AFM analysis of the multiple types of molecular interactions involved in rituximab lymphoma therapy on patient tumor cells and NK cells

Rituximab is a monoclonal antibody drug approved for the treatment of patients with lymphomas. Rituximab's main killing mechanism is antibody-dependent cellular cytotoxicity (ADCC). During ADCC, rituximab's fragment antigen binding (Fab) region binds to the CD20 antigen on the tumor cell and its fragment crystallizable (Fc) region binds to the Fc receptor (FcR) on the natural killer (NK) cells. In this study, two types of molecular interactions (CD20-rituximab, FcR-rituximab) involved in ADCC were measured simultaneously on cells prepared from biopsy specimens of lymphoma patients by utilizing atomic force microscopy (AFM) with functionalized tips carrying rituximab. NK cells were detected by specific NKp46 fluorescent labeling and tumor cells were detected by specific ROR1 fluorescent labeling. Based on the fluorescence recognition, the binding affinity and distribution of FcRs on NK cells, and CD20 on tumor cells, were quantitatively measured and mapped. The binding affinity and distribution of FcRs (on NK cells) and CD20 (on tumor cells) were associated with rituximab clinical efficacy. The experimental results provide a new approach to simultaneously quantify the multiple types of molecular interactions involved in rituximab ADCC mechanism on patient biopsy cells, which is of potential clinical significance to predict rituximab efficacy for personalized medicine.

Development of a novel anti-canine CD20 monoclonal antibody with diagnostic and therapeutic potential

In humans, passive immunotherapy with anti-CD20 monoclonal antibodies (mAbs) has created immeasurable improvements in outcomes of patients with B-cell malignancies. However, the lack of comparable reagents has precluded development of this approach in dogs. We developed a novel anti-canine CD20 mAb designated as 6C8. 6C8 recognized the extracellular domain of canine CD20 and showed high-affinity binding to canine CD20 in solution, as well as in its native conformation on canine B-cells. The 6C8 target was expressed invariably in B-cell lineage cells, but not in T-cells or myeloid cells. 6C8 promoted phagocytosis of B-cell lymphoma cells by macrophages, but in its current framework, it did not induce direct cytotoxicity or complement dependent cytotoxicity. In summary, we have established a novel anti-canine CD20 mAb that is useful as a diagnostic tool to phenotype B-cells, and which could be integrated as a tool for passive immunotherapy to treat dogs with B-cell disorders.

TLR9 Ligand (CpG Oligodeoxynucleotide) Induces CLL B-Cells to Differentiate into CD20(+) Antibody-Secreting Cells

B-cell chronic lymphocytic leukemia (CLL) is the most frequent adult leukemia in the Western world. It is a heterogeneous disease characterized by clonal proliferation and the accumulation of CD5⁺ mature B lymphocytes. However, the normal counterpart from which the latter cells arise has not yet been identified. CD27 expression and gene expression profiling data suggest that CLL cells are related to memory B-cells. In vitro, memory B-cells differentiate into plasma cells when stimulated with CpG oligodeoxynucleotide (CpG). The objective of the present study was therefore to investigate the ability of CpG, in the context of CD40 ligation, to induce the differentiation of CLL B-cells into antibody-secreting cells (ASCs). CD20⁺CD38⁻ CLL B-cells were stimulated with a combination of CpG, CD40 ligand and cytokines (CpG/CD40L/c) in a two-step, 7-day culture system. We found that the CpG/CD40L/c culture system prompted CLL B-cells to differentiate into CD19⁺CD20⁺CD27⁺CD38⁻ASCs. These cells secreted large amounts of IgM and had the same shape as plasma cells. However, only IgMs secreted by ASCs that had differentiated from unmutated CLL B-cells were poly/autoreactive. Class-switch recombination (CSR) to IgG and IgA was detected in cells expressing the activation-induced cytidine deaminase gene (AICDA). Although these ASCs expressed high levels of the transcription factors PRDM1 (BLIMP1), IRF4, and XBP1s, they did not downregulate expression of PAX5. Our results suggest that CLL B-cells can differentiate into ASCs, undergo CSR and produce poly/autoreactive antibodies. Furthermore, our findings may be relevant for (i) identifying the normal counterpart of CLL B-cells and (ii) developing novel treatment strategies in CLL.

Myelo-enhancement by astragalus membranaceus in male albino rats with chemotherapy myelo-suppression. Histological and immunohistochemical study

Background and Objectives:

Myelosuppression is the most common toxicity encountered in the oncology clinic today. This study was planned to investigate the possible protective and therapeutic role of the traditional Chinese Medicinal Herb; Astragalus Membranaceus (AM), on chemotherapy-induced myelosuppression.

Methods and Results:

This study was carried out on thirty six adult male albino rats. They were divided into: Group I Control Group (n=6) received a vehicle of phosphate buffered saline (PBS) solution. Group II (n=12) were injected I.P. with cyclophosphamide (CY) for 3 days (gIIa n =6) and continued for one more week to receive AM orally (gIIb n=6). Group III (n=6) received CY I.P. together with AM orally for 3 days. Group IV (n=12) received AM orally for one week (gIVa n=6) and continued for extra three days receiving CY I.P. with AM orally (gIVb n=6). Blood samples were analysed for Total Leucocytic Count and Lymphocytic Count. Counting of CD34 +ve cells in bone marrow was performed by flowcytometry. Bone marrow sections were subjected to H&E stain as well as immunohistochemical staining for anti- CD20 antibody. The mean area % of cellular bone marrow regions occupied by developing haemopoietic cells, mean area of fat cells and mean number of CD20 immunopositive B lymphocytes in the bone marrow were measured by histomorphometric studies and statistically compared. AM proved to have a myelo-protective and myelo-therapeutic capacity, evidenced at both laboratory and morphological levels.

Conclusions:

The greatest myelo-potentiating effect of AM was achieved when supplied before and together with CY therapy.

Obinutuzumab for B-cell malignancies

INTRODUCTION

We analyse data for the use of obinutuzumab in the treatment of CD20(+) lymphoproliferative disorders with a focus on chronic lymphocytic leukaemia (CLL). Targeted therapy against CD20 with the mAb rituximab led to significant improvements in survival for patients with B-cell non-Hodgkin lymphoma (NHL) and is the current mainstay of treatment for CD20(+) malignancies. Despite this, many patients relapse or become refractory after rituximab-containing therapies, so efforts have been made to develop better anti-CD20 mAbs. Obinutuzumab recently demonstrated superiority over rituximab in the only published Phase III study comparing the two antibodies.

AREAS COVERED

Obinutuzumab is a humanised, anti-CD20 mAb being compared to rituximab in several Phase III studies. An overview of obinutuzumab, its mechanisms of action and results of Phase I-III studies are presented.

EXPERT OPINION

The demonstration of superiority of obinutuzumab over rituximab in the CLL11 Phase III study is potentially practice-changing. Obinutuzumab has also proven safe and efficacious in CD20(+) NHL in Phase I/II studies and results of Phase III studies in NHL are eagerly awaited. The potential implications of improved outcomes for CLL and NHL with the introduction of this more potent anti-CD20 antibody are tremendous given the impressive results obtained after the introduction of rituximab over a decade ago.

