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Biomedical subjects

G Riethmüller

Publications and source records attributed to G Riethmüller.

At least 37 records · Page 2Linked to original sources

Micrometastases of bone marrow in localized prostate cancer: correlation with established risk factors.

PURPOSE: The presence of cytokeratin 18-positive cells in bone marrow correlates with conventional risk factors in many tumors. We examined whether this was also valid for localized or lymphatically spread prostate cancer. PATIENTS AND METHODS: Immediately before radical prostatectomy, bone marrow aspirates from both sides of the iliac crest were taken from 287 patients. The presence of cells containing cytokeratin 18 was interpreted as micrometastasis. RESULTS: In patients with negative lymph nodes (n = 219), conventional risk factors (Gleason score, pathologic stage, ploidy, and preoperative prostate-specific antigen) did not correlate with the preoperative detection of cells containing cytokeratin 18. There was also no correlation with lymph node metastases. Furthermore, there was no interdependency between the preoperatively detected number of cells and the established risk factors. CONCLUSION: We assume the presence of epithelial cells in bone marrow to be an independent parameter, the clinical importance of which must be substantiated by further studies.

Adenocarcinoma↗

Monoclonal antibody therapy with edrecolomab in breast cancer patients: monitoring of elimination of disseminated cytokeratin-positive tumor cells in bone marrow.

Despite current advances in antibody-based immunotherapy of breast and colorectal cancer, we have recently shown that the actual target cells (e.g., tumor cells disseminated to bone marrow) may express a heterogeneous pattern of the potential target antigens. Tumor antigen heterogeneity may therefore represent an important limitation of the efficacy of monospecific antibody therapy. To measure the efficacy of such a monospecific approach, we analyzed the elimination of tumor cells coexpressing the epithelial cell adhesion molecule (EpCAM) under therapy with murine monoclonal antibody 17-1A (Edrecolomab) directed against EpCAM. In bone marrow aspirates from 10 breast cancer patients with metastatic (n = 8) and locoregional recurrence (n = 2), tumor cells were identified with the antibody A45-B/B3 directed against the epithelial differentiation marker cytokeratin (CK) and simultaneously typed for EpCAM expression using the antibody 17-1A. Patients were treated with a single dose of 500 mg of Edrecolomab and monitored by bone marrow analyses before and at days 5-7 after antibody treatment. In all 10 patients, we assessed a marked reduction in the mean numbers of both CK+ cells (73 versus 15; P = 0.003, t test) and EpCAM+/CK+ cells (17 versus 1; P = 0.003, t test) per 10(6) bone marrow cells. Complete elimination of EpCAM+ cells was possible in four patients. We conclude that Edrecolomab can be used in breast cancer patients to target isolated EpCAM+/CK+ cancer cells. Using CK-based immunoassays, we reliably detected residual tumor cells in bone marrow and typed EpCAM expression. This allowed us to monitor the cytotoxic elimination of such cells after Edrecolomab application. Selection of EpCAM-/ CK+ tumor clones showed that further antibodies directed against tumor-associated antigens are warranted to improve the efficacy of monospecific approaches.

Antibodies, Monoclonal↗

A novel dendritic cell population in human blood: one-step immunomagnetic isolation by a specific mAb (M-DC8) and in vitro priming of cytotoxic T lymphocytes.

Originating from a common progenitor cell, dendritic cells (DC) appear to develop along early branched pathways into various yet ill-defined subpopulations residing at various sites throughout the body where they capture and present antigen in the most professional fashion. Here we give evidence for a unique subpopulation of human DC circulating in blood that account for 0.5-1% of blood leukocytes only, their most specific characteristic being the expression of a cell surface protein recognized by a novel monoclonal antibody (M-DC8) which enables their isolation by a one-step immunomagnetic procedure. The isolated cells (> 97% pure) present morphologically as typical dendritic cells. They express the Fc(gamma)RIII (CD16), so far not found on DC, and avidly phagocytose latex beads as well as opsonized erythrocytes. These cells not only present antigens efficiently to naive T cells but also induce purified CD8+ T cells to become alloantigen-specific cytotoxic cells. Furthermore, when loaded with a tyrosinase-derived peptide they stimulate T cells from normal donors and melanoma patients to exhibit MHC-restricted specific cytotoxicity against melanoma cells.

