Therapeutic plasmapheresis and protein A immunoadsorption in malignancy: a brief review

Cancer-driven IgG promotes the development of prostate cancer though the SOX2-CIgG pathway

BACKGROUND

Although androgen deprivation therapy (ADT) is the initial treatment strategy for prostate cancer (PCa), recurrent castration-resistant prostate cancer (CRPC) eventually ensues. In this study, cancer-derived immunoglobulin G (CIgG) is found to be induced after ADT, identifying CIgG as a potential CRPC driver gene.

METHODS

The expression of CIgG and its clinical significance in PCa tissue was analyzed by The Cancer Genome Atlas database and immunohistochemistry. Subsequently, the sequence features of prostate cell line VHDJH rearrangements were analyzed. We also assessed the effect of CIgG on the migratory, invasive and proliferative abilities of PCa cells in vitro and vivo. Suspended microsphere, colony formation and drug-resistant assays were performed using PC3 cells with high CIgG expression (CIgG^high ) and low CIgG expression (CIgG^-/low ), and A nonobese diabetic/severe combined immunodeficiency mouse tumor xenograft model was developed for the study of the tumorigenic effects of the different cell populations. The SOX2-CIgG signaling pathway was validated by immunohistochemistry, immunofluorescence, quantitative reverse transcription-polymerase chain reaction, Western blot, luciferase, and chromatin immunoprecipitation assays and bioinformatics analyses. Finally, we investigated the effect of RP215 inhibition on the progression of PCa in vivo using a Babl/c nude mouse xenograft model.

RESULTS

CIgG is frequently expressed in PCa and associated with clinicopathological characteristics, moreover, CIgG transcripts with unique patterns of VHDJH rearrangements are found in PCa cells. Functional analyses identified that CIgG was induced by ADT and upregulated by SOX2 (SRY (sex determining region Y)-box 2) in PCa, promoting the development of PCa. In addition, our findings underscore a novel role of CIgG signaling in the maintenance of stemness and the progression of cancer through mitogen activated protein kinase/extracellular-signal-regulated kinase and AKT in PCa. In vivo experiments further demonstrated that depleting CIgG significantly suppressed the growth of PCa cell xenografts. Furthermore, a CIgG monoclonal antibody named RP215 exhibits tumor inhibitory effect as well.

CONCLUSION

Our data suggests that CIgG could be a driver of PCa development, and that targeting the SOX2-CIgG axis may therefore inhibit PCa development after ADT.

Cancer-derived sialylated IgG promotes tumor immune escape by binding to Siglecs on effector T cells

To date, IgG in the tumor microenvironment (TME) has been considered a product of B cells and serves as an antitumor antibody. However, in this study, using a monoclonal antibody against cancer-derived IgG (Cancer-IgG), we found that cancer cells could secrete IgG into the TME. Furthermore, Cancer-IgG, which carries an abnormal sialic acid modification in the CH1 domain, directly inhibited effector T-cell proliferation and significantly promoted tumor growth by reducing CD4⁺ and CD8⁺ T-cell infiltration into tumor tissues. Mechanistic studies showed that the immunosuppressive effect of sialylated Cancer-IgG is dependent on its sialylation and binding to sialic acid-binding immunoglobulin-type lectins (Siglecs) on effector CD4⁺ and CD8⁺ T cells. Importantly, we show that several Siglecs are overexpressed on effector T cells from cancer patients, but not those from healthy donors. These findings suggest that sialylated Cancer-IgG may be a ligand for Siglecs, which may serve as potential checkpoint proteins and mediate tumor immune evasion.

