A serosurvey examining exposure to Borrelia burgdorferi sensu lato and tick-borne encephalitis virus in Danish blood donors, August 2022.

Objectives: Borrelia burgdorferi sensu lato (Bbsl) and tick-borne encephalitis virus (TBEV) are tick-borne pathogens. This study aimed to investigate the seroprevalence of these pathogens in Danish blood donors. Methods: A total of 1000 plasma samples equally distributed (n = 200) from all five Danish regions were analyzed. Commercially available enzyme-linked immunosorbent assays were used to screen the samples for immunoglobulin G antibodies against Bbsl and TBEV. The samples positive for antibodies against TBEV were further examined with a commercially available enzyme-linked immunosorbent assay and a Luminex-based TBEV suspension multiplex immunoassay for specific antibodies against non-structural protein 1 (NS1) antigen suggestive of previous infection. Results: A total of 62 samples tested positive for immunoglobulin G antibodies against Bbsl. A total of 40 samples were positive or borderline for antibodies against TBEV, indicating potential infection or vaccination. Of these, one had antibodies against NS1, indicating past infection. The seroprevalence of Bbsl was 6.2% (95% confidence interval 4.8-7.8), with equal seroprevalence in all five regions. The seroprevalence of TBEV was 0.1% (95% confidence interval 0.01-0.62%). Conclusions: The seroprevalence of Bbsl was similar throughout the country and corresponds well with previous studies. The seroprevalence of TBEV NS1 was low, which is in line with a low number of reported tick-borne encephalitis cases in Denmark. The NS1 positive sample was from the Capital Region, an endemic TBEV area.

Neoehrlichiosis associated with ocrelizumab in a patient with multiple sclerosis: A case report.

OBJECTIVE: To describe a case of neoehrlichiosis, an emerging opportunistic tick-borne infection, in a patient with multiple sclerosis (MS) treated with ocrelizumab. METHODS: This is a case study. RESULTS: Our patient developed clinical infection over several months while on ocrelizumab and was ultimately diagnosed with neoehrlichiosis, caused by the bacteria Neoehrlichia mikurensis. Resolution of symptoms began within a few days after the initiation of antibiotic treatment. CONCLUSION: We describe the first probable case of ocrelizumab-associated neoehrlichiosis in a patient with MS. Clinicians should be aware of this potentially debilitating and life-threatening infection in patients receiving CD20-depleting therapy.

Neoehrlichia mikurensis in Danish immunocompromised patients: a retrospective cohort study.

BACKGROUND: The tick-borne bacterium, Neoehrlichia mikurensis (N. mikurensis) can cause severe febrile illness and thromboembolic complications in immunocompromised individuals. We investigated the presence of N. mikurensis DNA in retrospectively collected plasma from a well-characterized cohort of Danish immunocompromised patients. METHODS: Plasma samples from 239 patients with immune dysfunction related to hematological or rheumatological disease or due to immunosuppressive therapy, were retrieved from a transdisciplinary biobank (PERSIMUNE) at Rigshospitalet, Copenhagen, Denmark. Serving as immunocompetent controls, plasma samples from 192 blood donors were included. All samples were collected between 2015 and 2019. Real-time PCR targeting the groEL gene was used to detect N. mikurensis DNA. Sequencing was used for confirmation. Borrelia burgdorferi sensu lato IgG antibodies were detected by ELISA as a proxy of tick exposure. Prevalence was compared using Fisher's exact test. RESULTS: Neoehrlichia mikurensis DNA was detected in 3/239 (1.3%, 95% confidence interval (CI): 0.3 - 3.6%) patients, all of whom primarily had a hematological disease. Follow-up samples of these patients were negative. N. mikurensis DNA was not detected in any of the blood donor samples. IgG antibodies against B. burgdorferi s.l. were detected with similar prevalence in immunocompromised patients and blood donors, i.e., 18/239 (7.5%, 95% CI: 4.8-11.5%) and 11/192 (5.7%, 95%: CI 3.2-10.0%). CONCLUSION: In this study, patients with N. mikurensis were not identified by clinical indication and N. mikurensis may therefore be underdiagnosed in Danish patients. Further investigations are needed to explore the clinical significance and implications of this infection.

