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Purpose The tick-borne bacterium Neoehrlichia mikurensis causes the infectious disease neoehrlichiosis in humans. Vascular endothelium is one of the target cells of the infection. Neoehrlichiosis patients with compromised B cell immunity present with more severe inflammation than immunocompetent patients. The aim of this study was to compare the cytokine profiles of immunocompetent and immunosuppressed patients with neoehrlichiosis. Methods Blood samples from Swedish and Norwegian immunosuppressed (N = 30) and immunocompetent (N = 16) patients with neoehrlichiosis were analyzed for the levels of 30 cytokines, using a multiplex cytokine assay and ELISA. A gender-matched healthy control group (N = 14) was analyzed in parallel. Data were analyzed using the multivariate method OPLS-DA. Results The multiplex cytokine analyses generated more cytokine results than did the uniplex ELISA analyses. Multivariate analysis of the multiplex cytokine results established that increased levels of FGF2, GM-CSF, CXCL10, and IFN-γ were associated with immunosuppressed patients, whereas increased levels of IL-15 and VEGF were associated with immunocompetent neoehrlichiosis patients. When multivariate analysis findings were confirmed with uniplex ELISA, it was found that both groups of patients had similarly elevated levels of VEGF, FGF2 and IFN-γ. In contrast, the immunosuppressed patients had clearly elevated levels of CXCL10, CXCL13 and BAFF, whereas the immunocompetent patients had the same levels as healthy controls. Conclusion Pro-angiogenic and type 1 cytokines were produced as part of the host response of neoehrlichiosis independent of immune status, whereas immunosuppressed neoehrlichiosis patients produced cytokines required for B cell-mediated defense.

Objectives The purpose of this study was to evaluate levels and kinetics of cerebrospinal fluid (CSF) markers of inflammation and brain injury in patients with Lyme neuroborreliosis (LNB). Methods Adult patients with clinically suspected LNB were enrolled, in a prospective clinical study in the South East of Sweden. Patients were classified according to the European Federation of Neurological Societies’ guidelines. Definite cases of LNB were re-examined one month later including a repeat CSF investigation. Routine laboratory parameters were investigated along with CSF levels of neurodegenerative markers glial fibrillary acidic protein (GFAp), total tau (t-tau) and neurofilament light protein (NFL), as well as neuroinflammatory markers soluble triggering receptor expressed on myeloid cells 2 (sTREM2), YKL-40 and CXCL13. Non-LNB served as controls. An additional comparison group consisted of spinal anesthesia subjects (SAS) without known central nervous system conditions. Results CSF levels of sTREM2 and CXCL13 were elevated in definite LNB patients at diagnosis compared with non-LNB patients (p Conclusions Although in a limited number of LNB patients, the results indicate a predominance of microglial and neuroinflammatory involvement rather than parenchymal CNS injury in CSF at diagnosis of LNB with a prompt decline after antibiotic treatment. The findings provide pathogenetic insights and may be of value in differential diagnosis of CSF findings.

Background Migratory birds can cross geographical and environmental barriers and are thereby able to facilitate transmission of tick-borne pathogens both as carriers of infected ticks and as reservoirs of pathogenic microorganisms. Ixodes ricinus is one of the most abundant tick species in the Northern Hemisphere and a main vector of several Babesia species, some which pose a potential threat to human and animal health. At present only two cases of overt babesiosis in humans have so far been reported in Sweden. To better understand the potential role of birds as disseminators of zoonotic Babesia protozoan parasites, we investigated the presence of Babesia species in ticks removed from migratory birds. Methods Ticks were collected from birds captured at Ottenby Bird Observatory, south-eastern Sweden, from March to November 2009. Ticks were molecularly identified to species, and morphologically to developmental stage, and the presence of Babesia protozoan parasites was determined by real-time PCR. Results In total, 4601 migratory birds of 65 species were examined for tick infestation. Ticks removed from these birds have previously been investigated for the presence of Borrelia bacteria and the tick-borne encephalitis virus. In the present study, a total of 1102 ticks were available for molecular analysis of Babesia protozoan parasites. We found that 2.4% of the ticks examined, all I. ricinus, were positive for mammal-associated Babesia species. Out of all Babesia-positive samples, Babesia venatorum was the most prevalent (58%) species, followed by Babesia microti (38%) and Babesia capreoli (4.0%). B. venatorum and B. capreoli were detected in I. ricinus larvae, whereas B. microti was only present in I. ricinus nymphs. This supports the view that the two first-mentioned species are vertically (transovarially) transmitted in the tick population, in contrast to B. microti. The largest number of Babesia-infected ticks was removed from the common redstart (Phoenicurus phoenicurus) and European robin (Erithacus rubecula). Conclusions This study reveals that Babesia protozoan parasites are present in ticks infesting migratory birds in south-eastern Sweden, which could potentially lead to the dissemination of these tick-borne microorganisms into new areas, thus posing a threat to humans and other mammals. Graphical Abstract

