Long COVID (LC) describes the clinical phenotype of symptoms after infection with the severe acut... more Long COVID (LC) describes the clinical phenotype of symptoms after infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diagnostic and therapeutic options are limited, as the pathomechanism of LC is elusive. As the number of acute SARS-CoV-2 infections was and is large, LC will be a challenge for the healthcare system. Previous studies revealed an impaired blood flow, the formation of microclots, and autoimmune mechanisms as potential factors in this complex interplay. Since functionally active autoantibodies against G-protein-coupled receptors (GPCR-AAbs) were observed in patients after SARS-CoV-2 infection, this study aimed to correlate the appearance of GPCR-AAbs with capillary microcirculation. The seropositivity of GPCR-AAbs was measured by an established cardiomyocyte bioassay in 42 patients with LC and 6 controls. Retinal microcirculation was measured by OCT–angiography and quantified as macula and peripapillary vessel density (VD) by the Erlangen-...
The non-nucleoside reverse transcriptase inhibitor (NNRTI) Efavirenz is frequently used in human ... more The non-nucleoside reverse transcriptase inhibitor (NNRTI) Efavirenz is frequently used in human immunodeficiency virus treatment, but also efficient against cancer in mouse models. Its radiosensitizing effect makes it a promising drug for combination with radiotherapy. The efficacy of Efavirenz combined with irradiation was assessed with immunostaining of DNA-damage markers and colony formation assays in BxPC-3 pancreatic cancer cells. Gene expression and protein phosphorylation of the Efavirenz-sensitive BxPC-3 cells was compared to the resistant primary fibroblasts SBL-5. Oxidative stress, mitochondrial damage and cell death were studied with live-cell microscopy and flow cytometry. Combined Efavirenz and radiation significantly increased the number of γH2AX and phospho-ataxia telangiectasia mutated foci. Efavirenz and ionizing radiation had a synergistic effect using the clonogenic survival assay. Efavirenz selectively induced cell death in the BxPC-3 cells. The differing gene e...
International archives of allergy and immunology, 2017
Antibiotics are known to cause severe cutaneous adverse reactions, such as the rare acute general... more Antibiotics are known to cause severe cutaneous adverse reactions, such as the rare acute generalized exanthematous pustulosis (AGEP). Unlike Stevens-Johnson syndrome or toxic epidermal necrolysis, AGEP is rarely life-threatening. Systemic involvement is not typical, and if present usually coincides with a mild elevation of the hepatic enzymes and a decrease in renal function. Hence, AGEP is known to have a good prognosis and to be life-threatening only in elderly patients or patients with chronic diseases. Herein, we report a case of AGEP in a young healthy male leading to systemic inflammatory response syndrome and to treatment in an intensive care unit after being treated with 5 different antibiotics. Initial symptoms were not indicative for AGEP and the patient's course of disease led promptly to critical cardiorespiratory symptoms and systemic inflammatory response syndrome. We assume that the administration of the 5 different antibiotics resulted in type IV allergy as well...
Many effector mechanisms of neutrophils have been implicated in the pathogenesis of systemic lupu... more Many effector mechanisms of neutrophils have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Neutrophil extracellular traps (NETs) have been assigned a particularly detrimental role. Here we investigated the functional impact of neutrophils and NETs on a mouse model of lupus triggered by intraperitoneal injection of the cell death-inducing alkane pristane. Pristane-induced lupus (PIL) was aggravated in 2 mouse strains with impaired induction of NET formation, i.e., NOX2-deficient (Ncf1-mutated) and peptidyl arginine deiminase 4-deficient (PAD4-deficient) mice, as seen from elevated levels of antinuclear autoantibodies (ANAs) and exacerbated glomerulonephritis. We observed a dramatically reduced ability to form pristane-induced NETs in vivo in both Ncf1-mutated and PAD4-deficient mice, accompanied by higher levels of inflammatory mediators in the peritoneum. Similarly, neutropenic Mcl-1ΔMyelo mice exhibited higher levels of ANAs, which indicates a regulator...