Antibodies, Monoclonal↗

Diagnosis and therapeutic relevance of micrometastases.

The disseminated isolated tumor cell has become a formidable object of solid tumor research for at least three good reasons: it can be identified in organ compartments such as bone marrow, blood, and lymph nodes and, once found, it can be morphologically characterized with respect to tumor-associated antigens, oncogenes, tumor suppressor genes, proliferation markers, and/or growth receptors. Thirdly, it is also an ideal target for immunotherapy directed at accessible, well-defined membrane-associated antigens of the tumor cell.

Antigens, Neoplasm↗

Lack of protection from HIV infection by the mutant HIV coreceptor CCR5 in intravenously HIV infected hemophilia patients.

The CCR5 chemokine receptor is an important coreceptor for macrophage-tropic HIV strains. Homozygous carriers of the mutated CCR5 receptor with a 32 bp deletion (delta 32-CCR5) are highly protected against HIV infection. A protective effect has also been described for heterozygous individuals carrying both mutated and wildtype CCR5 receptors. We compared the frequency of the mutated delta 32-CCR5 HIV coreceptor in HIV positive patients infected by sexual contact (N = 160) with intravenously HIV infected hemophilic patients (N = 84) and HIV negative individuals (N = 421). We found no protective effect of delta 32-CCR5 HIV coreceptor in hemophilic patients (p = 0.0134). If proteins of plasma concentrates would be responsible for facilitating the entry of HIV macrophages by upregulation of the CCR5 wildtype receptor it would be of therapeutical interest to identify the responsible plasma proteins.

Female↗

Reduced expression of plakoglobin indicates an unfavorable prognosis in subsets of patients with non-small-cell lung cancer.

PURPOSE: Plakoglobin is thought to play a key role in cadherin-mediated epithelial cell adhesion, because it is a common component of desmosomal and nondesmosomal adherens junctions. Because loss of homotypic cell adhesion is an important early step in invasion and metastasis of solid tumors, we evaluated the frequency and prognostic significance of a deficient expression of plakoglobin in human lung cancer. PATIENTS AND METHODS: At primary surgery, representative specimens of the primary tumor were obtained from 96 consecutive patients with completely resected non-small-cell lung carcinoma (NSCLC) without overt distant metastases. Cryostat sections of these specimens and metastatic lymph nodes were stained with monoclonal antibody (mAb) PG 5.1 against plakoglobin, using an immunoperoxidase technique. Patients were monitored for a median of 39 months (range, 12 to 56) after surgery. RESULTS: Absent or severely reduced expression of plakoglobin (ie, < 30% positive tumor cells) was observed in 39 patients (40.6%). There was no significant correlation to established risk factors, such as the histology, extension, and histologic grade of the primary tumor and metastatic lymph node involvement, or expression of alpha-catenin. Expression of plakoglobin in lymph node metastases ranged from 0% to greater than 60% positive tumor cells. Deficient plakoglobin expression on the primary tumor was significantly correlated to a shortened disease-free and overall survival in patients with adenocarcinomas, pT1-2 tumors, or negative lymph nodes (pN0). In patients with pT1-2 tumors, the independence of this prognostic influence from established risk factors was demonstrated by Cox regression analyses (disease-free survival, P = .002; overall survival, P = .038). CONCLUSION: Deficient expression of plakoglobin appears to be an important event in the progression of NSCLC.

Adult↗

Monoclonal antibody therapy for resected Dukes' C colorectal cancer: seven-year outcome of a multicenter randomized trial.

