Longitudinal analysis of frequency and reactivity of Epstein-Barr virus-specific T lymphocytes and their association with intermittent viral reactivation.

Persistent Epstein-Barr virus (EBV) infection is controlled tightly by virus-specific T cells. EBV infection is reactivated intermittently over time, even in apparently healthy carriers. Changes in frequency and reactivity of memory T cells, particularly of CD8(+) origin, have not been assessed in this context. It is hypothesized that viral reactivation is facilitated by diminished EBV-specific T-cell immunity. To this end, blood samples from 14 healthy donors were collected at irregular time intervals for a period of about 1 year. Samples were screened for both EBV plasma viremia and increases in viral load in PBMCs as parameters of EBV reactivation. PBMCs were subject to IFN-γ ELISPOT analysis using the autologous EBV-transformed lymphoblastoid cell line (EBV-LCL) or appropriate HLA class I-restricted EBV peptides as stimulators. Frequencies of epitope-specific CD8(+) T cells were monitored further using HLA tetramers and flow cytometry. Twelve of 14 donors exhibited signs of asymptomatic EBV reactivation. Viral reactivation was accompanied by either substantially decreased IFN-γ responses against autologous EBV-LCL (eight of 12 study participants) and/or increased responses against particular EBV peptides (six of 12 donors). In seven persons with HLA-A2 and/or -B8 alleles numbers of HLA tetramer-positive CD8(+) T cells also varied over time, but showed no correlation to episodes of detectable viral activity. In summary, IFN-γ reactivity of EBV-specific T cells is not constant. Viral reactivation is detected preferably at times of diminished EBV-LCL-specific cellular immunity. However, increased reactivity of single immunodominant CD8(+) EBV-specific T-cell clones may occur in response to virus replication.

Distinct proteinase 3-induced cytokine patterns in Wegener´s granulomatosis, Churg-Strauss syndrome, and healthy controls.

OBJECTIVES: To analyse whether a specific cytokine pattern is elicited in response to the autoantigen proteinase 3 (PR3) in active Wegener's granulomatosis (WG). METHODS: Six-colour flow cytometry was used to analyse cytokine production and surface markers of the total CD4+ T-cell population ex vivo and in PR3-stimulated T-cell lines of patients with active PR3-ANCA-positive WG, PR3-ANCA-negative Churg-Strauss syndrome (CSS), and healthy controls (HC). RESULTS: The cytokine response of the total PB CD4+ T cell population was skewed towards distinct pro-inflammatory cytokine patterns in WG (Th1-type) and CSS (Th17, Th1-/Th2-type). Th2-type as well as Th17 cell populations including Th17/Th1, Th17/Th2 and Th22 cells were elicited in response to PR3 stimulation in WG. In contrast, CSS patients displayed a Th2-type dominated response following PR3 stimulation. CONCLUSIONS: These data suggest that the cytokine response of the total CD4+ T-cell population and PR3-specific cells is influenced by the underlying disorder.

Lower numbers of FoxP3 and CCR4 co-expressing cells in an elevated subpopulation of CD4+CD25high regulatory T cells from Wegener's granulomatosis.

Defects in regulatory T (Treg) cells have been implicated in the pathogenesis of chronic inflammatory and autoimmune diseases, such as Wegener's granulomatosis (WG). This study aimed at evaluating numbers, phenotype and suppressive capacity of Treg cells in WG. Peripheral blood (PB) mononuclear cells from 22 WG-patients (17 active, 5 remission) and 22 sex- and age-matched healthy controls (HC) were examined for Treg cells by flow cytometry measuring CD4, CD25, transcription factor forkhead box P3 (FoxP3), chemokine receptor CCR4 and interferon receptor I (IFNRI). Suppressive function of CD4+CD25high Treg cells from 3 WG-patients and 3 HC was analysed using a carboxyfluoresceindiacetate-succinimidylester-based in vitro proliferation assay. Endonasal biopsies of 10 WG- and 5 sinusitis-patients were investigated for CD3+FoxP3+ cells, employing double immunohistochemistry. WG-patients displayed elevated numbers of CD4+CD25med T cells and of CD4+CD25high Treg cells. CD4+ T cells of WG-patients contained higher numbers of CCR4+ cells. However, CD4+CD25high Treg cells of WG-patients exhibited decreased numbers of cells co-expressing FoxP3 and CCR4. A low but significant increase of CD4+CD25highIFNRI+ Treg cells was detected in WG-patients. 9 days following stimulation with interferon (IFN)alpha + proteinase 3 (PR3), a reduced suppression of proliferation of responder T cells was observed for WG and proliferated CD4+CD25high Treg cells still showed downregulated co-expressions of FoxP3 and CCR4. Wegener's granuloma exhibited increased numbers of CD3+FoxP3+ cells. The results indicate upregulated numbers of Treg cells in PB and nasal mucosa as well as phenotypical and functional alterations of PB Treg cells in WG, some presumably mediated through PR3 and IFN-alpha.

