Perspectives on outpatient administration of CAR-T cell therapy in aggressive B-cell lymphoma and acute lymphoblastic leukemia.

Chimeric antigen receptor (CAR) T-cell therapies that specifically target the CD19 antigen have emerged as a highly effective treatment option in patients with refractory B-cell hematological malignancies. Safety and efficacy outcomes from the pivotal prospective clinical trials of axicabtagene ciloleucel, tisagenlecleucel and lisocabtagene maraleucel and the retrospective, postmarketing, real-world analyses have confirmed high response rates and durable remissions in patients who had failed multiple lines of therapy and had no meaningful treatment options. Although initially administered in the inpatient setting, there has been a growing interest in delivering CAR-T cell therapy in the outpatient setting; however, this has not been adopted as standard clinical practice for multiple reasons, including logistic and reimbursement issues. CAR-T cell therapy requires a multidisciplinary approach and coordination, particularly if given in an outpatient setting. The ability to monitor patients closely is necessary and proper protocols must be established to respond to clinical changes to ensure efficient, effective and rapid evaluation either in the clinic or emergency department for management decisions regarding fever, sepsis, cytokine release syndrome and neurological events, specifically immune effector cell-associated neurotoxicity syndrome. This review presents the authors' institutional experience with the preparation and delivery of outpatient CD19-directed CAR-T cell therapy.

Concepts in immuno-oncology: tackling B cell malignancies with CD19-directed bispecific T cell engager therapies.

The B cell surface antigen CD19 is a target for treating B cell malignancies, such as B cell precursor acute lymphoblastic leukemia and B cell non-Hodgkin lymphoma. The BiTE® immuno-oncology platform includes blinatumomab, which is approved for relapsed/refractory B cell precursor acute lymphoblastic leukemia and B cell precursor acute lymphoblastic leukemia with minimal residual disease. Blinatumomab is also being evaluated in combination with other agents (tyrosine kinase inhibitors, checkpoint inhibitors, and chemotherapy) in various treatment settings, including frontline protocols. An extended half-life BiTE molecule is also under investigation. Patients receiving blinatumomab may experience cytokine release syndrome and neurotoxicity; however, these events may be less frequent and severe than in patients receiving other CD19-targeted immunotherapies, such as chimeric antigen receptor T cell therapy. We review BiTE technology for treating malignancies that express CD19, analyzing the benefits and limitations of this bispecific T cell engager platform from clinical experience with blinatumomab.

Chimeric Antigen Receptor T Cell Therapy During the COVID-19 Pandemic.

The SARS-CoV-2 coronavirus (COVID-19) pandemic has significantly impacted the delivery of cellular therapeutics, including chimeric antigen receptor (CAR) T cells. This impact has extended beyond patient care to include logistics, administration, and distribution of increasingly limited health care resources. Based on the collective experience of the CAR T-cell Consortium investigators, we review and address several questions and concerns regarding cellular therapy administration in the setting of COVID-19 and make general recommendations to address these issues. Specifically, we address (1) necessary resources for safe administration of cell therapies; (2) determinants of cell therapy utilization; (3) selection among patients with B cell non-Hodgkin lymphomas and B cell acute lymphoblastic leukemia; (4) supportive measures during cell therapy administration; (5) use and prioritization of tocilizumab; and (6) collaborative care with referring physicians. These recommendations were carefully formulated with the understanding that resource allocation is of the utmost importance, and that the decision to proceed with CAR T cell therapy will require extensive discussion of potential risks and benefits. Although these recommendations are fluid, at this time it is our opinion that the COVID-19 pandemic should not serve as reason to defer CAR T cell therapy for patients truly in need of a potentially curative therapy.

High resolution melting analysis (HRM) for the assessment of clonality in feline B-cell lymphomas.