PURPOSE: As previously shown, antibody treatment increased survival of patients with resected colorectal cancer of stage Dukes' C. Since the 5-year analysis was criticized because of the wide range (2.7 to 7.5 years) of follow-up time, we performed a 7-year analysis with only four of 189 patients monitored for less than 5 years. PATIENTS AND METHODS: A total of 189 patients with resected Dukes' C colorectal cancer were randomly allocated to infusions of a total of 900 mg 17-1A antibody, 500 mg postoperatively followed by 4 monthly doses of 100 mg (n=99), or to observation only (n=90). Primary end points were overall survival and disease-free interval. Patients were stratified by a dynamic randomization according to center, sex, location of tumor, number of affected lymph nodes, and preoperative carcinoembryonic antigen concentration. RESULTS: Randomization produced balanced distribution of risk factors. After 7 years of follow-up evaluation, treatment had reduced overall mortality by 32% (Cox's proportional hazard, P < .01; log-rank, P=.01) and decreased the recurrence rate by 23% (Cox's proportional hazard, P < .04; log-rank, P=.07). The intention-to-treat analysis gave a significant effect for overall survival (Cox's proportional hazard, P < .01; log-rank, P=.02) and disease-free survival (Cox's proportional hazard, P=.02; log-rank, P=.11 ). While distant metastases were significantly reduced (Cox's proportional hazard, P=.004; log-rank, P=.004), local relapses were not (Cox's proportional hazard, P=.65; log-rank, P=.52). This differential effect of 17-1A antibody on disseminated isolated tumor cells versus occult local satellites may explain the increased significance seen in the overall survival. CONCLUSION: The now-matured study shows that 17-1A antibody administered after surgery prevents the development of distant metastasis in approximately one third of patients. The therapeutic effect is maintained after 7 years of follow-up evaluation.

Adenocarcinoma↗

Depletion of CD8+ T lymphocytes by murine monoclonal CD8 antibodies and restored specific T cell proliferation in vivo in a patient with chronic hepatitis C.

Cellular immune mechanisms, especially those mediated by CD8+ T cells, are important in the pathogenesis and control of viral infections. On the other hand, as shown for chronic lymphocytic choriomeningitis virus infection in the mouse, CD8+ T cells may not only hinder the elimination of a virus, but make the host unresponsive to a second viral infection. In hepatitis C virus (HCV) infections, at least 50% of the patients become chronically infected, despite the detection of HCV-specific CTL and a specific proliferative response to HCV Ags in PBL and in lymphocytes isolated from the liver. To better understand the immunopathologic mechanisms of CD8+ cells in vivo and to search for a potential treatment, we applied murine CD8 mAbs to a patient with therapy-resistant chronic HCV. A drastic reduction of CD8+ circulating lymphocytes, a reduction of CD8 molecule density, and complement fixation on CD8+ cells were observed. The reduction of CD8+ cells was compensated partially by an elevation of CD4+ cells. High concentrations of neutralizing human anti-mouse Abs were induced. After the Ab infusions, the CD4/CD8 ratio in peripheral blood increased from 1.6 to values of about 3 during therapy, and gradually decreased to 2.3 1 yr after the last mAb infusion. A continuing decrease of serum aminotransferases and clinical improvement was observed. Interestingly, after initiation of treatment, a significant proliferative response to HCV-specific Ags became measurable.

Adult↗

Immunocytochemical monitoring of micrometastatic disease: reduction of prostate cancer cells in bone marrow by androgen deprivation.

Occult dissemination of tumor cells mainly determines the prognosis of patients with primary prostate cancer. The effect of androgen deprivation on micrometastatic tumor cells in these patients is currently unknown. We therefore used an immunocytochemical assay with monoclonal antibodies (MAbs) directed against epithelial cytoskeleton proteins (i.e., cytokeratins) to monitor the concentration of isolated tumor cells in the bone marrow of 36 prostate cancer patients (stage C), who underwent hormonal androgen deprivation with Flutamide and Leuprorelin acetate. Tumor cells in cytologic bone marrow preparations were detected using an assay that employed the MAb CK2 directed against cytokeratin (CK) 18 and the alkaline anti-alkaline phosphatase staining method. Prior to therapy, we detected between 1 and 38 CK-positive cells per sample of 2 x 10(6) nucleated cells in 21 patients, while the remaining 15 patients displayed tumor-free marrow samples. There was no significant correlation between the concentration of CK-positive cells and the volume of hypo-echogenic lesions as an indicator of the primary tumor volume or the serum level of prostate-specific antigen (PSA). After androgen deprivation, 20 of the 21 initially positive patients either became negative (n = 16) or showed at least a reduction in the concentration of CK-positive cells (n = 4). Moreover, only 2 of the 15 patients with negative pre-treatment findings became positive. All of the 7 patients with remaining tumor cells in the bone marrow after therapy showed no detectable amounts of PSA in their serum. Our findings suggest that serum PSA concentration is no indicator of micrometastatic disease in bone marrow. Neoadjuvant androgen deprivation appears to eliminate disseminated CK-positive tumor cells present in bone marrow, a preferred site of overt metastasis in prostate cancer patients.

