A possible link between recurrent upper respiratory tract infections and lower cytokine production in patients with Q fever fatigue syndrome.

Besides fatigue, many Q fever fatigue syndrome (QFS) patients also complain of frequently recurring upper respiratory tract infections with severe symptoms. We investigated whether immunologic dysregulation contributes to these complaints. Cytokine and chemokine production was measured after stimulating monocytes of QFS patients and age- and sex-matched healthy controls with LPS and several viral ligands. The H3K4me3 mark of open chromatin was measured at the promoter regions of cytokines and chemokines that differed significantly from healthy controls. Monocytes of QFS patients produced significantly less TNF-α (p = 0.032), IL-1ß (0.004, 0.024, and 0.008), IL-6 (0.043), RANTES (0.033), IP-10 (0.049), MCP-1 (0.022), IL- 13 (0.029), and IL-10 (0.026) than healthy controls when stimulated with various ligands. H3K4me3 expression was significantly lower in QFS patients than in healthy controls on the promoter regions of IL-1ß (p = 0.004), MCP-1 (<0.001 and <0.001), IP-10 (<0.001), IL-10 (0.041), and IL-13 (<0.001, <0.001, and 0.001). QFS patients showed diminished cytokine responses to various stimuli compared to age- and sex-matched healthy controls, likely due to epigenetic remodeling and long-term memory as a result from the acute Q fever infection. This might explain the upper respiratory tract ailments in QFS.

Multi-omics examination of Q fever fatigue syndrome identifies similarities with chronic fatigue syndrome.

BACKGROUND: Q fever fatigue syndrome (QFS) is characterised by a state of prolonged fatigue that is seen in 20% of acute Q fever infections and has major health-related consequences. The molecular mechanisms underlying QFS are largely unclear. In order to better understand its pathogenesis, we applied a multi-omics approach to study the patterns of the gut microbiome, blood metabolome, and inflammatory proteome of QFS patients, and compared these with those of chronic fatigue syndrome (CFS) patients and healthy controls (HC). METHODS: The study population consisted of 31 QFS patients, 50 CFS patients, and 72 HC. All subjects were matched for age, gender, and general geographical region (South-East part of the Netherlands). The gut microbiome composition was assessed by Metagenomic sequencing using the Illumina HiSeq platform. A total of 92 circulating inflammatory markers were measured using Proximity Extension Essay and 1607 metabolic features were assessed with a high-throughput non-targeted metabolomics approach. RESULTS: Inflammatory markers, including 4E-BP1 (P = 9.60-16 and 1.41-7) and MMP-1 (P = 7.09-9 and 3.51-9), are significantly more expressed in both QFS and CFS patients compared to HC. Blood metabolite profiles show significant differences when comparing QFS (319 metabolites) and CFS (441 metabolites) patients to HC, and are significantly enriched in pathways like sphingolipid (P = 0.0256 and 0.0033) metabolism. When comparing QFS to CFS patients, almost no significant differences in metabolome were found. Comparison of microbiome taxonomy of QFS and CFS patients with that of HC, shows both in- and decreases in abundancies in Bacteroidetes (with emphasis on Bacteroides and Alistiples spp.), and Firmicutes and Actinobacteria (with emphasis on Ruminococcus and Bifidobacterium spp.). When we compare QFS patients to CFS patients, there is a striking resemblance and hardly any significant differences in microbiome taxonomy are found. CONCLUSIONS: We show that QFS and CFS patients are similar across three different omics layers and 4E-BP1 and MMP-1 have the potential to distinguish QFS and CFS patients from HC.

A possible role for mitochondrial-derived peptides humanin and MOTS-c in patients with Q fever fatigue syndrome and chronic fatigue syndrome.