Enhancement of Rituximab-induced cell death by the physical association of CD20 with CD40 molecules on the cell surface

CD20 is an attractive therapeutic target given the success of its monoclonal antibody, Rituximab, in the treatment of B-cell malignancies and B-cell-mediated autoimmune diseases. Treatment with Rituximab causes a rapid depletion of B cells and a decrease in disease symptoms. Despite the clinical efficiency of Rituximab, its mechanism of action is not completely understood. In this study, we aimed at further investigating the Rituximab-induced cell death and the factors affecting such responses. Our results indicate that Rituximab-induced cell death depends on the nature of the cells and levels of CD20 expression on the cell surface. Coexpression of CD20 with CD40, a member of the TNF receptor family that is known to be physically associated with CD20 on the cell surface, enhances the apoptotic response induced by Rituximab. Inhibiting the formation of CD40 disulfide-bound-homodimers, a process required for some CD40 signaling, further enhances Rituximab-induced cell death. Cell death induced by anti-CD40 mAb is also upregulated by the presence of CD20, suggesting a bidirectional influence of the CD20/CD40 association. Moreover, treating cells with both anti-CD20 and anti-CD40 antibodies improves the cell death response induced by a single-agent treatment. These results highlight the role of the CD20/CD40 association in triggering B-cell depletion and may pave the way for an alternative more efficient therapeutic strategy in treating B-cell-mediated disorders.

Antibodies and antibody-drug conjugates in the treatment of Hodgkin lymphoma

Hodgkin lymphoma (HL) is a B cell-derived lymphoid malignancy most often affecting young adults. More than 80% of HL patients achieve long-term remission after appropriate first-line treatment consisting of multiagent chemotherapy and/or radiotherapy (RT). In addition, approximately 50% of patients with disease recurrence remain relapse-free after salvage therapy with high-dose chemotherapy followed by autologous stem cell transplantation (ASCT). However, patients with multiple relapses are mostly in a palliative situation, and novel drugs for this patient group are needed. Furthermore, novel less toxic but equally effective first-line and second-line approaches are required as therapy-related late sequelae represent a relevant cause of morbidity and mortality in HL survivors. Several antibodies and antibody-drug conjugates (ADC) targeting CD30 and CD20 have recently been evaluated in HL. Excellent response rates in heavily pretreated patients were observed with the ADC brentuximab vedotin directed against CD30. Thus, ongoing trials investigate brentuximab vedotin in different additional indications. One example is the first-line treatment of advanced HL where the drug is currently being evaluated in combination with variants of the first-line protocols ABVD (adriamycin, bleomycin, vinblastine, dacarbazine) and escalated BEACOPP (bleomycin, etoposide, adriamycin, cyclophosphamide, vincristine, procarbazine, prednisone). Anti-CD20 antibodies given either as single agent or in combination with conventional chemotherapy have also been investigated and still undergo investigation in prospective studies including HL patients. This article reviews the available data on treatment approaches including antibodies and ADC in HL patients.

Anti-CD20 monoclonal antibodies and associated viral hepatitis in hematological diseases

Over the past decade, the administration of anti-CD20 monoclonal antibodies such as rituximab has demonstrated various degrees of effectiveness and has improved patients’ outcomes during the treatment of autoimmune hematological disorders and hematological malignancies. However, the depletion of B-cells, the distribution of T-cell populations, and the reconstruction of host immunity resulting from the use of anti-CD20 monoclonal antibodies potentially lead to severe viral infections, such as hepatitis B virus (HBV), hepatitis C virus (HCV), parvovirus B19, and herpes viruses, in patients who are undergoing immune therapy or immunochemotherapy. Of these infections, HBV- and HCV-related hepatitis are a great concern in endemic areas because of the high morbidity and mortality rates in untreated patients. As a result, prophylaxis against HBV infection is becoming a standard of care in these areas. Parvovirus B19, a widespread pathogen that causes red blood cell aplasia in immunocompromised hosts, also causes hepatitis in healthy individuals. Recently, its association with hepatitis was recognized in a patient treated with rituximab. In addition, adenovirus, varicella-zoster virus, hepatitis E virus, and rituximab itself have been linked to the occurrence of hepatitis during or after rituximab treatments. The epidemiologies and pathogeneses of these etiologies remain unknown. Because of the increasing use of anti-CD20 monoclonal antibodies for the treatment of hematological malignancies or autoimmune hematological disorders, it is imperative that physicians understand and balance the risks of hepatotropic virus-associated hepatitis against the benefits of using anti-CD20 monoclonal antibodies.

Bariatric surgery-induced weight loss changes immune markers in the endometrium of morbidly obese women

BACKGROUND

Obesity has been linked to abnormal estrogen regulation, endometrial hyperplasia, and endometrial cancer (EC). Our group has shown that hormone receptor expression profiles in the endometria of morbidly obese women change with weight loss, in some cases concordantly with resolving hyperplasia; however other potential drivers of neoplasia, including altered immunologic tolerance exist. The objective of this study was to evaluate the effect of bariatric surgery induced weight loss on the expression patterns of nonhormone receptor biomarkers associated with cancer and immunity.

METHODS

Endometrial biopsies were obtained from 59 asymptomatic, morbidly obese women at the time of bariatric surgery and again 1 year postsurgery. Tissue microarrays were created and immunohistochemical stains for CD3, CD20, and PTEN were performed on all samples and evaluated by 2 blinded pathologists independently. Approximately 50% of participants had sufficient tissue for analysis at both visits. McNemar/Bowker tests of symmetry were performed to compare proportions between categories for matched pairs (pre- and post-treatment).

RESULTS

Endometrial hyperplasia was identified in 4 women despite negative clinical histories and resolution of hyperplasia after weight loss occurred in 3 women. While overall no significant differences were observed between matched pre and postsurgery levels of CD20 and CD3 positive cells, a tendency toward decreased expression levels from baseline status was observed for CD20. No differences were observed for PTEN.

CONCLUSION

Our data demonstrate that the prevalence of endometrial pathology appears to be partially mitigated by weight loss. Weight loss is associated with alterations in the hormone receptor profiles, but these data suggest that changes in the immune response, as measure be expression of CD20+, may be relevant targets for EC prevention research.

Benefits of skin biopsy of senile hemangioma in intravascular large B-cell lymphoma: A case report and review of the literature

Intravascular large B-cell lymphoma (IVLBCL) is a rare subtype of B-cell lymphoma characterized by selective growth of clonal B-cells in the lumen of the small vessels of various organs including the liver, spleen, lungs, skin, brain, and kidney. An 86-year-old male presented with weight loss, fever and night sweats (known as B symptoms). Blood examination revealed pancytopenia, high lactate dehydrogenase and high soluble interleukin-2 receptor, suggesting hematopoietic malignancy. However, there were no abnormal hematopoietic cells in the peripheral blood. No lymph node swelling was identified on examination by whole-body computed tomography scan. Therefore, IVLBCL was suspected, and random skin biopsies and a skin biopsy from a senile hemangioma were carried out. A small number of large atypical lymphoid cells resided in the small blood vessels in the deep dermis and subcutaneous tissue of the random skin biopsies, and numerous atypical lymphoid cells were identified in the small vessels of the senile hemangioma. These results suggest the usefulness of skin biopsy from senile hemangiomas in the diagnosis of IVLBCL.