Severe Refractory Paraneoplastic Mucous Membrane Pemphigoid Successfully Treated With Rituximab

Mucous membrane pemphigoid (MMP) is a rare autoimmune bullous disease of the mucous membranes, which can cause irreversible scarring and is discussed to be associated with cancer, if laminin-332-autoantibodies are present. MMP with severe ocular and laryngeal involvement is difficult to treat and can be treatment-refractory to conventional immunosuppressant therapy. A 67-year-old man with a history of prostate cancer presented to our clinic with sore throat, intraoral bullae, odynophagia, dysphonia, exertional dyspnea, and erosions of the glans penis. Clinical examination confirmed a laryngo-pharyngitis with involvement of the epiglottis and bilateral symblepharon. Diagnostics comprising multiple biopsies, direct and indirect immunofluorescence, serology analysis, and immunoblotting confirmed the diagnosis of a paraneoplastic MMP by showing a subepithelial split in histology and the presence of anti-laminin-332-antibodies. Despite combined systemic treatment with prednisolone and either dapsone or azathioprine, a progress of the disease occurred leading to severe ocular and laryngeal complications. Two month after rituximab treatment, complete disease control was achieved. This case report shows a severe ocular and life threatening laryngeal involvement of therapy-refractory paraneoplastic MMP highlighting the importance of interdisciplinary management and difficulty of diagnosing MMP despite repeated diagnostic testing.

Value of the pretreatment albumin to globulin ratio in predicting long-term mortality in breast cancer patients

BACKGROUND

Prior studies have demonstrated the prognostic value of pretreatment serum albumin in different types of cancer. The aim of this study was to assess the predictive value of the albumin to globulin ratio (AGR) on survival in breast cancer patients.

METHODS

This retrospective study used an unselected cohort of 354 breast cancer patients who had documented total protein and albumin levels prior to chemotherapy. Survival status was obtained from our cancer registry. Survival analysis, stratified by AGR tertiles, was used to evaluate the prognostic value of AGR.

RESULTS

Patients in the highest AGR tertiles (AGR > 1.45) had a lower 5-year mortality rate compared with those in the middle (AGR 1.21 to 1.45) and the lowest (AGR < 1.21) tertiles (6% vs. 18% and 32%, P < .001). After adjusting for confounding variables, AGR remained a significant predictor of mortality (P < .002). Moreover, after excluding the patients with albumin levels less than 3.6, the AGR remained a significant predictor of survival (P .0018).

CONCLUSIONS

Pretreatment AGR is an independent, significant predictor of long-term mortality in breast cancer patients, even in patients with normal albumin levels.

Protein�A immunoadsorption therapy for refractory, mitomycin�C?associated thrombotic microangiopathy

BACKGROUND

Mitomycin C-associated thrombotic microangiopathy (TMA) has a poor prognosis with limited therapeutic options. Most patients die within 4 months of diagnosis due to pulmonary or renal failure. Here, a patient resistant to total plasma exchange (TPE) and immunosuppressive therapy with glucocorticoids, rituximab, vincristine, and splenectomy who was successfully treated with protein A immunoadsorption is described.

CASE REPORT

A 29-year-old woman developed a TMA after chemotherapy with mitomycin C. She presented with thrombocytopenia, pulmonary edema, hemolytic anemia with presence of schistocytes, and renal failure. Immediate TPE (>120 times) and immunosuppressive therapy with glucocorticoids, however, did not improve her clinical situation. Furthermore, she was refractory to subsequent immunosuppressive therapy with rituximab and vincristine and laparoscopic splenectomy. Finally, after 12 cycles of extracorporeal protein A immunoadsorption with a commercially available immunoadsorption system (Immunosorba, Fresenius AG), platelet counts increased with disappearance of hemolytic syndromes.

CONCLUSION

Extracorporeal protein A immunoadsorption with the Immunosorba system emerges as a potentially effective and safe treatment for refractory mitomycin C-associated TMA with only moderate side effects. This therapeutic option may be considered at an early state of the disease to prevent extensive immunosuppression.

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.

