Management of moderate to severe psoriasis with brodalumab-Real-world evidence from the LIBERO study

BACKGROUND

Brodalumab, a fully human monoclonal immunoglobulin IgG2 antibody that binds the human interleukin 17 receptor subunit A, is available for the treatment of moderate-to-severe plaque psoriasis in Europe since September 2017, but so far there are only a few studies on its use in real-world conditions.

OBJECTIVES

To assess the management of moderate-to-severe psoriasis with brodalumab 210 mg in daily practice after 12 and 52 weeks (W). In addition, patient profiles and treatment pathways are described.

METHODS

LIBERO is a prospective, multicenter, non-interventional study including adult patients with plaque psoriasis treated with brodalumab 210 mg.

RESULTS

In total, 638 patients (65% male, mean age: 49.3 ± 14.4 years) from 148 sites in Germany were enrolled. The majority suffered from severe (51.1%) or very severe (13.1%) psoriasis according to physician global assessment (PGA0-5). When starting with brodalumab, 58.5% were biologic naïve and 41.5% were previously treated with another biologic, mainly adalimumab (18.5%) and secukinumab (17.9%). About 74.0% of patients met the primary endpoint of an absolute PASI ≤3 at ~W12 (n = 618, LOCF). The mean PASI was reduced significantly as of ~W2 from 17.2 (±11.7) to 9.7 (±8.8) and improved further to 3.3 (±6.3) at ~W12 (p < 0.001). At ~W52 85.5% of patients reached a PGA0/1-response (primary endpoint) and 54.1% patients were assessed as completely clear (PGA0) (both n = 399, as observed). Effectiveness of brodalumab was confirmed in relevant subgroup analysis by previous treatment regimen. Most frequently reported adverse events were nasopharyngitis (4.6%), psoriasis (4.6%) and arthralgia (4.1%), new safety signals were not detected.

CONCLUSION

This representative, non-interventional study confirms the short- and long-term effectiveness and safety profile of brodalumab in the management of psoriasis in daily practice as well as in relevant treatment pathways.

Exaggerated IDO1 expression and activity in Langerhans cells from patients with atopic dermatitis upon viral stimulation: a potential predictive biomarker for high risk of Eczema herpeticum

BACKGROUND

Atopic dermatitis (AD) is a heterogenous and highly complex disease characterized by an increased microbial colonization. For unknown reasons, a subgroup of patients with AD develops Eczema herpeticum (EH), a severe viral complication due to spreading of herpes simplex virus (HSV). Indoleamine 2,3-dioxygenase (IDO1) is a tryptophan (Trp)-catabolizing enzyme which is assumed to be instrumental in the antibacterial and antiviral defence mechanisms.

METHODS

Comparative investigation of the IDO1 expression and activity in freshly isolated monocytes, plasmacytoid DC (pDC) and in vitro-generated Langerhans cells (LC) obtained from AD patients with HSV infections and EH and nonatopic controls.

RESULTS

We demonstrate an increase in Trp degradation in the serum of patients during acute EH episodes. Circulating pDC from patients with history of EH display an increased IDO1 expression. An increased Trp degradation is detected in the supernatants of circulating monocytes from AD patients with acute EH. Mature LC from AD patients with history of EH and with acute EH display an increased IDO1 expression and activity, respectively. In LC from patients with history of EH, viral signals induce an exaggerated IDO1 expression and activity.

CONCLUSION

IDO1 expression and activity in LC seem to be involved in the pathophysiology of EH in AD and could represent a predictive biomarker for patients with risk to develop EH and other viral complications.

[10 theses of the disabled persons' organizations - why participation research with a social perspective is needed]

The 5 professional associations for the disabled and the self-help organisations of disabled people state that in Germany a general concept for "participation research" is needed. This concept should address expectations and processes in developing aid services and improve self-determined participation of people with disabilities according to the human rights postulated in the UN Convention on the Rights of People with Disabilities (2006). A concept of "participation research" will go beyond the objectives and methods of i. e., disability studies - it is a focus in the context of which the social and equal participation of the disabled (especially those with multiple and/or intellectual handicaps) has to be addressed. In this context the 5 professional associations for the disabled have drafted 10 theses which are presented in the following article.

