T-cell Axis Research Articles

MERTK inhibition selectively activates a DC - T-cell axis to provide anti-leukemia immunity.

TAM-family tyrosine kinases (TYRO3, AXL and MERTK) are potential cancer therapeutic targets. In previous studies MERTK inhibition in the immune microenvironment was therapeutically effective in a B-cell acute leukemia (B-ALL) model. Here, we probed anti-leukemia immune mechanisms and evaluated roles for TYRO3 and AXL in the leukemia microenvironment. Host Mertk knock-out or MERTK inhibitor MRX-2843 increased CD8α+ dendritic cells (DCs) with enhanced antigen-presentation capacity in the leukemia microenvironment and inhibited leukemogenesis. High MERTK or low DC gene expression were associated with poor prognosis in pediatric ALL patients, indicating the clinical relevance of these findings. MRX-2843 increased CD8+ T-cell numbers and prevented induction of exhaustion markers, implicating a DC - T-cell axis. Indeed, combined depletion of CD8α+ DCs and CD8+ T-cells was required to abrogate anti-leukemia immunity in Mertk-/- mice. Tyro3-/- mice were also protected against B-ALL, implicating TYRO3 as an immunotherapeutic target. In contrast to Mertk-/- mice, Tyro3-/- did not increase CD8α+ DCs with enhanced antigen-presentation capacity and therapeutic activity was less dependent on DCs, indicating a different immune mechanism. Axl-/- did not impact leukemogenesis. These data demonstrate differential TAM kinase roles in the leukemia microenvironment and provide rationale for development of MERTK and/or TYRO3-targeted immunotherapies.

Nuclear IL-33 in Fibroblasts Promotes Skin Fibrosis

Systemic sclerosis (SSc) is a complex and poorly understood connective tissue disease characterized by diffuse fibrosis in several organs, especially the skin ( Asano, 2017 Asano Y. Recent advances in the treatment of skin involvement in systemic sclerosis. Inflamm Regen. 2017; 37: 12 Crossref Scopus (6) Google Scholar , Bhattacharyya et al., 2012 Bhattacharyya S. Wei J. Tourtellotte W.G. Hinchcliff M. Gottardi C.G. Varga J. Fibrosis in systemic sclerosis: common and unique pathobiology. Fibrogenesis Tissue Repair. 2012; 5: S18 Crossref Scopus (30) Google Scholar , Denton et al., 2006 Denton C.P. Black C.M. Abraham D.J. Mechanisms and consequences of fibrosis in systemic sclerosis. Nat Clin Pract Rheumatol. 2006; 2: 134-144 Crossref Scopus (156) Google Scholar ). Interleukin (IL)-33 is found to regulate tissue fibrosis in multiple organs ( Kotsiou et al., 2018 Kotsiou O.S. Gourgoulianis K.I. Zarogiannis S.G. IL-33/ST2 Axis in Organ Fibrosis. Frontiers in immunology. 2018; 9: 2432 Crossref PubMed Scopus (96) Google Scholar , Xu et al., 2016 Xu J. Zheng J. Song P. Zhou Y. Guan S. IL33/ST2 pathway in a bleomycininduced pulmonary fibrosis model. Mol Med Rep. 2016; 14: 1704-1708 Crossref Scopus (13) Google Scholar ). However, the exact role of IL-33 in fibrosis remains controversial ( Kotsiou et al., 2018 Kotsiou O.S. Gourgoulianis K.I. Zarogiannis S.G. IL-33/ST2 Axis in Organ Fibrosis. Frontiers in immunology. 2018; 9: 2432 Crossref PubMed Scopus (96) Google Scholar ). Previous studies have shown a pro-fibrotic role for IL-33 cytokine through its receptor, interleukin-1 receptor-like 1(IL1RL1 or ST2), regulating the secretion of pro-fibrotic cytokine, IL-13, from eosinophils, M2 macrophages and type 2 innate lymphoid cells (ILC2) ( Li et al., 2014 Li D. Guabiraba R. Besnard A.G. Komai-Koma M. Jabir M.S. Zhang L. et al. IL-33 promotes ST2-dependent lung fibrosis by the induction of alternatively activated macrophages and innate lymphoid cells in mice. The Journal of allergy and clinical immunology. 2014; 134: 1422-1432 e11 Abstract Full Text Full Text PDF PubMed Scopus (268) Google Scholar , Rankin et al., 2010 Rankin A.L. Mumm J.B. Murphy E. Turner S. Yu N. McClanahan T.K. et al. IL-33 induces IL-13-dependent cutaneous fibrosis. J Immunol. 2010; 184: 1526-1535 Crossref PubMed Scopus (188) Google Scholar , Wu et al., 2018 Wu L. Luo Z. Zheng J. Yao P. Yuan Z. Lv X. et al. IL-33 Can Promote the Process of Pulmonary Fibrosis by Inducing the Imbalance Between MMP-9 and TIMP-1. Inflammation. 2018; 41: 878-885 Crossref PubMed Scopus (30) Google Scholar ). However, IL-33 can also play an anti-fibrotic role through the induction of ILC2 cells and regulatory T cells in several organs including the skin ( Cheon et al., 2022 Cheon S.Y. Park J.H. Ameri A.H. Lee R.T. Nazarian R.M. Demehri S. IL-33/Regulatory T-Cell Axis Suppresses Skin Fibrosis. The Journal of investigative dermatology. 2022; Google Scholar , Garbern et al., 2019 Garbern J.C. Williams J. Kristl A.C. Malick A. Rachmin I. Gaeta B. et al. Dysregulation of IL-33/ST2 signaling and myocardial periarteriolar fibrosis. J Mol Cell Cardiol. 2019; 128: 179-186 Abstract Full Text Full Text PDF Scopus (12) Google Scholar , Riedel et al., 2017 Riedel J.H. Becker M. Kopp K. Duster M. Brix S.R. Meyer-Schwesinger C. et al. IL-33-Mediated Expansion of Type 2 Innate Lymphoid Cells Protects from Progressive Glomerulosclerosis. J Am Soc Nephrol. 2017; 28: 2068-2080 Crossref Scopus (71) Google Scholar ). Thus, it is critical to determine the full spectrum of IL-33 effect in fibrosis to develop optimal therapies for its utilization in the treatment of SSc and other fibrosis-associated diseases.