Analysis of clonality is gaining importance in diagnosing lymphomas in veterinary medicine. Usually, PCR for the analysis of antigen receptor rearrangement (PARR) is followed by electrophoretic separation of the PCR products. Aim of this study was to test the feasibility of HRM for the assessment of clonality in B-cell lymphomas of cats. High resolution melting analysis differentiates PCR products by their different melting point using the decrease in fluorescence of an intercalating dye during melting of the PCR product. Additionally, the method is easy to use with no post-PCR manipulation of the samples. Forty-seven feline B-cell lymphomas and 31 reactive lymphatic proliferations of cats were investigated by PARR followed either by capillary electrophoresis or an HRM assay. To objectify the interpretation of the HRM results a recently published mathematical approach was applied to the melting curve. To overcome discrepancies between the visual interpretation and the mathematical approach, the latter was modified to include testing of reproducibility and recognition of pseudoclonality. In 11 of 47 lymphoma cases clonal populations were detectable by HRM assay compared to 14 of 47 lymphomas in which clonal populations were detected by capillary electrophoresis assay. Neither of the methods showed a clonal pattern in any of the reactive samples. However, the HRM assay showed a unique pattern in cases of follicular lymphatic hyperplasia that had no corresponding pattern in capillary electrophoresis. CONCLUSION: The capillary electrophoresis assay could identify 3 lymphomas that were not detected by the HRM assay and is therefore regarded superior to the HRM assay. The comparison however, was hampered by the overall bad performance of the PARR, that might be the consequence of insufficient primer binding due to somatic hypermutation of the binding sites during antigen stimulated proliferation of the B lymphocytes.

Quantitative assessment of informative immunophenotypic markers increases the diagnostic value of immunophenotyping in mature CD5-positive B-cell neoplasms.

BACKGROUND: The data on the clinical utility of the quantitative assessment of immunophenotypes in distinguishing mature CD5-positive B-cell neoplasms is limited. The study aim was to assess the diagnostic value of the quantitative assessment of a panel of 18 markers and to identify the most informative ones. METHODS: The immunophenotype of the neoplastic population was determined in diagnostic specimens from 188 patients. BD FACSCanto II flow cytometer and FACSDiva software were used to analyze the positivity/negativity and mean fluorescence intensity (MFI) of the surface expression of 18 markers. Advanced data mining methods were used to define the key differential diagnostic features of CLL/SLL (chronic lymphocytic leukemia/small lymphocytic lymphoma), MCL (mantle cell lymphoma), and CD5+ MZL (marginal zone lymphoma). RESULTS: The most informative markers for the distinction of CLL/SLL, MCL, CD5+ MZL, including atypical cases, were the MFI values of CD79b, CD20, CD23, CD43, CD38, CD11c, FMC7, CD200, kappa light chain, and their combinations. CD23 and CD200 were the most discriminant between CLL/SLL and MCL and CD23 plus CD79b between CLL/SLL and CD5+ MZL. The quantitative analysis of the most informative markers failed to accurately distinguish MCL and CD5+ MZL. The study highlights the data mining methods for the analysis and selection of the most informative immunophenotypic markers and for the design of a predictive model (diagnostic classifier), minimizing the subjectivity of expert-based assessment. CONCLUSIONS: Our data confirmed that the quantification of the expression of informative markers increases the diagnostic value of immunophenotyping in mature CD5+ B-cell neoplasms. © 2017 International Clinical Cytometry Society.

Tbo-Filgrastim versus Filgrastim during Mobilization and Neutrophil Engraftment for Autologous Stem Cell Transplantation.

There are limited data available supporting the use of the recombinant granulocyte colony-stimulating factor (G-CSF), tbo-filgrastim, rather than traditionally used filgrastim to mobilize peripheral blood stem cells (PBSC) or to accelerate engraftment after autologous stem cell transplantation (ASCT). We sought to compare the efficacy and cost of tbo-filgrastim to filgrastim in these settings. Patients diagnosed with lymphoma or plasma cell disorders undergoing G-CSF mobilization, with or without plerixafor, were included in this retrospective analysis. The primary outcome was total collected CD34(+) cells/kg. Secondary mobilization endpoints included peripheral CD34(+) cells/µL on days 4 and 5 of mobilization, adjunctive use of plerixafor, CD34(+) cells/kg collected on day 5, number of collection days and volumes processed, number of collections reaching 5 million CD34(+) cells/kg, and percent reaching target collection goal in 1 day. Secondary engraftment endpoints included time to neutrophil and platelet engraftment, number of blood product transfusions required before engraftment, events of febrile neutropenia, and length of stay. A total of 185 patients were included in the final analysis. Patients receiving filgrastim (n = 86) collected a median of 5.56 × 10(6) CD34(+) cells/kg, compared with a median of 5.85 × 10(6) CD34(+) cells/kg in the tbo-filgrastim group (n = 99; P = .58). There were no statistically significant differences in all secondary endpoints with the exception of apheresis volumes processed (tbo-filgrastim, 17.0 liters versus filgrastim, 19.7 liters; P < .01) and mean platelet transfusions (tbo-filgrastim, 1.7 units versus filgrastim, 1.4 units; P = .04). In conclusion, tbo-filgrastim demonstrated similar CD34(+) yield compared with filgrastim in mobilization and post-transplantation settings, with no clinically meaningful differences in secondary efficacy and safety endpoints. Furthermore, tbo-filgrastim utilization was associated with cost savings of approximately $1406 per patient utilizing average wholesale price.