Morphology of basal cell carcinoma in high definition optical coherence tomography: en-face and slice imaging mode, and comparison with histology

BACKGROUND

Optical coherence tomography (OCT) allows real-time, in vivo examination of basal cell carcinoma (BCC). A new high definition OCT with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode offers additional information in the diagnosis of BCC and may potentially replace invasive diagnostic biopsies.

OBJECTIVES

To define the characteristic morphologic features of BCC by using high definition optical coherence tomography (HD-OCT) compared to conventional histology.

METHODS

A total of 22 BCCs were examined preoperatively by HD-OCT in the en-face and slice imaging mode and characteristic features were evaluated in comparison to the histopathological findings.

RESULTS

The following features were found in the en-face mode of HD-OCT: lobulated nodules (20/22), peripheral rimming (17/22), epidermal disarray (21/22), dilated vessels (11/22) and variably refractile stroma (19/22). In the slice imaging mode the following characteristics were found: grey/dark oval structures (18/22), peripheral rimming (13/22), destruction of layering (22/22), dilated vessels (7/22) and peritumoural bright stroma (11/22). In the en-face mode the lobulated structure of the BCC was more distinct than in the slice mode compared to histology.

CONCLUSION

HD-OCT with a horizontal and vertical imaging mode offers additional information in the diagnosis of BCC compared to conventional OCT imaging and enhances the feasibility of non-invasive diagnostics of BCC.

Atopic dermo-respiratory syndrome is a correlate of eczema herpeticum

BACKGROUND

Factors favoring the emergence of eczema herpeticum (EH) in patients with atopic dermatitis (AD) remain elusive. The aim of this work was to identify changes in clinical and laboratory parameters in acute EH patients, before and after 6 weeks of treatment, as well as differences between AD patients with and without a history of EH.

METHODS

A total of 235 adult subjects were included and subdivided into six groups: (i) AD patients with acute EH, (ii) AD patients with history of EH, (iii) AD without EH but with recurrent herpes simplex virus (HSV) infections, (iv) AD without EH or recurrent HSV infections and healthy non-AD controls (v) with and (vi) without recurrent HSV infections. Clinical examination of AD, assessment of atopic status and severity were performed. Total IgE, allergen-specific IgE and differential blood count were analyzed. Clinical diagnosis of acute EH was confirmed by PCR.

RESULTS

More male patients with AD were affected by EH than female patients. Acute episodes of EH are characterized by lower levels of lymphocytes and higher levels of monocytes. AD patients with history of EH display higher total IgE serum levels (ADEH(+) HSV(+) vs ADEH(-) HSV(+) , P < 0.001) and higher sensitization profiles and stronger severity of AD (EASI and SCORAD; ADEH(+) HSV(+) vs ADEH(-) HSV(+) , P < 0.001). Concomitant asthma and rhinitis were identified as correlates of EH.

CONCLUSION

From these data, we conclude that AD patients with EH display a distinct clinical and biological phenotype.

Regulatory requirements for clinical trial and marketing authorisation application for cell-based medicinal products

The new era of regenerative medicine has led to rapid development of new innovative therapies especially for diseases and tissue/organ defects for which traditional therapies and medicinal products have not provided satisfactory outcome. Although the clinical use and developments of cell-based medicinal products (CBMPs) could be witnessed already for a decade, robust scientific and regulatory provisions for these products have only recently been enacted. The new Regulation for Advanced Therapies (EC) 1394/2007 together with the revised Annex I, Part IV of Directive 2001/83/EC provides the new legal framework for CBMPs. The wide variety of cell-based products and the foreseen limitations (small sample sizes, short shelf life) vs. particular risks (microbiological purity, variability, immunogenicity, tumourigenicity) associated with CBMPs have called for a flexible, case-by-case regulatory approach for these products. Consequently, a risk-based approach has been developed to allow definition of the amount of scientific data needed for a Marketing Authorisation Application (MAA) of each CBMP. The article provides further insight into the initial risk evaluation, as well as to the quality, non-clinical, and clinical requirements of CBMPs. Special somatic cell therapies designed for active immunotherapy are also addressed.