Nephrotoxicity of Calcineurin Inhibitors in Kidney Epithelial Cells is Independent of NFAT Signaling.

Background: Calcineurin inhibitors (CNIs) such as cyclosporine A and tacrolimus are commonly used after renal transplantation to suppress the immune system. In lymphoid cells, cyclosporine A acts via the calcineurin/nuclear factor of activated T-cell (NFAT) axis. In non-lymphoid cells, such as kidney epithelial cells, cyclosporine A induces calcineurin inhibitor toxicity. It is unknown via which off-targets cyclosporine A induces calcineurin inhibitor toxicity in kidney epithelial cells. Methods: To measure a compound’s potential to induce nephrotoxicity, the expression of the surrogate marker Fn14 was measured by flow cytometry. Compounds were tested for their potential to induce Fn14 either chemically or plasmid-mediated. Mice were injected with various compounds, and changes in nephrotoxic gene expression levels of the kidney epithelial cells were then analyzed. Results: Fn14 is specifically upregulated due to calcineurin inhibitor toxicity inducing agents. Inhibition of the NFAT axis showed no increase of the Fn14 expression on the surface of kidney cells. However, inhibition of p38 MAPK, phosphoinositide-3-kinase (PI3K)/Akt, protein kinase C (PKC), and inhibitor of nuclear factor-κB (IκB) kinase (IKK) showed clear induction of Fn14 and increased expressions of nephrotoxic, inflammatory, and fibrotic genes in vitro and in vivo. Conclusions: These findings show that cyclosporine A acts independently of NFAT on kidney epithelial cells. Moreover, inhibition of serine/threonine protein kinases mimics cyclosporine A’s activity on kidney epithelial cells. This mimicking effect indicates that these protein kinases are off-targets of cyclosporine A and damage structural renal cells when inhibited and therefore contributes likely to the development and progression of calcineurin inhibitor toxicity.

Personalized Cytokine-Directed Therapy With Tocilizumab for Refractory Immune Checkpoint Inhibitor-Related Cholangiohepatitis.

