of TAG-72 are drastically reduced.

RESULTS

The impact of this TAA suppression on the tumor recurrence process is analyzed in a sample of 24 patients. The immune corrective surgical procedure did not increase morbidity. Five years after surgery the following were disease free: 5 of 5 stage I, 6 of 6 stage II, and 10 of 13 stage III. The global survival of this group was 87.5%. Compared with the standard surgical treatment of colon cancer (58% survival for the same stages), this surgical immune corrective procedure introduces a statistically significant improvement of 29% (P <0.001).

CONCLUSIONS

The surgical removal of lymph nodes involved in the persistent humoral immune response against TAA has an important beneficial impact on colon cancer treatment.

Chemotherapy in non-small cell lung cancer: a meta-analysis using updated data on individual patients from 52 randomised clinical trials. Non-small Cell Lung Cancer Collaborative Group

OBJECTIVE

To evaluate the effect of cytotoxic chemotherapy on survival in patients with non-small cell lung cancer.

DESIGN

Meta-analysis using updated data on individual patients from all available randomised trials, both published and unpublished.

SUBJECTS

9387 patients (7151 deaths) from 52 randomised clinical trials.

MAIN OUTCOME MEASURE

Survival.

RESULTS

The results for modern regimens containing cisplatin favoured chemotherapy in all comparisons and reached conventional levels of significance when used with radical radiotherapy and with supportive care. Trials comparing surgery with surgery plus chemotherapy gave a hazard ratio of 0.87 (13% reduction in the risk of death, equivalent to an absolute benefit of 5% at five years). Trials comparing radical radiotherapy with radical radiotherapy plus chemotherapy gave a hazard ratio of 0.87 (13% reduction in the risk of death; absolute benefit of 4% at two years), and trials comparing supportive care with supportive care plus chemotherapy 0.73 (27% reduction in the risk of death; 10% improvement in survival at one year). The essential drugs needed to achieve these effects were not identified. No difference in the size of effect was seen in any subgroup of patients. In all but the radical radiotherapy setting, older trials using long term alkylating agents tended to show a detrimental effect of chemotherapy. This effect reached conventional significance in the adjuvant surgical comparison.

CONCLUSION

At the outset of this meta-analysis there was considerable pessimism about the role of chemotherapy in non-small cell lung cancer. These results offer hope of progress and suggest that chemotherapy may have a role in treating this disease.

Protein A immobilized polyhydroxyethylmethacrylate beads for affinity sorption of human immunoglobulin G

Protein A immobilized polyhydroxyethylmethacrylate (PHEMA) microbeads were investigated for the specific removal of HIgG from aqueous solutions and from human plasma. PHEMA microbeads were prepared by a suspension polymerization technique and activated by CNBr in an alkaline medium (pH 11.5). Protein A was then immobilized by covalent binding onto these microbeads. The amount of immobilized protein A was controlled by changing pH and the initial concentrations of CNBr and protein A. The maximum protein A immobilization was observed at pH 9.5. Up to 3.5 mg protein A/g PHEMA was immobilized on the CNBr activated PHEMA microbeads. The maximum HIgG adsorption on the protein A immobilized PHEMA microbeads was observed at pH 8.0. The non-specific HIgG adsorption onto the plain PHEMA microbeads was low (about 0.167 mg of HIgG/g PHEMA). Higher adsorption values (up to 6.0 mg of HIgG/g PHEMA) were obtained in which the protein A immobilized PHEMA microbeads were used. Much higher amounts of HIgG (up to 24.0 mg of HIgG/g PHEMA) were adsorbed from human plasma.

A phase II trial of extracorporeal plasma immunoadsorption of patient plasma with PROSORBA columns for treating metastatic breast cancer

BACKGROUND

Circulating immune complexes (CIC) have been implicated as a cause of malignancy-associated immunosuppression and disease progression. Previous attempts to remove CIC by pheresis or immunoadsorption over a Staphylococcus aureus protein A column have resulted in a few clinical responses, however the relationship between removal of CIC and tumor response in these trials is not clear. Based on these data, a Phase II trial of immunoadsorption over a Staphylococcus aureus protein A column was initiated for patients with metastatic breast cancer. The authors sought to correlate clinical response with amount of CIC eluted from the columns after immunoadsorption.