Clonality assessment of cutaneous B-cell lymphoid proliferations: a comparison of flow cytometry immunophenotyping, molecular studies, and immunohistochemistry/in situ hybridization and review of the literature.

Cutaneous lymphoid infiltrates are diagnostically challenging. Although ancillary techniques to assess clonality can help distinguish between reactive lymphoid hyperplasia and lymphoma, one of the most widely used techniques in hematopathology, flow cytometry immunophenotyping (FCI), has not been routinely applied to skin specimens. We performed FCI on 73 skin specimens from 67 patients clinically suspected of having a cutaneous B-cell lymphoma (CBCL) and compared the results with those obtained from immunoglobulin heavy chain (IGH) gene molecular studies (58 cases, primarily by polymerase chain reaction) and either immunohistochemistry (IHC) or in situ hybridization to evaluate for light chain restriction (22 and 2 cases, respectively). Sufficient quantity of CD45 (leukocyte common antigen)-positive cells and staining quality were achieved in 88% of cases by FCI, and clonality was detected in 68% of CBCLs versus molecular studies showing sufficient DNA quality in 74% and only 39% clonality detection, and interpretable/contributory IHC results in 84% of cases with 55% clonality detection. Clonality was documented more frequently in secondary rather than primary CBCLs by all 3 techniques. Therefore, FCI is feasible and appears to be more reliable than molecular studies or IHC/in situ hybridization for detecting clonality in CBCLs and can provide additional prognostically and therapeutically relevant information. The exception is cases with plasmacytic differentiation such as marginal zone lymphoma for which IHC might be a superior tool. We have also shown that a large subset of primary cutaneous follicle center lymphomas express CD10 and/or BCL2 by FCI. Recent advances in FCI beg the question of applicability to cutaneous T-cell and NK-cell lymphomas.

Standard International prognostic index remains a valid predictor of outcome for patients with aggressive CD20+ B-cell lymphoma in the rituximab era.

PURPOSE: The International Prognostic Index (IPI) is widely used for risk stratification of patients with aggressive B-cell lymphoma. The introduction of rituximab has markedly improved outcome, and R-CHOP (rituximab + cyclophosphamide, doxorubicin, vincristine, prednisone) has become the standard treatment for CD20(+) diffuse large B-cell lymphoma. To investigate whether the IPI has maintained its power for risk stratification when rituximab is combined with CHOP, we analyzed the prognostic relevance of IPI in three prospective clinical trials. PATIENTS AND METHODS: In total, 1,062 patients treated with rituximab were included (MabThera International Trial [MInT], 380 patients; dose-escalated regimen of cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisone (MegaCHOEP) trial, 72 patients; CHOP + rituximab for patients older than age 60 years [RICOVER-60] trial, 610 patients). A multivariate proportional hazards modeling was performed for single IPI factors under rituximab on event-free, progression-free, and overall survival. RESULTS: IPI score was significant for all three end points. Rituximab significantly improved treatment outcome within each IPI group resulting in a quenching of the Kaplan-Meier estimators. However, IPI was a significant prognostic factor in all three end points and the ordering of the IPI groups remained valid. The relative risk estimates of single IPI factors and their order in patients treated with R-CHOP were similar to those found with CHOP. CONCLUSION: The effects of rituximab were superimposed on the effects of CHOP with no interactions between chemotherapy and antibody therapy. These results demonstrate that the IPI is still valid in the R-CHOP era.

[Alteration in antibody-mediated immunity in patients with rituximab-combined chemotherapy and incidence of herpes zoster].