[Advances in the pathogenesis of atopic dermatitis]

The incidence of atopic dermatitis (AD) is noticeably increasing in industrialized countries. New insights into the pathogenesis of this disease are mirrored by a changed terminology suggested by the World Allergy Organization: a distinction between a so-called atopic and non-atopic dermatitis. The pathogenesis of the AD, which this article concentrates on, is highly complex. Genetic and environmental factors play a pivotal role in triggering AD. The complex pattern of cytokines and chemokines, reflecting a deviated immune response in AD patients, is a focus of research, as are the involvement of various cells and the epidermal barrier. Research concerning T cells with regulatory features as well as IgE-mediated autoreactivity will soon give insight into the defective tolerance of atopic patients and might possibly lead to new concepts in the management of the disease.

Comparative immunophenotyping of monocytes from symptomatic and asymptomatic atopic individuals

BACKGROUND

Allergy has at least two components - a genetic predisposition referred to as atopy and the progress from an atopic state to clinically apparent disease. Peripheral blood monocytes are circulating myeloid precursors of antigen-presenting cells. The expression of cell surface proteins on monocytes may therefore witness the disease status and affect the development of allergic disease.

METHODS

Monocytes were isolated from atopic individuals with seasonal allergic rhinitis (n = 10), from atopic individuals sensitized to aeroallergens but without any signs of acute disease (n = 11), and from healthy nonatopic donors (n = 21). Detailed comparative phenotypic analysis of CD14(+) and FcepsilonRI(+)CD14(+) monocytes was performed by flow cytometry.

RESULTS

CD14(+) monocytes from symptomatic atopic donors showed a significant increase in the cell surface intensity of the integrin adhesion molecule CD11c over monocytes from asymptomatic atopic and nonatopic donors. Asymptomatic atopic individuals showed significantly enhanced expression of FcepsilonRI on the CD14(high)CD16(dim) monocyte subset compared with this subset from symptomatic atopic and nonatopic donors.

CONCLUSION

The increase in monocyte surface intensity of the adhesion molecule CD11c may be involved in the manifestation of allergic disease. FcepsilonRI on CD14(high)CD16(dim) monocytes of asymptomatic atopic donors may be of functional importance for the maintenance of clinical unresponsiveness toward allergens.

Differentiating vector-derived mRNA from contaminating DNA templates by inverse RT-PCR

Inverse RT-PCR was used for detecting doxycycline-induced mRNA expression after viral transduction with a retroviral vector harboring human TDAG51. After the circularization of double-stranded cDNA, induced transcripts originating from integrated vector genomes were selectively amplified, even in the presence of DNA templates. Thus, DNase treatment before amplification was unnecessary.

Inhibition of protein synthesis by the T cell receptor-inducible human TDAG51 gene product

The T cell death associated gene 51 (TDAG51) was shown to be required for T cell receptor (TCR)-dependent induction of Fas/Apo1/CD95 expression in a murine T cell hybridoma. Despite the absence of a nuclear localization sequence and a nucleic acid binding domain, it was suggested to be localized in the nucleus and to function as a transcription factor regulating Fas-expression. However, we demonstrate that the human (h)TDAG51 protein is localized in the cytoplasm and the nucleoli, suggesting a role in ribosome biogenesis and/or translation regulation. Indeed, it strongly inhibited translation of a luciferase mRNA in a reticulocyte translational extract. Furthermore, cotransfection of hTDAG51 and the luciferase gene into 293T cells resulted in a strong inhibition of luciferase mRNA translation. Our findings were further strengthened by isolating in a yeast two-hybrid screen three proteins which are involved in the regulation of translation. We speculate that hTDAG51 couples TCR signaling to inhibition of protein biosynthesis in activated T lymphocytes.

Dual TCR-expressing T lymphocytes in health and disease

The authors briefly review recent experimental advances in elucidating the role of dual T cell receptor (TCR)-expressing lymphocytes in the development of diseases with special emphasis on autoimmunity. Moreover, they summarize present knowledge about these cells concerning their proportion among peripheral blood mononuclear cells, their functionality, and their impact on allorecognition and memory both in humans and in mice. Finally, they describe disease-associated clonal expansions of dual TCR-expressing cells in humans, most of which have been observed in peripheral T cell malignancies. Other cases occurred in inflammatory bowel disease and in HIV infection. They propose that expression of two distinct TCR on malignant T lymphocytes might be much higher than is suggested by the few cases described so far, and that their presence might impinge on therapeutic immunization strategies which make use of the TCR itself as a target.