METHODS

The potential role of extracorporeal immunoadsorption was determined using protein A columns in treating patients with advanced breast cancer. An immunoadsorbent column composed of protein A was bound covalently to an inert silica matrix (PROSORBA [IMRE Corporation, Seattle, WA] column). Patients underwent a 3-hour on-line procedure phlebotomizing 2000 ml of whole blood. Patient plasma was passed over PROSORBA columns to remove immunoglobulin G (IgG) and IgG-related CIC. The treated plasma then was reunited with formed elements and reinfused into the patient. Patients were treated three times per week for a total of 4 weeks. Analyses of tumor-associated Le(x)-containing CIC adsorbed on PROSORBA columns were performed using an enzyme-linked immunosorbent assay technique with a monoclonal antibody specific for the Le(x) moiety.

RESULTS

Sixteen patients were entered in this Phase II study, with a mean age of 57 years (range, 40-69 years). All patients received prior treatment for Stage IV breast cancer. The median number of PROSORBA treatments was 12 (range, 1-15 treatments). No toxicities or major objective responses were seen noted the 16 patients. One patient with severe chest wall pain had a symptomatic response. The remaining patients all had disease progression. Analyses of column eluates from 11 patients in this study revealed no detectable Le(x)-containing immune complexes when compared with control subjects.

CONCLUSIONS

Immunoadsorption over a Staphylococcus aureus Protein A column had no meaningful antitumor activity in patients with advanced breast cancer. In this cohort of patients, an elevated level of Le(x) CIC was not confirmed in the eluates of the column compared with a control group of patients without cancer.

Evidence for proteolytic cleavage of covalently bound protein A from a silica based extracorporeal immunoadsorbent and lack of relationship to treatment effects

Studies were conducted to evaluate the potential cause for release of covalently bound Staphylococcal protein A (SpA) from a silica based extracorporeal immunoadsorbent matrix. In vitro tests revealed that SpA could be detected in human plasma, human serum, and chicken serum upon exposure to the immunoadsorbent matrix which had been treated to remove non-covalently bound SpA. In contrast, only minute quantities of SpA were detected after exposure of a physiologic mixture of purified albumin and immunoglobulin G (IgG) to the immunoadsorbent matrix. Additional tests, employing a cocktail of protease inhibitors and formalin as a general stabilizer and protease inhibitor, revealed significant inhibition of endogenous proteolytic activity present in plasma and serum. Prevention of this proteolytic activity also significantly inhibited the release of covalently bound SpA from the immunoadsorbent matrix upon contact with plasma or serum samples. Further analyses of serum samples from patients with immune thrombocytopenia, chemotherapy associated thrombotic thrombocytopenic purpura-hemolytic uremic syndrome, and breast cancer revealed a lack of association between the quantity of SpA proteolytically released and observed clinical responses or adverse effects experienced during immunoadsorption treatments. These studies indicate that SpA detected in plasma or serum after exposure to the immunoadsorbent is due to inherent endogenous proteolytic activity which cleaves protein fragments from the matrix and that these cleaved SpA fragments do not appear to contribute to the observed clinical responses or adverse effects in treated patients.

Treatment of autoimmune disease by immunomodulation through extracorporeal elimination and intravenous immunoglobulin

If customary drug mediated immunosuppressive therapy leads to intolerable side effects or is inefficient, extracorporeal elimination and untargeted or targeted immunoglobin therapy modulating the immune response are taken into consideration for the treatment of patients with autoimmune diseases. Both elimination and immunoglobulin therapy, are not alternatives but appear to act complementary, if sequentially applied. Selective immunoadsorption is increasingly applied for extracorporeal elimination and is able to replace plasma exchange therapy. Both, hydrophobic interaction chromatography and affinity chromatography are effective in given clinical conditions. Therapeutic affinity chromatography appears to be superior to hydrophobic interaction chromatography, if an effective, rapid elimination of the disease promoting agent is desired. Experience with therapeutic chromatography collected in the past, indicates that a rapid elimination of immunoglobulins and the subsequent intravenous infusion of 7S immunoglobulin is superior to elimination or untargeted immunomodulation alone. These experimental approaches lead to an extension of the available treatment modalities. However, controlled trials rather than anecdotal reports are needed, to provide substantial information.