The risk of contracting babesiosis after a tick bite in Sweden and on the Aland Islands, Finland, is unknown. We investigated clinical and serological outcomes in people bitten by Ixodes ricinus ticks positive for Babesia species. Ticks, blood and questionnaires were obtained from study participants in Sweden and on the Aland Islands. Sixty-five of 2098 (3.1 %) ticks were positive by real-time PCR. Three Babesia species were detected, Babesia microti (n = 33), B. venatorum (n = 27) and B. capreoli (n = 5), the latter species not known to cause human infection. Half (46 %) of the Babesia PCR-positive ticks also contained Borrelia spp. Fifty-three participants bitten by a Babesia PCR-positive tick and a control group bitten by a Babesia PCR-negative tick were tested for B. microti IgG antibodies by IFA. The overall seroprevalence was 4.4 %, but there was no significant difference between the groups. None of the participants seroconverted and no participant with a Babesia PCR-positive tick sought medical care or reported symptoms suggestive of babesiosis. Given the prevalence of Babesia in I. ricinus ticks in southern Sweden and on the Aland Islands, babesiosis should be considered a possible diagnosis in symptomatic residents who seek medical care following tick exposure.

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The risk of contracting human granulocytic anaplasmosis (HGA) after a tick bite is mainly unknown. In this study we investigated the clinical and serological response in 30 humans bitten by ticks positive for Anaplasma phagocytophilum (Group A), 30 humans bitten by Borrelia burgdorferi sensu lato (s.l.)-positive ticks (Group B), and 30 humans bitten by ticks negative for both A. phagocytophilum and B. burgdorferi s.l. (Group C). Ticks, blood samples and questionnaires were collected from tick-bitten humans at 34 primary healthcare centres in Sweden and in the Åland Islands, Finland, at the time of the tick bite and after three months. A total of 2553 ticks detached from humans in 2007-2009 were analyzed by polymerase chain reaction, and 31 (1.2%) were positive for A. phagocytophilum, 556 (21.8%) were positive for B. burgdorferi s.l., and eight (0.3%) were co-infected by A. phagocytophilum and B. burgdorferi s.l. The overall prevalence of Anaplasma IgG antibodies in the included participants (n=90) was 17%, and there was no significant difference between the groups A-C. Only one of the participants (in Group C) showed a four-fold increase of IgG antibodies against A. phagocytophilum at the three-month follow-up, but reported no symptoms. The frequency of reported symptoms did not differ between groups A-C, and was unrelated to the findings of A. phagocytophilum and B. burgdorferi s.l. in the detached ticks. We conclude that the risk for HGA or asymptomatic seroconversion after a tick bite in Sweden or in the Åland Islands is low, even if the tick is infected by A. phagocytophilum. Funding text: Swedish Research Council; Medical Research Council of Southeast Sweden (FORSS); Futurum Academy of Healthcare; Jonkoping County Council; Interreg IV A Programme ScandTick; Division of Medical Services, Ryhov County Hospital, Jonkoping

The prevalence of Candidatus Neoehrlichia mikurensis infection was determined in 102 persons bitten by ticks in Sweden. Two infected women had erythematous rashes; 1 was co-infected with a Borrelia sp., and the other showed seroconversion for Anaplasma phagocytophilum. Both patients had increased levels of Neoehrlichia DNA and serum cytokines for several months.