For patients with corticosteroid (CS)-refractory immune checkpoint inhibitor-related cholangiohepatitis (irCH), no consensus exists regarding treatment, and outcomes remain poor. We evaluated the possibility of personalized treatment according to the patient's cytokine profile and the immunohistopathologic assessment of the predominant immune infiltrate type of liver tissue. NSCLCs with CS-refractory irCH were analyzed by immunohistochemistry of liver biopsy specimen, serum cytokine panel, and assessment of peripheral blood mononuclear cell immune cell monitoring by mass cytometry. A total of three consecutive patients with irCH were identified. We found a predominant T-cell infiltrate and an interferon-gamma or T helper 1 proinflammatory cytokine profile. Here, we report for the first time that a T-cell-targeted therapy with the interleukin (IL)-6 receptor-neutralizing antibody tocilizumab, which inhibits signaling downstream of interferon-gamma and several other Janus kinase-dependent cytokines, is an effective single cytokine-directed therapy for CS-refractory irCH. Three patients with severe, CS-refractory irCH who were treated with tocilizumab were found to have persistent clinical and biological remission. Dysregulation of the IL-6/T-cell axis may contribute to the pathogenesis of CS-refractory irCH. Our observations suggest that IL-6 blockade seems to have promise in the treatment of CS-refractory irCH. The results from our three patients need to be confirmed in a larger patient population.

The critical role of CD4+ T cells in PD-1 blockade against MHC-II–expressing tumors such as classic Hodgkin lymphoma

AbstractClassic Hodgkin lymphoma (cHL) responds markedly to PD-1 blockade therapy, and the clinical responses are reportedly dependent on expression of major histocompatibility complex class II (MHC-II). This dependence is different from other solid tumors, in which the MHC class I (MHC-I)/CD8+ T-cell axis plays a critical role. In this study, we investigated the role of the MHC-II/CD4+ T-cell axis in the antitumor effect of PD-1 blockade on cHL. In cHL, MHC-I expression was frequently lost, but MHC-II expression was maintained. CD4+ T cells highly infiltrated the tumor microenvironment of MHC-II–expressing cHL, regardless of MHC-I expression status. Consequently, CD4+ T-cell, but not CD8+ T-cell, infiltration was a good prognostic factor in cHL, and PD-1 blockade showed antitumor efficacy against MHC-II–expressing cHL associated with CD4+ T-cell infiltration. Murine lymphoma and solid tumor models revealed the critical role of antitumor effects mediated by CD4+ T cells: an anti-PD-1 monoclonal antibody exerted antitumor effects on MHC-I−MHC-II+ tumors but not on MHC-I−MHC-II− tumors, in a cytotoxic CD4+ T-cell–dependent manner. Furthermore, LAG-3, which reportedly binds to MHC-II, was highly expressed by tumor-infiltrating CD4+ T cells in MHC-II–expressing tumors. Therefore, the combination of LAG-3 blockade with PD-1 blockade showed a far stronger antitumor immunity compared with either treatment alone. We propose that PD-1 blockade therapies have antitumor effects on MHC-II–expressing tumors such as cHL that are mediated by cytotoxic CD4+ T cells and that LAG-3 could be a candidate for combination therapy with PD-1 blockade.

Targeting of the Cancer-Associated Fibroblast-T-Cell Axis in Solid Malignancies.

The introduction of a wide range of immunotherapies in clinical practice has revolutionized the treatment of cancer in the last decade. The majority of these therapeutic modalities are centered on reinvigorating a tumor-reactive cytotoxic T-cell response. While impressive clinical successes are obtained, the majority of cancer patients still fail to show a clinical response, despite the fact that their tumors express antigens that can be recognized by the immune system. This is due to a series of other cellular actors, present in or attracted towards the tumor microenvironment, including regulatory T-cells, myeloid-derived suppressor cells and cancer-associated fibroblasts (CAFs). As the main cellular constituent of the tumor-associated stroma, CAFs form a heterogeneous group of cells which can drive cancer cell invasion but can also impair the migration and activation of T-cells through direct and indirect mechanisms. This singles CAFs out as an important next target for further optimization of T-cell based immunotherapies. Here, we review the recent literature on the role of CAFs in orchestrating T-cell activation and migration within the tumor microenvironment and discuss potential avenues for targeting the interactions between fibroblasts and T-cells.

Th1/17 cells, a subset of Th17 cells, are expanded in patients with active systemic lupus erythematosus

Skewed cytokine production characterizes T cells in Systemic Lupus Erythematosus (SLE). Among Th17 cells that are expanded in lupus, a subset (Th1/17) retains the ability to produce IFNγ.We aimed to analyze Th17 and Th1/17 cells in patients with SLE. Patients with active disease displayed increased percentages of circulating Τh17 and Th1/17 cells. Stimulated T cells from patients with lupus secreted significantly more IL-17 compared to healthy donors.Also, T cells from patients with active SLE released significantly lower levels of IFN-γ compared to controls. However, following stimulation, levels of IFN-γ also rose significantly. Our data suggest that lupus Th1/17 cells are not only expanded but also functional.In summary, in this study it was shown that patients with active SLE display increased Th17 and functional Th1/17 cells. This impaired T-cell axis might represent a possible future therapeutic target.