Ocaratuzumab, an Fc-engineered antibody demonstrates enhanced antibody-dependent cell-mediated cytotoxicity in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is common in both developed and developing nations where the need for inexpensive and convenient administration of therapy is apparent. Ocaratuzumab is a novel Fc-engineered humanized IgG1 anti-CD20 monoclonal antibody (mAb) designed for effective antibody-dependent cell-mediated cytotoxicity (ADCC) at very low concentrations that may facilitate sub-cutaneous (vs. intravenous) dosing. Here, we report ocaratuzumab's potency against CLL cells. In vitro assessment of ocaratuzumab's direct cytotoxicity (DC), complement-dependent cytotoxicity (CDC), antibody-dependent cellular phagocytosis (ADCP), and ADCC was performed on CLL cells. Ocaratuzumab induced DC, CDC, and ADCP similarly to rituximab or ofatumumab (anti-CD20 mAbs). However, ocaratuzumab showed an advantage in NK cell-mediated ADCC over these antibodies. In allogeneic ADCC, [E:T (effector:target) ratios = 25:1, 12:1, 6:1], ocaratuzumab (10 µg/mL) improved ADCC by ~3-fold compared with rituximab or ofatumumab (P<0.001 all tested E:T ratios). Notably, the superiority of ocaratuzumab-induced ADCC was observed at low concentrations (0.1-10 ug/ml; P<0.03; allogeneic assays). In extended allogeneic ADCC E:T titration, ocaratuzumab (0.1 µg/mL) demonstrated 19.4% more cytotoxicity than rituximab (E:T = 0.38:1; P = 0.0066) and 21.5% more cytotoxicity than ofatumumab (E:T = 1.5:1; P = 0.0015). In autologous ADCC, ocaratuzumab (10 µg/mL) demonstrated ~1.5-fold increase in cytotoxicity compared with rituximab or ofatumumab at all E:T ratios tested (E:Ts = 25:1,12:1,6:1; all P<0.001). Obinutuzumab, a glyco-engineered anti-CD20 mAb, showed no improvement in ADCC activity compared with ocaratuzumab. The enhanced ADCC of ocaratuzumab suggests that it may be effective at low concentrations. If supported by clinical investigation, this feature could potentially allow for subcutaneous dosing at low doses that could expand the potential of administering chemoimmunotherapy in developing countries.

Nanoscale distribution of CD20 on B-cell lymphoma tumour cells and its potential role in the clinical efficacy of rituximab

Rituximab is an exciting monoclonal antibody drug approved for treating B-cell lymphomas and its target is the CD20 antigen which is expressed on the surface of B cells. In recent years, the variable efficacies of rituximab among different lymphoma patients have become an important clinical issue and urgently need to be solved for further development of antibodies with enhanced efficacies. In this work, atomic force microscopy (AFM) was used to investigate the nanoscale distribution of CD20 on the surface of tumour B cells from lymphoma patients to examine its potential role in the clinical therapeutic effects of rituximab. By performing ROR1 fluorescence labelling (ROR1 is a specific tumour cell surface marker) on the bone marrow cells prepared from B-cell lymphoma patients, the tumour B cells were recognized, and then AFM tips carrying rituximabs via polyethylene glycol crosslinkers were moved to the tumour cells to probe the specific CD20-rituximab interactions. By applying AFM single-molecule force spectroscopy (SMFS) at the local areas (500×500 nm²) on the surface of tumour B cells, the nanoscale distributions of CD20 on the surface of tumour B cells were mapped, visually showing that CD20 distributed heterogeneously on the cell surface. Bone marrow cell samples from three clinical B-cell lymphoma cases were collected to analyze the binding affinity and nanoscale distribution of CD20 on tumour cells. The experimental results showed that CD20 distribution on tumour cells were to some extent related to the clinical therapeutic outcomes while the CD20-rituximab binding forces did not have distinct effects to the clinical outcomes. These results can provide novel insights in understanding the rituximab's clinical efficacies from the nanoscale distribution of CD20 on the tumour cells at single-cell and single-molecule levels.

Possible role of CD22, CD79b and CD20 expression in distinguishing small lymphocytic lymphoma from chronic lymphocytic leukemia

Aim of the study

Flow cytometry has an important role in diagnosis and classification of B-cell lymphoproliferative disorders (BCLPDs). However, in distinguishing chronic lymphocytic leukemia (CLL) from small lymphocytic lymphoma (SLL) only clinical criteria are available so far. Aim of the study was to determine differences in the expression of common B cell markers (CD22, CD79b and CD20) on the malignant lymphocytes in the peripheral blood samples of CLL and SLL patients.

Material and methods

Peripheral blood samples of 56 CLL and 11 SLL patients were analyzed by 5-color flow cytometry on the CD45/CD19/CD5 gate for CD22, CD79b and CD20.

Results

In the samples collected from the CLL patients, CD22 expression was detected in only 20% of patients in the low pattern, while in SLL patients the expression was medium and present in 90.9% of patients (p < 0.0001). For CD79b expression, statistical significance is reached both in the expression pattern, which was low/medium for CLL and high for SLL, and expression level (p = 0.006). The expression of CD20 was counted as the CD20/CD19 ratio. The average ratio was 0.512 in the CLL patients vs. 0.931 in the SLL patients (p = 0.0001).

Conclusions

The pattern of expression and expression level of CD22, CD79b and CD20 in peripheral blood could be used for distinguishing SLL from CLL patients.

Distribution of lymphocyte subpopulations in thyroid glands of human autoimmune thyroid disease

BACKGROUND

The autoimmune thyroid disease (AITD) is an organ-specific autoimmune disease characterized by the breakdown of self-tolerance to thyroid antigens. Some lymphocytes have been identified to be related notably to the pathogenesis of AITD. This article evaluated the distribution of the lymphocytic subpopulation in thyroid glands in order to develop the immunospecific forms of therapy for AITD.

METHODS

Damaged thyroid specimens were obtained from 18 Graves' disease (GD) and 17 Hashimoto's thyroiditis (HT) patients. Normal thyroid specimens were obtained from unaffected glands of 17 patients who underwent parathyroidectomy. We evaluated the distribution of lymphocytic subpopulation by analyzing the expression difference and correlationship among CD4+ T lymphocyte, CD8+ T lymphocyte, CD20+ B lymphocyte as well as regulatory T cells(Tregs)' marker FoxP3 in the thyroid tissues via immunohistochemistry.

RESULTS

Our research uncovered that no distinct lymphocyte infiltrated in the normal thyroid specimens. Scarcely any lymphocyte infiltration could be found in half of the totally 18 GD thyroid specimens. For the rest 9 GD specimens, CD8+ T cells and CD20+ B cells were expressed more or less in all of them, FoxP3+ Tregs were detected in 7 of them and CD4+ T cells were weakly expressed in only 2 of them. For the 17 HT thyroid specimens, CD20+ B cells were stained strongly in all of them, CD4+, CD8+ T cells were expressed more or less in most of them and FoxP3+ Tregs could be detected in 9 of them.