We report a case of human tick-borne encephalitis (TBE) in which the TBE virus was isolated from the biting tick. Viral growth and sequence were characterized and compared with those of a reference strain. Virus isolation from ticks from patients with TBE may offer a new approach for studies of epidemiology and pathogenicity.

Despite the presence of several microorganisms, other than Borrelia burgdorferi sensu lato (Bbsl) and TBE virus, in Ixodes ricinus ticks from the Nordic countries, data is lacking on their pathogenic potential in humans. In this study, we wanted to investigate the aetiology and clinical manifestations of tick-transmitted infections in individuals seeking medical care following a tick-bite. The sampling frame was participants of a large-scale, prospective, multi-centre, follow-up study of tick-bitten volunteers recruited in Sweden, Finland and Norway in the years 2007-2015. Participants who sought medical care during the three-month follow-up period and from whom blood samples were collected during this healthcare visit (n=92) were tested, using PCR, for exposure to spotted fever group (SFG) Rickettsia spp., Anaplasma phagocytophilum and Babesia spp. Moreover, 86 of these individuals had two serum samples, collected three months apart, tested serologically for six tick-borne microorganisms. The selected organisms-Bbsl, SFG rickettsiae, Anaplasma phagocytophilum, TBE virus, Babesia microti and Bartonella henselae-have all been detected in field-collected ticks from the Nordic countries. Medical records were reviewed and questionnaires were completed to determine clinical manifestations. We found Lyme borreliosis to be the most common tick-transmitted infection as seen in 46 (54%) of the 86 participants with available medical records. Among the 86 participants with paired sera, serological or molecular evidence of recent exposure to other microorganisms than Bbsl could be demonstrated in eight (9%). Five participants (6%) exhibited serological evidence of recent concomitant exposure to more than one tick-borne microorganism. Clinical presentations were mild with one exception (TBE). In conclusion, our data suggest a low risk of infection with tick-borne microorganisms, other than Bbsl, in immunocompetent tick-bitten persons from the examined regions, a low occurrence of co-infection and mostly mild or no overt clinical signs of infection in immunocompetent persons exposed to the studied agents. Funding Agencies|EUEuropean Union (EU) [20200422]; Swedish Research Council Branch of MedicineSwedish Research Council [K2008-58X-14631-06-3]; Medical Research Council of Southeast Sweden; County Council of Ostergotland [LIO-56191]; Independent Research Fund Denmark [8020-00344B]; Wilhelm and Else Stockmann Foundation; Foundation for Aland Medical Research of the Aland Culture Foundation

Lyme neuroborreliosis (LNB) in children is a challenging diagnosis based on clinical manifestations and laboratory findings. The aim of this study was to investigate whether herpes simplex virus (HSV) 1 or 2, varicella zoster virus (VZV), enterovirus or tick-borne encephalitis virus (TBEV) could be identified in cerebrospinal fluid (CSF) or serum from children being evaluated for LNB, in order to elucidate whether such infectious diseases may be missed by the clinician. Methods: Ninety-nine pediatric patients (n = 99) were retrospectively included from a previous study on LNB in southeast of Sweden. They had been diagnosed as “Possible LNB” or “Not determined” due to negative Borrelia antibody index in CSF. Routine polymerase chain reaction (PCR) methods were used for detection of herpes viral RNA or enteroviral DNA in CSF. An ELISA assay was used for detection of anti-TBEV antibodies (IgM and IgG) in serum. Results: One patient showed elevated anti-TBEV IgM and IgG antibodies in serum, indicating a current TBE infection. No positive PCR reactions for HSV 1 or 2, VZV or enterovirus were detected in CSF from any of the patients. In conclusion, our results suggest that undiagnosed herpes- or enteroviral infections are unlikely to explain CNS symptoms in children being evaluated for LNB, whereas missed TBE infections may occur. TBEV serology should be included when evaluating children for LNB in TBE endemic areas.