The effect of exposure to multiple lineups on face identification accuracy

This study examines the conditions under which an intervening lineup affects identification accuracy on a subsequent lineup. One hundred and sixty adults observed a photograph of one target individual for 60 s. One week later, they viewed an intervening target-absent lineup and were asked to identify the target individual. Two days later, participants were shown one of three 6-person lineups that included a different photograph of the target face (present or absent), a foil face from the intervening lineup (present or absent), plus additional foil faces. The hit rate was higher when the foil face from the intervening lineup was absent from the test lineup and the false alarm rate was greater when the target face was absent from the test lineup. The results suggest that simply being exposed to an innocent suspect in an intervening lineup, whether that innocent suspect is identified by the witness or not, increases the probability of misidentifying the innocent suspect and decreases the probability of correctly identifying the true perpetrator in a subsequent test lineup. The implications of these findings both for police lineup procedures and for the interpretation of lineup results in the courtroom are discussed.

Treatment of aggressive, or progressing indolent peripheral T- and NK-cell neoplasias by combination of fludarabine, cyclophosphamide and doxorubicine

BACKGROUND

Regarding standardization of treatment, classification, and pathophysiology of peripheral T- and NK-cell neoplasias the current knowledge is markedly behind that of B-cell lymphomas, which are approximately 10 times more frequent. In May 2000, the study group 'Peripheral T- and NK-cell Neoplasias' was founded in Frankfurt/M. This group decided on a clinical protocol and a scientific program for research on the pathophysiology of these entities. Rationales for the therapeutic regimen are the efficacy of cyclophosphamide and doxorubicine as shown in protocols for treatment of high grade lymphoma, the synergism of cyclophosphamide and fludarabine, and reports demonstrating the efficacy of fludarabine in T-cell neoplasias.

PATIENTS AND METHODS

Patients will be treated with a combination of fludarabine (30 mg/m(2) days 1-3), cyclophosphamide (1000 mg/m(2) day 1) doxorubicine (25 mg/m(2) day 2+3) (FCD). For patients > or =65 years a dose-reduced FCD regimen will be administered. In patients included in the treatment study and additionally in patients with indolent disease not requiring therapy, scientific projects on the biology of peripheral T- and NK-cell neoplasias will be performed.

CONCLUSIONS

Expected conclusions of the projected study are the establishment of treatment and diagnostic standards, and improvement of classification of these entities by clinical, morphologic and biologic parameters.

T-large granular lymphocyte leukaemia with natural killer cell-like cytotoxicity and expression of two different alpha- and beta-T-cell receptor chains

We describe a case of cytotoxic T-large granular lymphocyte leukaemia showing typical morphological features, expressing antigens characteristic for cytotoxic T cells and exhibiting marked natural killer-like cytotoxicity towards different target cells. Moreover, characterization of the T-cell receptors revealed simultaneous expression of two different types of beta-chains as well as alpha-chains by the malignant cell clone. The patient had an 8 year history of indolent disease, before progressing to an aggressive clinical course hardly responsive to chemotherapeutic treatment. This is the first description of a peripheral T-cell neoplasm expressing four distinct types of T-cell receptor molecules.

Identification of the T-cell receptor alpha variable (TRAV) gene(s) in T-cell malignancies

Due to the lack of a complete range of monoclonal antibodies (mAb) it is often impossible to rapidly identify by flow cytometry the T-cell receptor variable genes in patients suffering from T-cell malignancies. This applies especially to the alpha variable genes (TRAV), since only very few anti-TcR variable alpha mAb are available. We describe a very rapid method for inverse PCR amplification of the TcR alpha chain without prior purification of the double-stranded cDNA, provide the sequences for appropriate oligonucleotides, and describe a buffer system that dramatically enhances the amplification efficiency as compared to standard conditions.