Tumor-associated neutrophils suppress pro-tumoral IL-17+ γδ T cells through induction of oxidative stress.

Interleukin 17 (IL-17)–producing γδ T cells (γδ17 T cells) have been recently found to promote tumor growth and metastasis formation. How such γδ17 T-cell responses may be regulated in the tumor microenvironment remains, however, largely unknown. Here, we report that tumor-associated neutrophils can display an overt antitumor role by strongly suppressing γδ17 T cells. Tumor-associated neutrophils inhibited the proliferation of murine CD27− Vγ6+ γδ17 T cells via induction of oxidative stress, thereby preventing them from constituting the major source of pro-tumoral IL-17 in the tumor microenvironment. Mechanistically, we found that low expression of the antioxidant glutathione in CD27− γδ17 T cells renders them particularly susceptible to neutrophil-derived reactive oxygen species (ROS). Consistently, superoxide deficiency, or the administration of a glutathione precursor, rescued CD27− Vγ6+ γδ17 T-cell proliferation in vivo. Moreover, human Vδ1+ γδ T cells, which contain most γδ17 T cells found in cancer patients, also displayed low glutathione levels and were potently inhibited by ROS. This work thus identifies an unanticipated, immunosuppressive yet antitumoral, neutrophil/ROS/γδ17 T-cell axis in the tumor microenvironment.

Inhaled IL-10 Suppresses Lung Tumorigenesis via Abrogation of the Inflammatory Macrophage - T17-cell Axis

Abstract Lung tumorigenesis has been linked to chronic type 17 inflammation in both murine models and patients. Interleukin-10 is a pleiotropic regulatory cytokine with profound inhibitory effects on type 17 responses. Intratracheal administration of a sustained-release IL-10 formulation resulted in suppression of tumor development in the LSL-K-ras spontaneous lung cancer model. Analysis of lung lymphocyte populations demonstrated that the antitumor activity of IL-10 was associated with a rapid 3 to 5-fold decline in IL-17-producing T-cell populations. Type 17 T-cells did not express detectable levels of IL-10RA suggesting that IL-10 was not directly acting on T-cells. In contrast, select myeloid cell populations including macrophages and a small subset of dendritic cells were found to express IL-10RA in the lung. In tumor-bearing control mice macrophages displayed a pro-inflammatory phenotype that reverted to a naive-like state following IL-10 treatment. Importantly, depletion of phagocytes resulted in a 3 to 5-fold decline in type 17 T-cell numbers with a concurrent 7-fold reduction in tumor burden. These findings demonstrate that in the LSL-K-ras model lung tumorigenesis is driven by the inflammatory macrophage - type 17 T-cell axis and that IL-10 abrogates this process via its direct activity on macrophages. Inhaled IL-10 formulations may be of utility in prophylaxis of lung cancer in high-risk patients.

The Hypothesis of the Human iNKT/Innate CD8(+) T-Cell Axis Applied to Cancer: Evidence for a Deficiency in Chronic Myeloid Leukemia.

We recently identified a new human subset of NK-like [KIR/NKG2A(+)] CD8(+) T cells with a marked/memory phenotype, high Eomesodermin expression, potent antigen-independent cytotoxic activity, and the capacity to generate IFN-γ rapidly after exposure to pro-inflammatory cytokines. These features support the hypothesis that this new member of the innate T cell family in humans, hereafter referred to as innate CD8(+) T cells, has a role in cancer immune surveillance analogous to invariant natural killer T (iNKT) cells. Here, we report the first quantitative and functional analysis of innate CD8(+) T cells in a physiopathological context in humans, namely chronic myeloid leukemia (CML), a well-characterized myeloproliferative disorder. We have chosen CML based on our previous report that IL-4 production by iNKT cells was deficient in CML patients at diagnosis and considering the recent evidence in mice that IL-4 promotes the generation/differentiation of innate CD8(+) T cells. We found that the pool of innate CD8(+) T cells was severely reduced in the blood of CML patients at diagnosis. Moreover, like iNKT and NK cells, innate CD8(+) T cells were functionally impaired, as attested by their loss of antigen-independent cytotoxic activity and IFN-γ production in response to innate-like stimulation with IL-12 + IL-18. Remarkably, as previously reported for IL-4 production by iNKT cells, both quantitative and functional deficiencies of innate CD8(+) T cells were at least partially corrected in patients having achieved complete cytogenetic remission following tyrosine kinase inhibitor therapy. Finally, direct correlation between the functional potential of innate CD8(+) T and iNKT cells was found when considering all healthy donors and CML patients in diagnosis and remission, in accordance with the iNKT cell-dependent generation of innate CD8(+) T cells reported in mice. All in all, our data demonstrate that CML is associated with deficiencies of innate CD8(+) T cells that are restored upon remission, thereby suggesting their possible contribution to disease control. More generally, our study strongly supports the existence of an innate iNKT/innate CD8(+) T-cell axis in humans and reveals its potential contribution to the restoration of tumor immune surveillance.