BACKGROUND: B cell immunity, including the chemokine CXCL13, has an established role in Lyme neuroborreliosis, and also, T helper (Th) 17 immunity, including IL-17A, has recently been implicated. METHODS: We analysed a set of cytokines and chemokines associated with B cell and Th17 immunity in cerebrospinal fluid and serum from clinically well-characterized patients with definite Lyme neuroborreliosis (group 1, n = 49), defined by both cerebrospinal fluid pleocytosis and Borrelia-specific antibodies in cerebrospinal fluid and from two groups with possible Lyme neuroborreliosis, showing either pleocytosis (group 2, n = 14) or Borrelia-specific antibodies in cerebrospinal fluid (group 3, n = 14). A non-Lyme neuroborreliosis reference group consisted of 88 patients lacking pleocytosis and Borrelia-specific antibodies in serum and cerebrospinal fluid. RESULTS: Cerebrospinal fluid levels of B cell-associated markers (CXCL13, APRIL and BAFF) were significantly elevated in groups 1, 2 and 3 compared with the reference group, except for BAFF, which was not elevated in group 3. Regarding Th17-associated markers (IL-17A, CXCL1 and CCL20), CCL20 in cerebrospinal fluid was significantly elevated in groups 1, 2 and 3 compared with the reference group, while IL-17A and CXCL1 were elevated in group 1. Patients with time of recovery 3 months. CONCLUSIONS: By using a set of markers in addition to CXCL13 and IL-17A, we confirm that B cell- and Th17-associated immune responses are involved in Lyme neuroborreliosis pathogenesis with different patterns in subgroups. Furthermore, IL-17A, APRIL and BAFF may be associated with time to recovery after treatment. Funding agencies: Medical Research Council of Southeast Sweden (FORSS); Futurum-the Academy for Health and Care; Division of Medical Services, Region Jonkoping County; EU-Interreg project ScandTick Innovation

Background and purpose Tick-borne encephalitis (TBE) is an infection of the central nervous system (CNS) caused by tick-borne encephalitis virus (TBEV) and transmitted by ticks, with a variety of clinical manifestations. The incidence of TBE in Europe is increasing due to an extended season of the infection and the enlargement of endemic areas. Our objectives are to provide recommendations on the prevention, diagnosis and management of TBE, based on evidence or consensus decisions. Methods For systematic evaluation, the literature was searched from 1970 to 2015 (including early online publications of 2016), and recommendations were based on evidence or consensus decisions of the Task Force when evidence-based data were not available. Recommendations Vaccination against TBE is recommended for all age groups above 1 year in highly endemic areas (≥5 cases/100 000/year), but also for individuals at risk in areas with a lower incidence. Travellers to endemic areas should be vaccinated if their visits will include extensive outdoor activities. Post-exposure prophylaxis after a tick bite is not recommended. A case of TBE is defined by the presence of clinical signs of meningitis, meningoencephalitis or meningoencephalomyelitis with cerebrospinal fluid (CSF) pleocytosis (>5 × 106 cells/l) and the presence of specific TBEV serum immunoglobulin M (IgM) and IgG antibodies, CSF IgM antibodies or TBEV IgG seroconversion. TBEV-specific polymerase chain reaction in blood is diagnostic in the first viremic phase but it is not sensitive in the second phase of TBE with clinical manifestations of CNS inflammation. Lumbar puncture should be performed in all patients with suspected CNS infection unless there are contraindications. Imaging of the brain and spinal cord has a low sensitivity and a low specificity, but it is useful for differential diagnosis. No effective antiviral or immunomodulating therapy is available for TBE; therefore the treatment is symptomatic. Patients with a potentially life threatening meningoencephalitis or meningoencephalomyelitis should be admitted to an intensive care unit. In the case of brain oedema, analgosedation should be deepened; osmotherapy and corticosteroids are not routinely recommended. If intracranial pressure is increased, therapeutic hypothermia or decompressive craniectomy might be considered. Seizures should be treated as any other symptomatic epileptic seizures. Conclusions Tick-borne encephalitis is a viral CNS infection that may result in long-term neurological sequelae. Since its incidence in Europe is increasing due to broadening of endemic areas and prolongation of the tick activity season, the health burden of TBE is enlarging. There is no effective antiviral treatment for TBE, but the disease may be effectively prevented by vaccination.