Cytotoxic hepatosplenic gammadelta T-cell lymphoma following acute myeloid leukemia bearing two distinct gamma chains of the T-cell receptor. Biologic and clinical features

BACKGROUND AND OBJECTIVES

Hepatosplenic gd T-cell lymphoma is a rare entity of peripheral T-cell lymphomas. We characterized in detail the first case of hepatosplenic gd -T-cell lymphoma following acute myeloid leukemia.

DESIGN AND METHODS

Hepatosplenic gd -T-cell lymphoma was diagnosed in a woman who had been in complete remission (CR) of acute myeloid leukemia (AML) for two years. Improvement but no objective response of the disease was observed after various types of chemotherapy. CR was achieved after related donor stem cell transplantation. Thirteen months later relapse of hepatosplenic gd T-cell lymphoma was diagnosed. While being prepared for a second transplantation the patient developed meningeal lymphoma and died. The patient's lymphoma cells were studied by immunologic, functional and molecular techniques.

RESULTS

Lymphoma cells expressed the gd T-cell receptor (TCR), CD2, CD3, CD5, CD7, CD38, CD45, CD161 (NKR-P1), TIA and Ki67. Further analysis revealed expression of Vd1 and two distinct TCRg chains, Vg3 and Vg9, by the malignant cell clone. The clonality of the T-cells was confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) followed by sequencing of TCR Vg3, Vg9 and Vd1 junctional regions. Clone-specific PCR was negative at diagnosis of AML and was positive at all times during follow-up of the hepatosplenic gd T-cell lymphoma. The lymphoma cells mediated strong natural killer cell-like cytotoxic activity, possibly explained by expression of CD161 and a lack of killer inhibitory receptor.

INTERPRETATION AND CONCLUSIONS

Several so far undescribed features were observed in this case of hepatosplenic gd T-cell lymphoma, such as T-cell lymphoma following AML, expression of two distinct T-cell receptor g-chains, and an unexpected cytotoxic phenotype.

Cell-surface expression of transrearranged Vgamma-cbeta T-cell receptor chains in healthy donors and in ataxia telangiectasia patients

Transrearrangements between the T-cell receptor (TCR) VgammaI family and JbetaCbeta loci occur at increased frequencies in patients with ataxia telangiectasia (AT). We have used an optimized reverse transcriptase polymerase chain reaction (RT-PCR) approach to investigate the occurrence of TCRVgamma-JbetaCbeta transrearrangements involving the dominantly used Vgamma element in peripheral blood gammadelta T cells, i.e. Vgamma9. We detected in frame transcripts of Vgamma9-JbetaCbeta transrearrangements in 4/16 AT patients and in 3/13 healthy control donors. A panel of monoclonal antibodies (mAb) against all expressed TCRVgamma elements was used to monitor cell-surface expression of transrearranged TCR. A very low proportion (< 1%) of peripheral blood TCRalphabeta cells expressed Vgamma instead of Vbeta elements. For the first time, we have isolated and molecularly characterized alphabeta T cells with a Vgamma9-JbetaCbeta transrearrangement from two AT patients and we have shown that such TCR are functional. We conclude that functional TCR transrearrangements can also involve Vgamma9, the dominant Vgamma element in peripheral blood gammadelta T cells.

Factors influencing platelet recovery after autologous transplantation of G-CSF-mobilized peripheral blood stem/progenitor cells following myeloablative therapy in 50 heavily pretreated lymphoma patients

Delayed platelet recovery following autologous PBPCs transplantation after myeloablative therapy remains an unresolved problem in lymphoma patients heavily pretreated with several chemotherapy cycles and/or radiotherapy. In the present study of 50 lymphoma patients, the factors influencing platelet recovery after myeloablative therapy followed by autologous PBPCs transplantation were analysed retrospectively. The median age was 42 years (range, 15-58). Fourteen patients had HD and 36 had NHL (13 high-grade and 23 low-grade); most (80%) had stage III or IV. Twenty-two patients had received radiotherapy to various extents before mobilization. The mean number of previous chemotherapy cycles was seven (range 3-24) of different regimens (range 1-4). A median of three leukapheresis procedures (range 1-5) was performed after G-CSF mobilization. Single leukapheresis was sufficient in only one patient. A significant correlation was found between the BFU-E content of autografts and platelet recovery after transplantation. Neither the patient's age and sex nor the stage and grade of lymphoma had any effect on platelet recovery after transplantation. Neither the type of myeloablative therapy used or the dose of G-CSF administered after transplantation had any effect on platelet recovery after transplantation. The type of previous chemotherapy cycles was a major adverse factor affecting the progenitor cell yield in the autografts. Lymphoma patients previously treated with ASHAP and/or Dexa-BEAM cycles had less progenitor cell yield. The chemotherapeutic agents used in previous cycles also had a clear adverse effect on the progenitor cell yield in the autografts. Lymphoma patients previously treated with cycles including cytarabine and/or cisplatin showed significantly less progenitor cell yield and slower platelet recovery after transplantation. All seven patients with delayed platelet recovery had received cytarabine and/or cisplatin in several previous ASHAP and/or Dexa-BEAM cycles. All seven patients had a BFU-E count of less than 1 x 10(5)/kg yield in the autografts.