A Randomized Study of On-Line Plasma Perfusion over Protein A-Sepharose and 5-Fluorouracil Chemotherapy in Patients with Metastatic Colorectal Carcinoma

To evaluate the safety of on-line plasma perfusion over protein-A sepharose and the therapeutic advantage of combining plasma perfusion (PP) over protein-A sepharose with 5-fluorouracil (5-FU) chemotherapy in patients with metastatic colorectal carcinoma (MCRC), thirty patients were randomized after surgery of primary CRC to receive a combination of 5-FU and PP over protein-A sepharose (group A), or a combination of 5-FU and PP over sepharose (group B), or 5-FU alone (group C). Bi-weekly on-line PP over 200 ml protein-A sepharose gel (group A) or 200 ml sepharose gel (group B) were performed with a Cobe 2997 blood cell separator for a maximum of 19 treatments per patient. 5-FU was given at 1000 mg/m2/d on days 1-5 of a 4-weekly cycle until progression. PP was well tolerated and no severe or life-threatening toxicity was observed. Mild clinical side-effects consisted of fever and chills (36% in group A, 23% in group B). The most common biological effects of PP over protein-A sepharose were significant drops in IgG (66% of pre-PP values), CH50 and C3 (73% of pre-PP values) and a significant generation of C3a and C5a anaphylatoxins. Tumor response rates were 40% for group A, 0% for group B and 20% for group C. The median survival times tended to be longer in group A (17 months) than in group B (10 months) and in group C (9 months). This is the first randomized trial showing some therapeutic advantage in combining PP over protein-A sepharose with conventional chemotherapy in MCRC.

Minimal toxicity during protein A immunoadsorption treatment of malignant disease: an outpatient therapy

Extracorporeal removal or modulation of circulating immune complexes (CIC) from plasma of animals and humans with malignant disease may be associated with induction of immune-mediated anti-tumor responses. Immunoadsorption columns containing heat-killed and formalin-fixed Staphylococcus aureus or staphylococcal protein A have been used for this purpose but treatments have often been associated with cardiopulmonary toxicity. Recently, an immunoadsorption device containing highly purified protein A covalently attached to a silica matrix (PROSORBA column) was used to treat 142 patients with refractory malignancies and 22 of 104 patients evaluated for anti-tumor response had objectively measurable reduction in tumor burden. In contrast to earlier experience with other devices, the procedures used in this trial were well tolerated and could be performed on an outpatient basis. The most common side effects observed among 1,306 treatments were chills (28% of treatments), low grade fever (28%), and musculoskeletal pain (16%). Side effects were mild to moderate and required no treatment or only symptomatic treatment. Treatment schedules were interrupted due to side effects for only six patients and there were no treatment-related deaths. Of 64 patients available for long-term follow-up evaluation (mean of 11 months), none exhibited evidence of long-term treatment-related side effects. None of the patient deaths in that period were associated with short or long-term treatment-related side effects. Protein A-silica (PROSORBA columns) can be used safely for development of further experimental treatments of malignant disease.

Immunological aspects of mammary tumors in dogs and cats: a survey including own studies and pertinent literature

Naturally occurring cancer in companion animals parallels cancer in man more closely than does experimentally induced cancer in inbred laboratory animals. In dogs and cats, as in man, a role for immune responses is indicated in the development of tumors. A survey is presented based on the literature and our own studies concerning the immunological and immunotherapeutic aspects of canine and feline mammary neoplasia. In dogs bearing mammary neoplasms, circulating immune complexes appear to play a negative role in the generation of effective antitumor immune responses. The functional role of peripheral blood lymphocytes and tumor-infiltrating lymphocytes in dogs and cats with mammary tumors is not yet fully established. No tumor antigen responsible for humoral or cellular responses has yet been identified. Extracorporeal perfusion of serum of dogs with mammary tumors and subcutaneous administration of mitomycin- and neuraminidase-treated autologous tumor cells are associated with improved prognosis. The opposite was true for i.v. treatment with BCG or Corynebacterium parvum vaccine in our study, in contrast to a previous report. A number of other treatment modalities in cats and dogs with mammary carcinomas failed to induce tumor regression. Canine and feline mammary carcinomas are good candidates for modern immunotherapeutic approaches.