Patients seeking medical care with erythema migrans or flu-like symptoms after suspected or observed tick bite in the southeast of Sweden and previously investigated for Borrelia spp. and/or Anaplasma sp. were retrospectively examined for serological evidence of rickettsial infection (Study 1). Twenty of 206 patients had IgG and/or IgM antibodies to Rickettsia spp. equal to or higher than the cut-off titre of 1:64. Seven of these 20 patients showed seroconversion indicative of recent or current infection and 13 patients had titres compatible with past infection, of which five patients were judged as probable infection. Of 19 patients with medical records, 11 were positive for Borrelia spp. as well, and for Anaplasma sp., one was judged as positive. Five of the 19 patients had antibodies against all three pathogens. Erythema migrans or rash was observed at all combinations of seroreactivity, with symptoms including fever, muscle pain, headache and respiratory problems. The results were compared by screening an additional 159 patients (Study 2) primarily sampled for the analysis of Borrelia spp. or Mycoplasma pneumoniae. Sixteen of these patients were seroreactive for Rickettsia spp., of which five were judged as recent or current infection. Symptoms of arthritis, fever, cough and rash were predominant. In 80 blood donors without clinical symptoms, approximately 1 % were seroreactive for Rickettsia spp., interpreted as past infection. The study shows that both single and co-infections do occur, which illustrate the complexity in the clinical picture and a need for further studies to fully understand how these patients should best be treated.

Members of the genus Borrelia are among the most common infectious agents causing tick-borne disease in humans worldwide. Here, we developed a Light Upon eXtension (LUX) real-time PCR assay that can detect and quantify Borrelia species in ticks that have fed on humans, and we applied the assay to 399 such ticks. Borrelia PCR-positive ticks were identified to species level by sequencing the products of conventional PCR performed using Borrelia group-specific primers. There was a 19% prevalence of Borrelia spp. in the detached ticks, and the number of spirochetes per Borrelia PCR-positive tick ranged from 2.0 × 10 2 to 4.9 × 10 5 , with a median of 7.8 × 10 3 spirochetes. Adult ticks had a significantly larger number of spirochetes, with a median of 8.4 × 10 4 compared to the median of nymphs of 4.4 × 10 4 . Adult ticks also exhibited a higher prevalence of Borrelia (33%) than nymphs (14%). Among the identified species, Borrelia afzelii was found to predominate (61%) and was followed by B . garinii (23%), B . valaisiana (13%), B . burgdorferi sensu stricto (1%), B . lusitaniae (1%), and B . miyamotoi -like (1%). Also, 3% of the ticks were coinfected with multiple strains of B. afzelii . Notably, this is the first report of B. lusitaniae being detected in ticks in Sweden. Our LUX real-time PCR assay proved to be more sensitive than a corresponding TaqMan assay. In conclusion, the novel LUX real-time PCR method is a rapid and sensitive tool for detection and quantification of Borrelia spp. in ticks.

We studied the T-cell reactivity to overlapping peptides of B. garinii OspA, in order to locate possible immunodominant T-cell epitopes in neuroborreliosis. Cells from cerebrospinal fluid (CSF) and blood from 39 patients with neuroborreliosis and 31 controls were stimulated with 31 overlapping peptides, and interferon-gamma secreting cells were detected by ELISPOT. The peptides OspA(17-36), OspA(49-68), OspA(105-124), OspA(137-156), OspA(193-212) and OspA(233-252) showed the highest frequency of positive responses, being positive in CSF from 38% to 50% of patients with neuroborreliosis. These peptides also elicited higher responses in CSF compared with controls (P = 0.004). CSF cells more often showed positive responses to these peptides than blood cells (P = 0.001), in line with a compartmentalization to the central nervous system. Thus, a set of potential T-cell epitopes were identified in CSF cells from patients with neuroborreliosis. Further studies may reveal whether these epitopes can be used diagnostically and studies involving HLA interactions may show their possible pathogenetic importance.