Question: Foamy viruses (FV), and in particular PFV, have emerged in recent years as attractive g... more Question: Foamy viruses (FV), and in particular PFV, have emerged in recent years as attractive gene therapy vector candidates. Since the lack of knowledge on molecular events in FV replication is a major hurdle for broader usage of foamy virus vectors, we aimed at elucidating PFV biology by investigating interactions of its capsid protein, Gag, with host cell components. Methodology and result: To this end, we identified members of the mammalian PLK family as PFV Gag interactants in a commercial yeasttwo-hybrid (Y2H) screen and validated these results in detailed Y2H experiments for PLK1-3. In the yeast system, the intact PLK kinase and substrate recognition motifs were required for interactions with PFV Gag, in which a unique S 224-T-P 226 motif served as a PLK binding determinant. PFV Gag mutants harbouring alanine substitutions of STP residues (iSTP) or phosphomimetic mutations of the T 225 (pmSTP) failed to interact with PLK1-3 in yeast. These findings were corroborated by colocalization studies of ectopically expressed, fluorescently tagged proteins in mammalian cells, where mCherry-tagged PFV Gag was able to recruit eGFP-tagged PLK1 and 2 to condensed mitotic chromatin in an STP motif-dependent manner. When characterizing PFV virions containing wild type or STP mutant Gag proteins, we observed that the mutations did not interfere with particle assembly, release or reverse transcription, but led to a 70 % titer reduction relative to wild type in single-round infection experiments. These replication defects became more prominent in the replication-competent PFV context. Therefore, the lack of Gag STP mutant interaction with PLK proteins upon viral entry into host cells was likely underlying this replication deficit. This hypothesis was strengthened by the finding that enzymatic PLK inhibition in host cells during transduction with wild type PFV mimicked the replication phenotype of PFV STP mutants. In addition to the overall reduced infectivity of the mutants, we also observed that the STP mutations in particle-associated Gag lead to differential sensitivity to integrase inhibition by dolutegravir and resulted in decreased integration efficiency. Conclusions: Taken together, our results demonstrate that PLK proteins influence PFV replication by virtue of their interaction with the Gag protein, ensuring timely and efficient transduction. O2 A novel entry/uncoating assay reveals the presence of at least two species of viral capsids during synchronized HIV-1 infection
Collagen and calcium-binding EGF domain-containing protein 1 (CCBE1) bi-allelic mutations have be... more Collagen and calcium-binding EGF domain-containing protein 1 (CCBE1) bi-allelic mutations have been associated with syndromes of widespread congenital lymphatic dysplasia, including Hennekam Syndrome (HS). HS is characterized by lymphedema, lymphangiectasia, and intellectual disability. CCBE1 encodes a putative extracellular matrix protein but the HS-causing mutations have not been studied biochemically. We report two HS siblings, born to consanguineous parents of Turkish ancestry, whose clinical phenotype also includes protein losing enteropathy, painful relapsing chylous ascites, and hypogammaglobulinemia. We identified by whole exome and Sanger sequencing the homozygous CCBE1 C174Y mutation in both siblings. This mutation had been previously reported in another HS kindred from the Netherlands. In overexpression studies, we found increased intracellular expression of all forms (monomers, dimers,
Journal of acquired immune deficiency syndromes (1999), Jan 20, 2015
It has been reported that HIV-1-specific cytotoxic T-cells (CTL) recognizing the HLA-A2-restricte... more It has been reported that HIV-1-specific cytotoxic T-cells (CTL) recognizing the HLA-A2-restricted p17-epitope SLYNTVATL (SL9) can cross-react with the HLA-A2-restricted influenza matrix epitope GILGFVFTL (GL9). So far, the prevalence of GL9-cross-reacting HIV-1-specific CTL in larger cohorts of HIV-1-infected patients is unknown and there are no data yet whether SL9/GL9-cross-reactive CTL may influence the course of HIV-1 infection. We analyzed the presence of SL9/GL9-cross-reacting CTL in a cohort of 175 HLA-A2-positive HIV-1-infected patients. Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with SL9- and GL9-peptides and outgrowing cell lines were analyzed regarding cross-reactivity and recognition of viral variants in у-IFN-ELISPOT assays. SL9- and GL9-specific CTL could be generated in 52.6% and 53.7% of 175 patients, respectively. Both SL9- and GL9-specific CTL were more frequently observed in patients on antiretroviral treatment (ART). 65.2% of the 92 SL9-s...
Dehydroepiandrosterone in systemic lupus erythematosus. Results of a double-blind, placebo-contro... more Dehydroepiandrosterone in systemic lupus erythematosus. Results of a double-blind, placebo-controlled, randomized clinical trial.