CONCLUSION

Based on CD20+ B cells predominantly infiltrating in all HT thyroid tissues we suggested CD20 antibody might be of help for HT treatment. Furthermore based on FoxP3+ Tregs abundantly infiltrating in some of the AITD thyroid specimens, we considered that activating the Tregs' function in comparison to increasing the Tregs' number only, may be a more effective approach to the treatment of AITD in some cases.

De novo diffuse large B-cell lymphoma with a CD20 immunohistochemistry-positive and flow cytometry-negative phenotype: molecular mechanisms and correlation with rituximab sensitivity

CD20 is expressed in most B-cell lymphomas and is a critical molecular target of rituximab. Some B-cell lymphomas show aberrant CD20 expression, and rituximab use in these patients is controversial. Here we show both the molecular mechanisms and the clinical significance of de novo diffuse large B-cell lymphomas (DLBCL) that show a CD20 immunohistochemistry (IHC)-positive and flow cytometry (FCM)- negative (IHC[+]/FCM[−]) phenotype. Both IHC and FCM using anti-CD20 antibodies L26 and B1, respectively, were analyzed in 37 of the 106 cases of de novo DLBCL; 8 (22%) of these cases were CD79a(+)/CD20(+) with IHC and CD19(+)/CD20(−) with FCM. CD20 (MS4A1) mRNA expression was significantly lower in IHC(+)/FCM(−) cells than in IHC(+)/FCM(+) cells (P = 0.0005). No genetic mutations were detected in MS4A1 promoter and coding regions. Rituximab-mediated cytotoxicity in the CDC assay using IHC(+)/FCM(−) primary cells was significantly lower than in IHC(+)/FCM(+) cells (P < 0.05); however, partial effectiveness was confirmed. FCM using rituximab detected CD20 more efficiently than B1. No significant difference was observed between IHC(+)/FCM(−) and IHC(+)/FCM(+) patients in overall survival (P = 0.664). Thus, lower expression of CD20 mRNA is critical for the CD20 IHC(+)/FCM(−) phenotype. Lower CD20 expression with FCM does not rule out rituximab use in these patients if expression is confirmed with IHC. FCM using rituximab may be more informative than B1 for predicting rituximab effectiveness in IHC(+)/FCM(−) cases.

Primary gingival diffuse large B-cell lymphoma: a case report and a review of the literature

The patient was a 73-year-old male who came to our hospital with a chief complaint of pain and swelling of the left side of his jaw. Computed tomography revealed a mass in his left gingiva but no bone destruction. No lesions were observed at any other sites, and an incisional biopsy was performed on the gingival mass on the left side. Histologically, the mass was a diffuse large B-cell lymphoma (DLBCL), and it was CD20-positive, and CD5-negative, CD10-negative, surface immunoglobulin-negative, and Epstein-Barr virus-encoded RNA (EBER)-negative. A serum Human immunodeficiency virus (HIV)-antibody test was negative. A complete remission was achieved after 6 courses of systemic combination chemotherapy, and the complete remission has been maintained for approximately 3 years. According to the literature, primary gingival DLBCL have a high Ki-67-positive rate and many of the cases are stage I and international prognostic index low-risk. However, HIV patients have a high EBER-positive rate and a high risk of developing a CD20-negative, CD138-positive plasmablastic lymphoma, and they have a poor prognosis. By contrast, limited-stage primary gingival lymphomas whose data can be used have been rare in human immunodeficiency virus-negative patients, and only 12 cases, including our own, have ever been reported. Many of the patients have been around 65 years of age, and all of the cases have been CD20-positive, CD138-negative DLBCLs, and the CD5-negative, Epstein-Barr virus-positive rate has been low, with most cases having been non-germinal-center B-cell-like. The prognosis for relapse-free survival has been favorable.

Pruritus in patients treated with targeted cancer therapies: systematic review and meta-analysis

BACKGROUND

Pruritus has been anecdotally described in association with targeted cancer therapies. The risk of pruritus has not been systematically ascertained.

OBJECTIVE

A systematic review and meta-analysis of the literature was conducted for axitinib, cetuximab, dasatinib, erlotinib, everolimus, gefitinib, imatinib, ipilimumab, lapatinib, nilotinib, panitumumab, pazopanib, rituximab, sorafenib, temsirolimus, tositumomab, vandetanib, and vemurafenib.

METHODS

Databases from PubMed, Web of Science (January 1998 through July 2012), and American Society of Clinical Oncology abstracts (2004 through 2012) were searched. Incidence and relative risk of pruritus were calculated using random- or fixed-effects model.

RESULTS

The incidences of all-grade and high-grade pruritus were 17.4% (95% confidence interval 16.0%-19.0%) and 1.4% (95% confidence interval 1.2%-1.6%), respectively. There was an increased risk of all-grade pruritus (relative risk 2.90 [95% confidence interval 1.76-4.77, P < .001]) and variation among different drugs (P < .001).

LIMITATIONS

The reporting of pruritus may vary, resulting from concomitant medications, comorbidities, and underlying malignancies. We found a higher incidence of pruritus in patients with solid tumors, concordant with those targeted therapies with the highest pruritus incidences.

CONCLUSION

There is a significant risk of developing pruritus in patients receiving targeted therapies. To prevent suboptimal dosing and decreased quality of life, patients should be counseled and treated against this untoward symptom.

Morphology and expression status investigations of specific surface markers on B-cell chronic lymphocytic leukemia cells

The morphology of cells and expression status of specific surface markers [cluster of differentiation (CD)], such as CD5, CD19, CD20, CD38, and CD45, have long been considered as the essential indicators for the diagnosis and prognosis of B-cell chronic lymphocytic leukemia (B-CLL). Clinically, it is difficult to simultaneously obtain cell morphology and distribution of surface markers with flow cytometry, especially for some surrogate markers such as CD38. Here, as an alternative and complementary prognostic method, fluorescence microscopy and image processing method are introduced to directly visualize the cells from patients and to quantitatively determine the expression status of surface markers. In this study, the morphological parameters of B-CLL cells were measured to establish the correlation between the cellular morphology and the surface marker expression. It was clear that the CD38+ and CD38- B-CLL cells from the same CD38+ patients had hardly any size differences; however, an increase in perimeter was observed for CD38- patients. Moreover, the expression level of the receptors on the cell was independent of the cell size. There was no evidence showing that the expression intensities of CD19 and CD38 were related to each other for the CD38+ B-CLL cells. On the same cells, CD5 was more selectively expressed on the cell membrane; however, the expression patterns suggested that the cell membrane of CD38- B-CLL cells contained the least expression level of CD19.