Evaluation of children with clinically suspected neuroborreliosis (NB) is difficult. With a prospective study design we wanted to characterize children with signs and symptoms indicative for NB, investigate clinical outcome and, if possible, identify factors of importance for recovery.Children being evaluated for NB (n = 177) in southeast Sweden were categorized into 3 groups: "confirmed neuroborreliosis" (41%) with Borrelia antibodies in the cerebrospinal fluid, "possible neuroborreliosis" (26%) with pleocytosis but no Borrelia antibodies in the cerebrospinal fluid, and "not determined" (33%) with no pleocytosis and no Borrelia antibodies in the cerebrospinal fluid. Antibiotic treatment was given to 69% of children. Patients were followed during 6 months and compared with a matched control group (n = 174).Clinical recovery at the 6-month follow-up (n = 177) was generally good and no patient was found to have recurrent or progressive neurologic symptoms. However, persistent facial nerve palsy caused dysfunctional and cosmetic problems in 11% of patients. Persistent nonspecific symptoms, such as headache and fatigue, were not more frequently reported in patients than in controls. Influence on daily life was reported to the same extent in patients and controls. Consequently, persistent headache and fatigue at follow-up should not be considered as attributable to NB. No prognostic factors could be identified.Clinical recovery was satisfactory in children being evaluated for NB although persistent symptoms from facial nerve palsy occurred. Persistent nonspecific symptoms, such as headache and fatigue, were not more frequently reported in patients than in controls.

Tick-transmitted diseases are an emerging health problem, and the hard tick Ixodes ricinus is the main vector for Borrelia spp., tick-borne encephalitis virus and most of the spotted fever Rickettsiae in Europe. The aim of the present study was to examine the incidence of rickettsial infection in the southernmost and south central parts of Sweden and the Aland Islands in Finland the risk of infection in humans and its correlation with a bite of a Rickettsia-infected tick, the self-reported symptoms of rickettsial disease, and the prevalence of co-infection between Rickettsia spp. and Borrelia spp. Persons with a recent tick bite were enrolled through public media and asked to answer a questionnaire, provide a blood sample and bring detached ticks at enlistment and at follow-up three months later. Blood samples were previously analysed for Borrelia spp. antibodies and, for this report, analysed for antibodies to Rickettsia spp. by immunofluorescence and in 16 cases also using Western Blot. Ninety-six (44.0%) of the 218 participants were seropositive for IgG antibodies to Rickettsia spp. Forty (18.3%) of the seropositive participants had increased titres at the follow-up, indicating recent/current infection, while four (1.8%) had titres indicating probable recent/current infection (amp;gt;= 1: 256). Of 472 ticks, 39 (8.3%) were Rickettsia sp. positive. Five (31.3%) of 16 participants bitten by a Rickettsia-infected tick seroconverted. Experience of the selfreported symptoms nausea (p = 0.006) and radiating pain (p = 0.041) was more common among those with recent, current or probable infection compared to those who did not seroconvert. Participants who showed seroreactivity or seroconversion to Rickettsia spp. had more symptoms than those who were seronegative. Seven (3.2%) participants showed seroconversion to Borrelia spp., and three (1.4%) of these showed seroconversion to both Rickettsia spp. and Borrelia spp., in accordance with previous studies in Sweden. Symptoms of rickettsial disease were in most of the cases vague and general that were difficult to differentiate from other tick-borne diseases. Funding Agencies|Swedish Research Council Branch of Medicine [K2008-58X-14631-06-3]; EU Interreg IV A project ScandTick [167226]; County Council of Ostergotland [L10-56191]; Stiftelsen Olle Engqvist Byggmastare [11877]; Uppsala-Orebro-Regional Research 324 Council [25021]; Center for Clinical Research Dalarna [9028]

Hepatocyte growth factor (HGF) is a multifunctional growth factor with potent wound-healing properties that functions in the healing of chronic injuries. However, there may be a loss of HGF activity in certain chronic cases; this might be indicated by the presence of high amounts of HGF in body fluids and by the elevated expression of the HGF receptor in tissue biopsies. In such cases, a reliable means of assessing the activity of endogenous HGF would be valuable in allowing clinicians to decide if treatment with HGF would be useful. In this study, we developed an in vitro wound assay that used a mouse skin epithelial cell line to evaluate the biological activity of HGF. We showed that HGF accelerated the motility of the epithelial cells in a dose-dependent fashion with high sensitivity and specificity. This in vitro assay might be used to determine the activity of both endogenous and recombinant HGF.