Analysis of the TCR Vgamma repertoire in healthy donors and HIV-1-infected individuals

During the course of infection with HIV-1, striking alterations in the subset distribution of peripheral blood gammadelta T cells are observed. While TCR Vdelta2 expression dominates among peripheral blood gammadelta T cells in healthy adults, there is a clear preponderance of Vdelta1 cells in HIV-1-infected persons. In this study, we present the first flow cytometry (FCM) analysis of the complete TCR Vgamma gene repertoire in HIV-1-infected individuals using a panel of mAb against all expressed Vgamma genes. The quantitative analysis of TCR Vgamma transcripts after amplification of cDNA by inverse PCR suggested that Vgamma5 usage is increased in HIV-1+ donors. This was confirmed by FCM with a new anti-Vgamma5 mAb. In addition, all members of the TCR VgammaI gene family (i.e. Vgamma2, 3, 4, 5 and 8) were expressed on significantly higher percentages of gammadelta T cells in HIV+ as compared to HIV- donors, whereas VgammaII (Vgamma9) expression was drastically reduced. No preferential association of the expanded Vdelta1+ cells with a particular Vgamma gene was observed in HIV-1 + donors. These results indicate that the increase in Vgamma1+ cells during HIV-1 infection occurs independently of the Vgamma gene usage and support the hypothesis that a Vdelta1-selective ligand might be involved.

Identification of the complete expressed human TCR V gamma repertoire by flow cytometry

Five of the six expressed human TCR V gamma regions (V gamma 2, 3, 4, 8 and 9) can be detected by available mAb. No mAb with specificity for the remaining V gamma 5 region has been described. In this study, we have characterized mAb 56.3, which was obtained after immunization with V gamma 2/3/4/9-negative thymic gamma delta cells. V gamma transcripts were analyzed by inverse PCR and RT-PCR in 56.3+ cell lines and clones derived from peripheral blood. mAb 56.3 recognized all cells that expressed in-frame V gamma 5 transcripts. In addition, mAb 56.3 recognized some but not all cells expressing V gamma 3, but did not react with a large panel of clones expressing V gamma 2, 4, 8 or 9. In combination with anti-V gamma 2/3/4 mAb 23D12, V gamma 5-expressing cells could be clearly identified as 56.3+23D12(-). In some donors, mAb 56.3 also recognized a small fraction of TCR alpha beta cells. At the clonal level, these cells expressed in-frame V gamma 5-J beta-C beta or V gamma 3-J beta-C beta trans-rearrangements. When mAb 56.3 was combined with V gamma 2/3/4-, V gamma 8- and V gamma 9-specific mAb, all peripheral blood gamma delta T cells were stained. Thus, mAb 56.3 supplements the panel of available TCR V gamma-specific mAb. It is now possible to analyze the complete expressed human V gamma repertoire by flow cytometry.