Rituximab, a chimeric monoclonal antibody against the CD20 protein, has an antineoplastic effect resulting from antibody dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). In patients with rituximab-combined chemotherapy, a decline in immunoglobulin can be observed. This is more likely to cause virus reactivation, such as Herpes (H) zoster. However, this fact has not reported in a large-scale study. In order to research immunodeficiency conditions in patients with rituximab-combined therapy, we examined the alteration in immunoglobulin level throughout the treatment among 205 cases with B-cell lymphoma. We also studied the prevalence of H. zoster in those cases. The IgG level throughout the treatment was measured in 89 patients in the research. The median post-chemotherapy IgG level was 41.1% lower than its pre-chemotherapy IgG level. In 58 cases, the IgG level following chemotherapy was below the normal level. In 22 cases, the IgG level dropped to less than half of the pre-chemotherapy level. H. zoster developed in 17 cases (8.3%). There was no significant difference in IgG level between H. zoster-onset cases and non-H. zoster-onset cases. Antibody-mediated immunity can decrease greatly and prolong in cases with rituximab in combination with chemotherapy. Therefore, infection control is considered to be important.

A new subgroup of immunoglobulin heavy chain variable region genes for the assessment of clonality in feline B-cell lymphomas.

In human medicine, PCR-amplification of the complementarity determining region 3 of the immunoglobulin heavy chain genes followed by polyacrylamide gel electrophoresis (PAGE) is an accepted method to assess clonality in B-cell lymphomas and thereby facilitates the differentiation of neoplasias from benign hyperplasias or reactive infiltrates. To generate a basis for the development of a PCR-based assay for the assessment of clonality in feline B-cell lymphomas we analyzed 28 transcripts (cDNA) of the feline immunoglobulin heavy chain variable region genes (IGHV). Transcripts were generated using techniques for the amplification of unknown sequences (i.e. the SMART RACE and the CapFishing technique) as well as primers derived from sequences of the NCBI Trace archive of the cat. Analysis of this archive revealed traces similar to the human IGHV-1 and IGHV-3 subgroups of genes. By identification of the subgroup-specific leader sequence within the traces, two subgroup-specific primers for this region were designed and used to amplify the heavy chain variable region genes. Using all amplification techniques, transcripts of both subgroups were created and the subgroups were denominated according to their human counterparts as feline IGHV-1 and feline IGHV-3. By aligning previously described transcripts of the feline IGHV genes to our transcripts we were able to assign these to the IGHV-3 subgroup; therefore, this study provides the first description of the feline IGHV-1 subgroup of genes. On the basis of the IGHV-1 and IGHV-3 transcripts we developed a PCR-based assay. For each of the two subgroups we used one sense primer derived from the first and one sense primer derived from the third framework region each in combination with a mixture of three antisense primers derived from the fourth framework region. With these four sets of primers, the assay was able to detect monoclonality in 7/10 (70%) cats with histologically and immunohistochemically diagnosed B-cell lymphomas. In two of these cases, monoclonal rearrangement of the IGHV genes was only detectable with IGHV-1 subgroup-specific primers. Amplification of feline hyperplastic lymphatic tissue only gave results indicative of polyclonal populations. The use of a PCR-based assay in combination with standard techniques for the diagnosis of feline lymphoma is helpful and the characterization of the additional subgroup of feline variable regions genes puts this assay on a broader basis.

[Assessment of BIOMED-2 assays for detection of clonal Ig gene rearrangements in mature B-cell lymphomas].

OBJECTIVE: To evaluate the efficiency of the BIOMED-2 PCR assay and its implication in the diagnosis of mature B-cell non-Hodgkin's lymphomas. METHODS: Clinical, morphological and immunohistochemical features of 72 cases of non-Hodgkin's lymphomas were studied, including 25 reactive lymphoid hyperplasia, 37 diffuse large B cell lymphomas (DLBCL) and 35 extranodal marginal zone lymphomas of mucosa associated lymphoid tissues (MALT lymphoma and in addition, 25 cases of reactive lymphoid hyperplasia were used as the controls). DNA was exacted from the paraffin embedded formalin fixed tissue blocks and the quality of DNA was assessed using the BIOMED-2 specimen control reaction. Adequate samples were then analyzed by BIOMED-2 for immunoglobulin heavy and kappa light chain rearrangements. RESULTS: Adequate DNA was obtained in 83 of 97 samples, including 60 mature B cell lymphomas and 23 reactive lymphoid hyperplasia. Clonal B-cell gene rearrangements were detected in 57 of 60 (95%) lymphomas. In contrast, clonal Ig gene rearrangements were not detected in any of the 23 cases of reactive lymphoid hyperplasia. CONCLUSION: BIOMED-2 assay is highly sensitive and specific for the detection of clonal B cell gene rearrangement using routine paraffin embedded formalin fixed specimens.