Acute bacterial infectious diseases are mostly treated empirically at admission before the culture results are available. According to the risk for serious complications in the case of therapeutic failure, it is important to evaluate the therapy results and change to a more appropriate antibiotic regime as soon as possible. In the present study, 40 patients with X-ray-verified community-acquired pneumonia were examined and blood specimens were collected before and within 24 h of treatment. Body temperature, C-reactive protein (CRP) and hepatocyte growth factor (HGF) were investigated. Thirty-two patients received an appropriate initial antibiotic therapy regarding clinical outcome, but in 8 patients the treatment was changed because of therapy failure. Changes of HGF levels after 18–24 h of treatment could predict the therapeutic results accurately in 38 of 40 cases (sensitivity 100%, specificity 94%, positive likelihood ratio 16.0). HGF was significantly better to predict therapy outcome than CRP (p < 0.0001).

The tick-borne infectious agents, B. burgdorferi, A. phagocytophilum and the TBE-virus, can all cause clinical disease in humans and may all initially give rise to myalgia, arthralgia, headache and fever. The clinical manifestations of the infections range from subclinical or mild to severe, in some cases with a postinfectious sequel, and mixed infections may occur, confusing the clinical picture.The aim of this thesis was to investigate the occurrence and co-existence of these infections in a Scandinavian context. A further aim was to study aspects of the immunopathogenesis of B. burgdorferi infection and possible effects on the immune response when previously exposed to A. phagocytophilum. Finally, an attempt was made to improve the laboratory diagnosis of Lyme neuroborreliosis (LNB).In a prospective clinical study, patients were recruited based on two independent inclusion criteria; 1) patients with unspecific symptoms or fever, and 2) patients with erythema migrans (EM). Among 206 patients, we found 186 cases of Lyme borreliosis (LB) (174 with EM), 18 confirmed and two probable cases of human granulocytic anaplasmosis (HGA), and two cases of Tick-borne encephalitis (TBE). Thirteen of the HGA cases presented without fever. Furthermore, 22 of the EM patients had a subclinical co-infection with A. phagocytophilum, based on serology. Both TBE cases had co-infections, one with B. burgdorferi and one with A. phagocytophilum.In another investigation, IL-12p70 secretion in patients with current LB was compared in patients with or without previous A. phagocytophilum infection. Patients with serological evidence of previous exposure to A. phagocytophilum had a lower B. burgdorferi-induced IL-12p70 secretion. Since IL-12p70 induces the Th1 response, this finding indicates a reduced Th1 response, possibly caused by A. phagocytophilum. In a separate study, we showed that patients with LNB had increased levels of cytokines associated with cytotoxicity in cerebrospinal fluid (CSF), including the recently described cytokine IL-17.Since it is known that the adaptive immune system, especially the T cells, is activated during an infection with B. burgdorferi, a modified ELISPOT assay using cells from CSF was evaluated to be a useful complementary test in diagnosing LNB. However, we found that the diagnostic performance was too weak in our setting, and we could not recommend it for use in clinical laboratories at this stage.In conclusion, tick-borne co-infections are probably quite common in Sweden. Our HGA cases were most often discovered as co-infections with LB and would probably have been missed during a routine consultation. They presented with mild symptoms and often without fever, which in previous reports has been part of the disease definition.The immune response in LNB was shown to be compartmentalized to the target organ, also in terms of cytokine response. Furthermore, we found indications of possible long-term effects of A. phagocytophilum infection, demonstrated as a reduced IL-12p70 secretion in patients with ongoing LB. This could be a disadvantage when mounting a Th1 response to infection with B. burgdorferi. If this is so, the inter-play of these infectious agents in co-infections or consecutive infections may be of importance to clinical outcome.