A randomized study of combined 5-fluorouracil and plasma perfusion over protein A-sepharose in human advanced colorectal carcinoma

To evaluate the advantage with regard to toxicity, response rate, time to progression and survival of combination chemoimmunotherapy over single-agent chemotherapy in patients with metastatic colorectal carcinoma (CRC), 30 patients were randomized to receive a combination of 5-fluorouracil (5-FU) by continuous i.v. infusion and plasma perfusion (PP) over protein A-Sepharose (group A), or a combination of 5-FU and PP over sepharose (group B) or 5-FU alone (group C). 5-FU was given at 1,000 mg/m2/d on days 1-5 of a 4-weekly cycle until progression. Patients of groups A and B received bi-weekly on-line PPs until disease progression or for a maximum of 19 treatments. PP was well tolerated and no severe or life-threatening toxicity was observed. The response rates were 10% for the group A (1 PR), 0% for the group B and 20% for the group C (1 CR + 1 PR). The times to tumor progression for patients in groups A and C were 22 months, 12 and 11 months, respectively and the median survival times were 17 months, 10 months and 9 months. Although the time to progression and survival tended to be higher in patients treated with protein A. PP, these differences were not statistically significant. This is the first report of a randomized trial showing some therapeutic advantage in combining protein A. PP with 5-FU in CRC patients. Further randomized studies are required to demonstrate the real true value of this chemoimmunotherapeutic approach.

Trial of anticancer immunotherapy with immobilized pokeweed mitogen: immunotherapy by extracorporeal circulation

For the purpose of activating the immune system in the living body, we made use of pokeweed mitogen (PWM). PWM, a type of lectin, has the potential to induce anticancer cells. In order to utilize this potential and apply it to cancer therapy by hemoperfusion with PWM, the lectin is immobilized on the surface of synthetic polymer beads and these beads are packed into a minicolumn. Human peripheral lymphocytes were activated by circulatory contact stimulation through the PWM column for 1h. After circulatory contact stimulation through the column, lymphocytes were collected and used as effector cells. Cytotoxicity tests were measured by 51Cr-release assay using K-562 cells and Daudi cells for targets. This material could enhance natural killer activity and induce cytotoxicity against natural-killer-resistant Daudi cells. Lymphocytes activated by the PWM column were injected intraregionally into nude mice bearing MKN-1 tumor, and suppression of tumor growth was recognized. Anticancer activities by direct hemoperfusion treatment with a PWM minicolumn were examined in Vx2-tumor-bearing rabbits. A single treatment using the PWM column was performed 6 days after tumor inoculation. Suppression of the tumor growth was observable for 25 days. PWM minicolumns are a likely anticancer material, acting as immunomodulators.

Biocompatibility of extracorporeal immunoadsorption systems

Following the first publication of a technique aiming for clinical application in 1969, extracorporeal immunoadsorption is increasingly finding a place among haemapheresis techniques. The apparent advantages outweigh the technical difficulties and economical drawbacks still connected with this treatment modality. At present three different developments are under clinical investigation: Staphylococcus Protein-A based immunoadsorption (SpA), the antibody-mediated adsorption (therapeutic affinity chromotography) and hydrophobic interaction-based immunoglobulin adsorption. The exact binding capacity and mechanism has not been completely elucidated for SpA and amino acid-based techniques. The lack of knowledge about pathogenic substrates exclusively responsible for the pathogenicity of many diseases, appears to be the major drawback for the prospective development of affinity chromatography-based extracorporeal systems. The practical application of molecular-biologic diagnostic procedures with a high grade of detection specificity (monoclonal antibodies) appears to be promising for the development of extracorporeal immunoadsorption. The immunomodulatory effect that results from the interaction of blood and plasma with artificial surfaces is an interesting subject of investigation, derived mainly from biocompatibility studies. The careful clinical and laboratory investigation of the biocompatibility of extracorporeal immunoadsorption systems contribute considerably to the prevention of undesired side effects.