Cerebrospinal fluid levels of the macrophage-specific biomarker sCD163 are diagnostic for Lyme neuroborreliosis: An observational cohort study.

OBJECTIVES: We aimed to investigate levels of the macrophage-specific marker, sCD163, in cerebrospinal fluid and plasma in patients with Lyme neuroborreliosis. We tested the diagnostic value of CSF-sCD163 and ReaScan-CXCL13 and analyzed if plasma-sCD163 could monitor treatment response. METHODS: An observational cohort study: Cohort 1-Cerebrospinal fluid from adults with neuroborreliosis (n = 42), bacterial meningitis (n = 16), enteroviral meningitis (n = 29), and controls (n = 33); Cohort 2-Plasma from 23 adults with neuroborreliosis collected at diagnosis, three, and six months. sCD163 was determined using an in-house sandwich ELISA. ReaScan-CXCL13 measured semiquantitative concentrations of CXCL13, cut-off ≥ 250 pg/ml diagnosed neuroborreliosis. Receiver Operating Characteristics analyzed the diagnostic strength. A linear mixed model including follow-up as categorical fixed effect analyzed differences in plasma-sCD163. RESULTS: CSF-sCD163 was higher in neuroborreliosis (643 µg/l) than in enteroviral meningitis (106 µg/l, p < 0.0001) and controls (87 µg/l, p < 0.0001), but not bacterial meningitis (669 µg/l, p = 0.9). The optimal cut-off was 210 µg/l, area under the curve (AUC) 0.85. ReaScan-CXCL13 had an AUC of 0.83. Combining ReaScan-CXCL13 with CSF-sCD163 increased AUC significantly to 0.89. Plasma-sCD163 showed little variation and was not elevated during the 6 months of follow-up. CONCLUSION: CSF-sCD163 is diagnostic for neuroborreliosis with an optimal cut-off of 210 µg/l. Combining ReaScan-CXCL13 with CSF-sCD163 increases AUC. Plasma-sCD163 cannot monitor treatment response.

Neoehrlichiosis is a new tick-borne infection.

Neoeherlichiosis is an emerging tick-borne infection causing disease in individuals with inadequate B-cell responses because of haematologic cancer or treatment with B-cell depletion therapies such as rituximab. The infection has recently been found as a cause of prolonged fever among several patients receiving rituximab in Denmark. This review covers current knowledge on the clinical spectrum among healthy as well as immune compromised individuals, transmission, pathogenesis, diagnosis, and treatment.

Exploration of the induced cytokine responses in European Lyme neuroborreliosis: A longitudinal cohort study.

Lyme neuroborreliosis (LNB) is a prevalent tick-borne disease in Europe caused by Borrelia burgdorferi sensu lato complex. Slightly suppressed induced Th1- and Th17-responses are seen at diagnosis. The induced immune response following antibiotic therapy is unknown. We hypothesized that the immune responses normalize after completing antibiotic treatment. An observational longitudinal cohort study investigating the induced immune response in adult patients with LNB at diagnosis, three and six months after treatment. Whole blood was added to three TruCulture® (Myriad RBM, Austin, USA) tubes each containing one stimulation. An additional TruCulture® tube was without stimulation representing the in vivo activation of blood immune cells. Nine cytokines were measured using Luminex (LX200, R&D Systems, BIO-Teche LTD). Changes in immune response were analyzed with linear mixed model including follow-up as categorical fixed effect. A total of 21 patients with 55 samples were included. All had clinical improvement, but 5/21 patients reported residual symptoms after six months. The non-induced release of IL-17A and IL-1ß increased significantly from diagnosis to six month follow-up. Six months after treatment only IFN-α and TNF-α were below the reference range. Minor variations in the induced immune responses were seen during the study period. Th1- and Th17-responses continued to be low with low IFN-γ, IL-12p40, and IL-17A in multiple stimulations. Overall little dynamic was observed. The changes in the cytokine responses are most likely not linked to LNB pathogenesis and our results do not support the implementation of TruCulture® in the diagnostics or follow-up of LNB.