Expression of MS4A and TMEM176 Genes in Human B Lymphocytes

The MS4A gene family in humans includes CD20 and at least 15 other genes. CD20 exists as homo-oligomers in the plasma membrane, however different MS4A proteins expressed in the same cell may hetero-oligomerize. Given the importance of CD20 in B-cell function and as a therapeutic target, we sought to explore the potential for CD20 hetero-oligomerization with other MS4A proteins. We investigated expression in primary human B-cells of the four MS4A genes previously shown to be expressed in human B-cell lines (MS4A4A, MS4A6A, MS4A7, MS4A8B), as well as two genes comprising the closely related TMEM176 gene family, with a view to identifying candidates for future investigation at the protein level. TMEM176A and TMEM176B transcripts were either not detected, or were detected at relatively low levels in a minority of donor B-cell samples. MS4A4A and MS4A8B transcripts were not detected in any normal B-cell sample. MS4A6A and MS4A7 transcripts were detected at low levels in most samples, however the corresponding proteins were not at the plasma membrane when expressed as GFP conjugates in BJAB cells. We also examined expression of these genes in chronic lymphocytic leukemia (CLL), and found that it was similar to normal B-cells with two exceptions. First, whereas MS4A4A expression was undetected in normal B-cells, it was expressed in 1/14 CLL samples. Second, compared to expression levels in normal B-cells, MS4A6A transcripts were elevated in 4/14 CLL samples. In summary, none of the MS4A/TMEM176 genes tested was expressed at high levels in normal or in most CLL B-cells. MS4A6A and MS4A7 were expressed at low levels in most B-cell samples, however the corresponding proteins may not be positioned at the plasma membrane. Altogether, these data suggest that CD20 normally does not form hetero-oligomers with other MS4A proteins and that there are unlikely to be other MS4A proteins in CLL that might provide useful alternate therapeutic targets.

Radioimmunotherapy of B-Cell Non-Hodgkin's Lymphoma

This manuscript reviews current advances in the use of radioimmunotherapy (RIT) for the treatment of B-cell non-Hodgkin's lymphoma (NHL). RIT has been in use for more than 20 years and has progressed significantly with the discovery of new molecular targets, the development of new stable chelates, the humanization of monoclonal antibodies (MAbs), and the use of pretargeting techniques. Today, two products targeting the CD20 antigen are approved: (131)I-tositumomab (Bexxar(®)), and (90)Y-ibritumomab tiuxetan (Zevalin(®)). (131)I-tositumomab is available in the United States, and (90)Y-ibritumumab tiuxetan in Europe, the United States, Asia, and Africa. RIT can be integrated in clinical practice using non-ablative activities for treatment of patients with relapsed or refractory follicular lymphoma (FL) or as consolidation after induction chemotherapy in front-line treatment in FL patients. Despite the lack of phase III studies to clearly define the efficacy of RIT in the management of B lymphoma in the era of rituximab-based therapy, RIT efficacy in NHL has been demonstrated. In relapsing refractory FL and transformed NHL, RIT as a monotherapy induces around 30% complete response with a possibility of durable remissions. RIT consolidation after induction therapy significantly improves the quality of the response. Dose-limiting toxicity of RIT is hematological, depending on bone marrow involvement and prior treatment. Non-hematological toxicity is generally low. Different studies have been published assessing innovative protocols of RIT or new indications, in particular treatment in patients with aggressive lymphomas. High-dose treatment, RIT as consolidation after different therapeutic induction modalities, RIT in first-line treatment or fractionated RIT showed promising results. New MAbs, in particular humanized MAbs, or combinations of naked and radiolabeled MAbs, also appear promising. Personalized dosimetry protocols should be developed to determine injected activity.

Low-dose anti-CD20 veltuzumab given intravenously or subcutaneously is active in relapsed immune thrombocytopenia: a phase I study

Low doses of the humanized anti-CD20 monoclonal antibody, veltuzumab, were evaluated in 41 patients with immune thrombocytopenia (ITP), including 9 with ITP ≤1 year duration previously treated with steroids and/or immunoglobulins, and 32 with ITP >1 year and additional prior therapies. They received two doses of 80-320 mg veltuzumab 2 weeks apart, initially by intravenous (IV) infusion (N = 7), or later by subcutaneous (SC) injections (N = 34), with only one Grade 3 infusion reaction and no other safety issues. Thirty-eight response-assessable patients had 21 (55%) objective responses (platelet count ≥30 × 10(9) /l and ≥2 × baseline), including 11 (29%) complete responses (CRs) (platelet count ≥100 × 10(9) /l). Responses (including CRs) occurred with both IV and SC administration, at all veltuzumab dose levels, and regardless of ITP duration. Responders with ITP ≤1 year had a longer median time to relapse (14·4 months) than those with ITP >1 year (5·8 months). Three patients have maintained a response for up to 4·3 years. SC injections resulted in delayed and lower peak serum levels of veltuzumab, but B-cell depletion occurred after first administration even at the lowest doses. Eight patients, including 6 responders, developed anti-veltuzumab antibodies following treatment (human anti-veltuzumab antibody, 19·5%). Low-dose SC veltuzumab appears convenient, well-tolerated, and with promising clinical activity in relapsed ITP.(Clinicaltrials.gov identifier: NCT00547066.).

Functional recombinant extra membrane loop of human CD20, an alternative of the full length CD20 antigen

BACKGROUND

Targeting of CD20 antigen with monoclonal antibodies has become the mainstay in the treatment of non-Hodgkin's lymphomas and immunotherapeutic depletion of malignant B cells. Accessibility of antigen is one of the crucial factors in development of monoclonal antibodies against this antigen. One major problem in expression of full length CD20 is aggregation and misfolding. Therefore, production of an alternative polypeptide is easer and favorable comparing to that of a full length transmembrane protein CD20.

METHODS

In this study, we expressed the extra membrane loop of hCD20 (exCD20) consisting of a non-glycosylated 47-amino acids region. The exCD20 coding sequence was amplified by PCR and cloned in pET32a(+) expression vector. The desired protein was expressed in fusion with thioredoxin and 6× His tag in E. coli Origami strain. ELISA and Western-blotting data were performed to indicate the functionality of this protein.

RESULTS

We have obtained the exCD20 recombinant protein which can be detected in ELISA and Western-blot experiments. This recombinant fusion protein was soluble and stable without aggregation and misfolding problems.

CONCLUSION

The recombinant extra membrane loop of human CD20 protein in fusion with thioredoxin (exCD20) can be used in function assays and some applications such as ELISA, immuneblotting, affinity purification, immunization, screening, and development of anti-CD20 antibodies.

Rituximab pharmacokinetics in children and adolescents with de novo intermediate and advanced mature B-cell lymphoma/leukaemia: a Children's Oncology Group report

The ANHL01P1 trial was undertaken to determine pharmacokinetics and safety following the addition of rituximab to French-American-British/Lymphome Malins de Burkitt (FAB/LMB96) chemotherapy in 41 children and adolescents with Stage III/IV mature B-cell lymphoma/leukaemia. Patients received rituximab (375 mg/m(2) ) days -2 and 0 of two induction cycles and day 0 of two consolidation cycles. Highest peak levels were achieved following the second dose of each induction cycle [299 ± 19 and 384 ± 25 μg/ml (Group-B); 245 ± 31 and 321 ± 32 μg/ml (Group-C)] with sustained troughs and t½ of 26-29 d. Rituximab can be safely added to FAB chemotherapy with high early rituximab peak/trough levels and a long t½.