Combined blockade of the histamine H1 and H4 receptor suppresses peanut-induced intestinal anaphylaxis by regulating dendritic cell function.

Signaling through histamine receptors on dendritic cells (DCs) may be involved in the effector phase of peanut-induced intestinal anaphylaxis. The objective of this study was to determine the role of histamine H1 (H1R) and H4 receptors (H4R) in intestinal allergic responses in a model of peanut allergy. Balb/c mice were sensitized and challenged with peanut. During the challenge phase, mice were treated orally with the H1R antagonist, loratadine, and/or the H4R antagonist, JNJ7777120. Bone marrow-derived DCs (BMDCs) were adoptively transferred to nonsensitized WT mice. Symptoms, intestinal inflammation, and mesenteric lymph node and intestine mucosal DCs were assessed. Effects of the drugs on DC chemotaxis, calcium mobilization, and antigen-presenting cell function were measured. Treatment with loratadine or JNJ7777120 individually partially suppressed the development of diarrhea and intestinal inflammation and decreased the numbers of DCs in the mesenteric lymph nodes and lamina propria. Combined treatment with both drugs prevented the development of diarrhea and intestinal inflammation. In vitro, the combination suppressed DC antigen-presenting cell function to T helper cells and DC calcium mobilization and chemotaxis to histamine. Blockade of both H1R and H4R in the challenge phase had additive effects in preventing the intestinal consequences of peanut sensitization and challenge. These effects were mediated through the limitation of mesenteric lymph node and intestinal DC accumulation and function. Identification of this histamine H1R/H4R-DC-CD4+ T-cell axis provides new insights into the development of peanut-induced intestinal allergic responses and for prevention and treatment of peanut allergy.

Batf3 deficiency proves the pivotal role of CD8α+ dendritic cells in protection induced by vaccination with attenuated Plasmodium sporozoites.

Increasing evidence indicates that hepatic CD8α+ dendritic cells (DCs) are important antigen cross-presenting cells (APC) involved in the priming of protective CD8+ T-cell responses induced by live-attenuated Plasmodium sporozoites. Experimental proof for a critical role of CD8α+ DCs in protective pre-erythrocytic malaria immunizations has pivotal implications for vaccine development, including improved vectored subunit vaccines. Employing Batf3-/- mice, which lack functional CD8α+ DCs, we demonstrate that deficiency of these particular APCs completely abolishes protection and corresponding signatures of vaccine-induced immunity. We show that in wild-type, but not in Batf3-/- , mice CD8α+ DCs accumulate in the liver after immunization with live irradiation-attenuated P.berghei sporozoites. IFN-γ production by Plasmodium antigen-specific CD8+ T cells is dependent on functional Batf3. In addition, our results demonstrate that the dysfunctional cDC-CD8+ T-cell axis correlates with MHC class II upregulation on splenic CD8α- DCs. Collectively, these findings underscore the essential role of CD8α+ DCs in robust protection induced by experimental live-attenuated malaria vaccines.

Superoxide Production by Macrophages and T Cells Is Critical for the Induction of Autoreactivity and Type 1 Diabetes