Adenocarcinoma↗

Biologic properties of a bispecific single-chain antibody directed against 17-1A (EpCAM) and CD3: tumor cell-dependent T cell stimulation and cytotoxic activity.

Anti-CD3 x anti-tumor-bispecific Abs have been used to redirect cytotoxic T cells to tumor cells in an MHC-unrestricted fashion and to induce their rejection in vivo. We have recently described a recombinant bispecific single-chain Ab that combines four different V regions of two Abs, anti-17-1A and anti-CD3, on one polypeptide chain. It folds correctly to a 60-kDa globular protein and is secreted in fully functional form by a high producer Chinese hamster ovary cell line. In this work, we report that its remarkable cytotoxicity against 17-1A+ tumor cells is exerted via T cells without an apparent engagement of a detectable costimulatory pathway. T cells are activated only by the bispecific Ab when coincubated with 17-1A+ target cells. In a chromium release assay, CD8+ T cells reach maximal tumor cell cytotoxicity within 4 h, while CD4+ T cells need about 20 h to reach similar levels of cytotoxicity. Addition of costimulatory CD28 Abs did not lead to a further increase in cytotoxicity. Its remarkable stability at 37 degrees in serum, the ease of production, and purification by affinity chromatography via polyhistidine tail make this smaller version of a bispecific Ab a promising candidate for a therapeutic trial in patients with solid tumor. Because adjuvant therapy with an intact, much less cytotoxic IgG2a Ab against the 17-1A target had already increased the 7-yr survival of colorectal cancer patients by 30%, the presented small bispecific construct lacking the immunogenic murine Fc region as well as autochthonous T lymphocyte stimulatory activity warrants a therapeutic trial in patients with minimal residual 17-1A+ cancer.

Animals↗

Endothelial expression of CD40 in renal cell carcinoma.

Recently, the immunoregulative molecule CD40 has also been introduced as a potential surface determinant of endothelial cells that can be induced by various cytokines and thus might be involved in inflammatory vascular reactions. In this study, the ubiquitous endothelial expression of CD40 within the neovascularized areas of renal cell carcinoma is demonstrated. The strong capillary expression of CD40 in 12 tumor samples is contrasted by the absence of endothelial CD40 in the corresponding tumor-free kidney specimens in which only certain tubular segments and few interstitial cells carry CD40. Northern hybridization studies confirmed the presence of CD40 RNA in cytokine-treated endothelial cells and in renal cell carcinoma, whereas no hybridization signal was obtained with normal kidney tissue. That the presence of tumor cells is pertinent to the endothelial expression of CD40 could be substantiated by in vitro experiments, when a renal carcinoma cell line and its supernatant, but not normal kidney cells, could induce CD40 on endothelial cells in culture. According to further experimental results, the carcinoma-derived, CD40-inducing factor(s) is not represented within a variety of pleiotropic cytokines including IFN-gamma, interleukin 1, interleukin 6, and tumor necrosis factor alpha, or common angiogenic factors such as basic fibroblast growth factor, vascular endothelial cell growth factor, angiogenin, and erythropoietin. The immunohistological results showing a widespread, even distribution of CD40 in tumor capillaries suggest that within renal cell carcinoma, the appearance of endothelial CD40 may also be related to angiogenesis in addition to inflammation.

CD40 Antigens↗

Occult epithelial tumor cells detected in bone marrow by an enzyme immunoassay specific for cytokeratin 19.

The presence of isolated carcinoma cells detected immunocytochemically in bone marrow has been shown to be of prognostic relevance for cancer patients. Unfortunately, the immunocytochemical method (ICC) is laborious and depends on the subjective interpretation of the individual investigator. Therefore, an immunoassay was designed for detection of cytokeratin 19 (CK19). By analyzing blood samples from 52 healthy volunteers and 40 bone-marrow aspirates from control patients, a cut-off point of 250 pg/ml CK19 was determined. Application of this cut-off point enabled a specificity of 95% to be shown for bone marrow and of nearly 100% for venous blood. The assay detected 10 HT-29 colon-carcinoma cells among 5 x 10(6) peripheral-blood leukocytes. In comparison with controls, bone-marrow samples of cancer patients were found to have significantly elevated levels of CK19 (p < 0.05). In the analysis of 386 marrow aspirates of cancer patients, a significant concordance of ELISA and ICC was observed (chi 2 = 18.3; p < 0.001). Both procedures, nevertheless, differed in 147 (38%) samples, of which more than two thirds (101) were only ELISA-positive. The CK status detected by ELISA did not correlate with the TNM stage and the histological grading. The established immunoassay allowed sensitive and specific detection of disseminated epithelial tumor cells and appeared to be faster, less laborious and more objective than ICC. Follow-up studies are required to assess the prognostic relevance of this ELISA before it can be applied as a routine method for monitoring of minimal residual epithelial cancer.