False-positive immunogenicity responses are caused by CD20+ B cell membrane fragments in an anti-ofatumumab antibody bridging assay

An electrochemiluminescent (ECL) bridging assay to detect anti-ofatumumab antibodies (ADA) in human serum samples was developed and validated. Using this assay format, clinical samples were first screened to identify potential ADA positive samples, which were then further tested by adding excess drug, confirming the positive signals as drug specific. However, when the method was implemented into clinical studies for ADA testing, a high positive rate was observed in the pre-dose samples collected from patients with chronic lymphocytic leukemia (CLL). Since the positive signals were not associated with ofatumumab (Ofa) treatment, and diminished after treatment, it was suspected that matrix interference might be responsible, resulting in false-positive responses. We performed a series of experimental investigations to identify, characterize, minimize or eliminate the possible false-positive responses. One possible source was identified to be CD20 (the target of Ofa) present on cell membrane fragments (CMFs). The false-positive responses caused by CD20(+) CMFs could be reduced by solid-phase immunodepletion, ultracentrifugation, or inhibited by adding another anti-CD20 antibody (rituximab). As a consequence, the ADA method was modified to minimize the matrix interference caused by CD20(+) CMFs and, then, validated for sample testing.

Safety and efficacy of ofatumumab in patients with fludarabine and alemtuzumab refractory chronic lymphocytic leukaemia

There are now many therapeutic CD20 monoclonal antibodies undergoing clinical trials for B-cell malignancy and autoimmune conditions; which is optimal for cancer therapy is not clear. The novel human IgG1 CD20 monoclonal antibody ofatumumab has shown significant activity in difficult to treat patients with chronic lymphocytic leukemia, namely those resistant or refractory to fludarabine and alemtuzumab and has now been licensed for this uncommon indication. This brief review summarizes the clinical data obtained with ofatumumab in CLL in terms of both efficacy and toxicity.

Mechanisms of action of CD20 antibodies

Therapeutic monoclonal antibodies (mAbs) that target the CD20 antigen on B cells are successfully used in the clinic for the depletion of B cells to treat various forms of cancer and autoimmune diseases. The first CD20 mAb, approved by the FDA in 1998, was rituximab (RTX) and since then it has been widely used to treat more than one million patients thus far. The success of RTX has led to a general interest in the mechanism of action of CD20 mAbs. CD20 mAbs can induce tumor killing via various mechanisms, such as direct induction of apoptosis, antibody-dependent cell-mediated cytotoxicity (ADCC) or complement-dependent lysis (CDC). Although we now understand these mechanisms better, it is still unclear which of these mechanisms is the most important for in vivo RTX action. Not every patient respond to RTX treatment and eventually the overwhelming majority will experience a relapse. Therefore, there is an urgent need to improve the efficacy of CD20 mAbs. This review aims to summarize our current understanding on the mechanism of action of CD20 mAbs.

Efficacy and Complications of Intravitreal Rituximab Injection for Treating Primary Vitreoretinal Lymphoma

PURPOSE

To assess the long-term clinical outcomes of intravitreal injections of rituximab (IVR), an anti-CD20 monoclonal antibody, to treat CD20-positive primary vitreoretinal lymphoma (PVRL).

METHODS

Twenty eyes of 13 women (mean age, 66.2 ± 9.9 years) with CD20-positive PVRL were included in this prospective, interventional case series. All patients had discontinued previous intravitreal methotrexate (IVM) treatment because of severe corneal epitheliopathy. Weekly IVR injections (1 mg/0.1 ml) for 4 weeks were administered as a one-course protocol. Additional injections were administered when the PVRL recurred. The effects and the adverse events associated with IVR injections were evaluated.

RESULTS

All patients completed a 1-year follow-up (mean observation after IVR injections, 24.7 ± 6.3 months). Before treatment, diffuse keratic precipitates (KPs), anterior vitreous cells, or both were observed in 18 (90%) eyes of 11 patients, and typical subretinal infiltrates were seen in eight (40%) eyes of six patients; all improved with one treatment course. The anterior segment lesions recurred in 11 (55%) eyes of nine patients and resolved with another course of injections. Transient IOP elevations occurred in 12 (60%) eyes of 10 patients within 3.8 ± 1.9 weeks after the first treatment course; iridocyclitis with mutton-fat KPs developed in seven (35%) eyes of six patients with elevated IOP and resolved with topical treatment. No other significant ocular complications or systemic side effects developed.

CONCLUSIONS

Injections of IVR were shown to be an efficacious alternative treatment for PVRL, although the disease recurred in approximately half of the eyes. Complications included transient IOP elevations and iridocyclitis with mutton-fat KPs that were managed topically.

TRANSLATIONAL RELEVANCE

The results of this trial support IVR as one element of combined modality therapy for treating PVRL patients without CNS involvement, particularly for those who respond poorly and have side effects with IVM. (http://www.umin.ac.jp/ctr/ number, UMIN000005604).

Epstein-Barr virus-positive ileal extraosseous plasmacytoma containing plasmablastic lymphoma components with CD20-positive lymph node involvement

We report a case of Epstein–Barr virus (EBV)-positive ileal extraosseous plasmacytoma containing plasmablastic lymphoma components with CD20-positive lymph node involvement. A 34-year-old healthy Japanese male developed intussusception due to an ileal plasmacytoma. The lesion was positive for EBV-encoded small nuclear RNA in in situ hybridization, with the surrounding lymph nodes showing the expression of CD20. Tumor cells in the ileal and lymph node lesions contained high-grade malignant features compatible with plasmablastic lymphoma. Because his abdominal lymph nodes recurred 6 months after resection, he received six cycles of R-CHOP chemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone), and had a complete remission. Although his case was complicated by acute promyelocytic leukemia, he has so far survived, recurrence-free, for more than 7.5 years after chemotherapy for extraosseous plasmacytoma.

Subtle bone marrow involvement by large B-cell lymphoma with pronormoblast-like morphology and prominent but not exclusive sinusoidal distribution

Primary bone marrow presentation of diffuse large B-cell lymphoma (DLBCL) is unusual, and appreciation of the diffuse growth pattern may be difficult in cases with low-level involvement. In particular, subtle sinusoidal and interstitial bone marrow involvement and morphologic overlap of the tumor cells with pronormoblasts may result initially in a missed diagnosis. We describe the clinicopathologic features of 13 cases of morphologically subtle DLBCL involving the bone marrow, which were only identified with the aid of immunohistochemistry. The overwhelming majority of cases (12/13, 92%) presented with cytopenias, and 5 of 7 cases, with available information, had splenomegaly. The morphology of the tumor cells in the aspirate smears overlapped with pronormoblasts (immature erythroid precursors) in 12 of 13 cases. Similarly, in histologic sections, the tumor cells in virtually all cases (12/13) demonstrated round nuclear contours and oblong nucleoli, mimicking pronormoblasts. A CD20 immunohistochemical stain was essential in identifying the neoplastic infiltrate in all cases. The majority of cases (73%, 10/13) showed low-level bone marrow involvement by lymphoma, 10% or less. CD20 immunohistochemistry highlighted individually dispersed and small clusters of large lymphoid cells in a sinusoidal and/or interstitial growth pattern. Most of the cases that were assessed showed a non-germinal center phenotype (CD10-, BCL6-/+, IRF4/MUM1+). There was an aggressive disease course with a median overall survival of 6 months. We would recommend performing a CD20 immunostain in patients who present with unexplained cytopenias and/or splenomegaly. Further investigation is warranted to better describe the features of this unique and aggressive variant of DLBCL.