OBJECTIVEThe role of reactive oxygen species (ROS) and their dissipation in type 1 diabetes pathogenesis have garnered considerable controversy. Our recent work has demonstrated the importance of NADPH oxidase (NOX) activity for type 1 diabetes development and modulating T-cell autoreactivity. We previously linked decreased monocyte ROS with diabetes resistance in the alloxan-resistant mouse, and NOD-Ncf1m1J mice with a genetic ablation of NOX activity had reduced and delayed type 1 diabetes compared with NOD mice.RESEARCH DESIGN AND METHODSTo determine the required cellular sources of ROS that are necessary for type 1 diabetes initiation, we used antibody depletion and adoptive transfer experiments into NOD and NOD-Scid females, respectively. After receiving treatment, female mice were monitored for hyperglycemia and overt diabetes.RESULTSDepletion of macrophages and neutrophils fully protected NOD mice from type 1 diabetes. However, elimination of neutrophils alone showed no significant reduction or delay. Type 1 diabetes induction in NOD-Scid mice by adoptive transfer with NOD-Ncf1m1J splenocytes was significantly delayed compared with NOD splenocytes, suggesting macrophage ROS and modulation of effector responses are critical for diabetes. The adaptive immune response was also altered by the absence of NOX activity, as purified T cells from NOD-Ncf1m1J mice exhibited delayed transfer kinetics. Cotransfer experiments demonstrated the defect was intrinsic to NOX-deficient CD8+ T cells. After stimulation, cytotoxic T cells exhibited decreased effector function in the absence of superoxide production.CONCLUSIONSThese data demonstrate that the impaired autoreactive response of NOX-deficient NOD-Ncf1m1J immune system results from an alteration in the antigen-presenting cell–T-cell axis rather than failure of neutrophils to act as effector cells and that ROS signaling is important for the initiation of β-cell–directed autoimmunity by T cells.

The effects of trastuzumab on the CD4+CD25+FoxP3+ and CD4+IL17A+ T-cell axis in patients with breast cancer

In addition to the direct targeting effects on HER2-positive cells, trastuzumab may have a therapeutic role modulating the activity of the cellular immune system in patients with breast cancer. To investigate this further, the balance of T-regulatory (Treg), Th17, natural killer (NK) and NK T (NKT) cells before, during and after trastuzumab therapy was investigated. Sequential frequencies of circulating Treg cells, Th17 cells, NK and NKT cells were measured in peripheral blood of breast cancer patients and normal controls throughout therapy. Individuals with breast cancer had significantly higher Treg frequencies of peripheral blood compared with healthy controls (9.2 or 8.6 vs 6%; P<0.05), and no significant differences in Treg frequencies were observed between HER2-positive and HER2-negative individuals. The number of Th17 cells was lowest in HER2-positive patients compared with both healthy controls and HER2-negative patients (0.31 vs 0.75% or 0.84%; P=0.01). There appeared to be an inverse relationship between Treg and Th17 frequencies in metastatic breast cancer (MBC) with Treg levels significantly reduced during treatment with trastuzumab (P=0.04), whereas Th17 frequencies were concomitantly increased (P=0.04). This study supports earlier data that Treg cells are present at higher frequencies in breast cancer patients compared with healthy individuals. For the first time, we show that HER2-positive individuals with breast carcinomas have reduced numbers of circulating Th17 cells, which appear, in turn to have an inverse relationship with Treg frequency in MBC. The change in balance of the Treg : Th17 ratio appears to characterise the cancer state, and furthermore, is disrupted by trastuzumab therapy.

Psoriasis genomics: analysis of proinflammatory (type 1) gene expression in large plaque (Western) and small plaque (Asian) psoriasis vulgaris.

Type 1 T cells are hypothesized to be central in the immunopathogenesis of psoriasis. Through elaboration of interferon (IFN)-gamma, type 1 T cells regulate the expression of many 'downstream' inflammatory genes, including an array of chemokines that regulate leucocyte trafficking and activation in skin lesions. Accordingly, disease progression and/or severity might be controlled by the degree to which differing cytokines and chemokines are overexpressed in focal skin regions. To examine this possibility, we studied two forms of chronic psoriasis vulgaris that differ significantly in overall severity and progression: small plaque (SP) psoriasis occurring in Korean patients, and large plaque (LP) psoriasis occurring in North American patients. To characterize LP and SP psoriasis vulgaris with respect to expression of proinflammatory genes that define the type 1 T-cell axis in skin lesions [genes encoding interleukin (IL)-12, IFN-gamma, and IFN-gamma-regulated chemokines or inflammatory mediators]. Total cellular RNA of skin samples from groups of patients with LP or SP psoriasis was analysed by quantitative reverse transcription-polymerase chain reaction (TaqMan analysis) to compare the differences in mRNA expression of genes related to the IFN-gamma pathway. The mRNA expression of keratin 16, CD25, IFN-gamma, IL-12 p40, signal transducer and activator of transcription-1, inducible nitric oxide synthase, IL-8, macrophage inflammatory protein-3alpha, monocyte chemoattractant protein-1, S100A12, IFN-gamma-inducible protein of 10 kDa, IFN-inducible T-cell alpha-chemoattractant and monokine induced by IFN-gamma was increased in the lesions of both LP psoriasis and SP psoriasis. However, IL-18 mRNA expression was significantly different in the lesions of LP psoriasis in comparison with those of SP psoriasis. The results indicate that proinflammatory type 1 genes regulated by IFN-gamma are similarly increased in both SP and LP psoriasis, but a potential difference in IL-18 exists between these disease forms. The consistent activation of this set of genes argues for a central role of IFN-gamma as a molecular regulator of inflammation in these distinct subtypes of psoriasis vulgaris. In contrast, disease extent/severity must be controlled by yet other factors.