Clonal expansion of Vgamma3/Vdelta3-expressing gammadelta T cells in an HIV-1/2-negative patient with CD4 T-cell deficiency

Immunological investigations were carried out in an HIV-1/2//HTLV-1-negative patient with CD4 T-cell deficiency (0.357-0.6 x 10(9)/l) and expansion of gammadelta T cells which accounted for 26-42% of peripheral blood lymphocytes during an observation period of 3 years. Flow cytometry analyses with a panel of available Vgamma/Vdelta-specific monoclonal antibodies indicated that the pathologically expanded gammadelta population expressed Vgamma2 or Vgamma3 paired with Vdelta3 on the surface but lacked the expression of activation antigens such as CD38 or CD71. Cloning and sequencing of RT-PCR products obtained after amplification of cDNA with Vgamma-Cgamma and Vdelta-Cdelta specific primers confirmed the presence of a clonally expanded Vgamma3/Vdelta3 population in the peripheral blood of this patient. Cytotoxicity assays performed with purified gammadelta T cells as effectors and resting or preactivated autologous CD4 T cells as targets failed to reveal evidence for autoreactive cytotoxicity of Vgamma3/Vdelta3 cells as a possible mechanism of CD4 T-cell deficiency in this patient.

Clonal expansion of gamma delta T cells expressing two distinct T-cell receptors

92% of peripheral blood mononuclear cells from a patient with chronic lymphocytosis (WBC 22 x 10(9)/l) were recognized by pan-gamma delta monoclonal antibody (mAb) TCR delta 1. Further analysis with anti-V gamma/V delta mAb indicated that the expanded gamma delta T-cell population was stained by mAb specific for V gamma 2/3/4, V gamma 5 and V delta 1 but not mAb specific for V gamma 8, V gamma 9, V delta 2 or V delta 3. Cloning and sequencing of reverse transcription PCR products revealed the presence of V gamma 4, V gamma 5 and V delta 1 in-frame transcripts. All the cDNA clones obtained from each of these variable elements had identical junction regions, thus clearly demonstrating clonality. As far as we know, this is the first description of a pathological clonal expansion of gamma delta T cells with two distinct surface-expressed T-cell receptor molecules.

T cell receptor gamma delta repertoire in HIV-1-infected individuals

While V gamma 9/V delta 2 cells dominate among peripheral blood gamma delta T cells in healthy adults, the majority of gamma delta T cells in most HIV-1-infected individuals express V delta 1. We asked whether these elevated levels of V delta 1 T cells were due to clonal expansion. Three-color flow cytometry with monoclonal antibodies against V gamma 2/V gamma 3/V gamma 4, V gamma 4 and V gamma 9 was used to investigate V gamma usage in 27 patients with elevated numbers of V delta 1 T cells. While the relative proportion of V gamma 9 cells among gamma delta T cells was significantly reduced in HIV-1+ individuals (10 +/- 11% vs. 80 +/- 17%, p < 0.001), the fraction of gamma delta T cells using V gamma 5 or V gamma 8 was significantly increased (54 +/- 15% vs. 7 +/- 11%, p < 0.001). In 1 patient, 76% of the V delta 1 cells expressed V gamma 2 or V gamma 3, suggesting clonality of the V delta 1 population. In line with this assumption, analysis of the V delta 1-J delta junctional regions by reverse transcription-polymerase chain reaction (RT-PCR) resulted in products of only one junctional length, as demonstrated by electrophoresis on denaturing gels, and 12 out of 16 (75%) in-frame junctional sequences were identical in this patient. In other HIV-1+ patients, RT-PCR resulted in products of several distinct sizes, also indicating a highly restricted repertoire. After sequencing the V delta 1-J delta junctional regions of 3 additional patients, we found repeated but patient-specific in-frame junctions accounting for 10-30% of the sequenced clones. However, limited V delta 1-J delta junctional diversity was also seen in healthy donors. RT-PCR products from 10 healthy individuals resulted in distinct bands on denaturing gels. In 1 of them exhibiting a single prominent band, 10 out of 17 (58%) sequenced junctions were identical. Two other healthy donors displayed 2/14 and 5/18 identical junctional sequences, respectively. Taken together, our results reveal significant alterations of V gamma usage in HIV-1+ patients, while the V delta 1 junctional repertoire is similarly restricted in HIV-1+ and HIV-1- individuals. Therefore, these data argue against an obligatory clonal expansion of V delta 1-expressing cells during HIV-1 infection.