TLR9 ligand induces the generation of CD20+ plasmablasts and plasma cells from CD27+ memory B-cells

Plasma cells (PCs) have a heterogeneous phenotype in humans. While bone marrow PCs are CD20-CD138+, tonsil PCs are CD20+CD138+/- and peripheral plasmablasts (PBs) are CD20-CD138-. In vitro, PCs are mainly generated by the activation of CD27+ memory B-cells through transient stimulation of CD40, and their phenotype appears similar to that of bone marrow PCs. While CD20 expression is lost at the plasmablastic stage, CD138 expression appears only at the PC stage. Thus, the CD20+CD138± phenotype of tonsil PCs does not represent an intermediate stage in the differentiation of memory B-cells into PCs. Because it has been previously shown that TLR9 activation was more able than CD40 stimulation to induce the differentiation of IgM+ CD27+ B-cells, we wondered whether TLR9 or CD40 stimulation would induce the same phenotype of PCs. Thus, we compared the differentiation of CD27+ B-cells isolated from either the tonsils or peripheral blood and stimulated with either CD40L-expressing fibroblasts or a TLR9 ligand, CpG oligodeoxynucleotide (CpG ODN). We observed that CpG ODN mainly induced CD27+ B-cell differentiation into CD20+CD38+CD138- PBs and CD20+CD38+CD138± PCs, which appear similar to tonsil PCs. Removal of CpG ODN during differentiation induced a decrease in the CD20+ plasmablastic population, and, conversely, stimulation of CD40L-induced pre-plasmablasts with CpG ODN increased the population of CD20+CD38+ PBs. Analysis of Ig secretion showed that CpG ODN induced increased IgM secretion compared to CD40L. PCs from patients with multiple myeloma, the malignant counterpart of bone marrow PCs, rarely express CD20. We show that CpG ODN did not induce or increase CD20 in nine IgG or IgA myeloma cell lines. These data strongly suggest that CpG ODN mainly targets CD27+ IgM+ B-cells.

Autoimmune pancreatitis characterized by predominant CD8+ T lymphocyte infiltration

Autoimmune pancreatitis (AIP) is a rare form of pancreatitis characterized by prominent lymphocyte infiltration and pancreatic fibrosis resulting in organ dysfunction. The pathogenesis and pathology of AIP remain unknown. A 64-year-old Chinese man presented with symptoms and signs of bile duct obstruction diffuse enlargement of the head of pancreas, elevated IgG levels, and negative autoimmune antibody responses. A pylorus-preserving pancreatoduodenectomy was performed and a pancreatic tumor was suspected. However, periductal lymphoplasmacytic infiltration and fibrosis were found in the head of pancreas and nearby organs instead of tumor cells. Four months after surgery, the patient was readmitted because of reoccurrence of severe jaundice and sustained abdominal distension. Prednisone 30 mg/d was administered orally as an AIP was suspected. One and a half months later, the symptoms of the patient disappeared, and globulin, aminotransferase and bilirubin levels decreased significantly. Over a 9-mo follow-up period, the dose of prednisone was gradually decreased to 10 mg/d and the patient remained in good condition. We further demonstrated dominant CD3+/CD8+ populations, CD20+ cells and a few CD4+ cells in the pancreatic parenchyma, duodenum and gallbladder wall by immunohistochemical assay. This AIP case presented with significant CD8+ T lymphocyte infiltration in the pancreas and extra-pancreatic lesions, indicating that this cell population may be more important in mediating AIP pathogenesis than previously known and that AIP might be a poorly defined autoimmune disease with heterogeneous pathogenesis.

Primary diffuse large B-cell lymphoma of the ethmoid sinus

Malignant lymphoma of the ethmoid sinus is very rare. A case of diffuse large B-cell lymphoma (DLBCL) of the left ethmoid sinus is presented here. A 79-year-old Japanese man was consulted to our hospital because of head ache and disturbance of left eye movement. Nasal endoscopy revealed a tumor, and imaging modalities including CT and MRI detected a tumor in the left ethmoid sinus. The tumor was invasive into left eye and left nose. A biopsy was performed via the nasal cavity. The biopsy revealed a diffuse proliferation of atypical lymphocytes. The atypical lymphocytes were large and had enlarged hyperchromatic nuclei. Mitotic figures were scattered. Hodgkin's cells were absent. Follicular structures were not seen. Immunohistochemically, the tumor cells were negative for cytokeratins (AE1/2, polyclonal, KL-1, and CAM5.2, Dako) and epithelial membrane antigen, CD3, CD15, CD30, CD45RO, and TdT. In contrast, the tumor cells were positive for CD20, CD45, CD79α, and p53. KI-67 labeling was 100%. Light chain restriction was present; there were numerous λ-chain-positive cells, while κ-chain-positive cells were scant. The pathological diagnosis was DLBCL of the left ethmoid sinus. Imaging of the whole body revealed no tumors and lymphadenopathy other than the ethmoid DLBCL. The patient was treated with chemoradiation, and is now alive 3 months after the presentation. In conclusion, a very rare case of DLBCL of the ethmoid sinus was reported.

CD20 Positive T Cell Lymphoma Involvement of Skin

CD20 positive T cell lymphoma is a rare condition that is associated with the coexpressions of CD20 and T cell markers, such as, CD3, CD5, or UCHL-1. Positivity for CD20 in this tumor represents an aberrant immunophenotype, but the presence of monoclonal T cell receptor (TCR) gene rearrangements and negativity for immunoglobulin heavy chain gene rearrangement indicate that this tumor is a T cell lymphoma. The majority of cases of CD20 positive T cell lymphoma have been reported as immature peripheral T cell lymphoma not otherwise specified. However, we believe that this disease is likely to be re-listed as a new disease entity after its pathogenesis has been elucidated and more cases have been evaluated. Here, we present a case of peripheral T cell lymphoma coexpressing CD20 and T cell markers with a demonstrable TCR gene rearrangement, in a patient who had been misdiagnosed as having B cell type lymphoma 4 years previously. We hypothesize that in this case initially circulating normal CD20+ T cell subsets underwent neoplastic transformation and CD20 positive T cell lymphoma subsequently developed in the lymph node, and then recurred in the skin due to systemic disease or metastasized from the nodal disease.

Current and future treatment approaches for neuromyelitis optica

Neuromyelitis optica (NMO) is an inflammatory disease of the central nervous system (CNS) characterized by severe attacks of optic neuritis and myelitis, and which, unlike multiple sclerosis (MS), commonly spares the brain in the early stages. NMO used to be considered as a special form of MS. During the past 10 years, however, the two diseases have been shown to be clearly different. NMO is a B-cell-mediated disease associated with anti-aquaporin-4 antibodies in many cases and its pathophysiology seems to be near the acute lesion of necrotizing vasculitis. Assessment of prevalence shows that NMO is far less frequent than MS, which explains the absence of randomized clinical trials and NMO treatment strategies validated by evidence-based medicine. Recently, many data have been published that suggest that the therapeutic option in NMO should be immunosuppressive rather than immunomodulatory drugs. In the present study, after a brief overview of NMO, we review therapeutic studies and propose new therapeutic strategies in the relapse and disease-modifying fields.