Serum-free light chain assessment in hepatitis C virus-related lymphoproliferative disorders.

OBJECTIVE: To evaluate the relevance of serum-free light chain (FLC) assessment in hepatitis C virus (HCV)-related lymphoproliferative disorders, including mixed cryoglobulinemia (MC) and B cell non-Hodgkin lymphoma (B-NHL). PATIENTS AND METHODS: A total of 59 patients infected with HCV were prospectively followed, including patients without MC (n = 17), with asymptomatic MC (n = 7) and with MC vasculitis (n = 35, 9 of whom had B-NHL). Clinical and biological data were recorded at the time of the initial evaluation and at the end of follow-up. Serum FLC quantitation was carried out using a serum FLC assay. RESULTS: The mean (SD) serum kappa FLC level was higher in patients with asymptomatic MC (27.9 (8.6) mg/litre), MC vasculitis (36.7 (46.2) mg/litre) and B-NHL (51.3 (78.3) mg/litre) than without MC (21.7 (17.6) mg/litre) (p = 0.047, 0.025 and 0.045, respectively). The mean serum FLC ratio was higher in patients with MC vasculitis (2.08 (2.33)) and B-NHL (3.14 (3.49)) than in patients without MC (1.03 (0.26)) (p = 0.008). The rate of abnormal serum FLC ratio (>1.65) correlated with the severity of HCV-related B cell disorder: 0/17 (0%) without MC, 0/7 (0%) asymptomatic MC, 6/26 (23%) MC vasculitis without B-NHL and 4/9 (44%) B-NHL (p = 0.002). Serum kappa FLC levels and the serum FLC ratio correlated with the cryoglobulin level (r = 0.32, p<0.001 and r = 0.25, p = 0.002, respectively) and the severity of the B cell disorder (r = 0.26, p = 0.045 and r = 0.41, p = 0.001, respectively). Among patients with an abnormal serum FLC ratio at baseline, the FLC ratio correlated with the virological response to HCV treatment. CONCLUSIONS: In patients infected with HCV, an abnormal serum FLC ratio appears to be a very interesting marker, as it is consistently associated with the presence of MC vasculitis and/or B-NHL. After antiviral therapy, the serum FLC ratio could be used as a surrogate marker of the control of the HCV-related lymphoproliferation.

Improved clonality assessment in germinal centre/post-germinal centre non-Hodgkin's lymphomas with high rates of somatic hypermutation.

BACKGROUND: PCR detects clonal rearrangements of the Ig gene in lymphoproliferative disorders. False negativity occurs in germinal centre/post-germinal centre lymphomas (GC/PGCLs) as they display a high rate of somatic hypermutation (SHM), which causes primer mismatching when detecting Ig rearrangements by PCR. AIMS: To investigate the degree of SHM in a group of GC/PGCLs and assess the rate of false negativity when using BIOMED-2 PCR when compared with previously published strategies. METHODS: DNA was isolated from snap-frozen tissue from 49 patients with GC/PGCL (23 diffuse large B cell lymphomas (DLBCLs), 26 follicular lymphomas (FLs)) and PCR-amplified for complete (VDJH), incomplete (DJH) and Ig kappa/lambda rearrangements using the BIOMED-2 protocols, and compared with previously published methods using consensus primers. Germinal centre phenotype was defined by immunohistochemistry based on CD10, Bcl-6 and MUM-1. RESULTS: Clonality detection by amplifying Ig rearrangements using BIOMED-2 family-specific primers was considerably higher than that found using consensus primers (74% DLBCL and 96% FL vs 69% DLBCL and 73% FL). Addition of BIOMED-2 DJH rearrangements increased detection of clonality by 22% in DLBCL. SHM was present in VDJH rearrangements from all patients with DLBCL (median (range) 5.7% (2.5-13.5)) and FL (median (range) 5.3% (2.3-11.9)) with a clonal rearrangement. CONCLUSIONS: Use of BIOMED-2 primers has significantly reduced the false negative rate associated with GC/PGCL when compared with consensus primers, and the inclusion of DJH rearrangements represents a potential complementary target for clonality assessment, as SHM is thought not to occur in these types of rearrangements.