Large amounts of dead and dying cells are produced during cancer therapy and allograft rejection.... more Large amounts of dead and dying cells are produced during cancer therapy and allograft rejection. Depending on the death pathway and stimuli involved, dying cells exhibit diverse features, resulting in defined physiological consequences for the host. It is not fully understood how dying and dead cells modulate the immune response of the host. To address this problem, different death stimuli were studied in B16F10 melanoma cells by regulated inducible transgene expression of the pro-apoptotic active forms of caspase-3 (revCasp-3), Bid (tBid), and the Mycobacterium tuberculosis-necrosis inducing toxin (CpnTCTD). The immune outcome elicited for each death stimulus was assessed by evaluating the allograft rejection of melanoma tumors implanted subcutaneously in BALB/c mice immunized with dying cells. Expression of all proteins efficiently killed cells in vitro (>90%) and displayed distinctive morphological and physiological features as assessed by multiparametric flow cytometry analy...
Recognition Patterns of HLA-A2–Restricted Human Immunodeficiency Virus-1–Specific Cytotoxic T-Lymphocytes in a Cohort of HIV-1–Infected Individuals
Viral Immunology, 2005
The cytotoxic T-lymphocytes (CTL) response to three histocompatibility leukocyte antigen (HLA)-A2... more The cytotoxic T-lymphocytes (CTL) response to three histocompatibility leukocyte antigen (HLA)-A2-restricted CTL epitopes was investigated in a cohort of 51 HLA-A2-positive human immunodeficiency-1 (HIV-1)-infected subjects. CTL activity was evaluated by testing peptide stimulated peripheral blood mononuclear cells (PBMC) in chromium release assays. The most prevalent CTL response was directed to the RT-peptide ILKEPVHGV (IV9) recognized by 37.3%. The p17-peptide SLYNTVATL (SL9), reported to be the immunodominant epitope in chronically infected untreated patients, was recognized only by 13.7%. Only 9.8% recognized both IV9 and SL9, and none recognized the RT-peptide VIYQYMDDL (VL9). CTL activity correlated significantly with absolute CD8 T-cell counts but not with CD4 counts, viral load, or antiviral therapy. Analysis of the recognition patterns of amino acid substitutions in the IV9 epitope revealed the presence of at least four functionally different T-cell receptors (TCR) in this cohort. All analyzed mutations within the TCR recognition site of this epitope could abrogate CTL recognition by individual CTL clones, but all were fully immunogenic for other CTL clones with peptide-sensitizing capacities similar to that of IV9. Further studies should be performed to evaluate whether a convergent epitope vaccination strategy using immunogenic variants of CTL epitopes is a feasible approach to broaden the TCR repertoire and to inhibit CTL escape.
Gout is characterized by an acute inflammatory reaction and the accumulation of neutrophils in re... more Gout is characterized by an acute inflammatory reaction and the accumulation of neutrophils in response to monosodium urate (MSU) crystals. Inflammation resolves spontaneously within a few days, although MSU crystals can still be detected in the synovial fluid and affected tissues. Here we report that neutrophils recruited to sites of inflammation undergo oxidative burst and form neutrophil extracellular traps (NETs). Under high neutrophil densities, these NETs aggregate and degrade cytokines and chemokines via serine proteases. Tophi, the pathognomonic structures of chronic gout, share characteristics with aggregated NETs, and MSU crystals can induce NETosis and aggregation of NETs. In individuals with impaired NETosis, MSU crystals induce uncontrolled production of inflammatory mediators from neutrophils and persistent inflammation. Furthermore, in models of neutrophilic inflammation, NETosis-deficient mice develop exacerbated and chronic disease that can be reduced by adoptive transfer of aggregated NETs. These findings suggest that aggregated NETs promote the resolution of neutrophilic inflammation by degrading cytokines and chemokines and disrupting neutrophil recruitment and activation.
The aim of this study was to investigate the frequency of CYP2B6 polymorphisms (according to ethn... more The aim of this study was to investigate the frequency of CYP2B6 polymorphisms (according to ethnicity) and the influence of heterozygosity and homozygosity on plasma concentrations of efavirenz and nevirapine. Methods: Following written informed consent, 225 Caucasians and 146 Blacks were recruited from the German Competence Network for HIV/AIDS. Plasma concentrations of efavirenz and nevirapine were assessed by HPLC, and genotyping for 516G>T, 983T>C and 1459T>C polymorphisms in CYP2B6 was conducted by real-time PCR-based allelic discrimination. Results: The minor allele frequency for 516G>T, 983T>C and 1459T>C was 0.29, 0 and 0.08 in Caucasians and 0.34, 0.07 and 0.02 in Blacks, respectively. Two Black patients with the 983C allele receiving efavirenz were identified and both were withdrawn from therapy within 1 week of sampling due to toxicity. In multivariate analyses, efavirenz and nevirapine plasma concentrations were significantly associated with 983T>C (P < 0.0001 and P 5 0.02, respectively), 516G>T (P < 0.0001 and P 5 0.002, respectively) and time of drug analysis post-dose (P < 0.0001 for both). Body mass index was independently related to efavirenz (P 5 0.04) but not nevirapine concentrations, and age was related to nevirapine (P 5 0.05) but not efavirenz concentrations. Consistent with other studies, 1459C>T was not associated with plasma concentrations of either drug (P > 0.05 for both drugs). Conclusions: This is the first report that the 983T>C genotype (part of the CYP2B6*18 haplotype) impacts on nevirapine plasma concentrations and the first study to assess the impact of 983C homozygosity on efavirenz concentrations. These data have implications for administration of nonnucleoside reverse transcriptase inhibitors to Black patients.