BACKGROUND: Q fever fatigue syndrome (QFS) is a well-documented state of prolonged fatigue following around 20% of acute Q fever infections. It has been hypothesized that low grade inflammation plays a role in its aetiology. In this study, we aimed to identify transcriptome profiles that could aid to better understand the pathophysiology of QFS. METHODS: RNA of monocytes was collected from QFS patients (n = 10), chronic fatigue syndrome patients (CFS, n = 10), Q fever seropositive controls (n = 10), and healthy controls (n = 10) who were age- (± 5 years) and sex-matched. Transcriptome analysis was performed using RNA sequencing. RESULTS: Mitochondrial-derived peptide (MDP)-coding genes MT-RNR2 (humanin) and MT-RNR1 (MOTS-c) were differentially expressed when comparing QFS (- 4.8 log2-fold-change P = 2.19 × 10-9 and - 4.9 log2-fold-change P = 4.69 × 10-8), CFS (- 5.2 log2-fold-change, P = 3.49 × 10-11 - 4.4 log2-fold-change, P = 2.71 × 10-9), and Q fever seropositive control (- 3.7 log2-fold-change P = 1.78 × 10-6 and - 3.2 log2-fold-change P = 1.12 × 10-5) groups with healthy controls, resulting in a decreased median production of humanin in QFS patients (371 pg/mL; Interquartile range, IQR, 325-384), CFS patients (364 pg/mL; IQR 316-387), and asymptomatic Q fever seropositive controls (354 pg/mL; 292-393). CONCLUSIONS: Expression of MDP-coding genes MT-RNR1 (MOTS-c) and MT-RNR2 (humanin) is decreased in CFS, QFS, and, to a lesser extent, in Q fever seropositive controls, resulting in a decreased production of humanin. These novel peptides might indeed be important in the pathophysiology of both QFS and CFS.

Chronic Q fever associated with systemic sclerosis.

BACKGROUND: After the Q fever outbreak in the Netherlands between 2007 and 2010, more than 300 patients with chronic Q fever have been identified. Some patients were also diagnosed with systemic sclerosis, a rare immune-mediated disease. We aimed to increase awareness of concomitant chronic Q fever infection and systemic sclerosis and to give insight into the course of systemic sclerosis during persistent Q fever infection. MATERIALS AND METHODS: Chronic Q fever patients were identified after the Dutch Q fever outbreak in 2007-2010. Systemic sclerosis was diagnosed by a scleroderma expert and patients fulfilled the 2013 Classification Criteria for Systemic Sclerosis. RESULTS: Four cases presented with chronic Q fever, persistent Coxiella burnetii infection, shortly preceded or followed by the diagnosis of limited cutaneous systemic sclerosis. The three male patients of 60 years or older developed a relatively mild systemic sclerosis, which did not require immunosuppressive therapy during adequate treatment of the chronic Q fever infection. The 58-year-old female patient used immunosuppressives for her newly diagnosed systemic sclerosis at the time she likely developed a chronic Q fever infection. CONCLUSIONS: In this case series, chronic Q fever preceding systemic sclerosis was associated with a mild course of systemic sclerosis without the necessity of immunosuppressive drugs, while chronic Q fever development due to immunocompromised state was associated with a more deteriorating course of systemic sclerosis.

Interferon-γ and CXCL10 responses related to complaints in patients with Q fever fatigue syndrome.

Approximately 20% of patients with acute Q fever develop Q fever fatigue syndrome (QFS), a debilitating fatigue syndrome. This study further investigates the role of C. burnetii-specific IFNγ, but also IL-2, CXCL9, CXCL10, and CXLC11 production in QFS patients. C. burnetii-specific IFNy, IL-2, CXCL9, CXCL10, and CXCL11 production were tested in ex vivo stimulated whole blood of QFS patients who recovered from their complaints (n = 8), QFS patients with persisting complaints (n = 27), and asymptomatic Q fever seropositive controls (n = 10). With the exclusion of one outlier, stimulation with C. burnetii revealed significantly higher IFNy and CXCL10 production in QFS patients with persisting complaints (medians 288.0 and 176.0 pg/mL, respectively) than in QFS patients who recovered from their complaints (medians 93.0 and 85.5 pg/mL, respectively) (p = 0.041 and 0.045, respectively). No significant differences between groups were found for C. burnetii-specific IL-2, CXCL9, and CXCL11 production. These findings point towards a difference in cell-mediated immunity in QFS patients with persisting complaints compared to those who recovered from their complaints. Such a difference may aid to eventually diagnose QFS more objectively and might serve as an indicator of its underlying etiology.

