Antibody (rituximab) dependent cellular cytotoxicity is a key mechanism in killing CD20+ lymphoma cells. FcγRIIIA-158 V/F gene polymorphism results in expression of 3 variants of the FcγRIIIA receptor (FcγRIIIA) on cytotoxic lymphocytes with different receptor affinity. We studied 102 patients with newly diagnosed FL to assess whether the FcγRIIIA genotype influences outcome in patients treated with risk-adapted immunochemotherapy. The median age was 52 years (31-84); 90% of the patients had advanced (III/IV) clinical stages. The Follicular Lymphoma International Prognostic Index (FLIPI) scores were as follows: low 18.9%, intermediate 33.7% and high 47.4%. The front-line treatment was stratified according to the commonly used risk factors (FLIPI, beta-2-microglobuline and serum-Tyrosine-Kinase levels, bulky disease) into 3 treatment groups: (1) patients with FLIPI 0-1 treated with (R)-CHOP (51%), (2) patients under 60 (65) years of age with intermediate-risk disease (FLIPI 2) indicated for an intensive protocol (ProMACE-CytaBOM or sequential chemotherapy) (21%), and (3) patients under 60 (65) years with high-risk disease (FLIPI ≥3) treated with intensive chemotherapy plus autologous stem cell transplantation (28%). Rituximab was added to front-line chemotherapy in 59% of the patients. Generally, complete remission (CR) or unconfirmed CR was achieved in 85% of the patients, 11% had partial remission and 4% stable disease. Molecular CR (CRm) was achieved in 67.4% of 86 evaluable patients. Overall survival (OS) at 5 years reached 84% (95% CI 0.74-0.93); event-free survival (EFS) at 5 years was 58% (95% CI 0.45-0.71). The frequencies of FcγRIIIA-158 gene polymorphisms V/V, V/F and F/F were 8%, 50% and 42%, respectively. The FLIPI score distribution was not different in F/F patients as compared to V/F+V/V carriers (chi-square, P=0.7). The treatment modalities (treatment arm or rituximab administration) had the same distribution in V/V+V/F vs F/F patients (chi-square, P=0.16 and P=0.62, respectively). The CRm rates were similar in both subgroups of V/V+V/F vs F/F patients (chi-square, P=0.92). Survival curves for OS and EFS were not significantly different when comparing the subgroups of V/V+V/F vs F/F patients (P=0.28 and P=0.57, respectively). We found no difference in the quality of treatment response or survival after front-line immunochemotherapy between FcγRIIIA subgroups. FcγRIIIA polymorphism have no influence on the outcome of patients treated with risk-adapted chemotherapy with or without rituximab.

• MeSH
• autologní transplantace MeSH
• dospělí MeSH
• folikulární lymfom genetika   mortalita   terapie   MeSH
• genotyp MeSH
• kombinovaná terapie MeSH
• lidé středního věku MeSH
• lidé MeSH
• multivariační analýza MeSH
• protokoly protinádorové kombinované chemoterapie terapeutické užití   MeSH
• receptory IgG genetika   MeSH
• retrospektivní studie MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• transplantace hematopoetických kmenových buněk MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• FCGR3A protein, human MeSH Prohlížeč
• receptory IgG MeSH

BACKGROUND: CD16 was previously suggested to be a new marker of basophils that is subject to downregulation by FcεRI crosslinking. Certain compounds, including supraoptimal concentrations of the PKC inhibitors, bisindolylmaleimides, decouple the release of granules containing CD203c, CD63 and histamine, and may thus help to identify the mechanisms related to the CD16 externalization. OBJECTIVE: We hypothesized that CD16 is differentially expressed on the surface of basophils in patients with birch pollen or insect venom allergy and is subject to a regulation in response to allergens. We also employed CD203c and CD63 externalization decoupling by bisindolylmaleimides. METHODS: We performed a basophil activation test coupled with CD16 and histamine detection using cells isolated from patients with allergy to birch pollen or insect venom and negative controls. We employed two PKC inhibitors, bisindolylmaleimide II and Ro 31-8220 at their supraoptimal concentrations and, after difficulties reproducing previously published data, we analyzed the fluorescence of these inhibitors alone. We identified the CD16 isoforms by sequencing nested RT-PCR amplicons from flow cytometry sorted basophils and by cleaving the CD16b GPI anchor using a phospholipase C. RESULTS: We provide the first evidence that CD16a is expressed as a surface antigen on a small subpopulation of human basophils in patients with respiratory and insect venom allergy, and this antigen shows increased surface expression following allergen challenge or FcεRI crosslinking. We rejected the apparent decoupling of the surface expression of basophil activation markers following the administration of bisindolylmaleimides. CONCLUSIONS & CLINICAL RELEVANCE: The inclusion of αCD16 in negative selection cocktails selects against a subset of basophils that are CD16+ or CD16dim . Using CD16dim basophils and unstained leucocytes, we show that previous studies with supraoptimal concentrations of bisindolylmaleimides are likely flawed and are not associated with the differential expression of CD203c and CD63.