Expansion of circulating NKG2D+ effector memory T-cells and expression of NKG2D-ligand MIC in granulomaous lesions in Wegener's granulomatosis.

Expansion of circulating CD28- T-cells reminiscent of effector memory T-cells (T(EM)) has been reported in Wegener's granulomatosis (WG) recently. To investigate the role of T(EM) in WG, we analyzed the expression of the activating NK-receptor NKG2D and its ligand MIC on circulating T(EM) and in granulomatous lesions, respectively. NKG2D was anomalously expressed and preferentially detected on circulating CD4+CD28- T(EM) in WG. Compared to healthy controls, T(EM) display a more activated phenotype potentially favoring unbalanced proinflammatory responses in WG. Cluster-like formations of "Wegener's autoantigen" PR3 were surrounded by NKG2D+ and NKG2D-ligand MIC+ cells in WG-granulomata, but not in disease controls. Further, IL-15 - known to drive T(EM) differentiation and proliferation--was also expressed in WG-granulomata. Thus, through acquisition of NK-like "innate" properties, IL-15 stimulated NKG2D+ T(EM) could interact with MIC+ cells within WG-granulomata, thereby sustaining inflammation and autoimmunity and promoting self-perpetuating pathology in WG.

Analysis of BZLF1 mRNA detection in saliva as a marker for active replication of Epstein-Barr virus.

Monitoring replicative Epstein-Barr virus (EBV) infection still remains a challenge in modern laboratory routine. The immediate-early protein BZLF1 mediates the switch between latent and replicate forms of EBV infection. The aim of this study was to analyze the feasibility of BZLF1 mRNA detection in saliva as a marker for active replication of the virus. Various specimens (saliva, plasma, PBMC) from 17 patients with EBV-induced infectious mononucleosis (IM) and 4 control patients were examined for expression of viral BZLF1 mRNA by means of real-time PCR. BZLF1 expression was correlated to the amount of viral DNA in either compartment. Digestion of plasma and saliva samples with DNase I allowed distinguishing between encapsidated and naked viral DNA. BZLF1 transcripts were found in all different types of specimens in varying frequencies. BZLF1 expression in saliva, PBMC, and plasma correlated with viral load in each compartment. Interestingly, those patients with detectable BZLF1 expression in saliva had a more severe course of infection with longer duration of hospitalization. In conclusion, this study demonstrates the feasibility of BZLF1 mRNA detection in saliva specimens during replicative EBV infection. Its significance for the diagnosis of reactivated EBV infection, particularly under immunosuppression, has to be elucidated in further studies.

Increased frequency of CCR4+ and CCR6+ memory T-cells including CCR7+CD45RAmed very early memory cells in granulomatosis with polyangiitis (Wegener's).

INTRODUCTION: Chemokine receptors play an important role in mediating the recruitment of T cells to inflammatory sites. Previously, small proportions of circulating Th1-type CCR5+ and Th2-type CCR3+ cells have been shown in granulomatosis with polyangiitis (GPA). Wondering to what extent CCR4 and CCR6 expression could also be implicated in T cell recruitment to inflamed sites in GPA, we investigated the expression of CCR4 and CCR6 on T cells and its association with T cell diversity and polarization. METHODS: Multicolor flow cytometry was used to analyze CCR4, CCR6, and intracellular cytokine expression of T cells from whole blood of GPA-patients (n = 26) and healthy controls (n = 20). CCR7 and CD45RA were included for phenotypic characterization. RESULTS: We found a significant increase in the percentages of circulating CCR4+ and CCR6+ cells within the total CD4+ T cell population in GPA. In contrast, there was no difference in the percentages of CD8+CCR4+ and CD8+CCR6+ T cells between GPA and healthy controls. CCR4 and CCR6 expression was largely confined to central (TCM) and effector memory T cells (TEM, TEMRA). A significant increase in the frequency of CCR4+ and CCR6+ TEMRA and CCR6+ TCM was shown in GPA. Of note, we could dissect CCR4 and CCR6 expressing CCR7+CD45RAmed very early memory T cells (TVEM) from genuine CCR7+CD45RAhigh naïve T cells lacking CCR4 and CCR6 expression for peripheral tissue-migration within the CCR7+CD45RA+ compartment. The frequencies of CCR4+ and CCR6+ TVEM were also significantly increased in GPA. An increased percentage of IL-17+ and IL-22+ cells was detected in the CCR6+ cell subsets and IL-4+ cells in the CRR4+ cell subset when compared with CD4+ cells lacking CCR4 and CCR6 expression. CONCLUSIONS: Increased frequencies of circulating CCR4+ and CCR6+ memory T cell subsets including hitherto unreported TVEM suggest persistent T cell activation with the accumulation of CCR4+ and CCR6+ cells in GPA. CCR4 and CCR6 could be involved in the recruitment of T cells including cytokine-producing subsets to inflamed sites in GPA.