IgG immunoadsorption in experimental allergic neuritis: effect on antibody levels and clinical course

The effect of IgG immunoadsorption upon the course of chronic experimental allergic neuritis (EAN) is described. Miniature membrane plasma separators coupled with a Protein A (PA)-Sepharose immunoadsorbent column were used to perform upon conscious rabbits 5 IgG immunoadsorption treatments over 6 days. Quantitation of anti-myelin IgG and IgM by ELISA revealed that 55-65% of plasma IgG was removed per treatment. Rapid post-treatment antibody rebound was observed for anti-myelin IgG although no antibody overshoot above control levels could be observed. Anti-myelin IgM levels remained relatively unaffected by PA immunoadsorption. Comparisons of clinical scores between control and treatment animals showed that IgG immunoadsorption was significantly beneficial (day 1 post-treatment p less than 0.001; day 2 post-treatment p less than 0.05). However, rapid relapse was observed in all treatment animals such that by day 3 post-treatment no significant clinical difference between control and treatment groups could be observed. IgG immunoadsorption suppresses the clinical progression of chronic EAN in a manner similar to that seen with plasma exchange. This finding suggests that antibody modulates early disease pathogenesis.

Protein A immunoadsorption therapy in HIV-related immune thrombocytopenia: a preliminary report

Nine homosexual patients with immune thrombocytopenia were treated with autologous plasma that had been perfused over silica-immobilized Staphylococcus aureus protein A (SpA). Pretreatment platelet counts ranged from 10,000 to 98,000 cells/mm3 (mean: 54,000 cells/mm3). Six patients responded to therapy. Platelets increased by a mean of 95,000 cells/mm3 (p less than 0.007) and reached normal levels (greater than 150,000 cells/mm3) in four patients. Increased platelet counts are presently sustained in these four individuals after 5 months of follow-up. Increases in platelet counts significantly correlated with decreases in platelet-associated IgG (PAIgG), platelet-directed IgG (PDIgG), and immune complexes (CIC). PAIgG and PDIgG declined by a mean of 67% (p less than 0.003) and 58% (p less than 0.007), respectively. CIC decreased by a mean of 37% (p = 0.02). Complement was concomitantly activated in all four examined patients. C3a and C5a increased 23-fold and 2.6-fold, respectively, while total hemolytic complement decreased by 50%. Activated complement components and removal of CIC and IgG thus may contribute to the platelet-enhancing activity of SpA immunoadsorption therapy.

Serotherapy of cancer: cellular changes in primary rat mammary carcinomas after infusion of syngeneic sera absorbed with protein A-Sepharose

Serotherapy and plasma therapy have proved to be effective in the treatment of diverse neoplasms. The mechanisms of the tumoricidal or growth-inhibitory effects are unknown. We previously reported that activation of the alternative pathway of complement in absorbed sera correlated with the presence of anti-tumor activity. Complement components generated during absorption may serve as the initial mediators of cytotoxicity; for example, C5a may function in its role as a chemo-attractant. To further investigate the anti-tumor mechanisms, we undertook a series of sequential histological studies of in vivo changes in tumors following i.v. serotherapy. We found diffuse inflammatory cellular infiltrates in the interstitial compartments of primary mammary carcinomas of rats within 3-4 hr of administration of protein A-Sepharose absorbed syngeneic serum. The number of inflammatory cells was significantly higher in tumors from treated rats: total infiltrating cells (p = 0.002), eosinophils (p = 0.001), neutrophils (p = 0.001), macrophages (p = 0.001), lymphocytes (p = 0.004) and plasma cells (p = 0.001). Also, the mitotic index of tumor cells was significantly lower 4 hr after serotherapy when compared with that of untreated rat tumor cells. C3 in tumor tissue was decreased at 4 hr following serotherapy. Fibrosis was present in tumor nodules with retarded growth 5 weeks after the start of serotherapy. Localization of the infiltrating cells to tumor interstitial compartments prevents direct contact between inflammatory cells and neoplastic cells, making it unlikely that direct cell-cell killing occurs. Indirect cell killing within the tumor bed apparently occurs through several mechanisms involving interactions between serotherapy-initiated humoral mediators and inflammatory cells. The resulting anti-tumor effects include microvascular injury leading to localized ischemia, tumor infarction, and fibroblastic reactions obstructing tumor invasion and growth.