• Klíčová slova
• FcγRIIIA, IgG-mediated anaphylaxis, basophil activation test, bisindolylmaleimide, flow cytometry artifact,
• MeSH
• alergie imunologie   patologie   MeSH
• antigeny CD63 imunologie   MeSH
• bazofily imunologie   patologie   MeSH
• dospělí MeSH
• fosfodiesterasy imunologie   MeSH
• GPI-vázané proteiny imunologie   MeSH
• indoly chemie   MeSH
• jedy členovců toxicita   MeSH
• kousnutí a bodnutí hmyzem imunologie   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• maleimidy chemie   MeSH
• pyrofosfatasy imunologie   MeSH
• receptory IgG imunologie   MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny CD63 MeSH
• bisindolylmaleimide MeSH Prohlížeč
• CD63 protein, human MeSH Prohlížeč
• ENPP3 protein, human MeSH Prohlížeč
• FCGR3B protein, human MeSH Prohlížeč
• fosfodiesterasy MeSH
• GPI-vázané proteiny MeSH
• indoly MeSH
• jedy členovců MeSH
• maleimidy MeSH
• pyrofosfatasy MeSH
• receptory IgG MeSH

Recent studies in adult lymphoma patients have indicated a correlation between polymorphisms of Fc gamma-receptors (FcγRs, encoded by the respective FCGR genes) and the response to rituximab treatment. In vitro, cells expressing FcγRIIIa-158V mediate antibody-dependent cellular cytotoxicity (ADCC) more efficiently than cells expressing FcγRIIIa-158F. The impact of the FCGR2A-131HR polymorphism is unclear. In this study, the FCGR polymorphisms FCGR3A-158VF and FCGR2A-131HR were analyzed in pediatric patients with mature aggressive B cell non-Hodgkin lymphoma/leukemia (B-NHL). Pediatric patients received a single dose of rituximab monotherapy. Response was evaluated on day 5 followed by standard chemotherapy for B-NHL. Among 105 evaluable patients, a response to rituximab was observed in 21 % of those homozygous for FcγRIIa-131RR (5/24) compared to 48 % of patients who were HH and HR FcγRIIa-131 allele carriers (18/34 and 21/47, respectively; p = 0.044). Among patients with the FCGR3A-158 polymorphism, those homozygous for the FF genotype had a significantly favorable rituximab response rate of 59 % (22/37) compared to 32 % in patients who were FcγRIIIa-158VV and FcγRIIIa-VF allele carriers (2/9 and 20/59, respectively; p = 0.022). A stringent phase II response evaluation of children and adolescents with B-NHL after one dose of rituximab monotherapy showed a significant association between the rituximab response rate and FCGR polymorphisms. These findings support the hypothesis that FCGR polymorphisms represent patient-specific parameters that influence the response to rituximab.

• Klíčová slova
• Fc gamma-receptor, Lymphoma, Oncology, Response, Rituximab,
• MeSH
• B-buněčný lymfom krev   farmakoterapie   genetika   MeSH
• dítě MeSH
• frekvence genu MeSH
• genotyp MeSH
• indukce remise MeSH
• jednonukleotidový polymorfismus * MeSH
• L-laktátdehydrogenasa krev   metabolismus   MeSH
• lidé MeSH
• lokální recidiva nádoru MeSH
• mladiství MeSH
• multivariační analýza MeSH
• prognóza MeSH
• protinádorové látky terapeutické užití   MeSH
• receptory IgG genetika   MeSH
• rituximab terapeutické užití   MeSH
• výsledek terapie MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• FCGR2A protein, human MeSH Prohlížeč
• FCGR3A protein, human MeSH Prohlížeč
• L-laktátdehydrogenasa MeSH
• protinádorové látky MeSH
• receptory IgG MeSH
• rituximab MeSH

Bispecific antibodies that redirect the lytic activity of cytotoxic immune effector cells, such as T- and NK cells, onto tumor cells have emerged as a highly attractive and clinically validated treatment modality for hematological malignancies. Advancement of this therapeutic concept into solid tumor indications, however, is hampered by the scarcity of targetable antigens that are surface-expressed on tumor cells but demonstrate only limited expression on healthy tissues. To overcome this limitation, the concept of dual-targeting, i.e. the simultaneous targeting of two tumor-expressed surface antigens with limited co-expression on non-malignant cells, with multispecific antibodies has been proposed to increase tumor selectivity of antibody-induced effector cell cytotoxicity. Here, a novel CD16A (FcγRIIIa)-directed trispecific, tetravalent antibody format, termed aTriFlex, is described, that is capable of redirecting NK cell cytotoxicity to two surface-expressed antigens. Using a BCMA/CD200-based in vitro model system, the potential use of aTriFlex antibodies for dual-targeting and selective induction of NK cell-mediated target cell lysis was investigated. Bivalent bispecific target cell binding was found to result in significant avidity gains and up to 17-fold increased in vitro potency. These data suggest trispecific aTriFlex antibodies may support dual-targeting strategies to redirect NK cell cytotoxicity with increased selectivity to enable targeting of solid tumor antigens.

• Klíčová slova
• CD16A, NK cell, antibody, bispecific, trispecific,
• MeSH
• afinita protilátek MeSH
• aktivace lymfocytů MeSH
• buňky NK cytologie   imunologie   MeSH
• CD antigeny genetika   imunologie   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• cytotoxicita imunologická * MeSH
• exprese genu MeSH
• imunoterapie metody   MeSH
• kokultivační techniky MeSH
• lidé MeSH
• maturační antigen B-buněk genetika   imunologie   MeSH
• primární buněčná kultura MeSH
• protilátky bispecifické biosyntéza   genetika   MeSH
• protilátky nádorové biosyntéza   genetika   MeSH
• receptory IgG genetika   imunologie   MeSH
• rekombinantní proteiny biosyntéza   genetika   imunologie   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigens, CD200 MeSH Prohlížeč
• CD antigeny MeSH
• FCGR3A protein, human MeSH Prohlížeč
• maturační antigen B-buněk MeSH
• protilátky bispecifické MeSH
• protilátky nádorové MeSH
• receptory IgG MeSH
• rekombinantní proteiny MeSH
• TNFRSF17 protein, human MeSH Prohlížeč