Therapeutic plasmapheresis

Plasmapheresis is the process by which plasma containing components causing or thought to cause disease is removed from the circulation, and the remaining blood components are returned with plasma or a harmless plasma substitute to the donor. It primarily removes protein-bound solutes or high-molecular-weight solutes such as circulating protein-bound toxins, autoantibodies, immune complexes, or other abnormally occurring molecules. Plasmapheresis has been used in the treatment of more than 100 diseases in human medicine, including immune-mediated diseases, neoplasia, infectious diseases, sepsis, hyperlipidemia, thyrotoxicosis, and removal of toxins. In immune-mediated disease, it is most useful to rapidly decrease plasma concentrations of antibodies or immune complexes, whereas other immunosuppressive measures are used to prolong the effect.

Therapeutic apheresis in malignancy

Plasmapheresis (PP), staphylococcal protein A immunoadsorption (SPI), and extracorporeal photochemotherapy (EP) have been utilized in cancer treatment for about 20 years. PP removes immune complexes and induces a temporary increase in T4/T8 ratio, natural killer cell activity, and blastogenic responses. SPI removes immune complexes, enhances lymphocytic responses, and activates complement. EP increases lysis of circulating lymphoma cells by CD8+ cytotoxic T cells and increases tumor necrosis factor production by host monocytes. PP induces partial remission in about 28% of patients, but this remission is short lived. SPI gives similar results. Addition of PP to chemotherapy has been reported to prolong survival in patients with multiple myeloma. EP appears useful in treating cutaneous T cell lymphomas with 25% of patients achieving complete response and 50% of patients attaining partial remission. Thus, PP and SPI induce short-lived immune responses, but have no proven clinical utility. EP may be useful in the treatment of cutaneous T cell lymphomas.

The use of protein A columns in the treatment of cancer and allied diseases

The staphylococcal cell-wall protein known as protein A has been explored as a therapeutic modality in the treatment of cancer and allied diseases. Protein A binds the Fc fragment of IgG 1, 2 and 4, and preferentially binds to IgG incorporated into immune complexes. Early investigators focused on the immune-suppressive effects of immune complexes in cancer and, based on in vitro experiments, postulated that clearance of immune complexes in vivo would permit effective immune clearance of cancer cells. A large clinical trial of the perfusion of cancer patient plasma over protein A was subsequently undertaken. Results were generally disappointing, with no complete remissions and overall response rates of 22%. Response rates for Kaposi's sarcoma (39%) and breast adenocarcinoma (26%) were somewhat encouraging, and further clinical trials in these disorders are ongoing. More impressive have been the responses to protein A perfusion in immune thrombocytopenia and hemolytic-uremic syndrome. Using a protein A-silica device, Snyder et al. reported responses in 42% of immune thrombocytopenia patients, with mean increases in platelet count from 27 x 10(9)/l to 120 x 10(9)/l. On the basis of these results, the protein A-silica column was approved by the United States Food and Drug Administration for treatment of immune thrombocytopenia. Equally encouraging are reports of an overall 59% response rate in cancer chemotherapy-related hemolytic-uremic syndrome. Reported toxicities include fever, chills, hypotension, dyspnea and musculoskeletal pain. With rare exceptions, these reactions are easily treated and do not result in cessation of therapy. Unfortunately, the mechanism of action of plasma perfusion over protein A is very unclear.(ABSTRACT TRUNCATED AT 250 WORDS)

An unexpected complication following immunoadsorption with a staphylococcal protein A column

Extracorporeal immune adsorption with staphylococcal protein A (SPA) columns can remove immune complexes and immunoglobulins in the treatment of a variety of diseases. We present the case of an elderly man with neuropathy associated with monoclonal gammopathy, treated by 3 on-line SPA procedures. At the completion of these treatments his neuropathy relapsed, progressing to near-total paralysis. Return to a baseline clinical status required several months. The reason for this severe relapse is not clear. Possible explanations include SPA activation of T-lymphocytes, with release of gamma interferon and increased antigen recognition, or removal of an antiidiotype control mechanism. We advise caution in the application of immunoadsorption to conditions in which it has not yet been evaluated.