Biomarkers, Tumor↗

[Disseminated tumor cells: diagnosis, prognostic relevance, phenotyping and therapeutic strategies].

The incidence of local relapse after complete (R0) resection of solid tumors is largely determined by the skill of the surgeon, whereas metastatic relapse in distant organs is caused by pre- or perioperative systemic dissemination of tumor cells. The presence of individual disseminated tumor cells--e.g., in bone marrow as indicator organ--can be detected by sensitive immunocytochemical and molecular methods and is increasingly considered as a clinically relevant prognostic indicator. In contrast to solid metastases, isolated micrometastatic tumor cells are appropriate targets for intravenously applied anti-cancer therapeutics because they are easily accessible to macromolecules and immunologic effector cells. The majority of these tumor cells appear to be nonproliferating (i.e., in the G0 phase of the cell cycle), which may explain the failure of adjuvant chemotherapy. Adjuvant therapeutic strategies aimed at quiescent tumor cells are therefore of increasing interest. This therapeutic rationale has been tested and confirmed in a randomized clinical trial using antibody 17-1A in patients with non-metastatic colorectal carcinoma (UICC stage III). The antibody therapy kills also quiescent tumor cells ("dormant cells") and is independent from a potential chemotherapy resistance of the tumor cells. As treatment for minimal residual cancer, the clinical use of antibody therapy could be envisaged in conjunction with chemotherapy, applied either in parallel or sequentially. The aim of this review is to present and discuss the current state of research in the field of diagnosis and therapy of minimal residual cancer.

Antibodies, Neoplasm↗

Cellular and molecular analyses of major histocompatibility complex (MHC) restricted and non-MHC-restricted effector cells recognizing renal cell carcinomas: problems and perspectives for immunotherapy.

Renal cell carcinomas belong to the small group of tumors that are able to induce antitumor responses. Here we describe two general types of cytotoxic effector lymphocytes that can eliminate autologous tumor cells and discuss the role that major histocompatibility complex encoded molecules play in governing their specificities. Improved understanding of the cellular and molecular basis of renal cell carcinoma recognition opens new avenues of research with the potential to develop better immunotherapies for patients with metastatic disease.

Antigen-Antibody Reactions↗

Analysis of T cell activation pathways in patients with liver cirrhosis, impaired delayed hypersensitivity and other T cell-dependent functions.

Patients with cirrhosis of the liver frequently demonstrate anergy in intracutaneous tests and fail to respond to vaccination, suggesting impaired delayed hypersensitivity and other T cell-dependent functions in vivo. T cell activation through the coordinated interaction of different cells of the immune system (B cell, antigen-presenting cells (APC)) is an important step in the induction of cellular and humoral immune responses. Impaired T cell-dependent functions in patients with liver cirrhosis may thus be explained by defective T cell activation. We prospectively investigated T cell activation pathways in 12 patients (nine males, three females) with alcoholic liver cirrhosis (seven Child Pugh stage A and B (CP A + B), five Child Pugh stage C (CP C)) and five healthy controls and compared the in vitro results of T cell activation with data obtained in vivo, e.g. intracutaneous tests and vaccination against hepatitis B surface antigen (HBs-Ag). Five out of eight patients who completed vaccination against hepatitis B virus infection were non-responders; one of the three responders had a non-protective anti-HBs titre. Moreover, three of five patients with alcoholic liver cirrhosis CP A + B, and two out of three with CP C were anergic in intracutaneous tests to a set of diverse antigens. All parameters of T cell activation were normal, including proliferation mediated by CD2, CD3-T cell receptor (TCR) complex, and CD28; acquisition of responsiveness to exogenous IL-2 and IL-4; activation of proteinkinase C (PKC) by phorbol ester and calcium influx by addition of ionomycin. The ability of monocytes to deliver costimulatory signals was preserved in patients with alcoholic cirrhosis. In addition, serum of patients with alcoholic liver disease did not inhibit T cell proliferation. We conclude that, although in patients with alcoholic liver cirrhosis T cell-dependent functions are impaired in vivo, T cell activation pathways are not responsible for the observed immune defect.