[Assessment of the significance of histological, immunohistochemical and clinical data in the diagnosis of lymphoproliferative skin diseases in conformance with a consensus by international experts]. / Otsenka znachimosti gistologicheskikh, immunogistokhimicheskikh i klinicheskikh dannykh v diagnostike limfoproliferativnykh zabolevanii kozhi metodom mezhékspertnogo soglasiia.

The diagnosis of lymphoproliferative diseases of the skin remains a challenging problem in dermatology and requires a multidisciplinary approach. In our retrospective study two dermatopathologists independently reviewed 49 cases of skin lymphomas to determine the impact of diagnostic methods such as clinical examination, histological evaluation, and immunohistochemistry. The study was carried out in four independent review sessions consisting of (1) a review of histological sections only, (2) a review of immunohistochemical sections, (3) an introduction of the detailed clinical data, history, and staging information, and (4) and introduction of the follow-up. The agreement with the consensus was analyzed for every session, and statistics were calculated to evaluate the interobserver reliability. The agreement level with the consensus diagnosis was 18.8% for B-cell lymphomas and 12.5% for T-cell lymphomas after the first session, respectively, improved to 56.3% and 43.8% after the second session; to 100% and 79.7% after the third session, and to 100% and 85.9% after the forth one. The overall value for the diagnosis of T-cell lymphomas was 0.67 (good consensus) and for that of B-cell lymphomas was 1.00 (absolute consensus). The results of our study show that cutaneous lymphomas can be diagnosed reliably basing on the overall assessment of the clinical, histopathological, and immunohistochemical data. In some cases, however, molecular biologic methods may be required to diagnose cutaneous lymphomas properly.

Primary cutaneous follicular lymphoma: an assessment of clinical, histopathologic, immunophenotypic, and molecular features.

PURPOSE: Unlike nodal follicular lymphoma (NFL), Primary cutaneous follicular lymphomas (PCFLs) rarely express Bcl-2 protein or t(14;18)(q32;q21) (Bcl-2/IgH). The aim of this study was to further characterize PCFL in a large series from North America. PATIENTS AND METHODS: Clinical data and archival formalin-fixed, paraffin-embedded tissue were obtained from 32 patients. PCFL was defined as follicular lymphoma limited to the skin at the time of diagnosis and within the first 6 months after diagnosis. Specimens were analyzed for the expression of CD3, CD10, CD20, Bcl-2, and Bcl-6 proteins by immunohistochemistry as well as for the presence of t(14;18)(q32;q21) by polymerase chain reaction. RESULTS: The male-to-female ratio was 1.5:1, with a median age of 60 years. Twenty-four patients had lesions on the head and neck, five had lesions on the trunk, and three had lesions on both head and trunk. Follow-up data were available in all cases, with a mean length of 35.8 months. The majority of the patients were treated with radiation therapy. All patients were alive at last follow-up except one. Recurrence was noted in seven patients (22%), after a mean disease-free survival time of 17.7 months. CD10 and Bcl-6 expression were seen in 29 (91%) of 32 and 31 (97%) of 32 cases, respectively. Bcl-2 expression was noted in 13 (41%) of 32 cases. PCR results for t(14;18)(q32;q21) were positive in 11 (34%) of 32 patients and showed correlation with Bcl-2 protein expression. The sequencing of the t(14;18)(q32;q21) amplicons confirmed unique breakpoints in each of the seven tested cases. Comparison between the Bcl-2 and/or t(14;18)(q32;q21)-positive and t(14;18)(q32;q21)-negative cases revealed no significant difference in age, site, clinical course, or outcome. CONCLUSION: We demonstrated Bcl-2 protein expression and t(14;18)(q32;q21) in a significant minority of cases, suggesting a relationship with NFL. It remains to be seen whether, on longer follow-up, there is any clinical difference in cases with and without t(14;18)(q32;q21).

Locoregional treatment of low-grade B-cell lymphoma with CD3xCD19 bispecific antibodies and CD28 costimulation. II. Assessment of cellular immune responses.