JAIDS Journal of Acquired Immune Deficiency Syndromes, 2008
for the German Competence Network for HIV/AIDS Objectives: To study the role of cytotoxic T-lymph... more for the German Competence Network for HIV/AIDS Objectives: To study the role of cytotoxic T-lymphocyte (CTL) escape for disease progression in HIV-1 infection, we analyzed the CTL response to the dominant human leukocyte antigen (HLA)-B8restricted CTL epitope FLKEKGGL (FL8) in HIV-1 Nef. Methods: HIV-1 nef genes derived from 56 patients were analyzed by polymerase chain reaction (PCR)-based sequencing. T-cell responses against FL8 and mutated FL8 variants were detected by g-interferon (g-IFN) enzyme linked immunospot (ELISPOT) assay. Results: The longitudinal analysis of an HIV-1-infected patient with good control of HIV-1 viremia for several years demonstrated an association of rising viremia with the emergence of CTL escape mutations within the HLA-B8-restricted Nef-specific CTL epitopes FLKEKGGL and WPAIRERM. Analysis of nef genes in 56 HIV-1infected patients demonstrated a significant correlation between the occurrence of mutations in the FL8 epitope and the presence of HLA-B8. The mutations within the FL8 epitope could decrease CTL recognition; however, there was strong variation regarding the recognition of viral variants between individual donors. The presence of FL8 mutations was associated with lower CD4 cell counts and higher viral loads. Conclusions: Our data demonstrate a strong CTL selection pressure on the immunodominant HLA-B8-restricted CTL epitope FL8 in HIV-1 Nef. The association of FL8 mutations with lower CD4 cell counts indicates an important role of CTL escape mutations for disease progression.
Background: The survival rate in patients with systemic lupus erythematosus (SLE) has improved dr... more Background: The survival rate in patients with systemic lupus erythematosus (SLE) has improved dramatically during the past four decades to 96.6% (five year) in the Erlangen cohort, but it is nearly three times as high as in an age and sex matched control population. Reasons for death are mainly cardiovascular diseases (37%) and infections (29%). Objective: To find risk factors existing at disease onset for a severe outcome in the Erlangen cohort. Patients and methods: By using a database of 338 patients with SLE from a single centre, documented at least one to 15 years and including Systemic Lupus International Collaborating Clinics/ American College of Rheumatology (SLICC/ACR) damage score data and index (SDI) and an activity score (European Consensus Lupus Activity Measurement (ECLAM)), a retrospective search was made for risk factors for a severe outcome like death, end stage renal disease (ESRD), and thromboembolic events (TE) in SLE. For this purpose, multivariable Cox regression models were analysed using the statistical package SPSS 10.0 for Windows. Results: The following were defined as risk factors for death at disease onset: male sex (p<0.001, relative risk (RR)=3.5), age >40 at disease onset (p<0.0001, RR=19.9), nephritis (p<0.05, RR=1.6), a reduction of creatinine clearance (p<0.001, RR=1.8), heart disease (p=0.05, RR=1.5), and central nervous system (CNS) disease (p=0.06, RR=1.6). An increase in the SDI of two or more points from the first to the third year of disease was the worst prognostic factor (p<0.0001, RR=7.7). The existence of Ro or nRNP antibodies, or both, was protective (p<0.05, RR =0.1). A low C3 (p<0.01 RR=3.0) and splenomegaly (p<0.01 RR=2.7) at disease onset turned out to be risk factors for ESRD besides a nephritis. In patients with hypertension (p<0.05) and/or high titres of dsDNA antibodies (>70 U/l) (p<0.01) and/or a mean ECLAM score of 4 (p<0.01) in the course of disease, a prevalence of ESRD was recorded in 9% (p<0.05) and 10% (p<0.01), and 8% (p<0.01) v 4% in the whole group. Analysis of risk factors at disease onset for TE identified positive lupus anticoagulant (p=0.17, RR=1.6), cryoglobulins (p<0.05, RR=1.8), and nephritis (p=0.05, RR=1.4), in addition to an age >40 at disease onset. Conclusions: A subgroup of patients in the Erlangen cohort with a typical clinical and serological phenotype at disease onset that is at high risk for a worse outcome was identified. Identification of these white patients at risk at disease onset will enable treatment to be intensified and thereby possibly prevent or better control late stage manifestations.