Stimulated Immune Response by TruCulture® Whole Blood Assay in Patients With European Lyme Neuroborreliosis: A Prospective Cohort Study.

Introduction: Borrelia burgdorferi sensu lato complex (B. burgdorferi) can cause a variety of clinical manifestations including Lyme neuroborreliosis. Following the tick-borne transmission, B. burgdorferi initially evade immune responses, later symptomatic infection is associated with occurrence of specific antibody responses. We hypothesized that B. burgdorferi induce immune hyporesponsiveness or immune suppression and aimed to investigate patients with Lyme neuroborreliosis ability to respond to immune stimulation. Methods: An observational cohort study investigating the stimulated immune response by standardized whole blood assay (TruCulture®) in adult patients with Lyme neuroborreliosis included at time of diagnosis from 01.09.2018-31.07.2020. Reference intervals were based on a 5-95% range of cytokine concentrations from healthy individuals (n = 32). Patients with Lyme neuroborreliosis and references were compared using Mann-Whitney U test. Heatmaps of cytokine responses were generated using the webtool Clustvis. Results: In total, 22 patients with Lyme neuroborreliosis (19 definite, 3 probable) were included. In the unstimulated samples, the concentrations of cytokines in patients with Lyme neuroborreliosis were comparable with references, except interferon (IFN)-α, interleukin (IL)-17A, IL-1ß and IL-8, which were all significantly below the references. Patients with Lyme neuroborreliosis had similar concentrations of most cytokines in all stimulations compared with references. IFN-α, IFN-γ, IL-12 and IL-17A were lower than references in multiple stimulations. Conclusion: In this exploratory cohort study, we found lower or similar concentrations of circulating cytokines in blood from patients with Lyme neuroborreliosis at time of diagnosis compared with references. The stimulated cytokine release in blood from patients with Lyme neuroborreliosis was in general slightly lower than in the references. Specific patterns of low IL-12 and IFN-γ indicated low Th1-response and low concentrations of IL-17A did not support a strong Th17 response. Our results suggest that patients with Lyme neuroborreliosis elicit a slightly suppressed or impaired immune response for the investigated stimulations, however, whether the response normalizes remains unanswered.

Intracranial hypertension and papilloedema as a complication to low antiretroviral therapy adherence in a man living with chronic HIV.

We describe a 61-year-old man living with HIV on antiretroviral therapy (ART), who presented with headache, dizziness and blurred vision. Latest CD4+ cell count 3 months prior to admission was 570×106 cells/mL and HIV viral load <20 copies/mL. The patient was diagnosed with cerebrospinal fluid (CSF) lymphocytic pleocytosis, raised intracranial pressure and papilloedema. Neuroimaging showed normal ventricular volume and no mass lesions, suggesting (1) neuroinfection (2) idiopathic intracranial hypertension or (3) retroviral rebound syndrome (RRS) as possible causes. Neuroinfection was ruled out and idiopathic intracranial hypertension seemed unlikely. Elevated plasma HIV RNA level was detected consistent with reduced ART adherence prior to admission. RRS is a virological rebound after ART interruption, which can mimic the acute retroviral syndrome of acute primary infection. To the best of our knowledge, we describe the second case of RRS presenting as CSF lymphocytic pleocytosis and elevated intracranial pressure after low ART adherence.

Severe acute hepatitis E infection presenting with acute abdomen and meningoencephalitis.

We present a case of a 50-year-old man admitted due to acute abdomen, icterus and fever. The patient had a history of sufficiently treated type 2 diabetes and a high daily alcohol consumption, no recent travel history and had a strictly heterosexual and monogamous way of living. A full blood count displayed severe elevated liver enzymes. A CT of the abdomen was performed and revealed steatosis but no acute abdominal pathology. During admission, the patient developed signs of meningoencephalitis. A lumbar puncture was performed, and the cerebrospinal fluid revealed lymphocytic pleocytosis consistent with mild inflammation. Furthermore, hepatitis E was found in the blood and the definitive diagnosis was established. The patient gradually recovered and was discharged within 8 days of admission. To the best of our knowledge, we present the second case describing concomitant hepatitis and meningoencephalitis, resolving spontaneously and not giving rise to sequelae.