New monoclonal antibody (23D12) recognizing three different V gamma elements of the human gamma delta T cell receptor. 23D12+ cells comprise a major subpopulation of gamma delta T cells in postnatal thymus

The gamma delta TCR is expressed on 1 to 5% of CD3+ human peripheral blood T lymphocytes. The majority of peripheral blood gamma delta T cells expresses V gamma 9 paired with V delta 2; this subset strongly responds to certain microbial ligands. Other gamma delta T cell subsets with unknown Ag specificity expressing different V gamma elements are present in peripheral blood and lymphoid tissue. We describe a new anti-human V gamma mAb termed 23D12 with unusual specificity. As revealed by analysis of a large number of T cell clones and transfectants expressing molecularly well-defined gamma delta TCR, mAb 23D12 recognized several, but not all, members of the human V gamma 1 family, specifically V gamma 2, V gamma 3, and V gamma 4 but not V gamma 5 or V gamma 8. In combination with available mAb against V gamma 4, mAb 23D12 was used to identify V gamma 2- or V gamma 3-bearing cells. On average, 23D12+ cells accounted for 18% of peripheral blood gamma delta T cells and 56% of postnatal gamma delta thymocytes. In combination with anti-V gamma 9 mAb, mAb 23D12 23D12 identified gamma delta cells expressing V elements other than V gamma 2, V gamma 3, V gamma 4, or V gamma 9. Such cells are detectable in peripheral blood and postnatal thymus. Using mAb 23D12, we also confirmed the appearance of two distinct TCR gamma-chains on the surface of some gamma delta T cells.

New monoclonal antibody (23D12) recognizing three different V gamma elements of the human gamma delta T cell receptor. 23D12+ cells comprise a major subpopulation of gamma delta T cells in postnatal thymus

The gamma delta TCR is expressed on 1 to 5% of CD3+ human peripheral blood T lymphocytes. The majority of peripheral blood gamma delta T cells expresses V gamma 9 paired with V delta 2; this subset strongly responds to certain microbial ligands. Other gamma delta T cell subsets with unknown Ag specificity expressing different V gamma elements are present in peripheral blood and lymphoid tissue. We describe a new anti-human V gamma mAb termed 23D12 with unusual specificity. As revealed by analysis of a large number of T cell clones and transfectants expressing molecularly well-defined gamma delta TCR, mAb 23D12 recognized several, but not all, members of the human V gamma 1 family, specifically V gamma 2, V gamma 3, and V gamma 4 but not V gamma 5 or V gamma 8. In combination with available mAb against V gamma 4, mAb 23D12 was used to identify V gamma 2- or V gamma 3-bearing cells. On average, 23D12+ cells accounted for 18% of peripheral blood gamma delta T cells and 56% of postnatal gamma delta thymocytes. In combination with anti-V gamma 9 mAb, mAb 23D12 23D12 identified gamma delta cells expressing V elements other than V gamma 2, V gamma 3, V gamma 4, or V gamma 9. Such cells are detectable in peripheral blood and postnatal thymus. Using mAb 23D12, we also confirmed the appearance of two distinct TCR gamma-chains on the surface of some gamma delta T cells.

CPF1, a yeast protein which functions in centromeres and promoters

Centromeres and several promoters of Saccharomyces cerevisiae contain a highly conserved octanucleotide, RTCACRTG, called CDEI. Using biochemical, genetic and structural analyses, we show that the same protein binds in vivo to CDEI sites in centromeres and in promoters. This protein, called CPF1 for centromere promoter factor, binds DNA as a dimer. Inactivation of the gene is not lethal but leads to a partial loss of the centromere function and to a Met- phenotype. Changes of the chromatin structure due to inactivation of CPF1 are seen at centromeres and at several CDEI-carrying promoters (e.g. MET25, TRP1, GAL2). However promoter activities are affected in diverse ways making it presently difficult to describe a function for CPF1 in gene expression. The sequence of the cloned gene reveals in the carboxy-terminal part two potential amphipathic helices preceded by a positively charged stretch of amino acids very similar to the helix-loop-helix domains recently identified in factors controlling tissue specific transcription in higher eukaryotes. Carboxy-terminal truncations of CPF1 lacking this domain no longer bind to CDEI. The amino-terminal half of CPF1 carries two clusters of negatively charged amino acid residues. Surprisingly, deletions of these clusters still render cells Met+ and lead only to a marginal decrease in centromere activity.