Prethymic phenotype and genotype of pre-T (CD7+/ER-)-cell leukemia and its clinical significance within adult acute lymphoblastic leukemia [see comments

Pretreatment blast cells from 739 adults with acute lymphoblastic leukemia (ALL) were immunophenotyped as part of a prospective treatment protocol study. Among 192 patients (26%) with T lineage ALL, 47 (6%; 24% of T lineage ALL) had lymphoblasts without sheep erythrocyte rosette formation, but with pan-T antigen CD7 on the membrane and intracellular CD3 proteins mostly in perinuclear accumulation. The T- cell surface antigens CD5 and/or CD2 and focal acid phosphatase were additional markers of this subgroup traditionally called pre-T ALL, whereas thymocyte antigen CD1 as well as CD4 and CD8 antigens were not expressed. Hematopoietic progenitor cell markers, namely terminal deoxynucleotidyl transferase (TdT), and in part common ALL antigen (CD10), HLA-DR antigens, and/or My-10 (CD34), a unique antigen of marrow cells absent in thymus cells, further characterized this immature T-ALL form of putative prothymocytic phenotype (CD7+/intracellular CD3+/TdT+/My-10+/-/HLA-DR+/-/CD10+/-). The prethymic T cell character was supported by germ-line T-cell receptor beta genes found in 21 of 36 patients analyzed. In five cases only T gamma-chain genes were rearranged. Fifteen patients, however, had rearrangements of both T beta and T gamma genes. Immunoglobulin heavy chain genes were rearranged only in two cases. Pre-T ALL differed significantly from E-rosette+ T-ALL in some presenting clinical features, namely mediastinal mass, lymphoadenopathy, and platelet count, and independently of clinical factors in prognosis (P = .02, median remission duration: 15.7 v 33.5 months, and P = .02, median survival time: 24.6 v 50.7 months). We conclude that ALL classification based solely on T- or B-cell lineage affiliation is not sufficient but needs further subdivision according to relevant maturation stages as exemplified here within the T-cell axis. The putative prethymic T cell progenitor phenotype described might help elucidate the sequence of genetic events that commit normal hematopoietic cells to the T-cell lineage.

Prethymic Phenotype and Genotype of Pre-T (CD7+/ER-)-Cell Leukemia and Its Clinical Significance Within Adult Acute Lymphoblastic Leukemia

Pretreatment blast cells from 739 adults with acute lymphoblastic leukemia (ALL) were immunophenotyped as part of a prospective treatment protocol study. Among 192 patients (26%) with T lineage ALL, 47 (6%; 24% of T lineage ALL) had lymphoblasts without sheep erythrocyte rosette formation, but with pan-T antigen CD7 on the membrane and intracellular CD3 proteins mostly in perinuclear accumulation. The T-cell surface antigens CD5 and/or CD2 and focal acid phosphatase were additional markers of this subgroup traditionally called pre-T ALL, whereas thymocyte antigen CD1 as well as CD4 and CD8 antigens were not expressed. Hematopoietic progenitor cell markers, namely terminal deoxynucleotidyl transferase (TdT), and in part common ALL antigen (CD10), HLA-DR antigens, and/or My-10 (CD34), a unique antigen of marrow cells absent in thymus cells, further characterized this immature T-ALL form of putative prothymocytic phenotype (CD7+/intracellular CD3+/TdT+/My-10+/-/HLA-DR+/-/CD10+/-). The prethymic T cell character was supported by germ-line T-cell receptor beta genes found in 21 of 36 patients analyzed. In five cases only T gamma-chain genes were rearranged. Fifteen patients, however, had rearrangements of both T beta and T gamma genes. Immunoglobulin heavy chain genes were rearranged only in two cases. Pre-T ALL differed significantly from E-rosette+ T-ALL in some presenting clinical features, namely mediastinal mass, lymphoadenopathy, and platelet count, and independently of clinical factors in prognosis (P = .02, median remission duration: 15.7 v 33.5 months, and P = .02, median survival time: 24.6 v 50.7 months). We conclude that ALL classification based solely on T- or B-cell lineage affiliation is not sufficient but needs further subdivision according to relevant maturation stages as exemplified here within the T-cell axis. The putative prethymic T cell progenitor phenotype described might help elucidate the sequence of genetic events that commit normal hematopoietic cells to the T-cell lineage.