Adolescent↗

Limitations of reverse-transcriptase polymerase chain reaction analyses for detection of micrometastatic epithelial cancer cells in bone marrow.

PURPOSE: This study was designed to evaluate the potential of reverse-transcriptase polymerase chain reaction (RT-PCR) analyses for the detection of micrometastatic carcinoma cells in bone marrow (BM). PATIENTS AND METHODS: The specificity of RT-PCR assays with primers specific for various tumor-associated and organ-specific mRNA species was examined by analysis of 53 BM aspirates from control patients with no epithelial malignancy. In addition, BM samples from 63 patients with prostate cancer (n = 53) or breast cancer (n = 10) were analyzed by RT-PCR with primers specific for prostate-specific antigen (PSA) mRNA. As a reference method, all samples were analyzed simultaneously by an established immunocytochemical assay, using monoclonal antibodies (mAbs) against cytokeratins (CK) for tumor-cell detection. RESULTS: Seven of eight marker species could be detected in a considerable number of BM samples from control patients: epithelial glycoprotein-40 (EGP-40; 53 of 53 samples), desmoplakin I (DPI I; five of five), carcinoembryonic antigen (CEA; five of 19), erb-B2 (five of seven), erb-B3 (six of seven), prostate-specific membrane antigen (PSM; four of nine), and CK18 (five of seven). Only PSA mRNA was not detected in any of the 53 control BM samples. In serial dilution experiments, the PSA RT-PCR assay was able to detect five LNCaP prostate carcinoma cells in 4 x 10(6) BM cells. CK-positive cells were found in 20 patients (37.7%) with prostate cancer, while PSA mRNA was found in only 15 (28.3%; P = .04). Moreover, despite the recent observation that PSA is also expressed in mammary carcinomas, none of the 10 CK-positive BM samples were PSA mRNA-positive. CONCLUSION: Limiting factors in the detection of micrometastatic tumor cells by RT-PCR are (1) the illegitimate transcription of tumor-associated or epithelial-specific genes in hematopoietic cells, and (2) the deficient expression of the marker gene in micrometastatic tumor cells.

Biomarkers, Tumor↗

Frequency and prognostic significance of isolated tumour cells in bone marrow of patients with non-small-cell lung cancer without overt metastases.

BACKGROUND: Metastasis is generally looked on as a late event in the natural history of epithelial tumours. However, the poor prognosis of patients with apparently localised lung cancer indicates that micrometastases occur often before diagnosis of the primary tumour. METHODS: At primary surgery, disseminated tumour cells were detected immunocytochemically in bone marrow of 139 patients with non-small-cell lung carcinomas without evidence of distant metastases (pT(1-4)pN(1-2)M(0)). Tumour cells in bone-marrow aspirates were detected with monoclonal antibody CK2 against cytokeratin polypeptide 18. Patients were followed up for a median of 39 months (range 14-52) after surgery. 215 patients without epithelial cancer (ie, with benign epithelial tumours, non-epithelial neoplasms, or inflammatory diseases) acted as controls. FINDINGS: In 83 of 139 (59.7%) patients cytokeratin-positive cells were detected at frequencies of 1 in 100 000 to 1 in 1 000 000. Even without histopathological involvement of lymph nodes (pN(0)), tumour cells were found in 38 of 70 (54.3%) patients. 1 positive cell was found in each of 6 out of 215 controls. Surgical manipulation during primary tumour resection did not affect the frequency of these cells. In Cox's regression analyses, the presence of such cells was a significant and independent predictor for a later clinical relapse in node-negative patients (p=0.028). INTERPRETATION: Early dissemination of isolated tumour cells is a frequent and intrinsic characteristic of non-small-cell lung carcinomas. The finding of these cells may help to decide whether adjuvant systemic therapy is required for the individual patient.

Antibodies, Monoclonal↗