Background: Recently, a regression of precancerous lesions in HIV-1-infected patients after initi... more Background: Recently, a regression of precancerous lesions in HIV-1-infected patients after initiation of HAART was reported. Nonnucleoside reverse transcriptase inhibitors (NNRTIs) as efavirenz (EFV) might be mediators of this effect, as they are known to have a cytotoxic effect on tumour cells. A potential mechanism involved in this effect may be the activation of the cannabinoid receptor to mediate tumour toxicity. Methods: Several tumour-derived and fibroblast cell lines were studied. Cytotoxicity of EFV was evaluated by Annexin-Pi staining. The expression of the cannabinoid receptors CB1, CB2 and GPR55 was analysed by western blot, quantitative reverse transcriptase (qRT-PCR) and fluorescence activated cell sorting. The influence of the cannabinoid agonists and antagonists on the effects of EFV was investigated. Furthermore, the effect of EFV on the phosphorylation state of the growth factors Erk, Akt and the tumour suppressor protein p53 was tested. Results: EFV revealed a selective cytotoxic effect on several tumour cell lines, whereas primary fibroblasts were not affected. The cytotoxic effect was associated with the expression of CB1. The combination of EFV with cannabinoid agonists showed an increase in toxicity. The phosphorylation state of Erk and Akt was not affected by EFV, whereas p53 showed an increased phosphorylation. Conclusion: EFV has a selective cytotoxic effect on several tumour cells. Furthermore, EFV led to an activating phosphorylation of the tumour suppressor protein p53 going in line with earlier reports that EFV may be antitumourigenic and a potential cytostatic drug. The observed synergistic effect with cannabinoid agonists implicates an involvement of the cannabinoid system.
Objective: Efficient antiretroviral therapy (ART) of HIV-1 infection reduces the viral load to un... more Objective: Efficient antiretroviral therapy (ART) of HIV-1 infection reduces the viral load to undetectable levels and restores the immune system. However, therapy failure appears in a substantial fraction of patients and is mostly associated with the appearance of drug-resistant viruses. It is still not clear when the drug pressure leads to the earliest selection and appearance of drug-resistant HIV-1 populations. In this study, we wanted to determine whether drug-resistant viruses are already selected during viral decline within the first months of ART. Design and methods: Fifteen mostly chronically HIV-1 infected patients were included. None had received ART prior to this study. The selection of three key resistance mutations, L90M (protease), K103N and M184V (reverse transcriptase), were measured by allele-specific real-time PCR allowing us to track minority quasispecies with a discriminative power of 0.01-0.2%. Results: Drug-resistant HIV-1 variants were found in 7/15 patients (46.7%) prior to ART. Rapid selection of drug resistance was detected in six patients (40%) independent of the presence of drug-resistant HIV-1 prior to ART. The risk for the selection of drug resistant viruses was correlated with the time until viral load became undetectable (P ¼ 0.02). Besides the proportional increment of drug-resistant viruses, we observed in two patients a quantitative increase of this virus population while the total viral load decreased. Conclusions: Drug-resistant viruses can be selected and replicate even in the first weeks of suppressive ART, thus, intensification of ART during the initial treatment period should be considered and further evaluated in clinical studies.
Cryptococcus neoformans var. neoformans is the second most prevalent agent of cryptococcosis in c... more Cryptococcus neoformans var. neoformans is the second most prevalent agent of cryptococcosis in central Europe. Infections mostly present with localized skin and disseminated infections. Previous studies did not find these presentations to be determined by the fungal genotype as detected by multilocus sequence typing (MLST). However, phenotypic fungal traits may impact clinical presentation. Here, we studied the growth and virulence factors of C. neoformans var. neoformans isolates from disseminated and localized infections and an environmental isolate. We used coincubation with Acanthamoeba castellanii and the Galleria mellonella infection model to identify phenotypic characteristics potentially associated with clinical presentation. Clinical isolates of C. neoformans var. neoformans present a substantial phenotypic variability. Median survival of Galleria mellonella varied between 6 and 14 days. C. neoformans var. neoformans isolates from disseminated infections showed stronger me...
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Papers by Thomas Harrer