In vivo production of childhood acute lymphoblastic leukemia cells in relation to ploidy and immunological subtype

Eighteen pretreatment cases of acute lymphoblastic leukemia (ALL) in children were investigated by quantitative autoradiography in order to determine the labeling index (LI) as well as the DNA synthesis time ( t s). The ploidy of the leukemic blasts was evaluated by Feulgen-microphotometry. The group consisted of 12 cases expressing the common ALL (CALL) antigen only, while 6 showed varying degrees of development along the T-cell axis. The latter subgroup was taken together and termed T-ALL for the sake of simplicity. By dividing LI by t s the fractional birth rate (FBR) was derived representing the percentage of the total leukemic cell mass newly formed per unit of time. The present study confirms a previous investigation in which a higher LI was detected in association with hyperdiploidy. It shows that t s is simultaneously prolonged, while the DNA synthesis rate remains unchanged. This proves that in hyperdiploid cases the longer t s is caused by a larger amount of DNA to be synthesized. The FBR is the same for eu- and hyperdiploid, as well as for CALL and T-ALL cases, and there is no correlation between the FBR and the white blood cell count. So far, ALL is the only type of leukemia in which a prolongation of t s has been demonstrated in comparison to normal human lymphatic cells. This prolongation is not caused primarily by differences in ploidy. The type of growth is accumulative, since the relative rate of cell production is lower than normal. As a finding of practical importance, the labeling index is shown to correlate quite closely with the FBR. In this cell system the LI can thus be used as a parameter reflecting the rate of relative cell production.

Isoenzyme studies in human leukemia — II. Carboxylic esterase (E.C. 3.1.1.1.)

Isoelectric focusing analysis of esterase activity (E.C. 3.1.1.1.) has been carried out on polyacrylamide gel slabs of a variety of immunologically defined acute leukemia subtypes. Distinct isoenzyme bands and isoenzyme groups have been identified and characterized biochemically with regard to their features for substrate specificity, pH optimum and inhibition experiments. The esterase isoenzyme patterns permitted the distinction between acute myeloid and non-myeloid leukemias. Acute lymphocytic leukemias localized by their immunological profile along the T-cell axis exhibited a readily recognizable isoenzyme group (T group). Reproducible differences in isoenzyme patterns were observed in childhood common ALL which indicate that the immunologically determined entity cALL displays a clear heterogeneity with respect to biochemical profiles of enzyme markers. These results suggest that further combined biochemical and immunological characterization may significantly contribute to a better understanding of lymphopoietic and leukemic cell differentiation.

Purine pathway enzymes in the circulating malignant cells of patients with cutaneous T-cell lymphoma.

The activities of three purine pathway enzymes--adenosine deaminase (ADA), 5'-nucleotidase (5'N) and purine nucleoside phosphorylase (PNP)--were examined in the circulating malignant cells (Sezary cells) of eight patients with cutaneous T-cell lymphoma (CTCL). Cell lines derived from two other patients with CTCL were also studied. These were compared with enzyme activities in peripheral blood T-lymphocytes from 11 normal donors and six samples of human thymocytes. ADA activities were similar in the Sezary cells and peripheral blood T-cells (medians 7 U and 15 U, P = 0.14), and both of these groups demonstrated significantly lower activity than did the thymocytes (median 100 U, P = 0.002). 5'N activity in the Sezary cells was also similar to that of the T-lymphocytes (median 0.022 U and 0.030 U, P greater than 0.05) and both of these groups had significantly greater activity than did the thymocytes (median 0.002 U, P = 0.001). Median PNP activity in the Sezary cell population was also comparable to that measured in normal T-cells. These findings suggest there is a characteristic purine pathway enzyme pattern in Sezary cells that is similar to that seen in normal T-lymphocytes. This pattern is clearly distinguishable from that of thymocytes and from that previously described in lymphoblasts from patients with T-cell acute lymphoblastic leukaemia. These results support the concept that Sezary cells are well-differentiated with respect to the T-cell axis. Quantitation of purine pathway enzymes may be useful in defining subsets of T-cell malignancy.