CXCL9, a promising biomarker in the diagnosis of chronic Q fever.

BACKGROUND: In the aftermath of the largest Q fever outbreak in the world, diagnosing the potentially lethal complication chronic Q fever remains challenging. PCR, Coxiella burnetii IgG phase I antibodies, CRP and 18F-FDG-PET/CT scan are used for diagnosis and monitoring in clinical practice. We aimed to identify and test biomarkers in order to improve discriminative power of the diagnostic tests and monitoring of chronic Q fever. METHODS: We performed a transcriptome analysis on C. burnetii stimulated PBMCs of 4 healthy controls and 6 chronic Q fever patients and identified genes that were most differentially expressed. The gene products were determined using Luminex technology in whole blood samples stimulated with heat-killed C. burnetii and serum samples from chronic Q fever patients and control subjects. RESULTS: Gene expression of the chemokines CXCL9, CXCL10, CXCL11 and CCL8 was strongly up-regulated in C. burnetii stimulated PBMCs of chronic Q fever patients, in contrast to healthy controls. In whole blood cultures of chronic Q fever patients, production of all four chemokines was increased upon C. burnetii stimulation, but also healthy controls and past Q fever individuals showed increased production of CXCL9, CXCL10 and CCL8. However, CXCL9 and CXCL11 production was significantly higher for chronic Q fever patients compared to past Q fever individuals. In addition, CXCL9 serum concentrations in chronic Q fever patients were higher than in past Q fever individuals. CONCLUSION: CXCL9 protein, measured in serum or as C. burnetii stimulated production, is a promising biomarker for the diagnosis of chronic Q fever.

A fatal case of disseminated chronic Q fever: a case report and brief review of the literature.

BACKGROUND: Chronic Q fever is a rare infection, which mainly manifests as endocarditis, infection of vascular prostheses or aortic aneurysms. We present the case of a 74-year-old immunocompromised man with a haematologically disseminated Coxiella burnetii infection, which has never been reported before. CASE REPORT: He was diagnosed with a chronic Q fever infection of an aneurysm with an endovascular prosthesis in 2015, but he died despite optimal treatment. Autopsy revealed a disseminated C. burnetii infection, confirmed by a positive PCR on samples from several organs. Retrospectively, he already had complaints and signs of inflammation since 2012, for which he had already been admitted in February 2014. At that time, Q fever diagnostics using PCR, complement fixation assay, and enzyme-linked immunosorbent assay on serum were all negative. In retrospect however, retesting available samples from February 2014 using immunofluorescence assay (IFA) already revealed serology compatible with chronic Q fever. CONCLUSION: Clinicians should be aware of this silent killer, especially in case of risk factors, and perform an appropriate diagnostic work-up for Q fever including IFA serology and PCR.

[Chronic fatigue syndrome: source of controversy]. / Het chronische-vermoeidheidsyndroom: bron van ophef.

Chronic fatigue syndrome (CFS) remains a controversial medical disorder. A combination of poorly executed studies using variable case definitions and diagnostic criteria have led to controversial results. These controversies cloud our vision on CFS, and lead to scepticism and frustration among patients, doctors and researchers. For future perspective, interdisciplinary studies of high quality with large well-defined patient groups and adequate controls are needed.

Mediation analysis shows that a decline in self-efficacy mediates the increase in fatigue severity following an initial positive response to cognitive behavioural therapy in Q fever fatigue syndrome.