A Systematic Review and Meta-Analysis of Rituximab in Antibody-mediated Renal Allograft Rejection

BACKGROUND

The standard treatment of antibody-mediated rejection (AMR) consists of antilymphocyte antibody, intravenous immunoglobulin, and plasmapheresis. This treatment is associated with a high rate of resistance and refractory AMR. Recent interest has focused on use of rituximab (RTX), a chimeric anti-CD20 monoclonal antibody.

OBJECTIVE

We conducted a systematic review and meta-analysis of studies of RTX in AMR of the renal allograft.

METHODS

Combining two comprehensive search themes (AMR and RTX), we searched electronic databases from 1969 through 2010, supplemented by a manual review of abstracts from nephrology and transplant meetings, and reference lists of review articles. All studies evaluating explicit response of patients with AMR to RTX were included. The outcome was pooled odds ratio (OR) of response to RTX.

RESULTS

A total of 114 studies were identified, 94 of which were excluded on initial screening. Analysis of the 10 studies (249 patients) showed an OR of 3.16 (95% CI: 1.75-5.70) for response to RTX. Reported adverse effects included BK virus nephropathy, cytomegalovirus (CMV) viremia, pneumonia, herpes zoster, and septic shock.

CONCLUSION

This study suggests that RTX is a reasonable therapeutic option in the treatment of AMR. Further randomized studies are necessary to establish its efficacy and safety.

CD20dim-positive T-cell large granular lymphocytic leukemia in a patient with concurrent hairy cell leukemia and plasma cell myeloma

We report a CD20dim- positive T-cell large granular lymphocytic (T-LGL) leukemia in a patient with concurrent hairy cell leukemia and plasma cell myeloma. This patient was first diagnosed with T-LGL leukemia with dim CD20 expression, which by itself was a rare entity. He received no treatment for T-LGL leukemia. The patient later developed a hairy cell leukemia, which went into complete clinical remission after one cycle of 2-CdA. Five years later, he was diagnosed with a third malignancy, plasma cell myeloma. Complex cytogenetic aberrancies were present at the time when plasma cell myeloma was diagnosed. This is the first report, to the best of our knowledge, in the English literature with the aforementioned three distinct hematopoietic malignancies in one patient.

Ofatumumab: a novel monoclonal anti-CD20 antibody

Ofatumumab, a novel humanized monoclonal anti-CD20 antibody, was recently approved by the FDA for the treatment of fludarabine and alemtuzumab refractory chronic lymphocytic leukemia (CLL). Ofatumumab effectively induces complement-dependent cytotoxicity (CDC) in vitro, and recent studies demonstrated that ofatumumab also effectively mediates antibody-dependent cellular cytotoxicity (ADCC). Pharmacokinetic studies indicated that increased exposure to the antibody correlated with improved clinical outcome in CLL. Thus, pharmacogenomics may be important in identifying which patients are more likely to respond to ofatumumab therapy, although such studies have not yet been performed. Patients with the high-affinity FCGR3a 158 V/V polymorphism may be more likely to respond to therapy, if ADCC is the primary in vivo mechanism of action of ofatumumab. Patients with increased expression of the complement defense proteins CD55 and CD59 may be less likely to respond if ofatumumab works in vivo primarily via CDC. Patients with increased metabolism and clearance of ofatumumab may have lower exposure and be less likely to respond clinically. Thus, pharmacogenomics may determine the responsiveness of patients to ofatumumab therapy.

Combination bortezomib and rituximab treatment affects multiple survival and death pathways to promote apoptosis in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a distinct histologic subtype of B cell non-Hodgkins lymphoma (NHL) associated with an aggressive clinical course. Inhibition of the ubiquitin-proteasome pathway modulates survival and proliferation signals in MCL and has shown clinical benefit in this disease. This has provided rationale for exploring combination regimens with B-cell selective immunotherapies such as rituximab. In this study, we examined the effects of combined treatment with bortezomib and rituximab on patient-derived MCL cell lines (Jeko, Mino, SP53) and tumor samples from patients with MCL where we validate reversible proteasome inhibition concurrent with cell cycle arrest and additive induction of apoptosis. When MCL cells were exposed to single agent bortezomib or combination bortezomib/rituximab, caspase dependent and independent apoptosis was observed. Single agent bortezomib or rituximab treatment of Mino and Jeko cell lines and patient samples resulted in decreased levels of nuclear NFkappaB complex(es) capable of binding p65 consensus oligonucleotides, and this decrease was enhanced by the combination. Constitutive activation of the Akt pathway was also diminished with bortezomib alone or in combination with rituximab. On the basis of in vitro data demonstrating additive apoptosis and enhanced NFkappaB and phosphorylated Akt depletion in MCL with combination bortezomib plus rituximab, a phase II trial of bortezomib-rituximab in patients with relapsed/refractory MCL is underway.

The role of ofatumumab in the treatment of chronic lymphocytic leukemia resistant to previous therapies

Chronic lymphocytic leukemia (CLL) is an indolent but incurable disease. Despite the improvement of the available therapies, the management of heavily-treated CLL patients represents a challenge for modern practitioners. Ofatumumab is a second-generation, fully human anti-CD20 monoclonal antibody that has shown activity in CLL patients who have failed very effective therapies such as fludarabine, alemtuzumab and rituximab. Potential benefits of ofatumumab include powerful complement-dependent cytotoxicity, less immunogenicity, faster infusions and activity in resistant CLL patients. Recently, the FDA has approved ofatumumab for the treatment of CLL patients who have failed fludarabine and alemtuzumab-based regimens. The aim of this review is to summarize the current knowledge regarding pharmacology, mechanism of action, pre-clinical and clinical development, and the role of ofatumumab for the treatment of CLL patients who have failed previous therapies. Further research is necessary to further define the role of ofatumumab in the treatment of CLL.

Helicobacter pylori and Gastric Mucosa-associated Lymphoid Tissue (MALT) Lymphoma: Updated Review of Clinical Outcomes and the Molecular Pathogenesis

In most H. pylori-positive patients, gastric low-grade mucosa-associated lymphoid tissue (MALT) lymphomas regress both endoscopically and histopathologically after H. pylori eradication, but no factors that can be predictive of the response to the eradication have been definitively identified, and there is little information on how to determine the optimal observation period before additional treatment can be started. Here, clinical studies dealing with the diagnosis and treatment of gastric MALT lymphomas and H. pylori published during the last 5 years were systematically reviewed, and studies identifying the molecular approaches involved in the pathogenesis were summarized. Most of the clinical studies indicate a favorable effect of H. pylori eradication on the clinical outcome of gastric MALT lymphomas. Some studies suggest the necessity of additional treatment in nonresponders to H. pylori eradication, while others suggest the adoption of a watch-and-wait strategy. The molecular characteristics of MALT lymphomas could play an important role in prognostic prediction and the selection of further therapeutic intervention after the eradication. This updated review of gastric MALT lymphomas illustrates the potential efficacy of H. pylori eradication in tumor remission, but further molecular characterization is necessary to establish the most suitable therapeutic strategy for patients who do not respond to eradication.