Ten patients with advanced B-cell lymphoma were treated with a single locoregional injection of CD3xCD19 bispecific and costimulating CD28 monospecific antibodies to activate tumor-infiltrating T-lymphocytes. Antibodies were administered at 4 different dose levels (30 microg, 270 microg, 810 microg, 1,600 microg of each antibody) either by intratumoral or intralymphatic injection. Most patients developed responses within different compartments of the immune systems (T cells, NK cells) subsequent to the antibody application. Comparative studies in 2 patients of which treated as well as untreated lymph nodes were available revealed the up-regulation of T-cell activation markers induced by the antibody injection. Additionally, in 1 patient the induction of apoptosis of lymphoma B cells in the antibody-treated lymph node was observed. Specificity analyses of peripheral blood T cells by means of IFN-gamma ELISpot measurement indicated the recruitment of idiotype-specific T cells, as in 1 out of 3 investigated patients an increased T-cell response toward autologous idiotype peptides could be demonstrated. We conclude that a single injection of CD3xCD19 bispecific antibodies is capable to induce an activation of autologous T lymphocytes if simultaneous costimulatory signaling by CD28 antibodies is provided. Furthermore, our data suggest that at least in some patients lymphoma-specific T cells can be recruited by this immunotherapeutic approach toward B-cell lymphoma.

Comparison of different polymerase chain reaction-based approaches for clonality assessment of immunoglobulin heavy-chain gene rearrangements in B-cell neoplasia.

Several frequently applied polymerase chain reaction strategies for analysis of immunoglobulin heavy-chain gene rearrangements were compared by analyzing 70 B-cell lymphoproliferative disorders and 24 reactive lymphoid lesions. Southern blot analysis was used as the "gold standard" for clonality assessment. For polymerase chain reaction analysis, primers directed against framework (FR) 3 (FR3-A and FR3-B), FR2, and FR1 of the variable gene segments and against joining gene segments of the immunoglobulin heavy-chain gene were used. Polymerase chain reaction products were analyzed by high-resolution fingerprinting analysis using radiolabeled nucleotides, gene scanning using fluorochrome-labeled primers, and heteroduplex analysis. All of the assays generated polyclonal patterns in the reactive tissues. The sensitivity in detecting monoclonality as defined by Southern blotting varied between 60% (heteroduplex analysis with FR3 primers) and 77% (high-resolution fingerprinting analysis with FR2 primers). Comparison of the three FR3 assays revealed that gene scanning had the highest sensitivity (69%), probably because it could detect small aberrant monoclonal amplicons. False-negative results were especially frequent in follicular center lymphoma (n = 20), but also in diffuse large B-cell lymphoma (n = 18), both renowned for having mutated variable gene segments, potentially leading to primer mismatching. For example, in follicular center lymphoma, the FR3, FR2, and FR1 region primer sets detected clonality in only 35 to 40, 65, and 50%, respectively. Combining these techniques, 17 (85%) of 20 follicular center lymphoma samples showed monoclonality. Therefore, especially in follicular center lymphoma, diffuse large B-cell lymphoma, and, to a lesser extent, in other lymphomas, multiple variable gene segment primer sets must be used for a reliable assessment of clonality. Our results also suggest that gene scanning is somewhat more sensitive than other read-out systems. Heteroduplex analysis, however, is a reliable alternative within a diagnostic setting, avoiding the use of radioactivity or expensive automated sequencing equipment and fluorochrome-labeled (oligo)nucleotides.

[Assessment of degree of malignancy in non-Hodgkin B-cell lymphoma with immunophenotyping]. / Otsenka stepeni zlokachestvennosti B-kletochnykh nekhodzhinskikh zlokachestvennykh limfom metodom immunofenotipirovaniia.

Due to immunophenotypic examination of bioptic samples from 30 patients with non-Hodgkin's lymphoma (NHL), malignancy of B-cell NHL was identified at an early stage of diagnosis, before histological analysis yielded the results. Negative expression of T-cell antigens, monoclonal character of light-weight chains of immunoglobulins, positive expression of B-cell antigens and marked expression of CD5+ are immunologic markers of low-malignancy B-cell NHL. A similar immunophenotypic pattern, involving negative expression of CD5- and positive one for Calla-antigen as well as one identifiable by monoclonal non-cluster antibody IPO3, is a marker of highly-malignant B-cell NHL.