OBJECTIVE: Q fever fatigue syndrome (QFS) is characterized by chronic fatigue following acute Q fever. Previously, it was shown that cognitive behavioural therapy (CBT), and not doxycycline, was significantly more effective than placebo in reducing fatigue severity in QFS patients. However, this effect was not maintained after one year. The aim of this study is to elucidate the cognitive and behavioural variables which mediate the positive effect of CBT on fatigue during the treatment and the relapse of fatigue after completion of CBT, by using multiple mediation analysis. METHODS: Additional analyses were performed on data of a randomized controlled trial that investigated the efficacy of CBT and antibiotics compared to placebo for QFS [1]. Only those patients in the CBT group who completed the allocated CBT treatment, and those patients in the medication group who did not follow additional CBT during follow-up, were included in this study. Two mediation models were tested, using respectively assessments at baseline and end-of-treatment (EOT), and EOT and follow-up, comparing the CBT group (n = 43) with the medication group (n = 89). RESULTS: During treatment, the decrease in fatigue brought on by CBT was completely mediated by an increase in self-efficacy with respect to fatigue. A reduction in self-efficacy partly mediated the increase in fatigue at follow-up in the CBT group. CONCLUSIONS: Given the decline in self efficacy, booster sessions focussing on restoration and maintenance of self-efficacy with respect to fatigue, may lead to elongation of the initial positive effects of CBT for QFS.

Long-term effect of cognitive behavioural therapy and doxycycline treatment for patients with Q fever fatigue syndrome: One-year follow-up of the Qure study.

BACKGROUND: Previously, we reported a randomized placebo-controlled trial, the Qure study, showing that cognitive behavioural therapy (CBT), and not doxycycline, was significantly more effective than placebo in reducing fatigue severity in Q fever fatigue syndrome (QFS) patients. This follow-up study evaluates the long-term effect of these treatment regimens, 1 year after completion of the original trial. METHODS: All patients who completed the Qure study, CBT (n = 50), doxycycline (n = 52), and placebo (n = 52), were included in this follow-up study. Between twelve and fifteen months after end of treatment (EOT), patients filled out web-based questionnaires including the main outcome measure fatigue severity, assessed with the Checklist Individual Strength (CIS), subscale fatigue severity. RESULTS: Fatigue severity in the CBT, but not doxycycline or placebo, group was significantly increased at follow-up compared to EOT (respective means 39.5 [95% CI, 36.2-42.9] and 31.3 [95% CI, 27.5-35.1], mean difference 8.2 [95% CI, 4.9-11.6]; P < .001). Fatigue severity scores of CBT (adjusted mean 39.8 [95% CI, 36.1-43.4]) and doxycycline (adjusted mean 41.0 [95% CI, 37.5-44.6]) groups did not significantly differ from the placebo group (adjusted mean 37.1 [95% CI, 33.6-40.7]; P = .92 and P = .38, respectively). CONCLUSION: The beneficial effect of CBT on fatigue severity at EOT was not maintained 1 year thereafter. Due to its initial beneficial effect and side effects of long-term doxycycline use, we still recommend CBT as treatment for QFS. We suggest further investigation on tailoring CBT more to QFS, possibly followed by booster sessions.

Cytokine profiles in patients with Q fever fatigue syndrome.

BACKGROUND: Q fever fatigue syndrome (QFS) is a state of prolonged fatigue following around 20% of acute Q fever cases. It is thought that chronic inflammation plays a role in its etiology. To test this hypothesis we measured circulating cytokines and the ex-vivo cytokine production in patients with QFS and compared with various control groups. MATERIALS/METHODS: Peripheral blood mononuclear cells (PBMCs), whole blood, and serum were collected from 20 QFS patients, 19 chronic fatigue syndrome (CFS) patients, 19 Q fever seropositive controls, and 25 age- and sex-matched healthy controls. Coxiella-specific ex-vivo production of tumor necrosis factor (TNF)α, interleukin (IL)-1ß, IL-6, and interferon (IFN) was measured, together with a total of 92 circulating inflammatory proteins. RESULTS: PBMCs of QFS patients produced more IL-6 (P = 0.0001), TNFα (P = 0.0002), and IL-1ß (P = 0.0005) than the various control groups when stimulated with Coxiella antigen. QFS patients had distinct differences in circulating inflammatory markers compared to the other groups, including higher concentrations of circulating IL-6 and IFNγ. CONCLUSION: QFS patients showed signs of chronic inflammation compared to asymptomatic Q fever seropositive controls, CFS patients, and healthy controls, of which the monocyte-derived cytokines TNFα, IL-1ß, and especially IL-6, are likely crucial components.

Autoimmunity and B-cell dyscrasia in acute and chronic Q fever: A review of the literature.

Q fever infection can lead to chronic Q fever, a potentially lethal disease occurring in 1-5% of patients infected with Coxiella burnetii, characterized by the persistence of this intracellular bacterium. It usually presents as endocarditis, infected vascular aneurysms, or infected vascular prostheses. This systematic review of the literature discusses the various autoimmune syndromes and B-cell dyscrasias in acute and chronic Q fever patients, that may interfere with or impede recognition and diagnosis of Q fever. Reportedly, high concentrations of anti-cardiolipin antibodies may be found in acute Q fever patients, while specifically cardiac muscle antibodies have been reported during chronic Q fever. Systemic lupus erythematosus and antiphospholipid syndrome are the most frequently reported autoimmune syndromes, followed by neuromuscular disorders and vasculitis. B-cell dyscrasia, mostly cryoglobulinaemia, is predominantly described in chronic Q fever patients with endocarditis. We conclude that immunological (epi)phenomena are not rare during Q fever and may obscure the infectious etiology of the disease.

Toll-like receptor 2 induced cytotoxic T-lymphocyte-associated protein 4 regulates Aspergillus-induced regulatory T-cells with pro-inflammatory characteristics.

Patients with cystic fibrosis, chronic obstructive pulmonary disease, severe asthma, pre-existing pulmonary lesions, and severely immunocompromised patients are susceptible to develop infections with the opportunistic pathogenic fungus Aspergillus fumigatus, called aspergillosis. Infections in these patients are associated with persistent pro-inflammatory T-helper (TH)2 and TH17 responses. Regulatory T-cells, natural suppressor cells of the immune system, control pro-inflammatory T-cell responses, but can also contribute to disease by shifting to a pro-inflammatory TH17-like phenotype. Such a shift could play an important role in the detrimental immunopathology that is seen in aspergillosis. Our study demonstrates that Aspergillus fumigatus induces regulatory T-cells with a TH17-like phenotype. We also demonstrate that these regulatory T-cells with a pro-inflammatory TH17-like phenotype can be reprogrammed to their "classical" anti-inflammatory phenotype by activating Toll-like receptor 2 (TLR2), which regulates the induction of cytotoxic T-lymphocyte-associated protein 4 (CTLA4). Similarly, soluble CTLA4 could reverse the pro-inflammatory phenotype of Aspergillus-induced regulatory T-cells. In conclusion, our results suggest a role for regulatory T-cells with a pro-inflammatory TH17-like phenotype in Aspergillus-associated immunopathology, and identifies key players, i.e. TLR2 and CTLA4, involved in this mechanism.

Altered interferon-γ response in patients with Q-fever fatigue syndrome.

OBJECTIVES: Whether immunological mechanisms underlie Q-fever fatigue syndrome (QFS) remains unclear. For acute Q-fever, the antigen-specific interferon-γ (IFNγ) response may be a useful tool for diagnosis, and the IFNγ/interleukin(IL)-2 production ratio may be a marker for chronic Q-fever and treatment monitoring. Here we explored the specific IFNγ production and IFNγ/IL-2 ratio in QFS patients. METHODS: IFNγ and IL-2 production were tested in ex-vivo stimulated whole blood of QFS patients (n = 20), and compared to those previously determined in seropositive controls (n = 135), and chronic Q-fever patients (n = 28). Also, the correlation between patient characteristics and IFNγ, IL-2, and IFNγ/IL-2 ratio was determined. RESULTS: QFS patients were younger (p < 0.001), but gender distribution was similar to seropositive controls and chronic Q-fever patients. Coxiella burnetii Nine Mile stimulation revealed a higher IFNγ production in QFS (median 319.5 pg/ml) than in seropositive controls (120 pg/ml, p < 0.01), but comparable to chronic Q-fever (2846 pg/ml). The IFNγ/IL-2 ratio was similar to that in seropositive controls, but lower than in chronic Q-fever patients (p < 0.01). Symptom duration was positively correlated with IL-2 production, and negatively correlated with the IFNγ/IL-2 ratio. CONCLUSIONS: These results point to an altered cell-mediated immunity in QFS, and suggest a different immune response than in chronic Q-fever.