The clinical course and outcome of several infectious diseases are dependent on the type of immune response elicited against the pathogen. In adults with neuroborreliosis (NB), a type 1 response with high production of Borrelia-specific IFN-gamma, but no IL-4, has been reported. Since children have a more benign course of NB than adults, we wanted to investigate type 1 and type 2 responses in children with NB. Cerebrospinal fluid (CSF) and blood were collected from children during the acute stage of 'confirmed NB' (n = 34), 'possible NB' (n = 30) and 'non-NB' (n = 10). The number of Borrelia-specific IL-4- and IFN-gamma-secreting cells was measured by enzyme-linked immunospot assay. Borrelia-specific secretion of both IL-4 and IFN-gamma was increased in CSF in confirmed (P0.05) and possible (P0.01) NB, when compared with non-NB controls. Furthermore, children with NB had significantly higher Borrelia-specific IL-4 secretion in CSF than an adult reference material with NB (P0.05). There were no differences in cytokine secretion in relation to onset or recovery of neurological symptoms. Since IL-4 is known to down-regulate the pro-inflammatory and possibly harmful effects of prolonged IFN-gamma responses, the prominent IL-4 response observed in the central nervous system compartment might contribute to the more benign disease course seen in children with Lyme NB.

Summary Innate immunity is important for early defence against borrelia spirochetes and should play a role in the clinical outcome of the infection. In order to study early cytokine responses, in vitro differentiated dendritic cells (DCs) and whole blood cells from 21 patients with different clinical outcomes of Lyme neuroborreliosis were stimulated with live borrelia spirochetes. The borrelia-induced secretion of interleukin (IL)-4, IL-10, IL-12p70, interferon (IFN)-γ and tumour necrosis factor (TNF)-α in DCs and IL-1β, IL-6, IL-8, IL-10, IL-12p70, TNF-α, regulated upon activation normal T cell expressed and secreted (RANTES), monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, MIP-1β and eotaxin in whole blood cells was measured by enzyme-linked immunospot (ELISPOT) and multiplex arrays, respectively. We found increased numbers of TNF-α-secreting DCs (P = 0·018) in asymptomatic seropositive individuals compared to patients with subacute neuroborreliosis and seronegative controls. Asymptomatic individuals were also found to have elevated levels of IL-12p70 (P = 0·031) in whole blood cell supernatants compared to seronegative controls. These results are in line with previous experiments using cells of the adaptive immune response, indicating that strong T helper type 1 (Th1) proinflammatory responses might be associated with a successful resolution of Lyme disease.

Five commercial Borrelia serology kits available in Sweden were evaluated and compared for their diagnostic performance in sera from clinically well-characterized patient groups. With the clinically defined groups as the gold standard, i.e. without knowledge of antibody status in serum and cerebrospinal fluid, the diagnostic performance of the kits was compared and important differences in diagnostic usefulness were found. The kits from Abbot and DAKO, that often predict clinically relevant Borrelia infection and do not detect antibodies in sera from patients without strong suspicion of Borrelia infection, were considered the most useful in the population studied. This kind of validation study is an important part of good laboratory practice and should be performed by laboratories serving patient populations with varying endemicity of Borrelia.

Hepatocyte growth factor (HGF) is a potent mitogen of mature epithelial cells which is produced after organ injuries and acts as a trigger for regeneration in the impaired organ. The aim of the present study was to investigate local production of HGF during infectious gastroenteritis. We measured the concentration of HGF in serum and faeces in 49 patients with acute infectious gastroenteritis (bacterium = 30, virus = 10, amoebae = 1, and probable infection = 8) at the time of referral to hospital and at convalescence (n = 31). The values were compared with normal healthy vaccination volunteers (n = 11) as well as patients with acute non-infectious diarrhoea (n = 10). The presence of HGF in faeces was confirmed by ELISA and Western immunoblot. HGF concentrations in faeces was significantly higher in the patients with infectious gastroenteritis compared to the control groups (p0.0001). Using a cut-off concentration of 20 ng/g, the overall sensitivity of faeces HGF to distinguish infectious gastroenteritis (bacterial, viral, probable infection) was 98% with a specificity of 100%. At convalescence all patients had normal values. There was no significant correlation between HGF concentrations in faeces and serum. Determination of faeces HGF may identify cases of transmittable diarrhoea requiring isolation at an early stage.

The immuno-pathogenetic mechanisms underlying chronic Lyme neuroborreliosis are mainly unknown. Human Borrelia burgdorferi (Bb) infection is associated with Bb-specific secretion of interferon-gamma (IFN-gamma), which may be important for the elimination of Bb, but this may also cause tissue injury. In order to increase the understanding of the pathogenic mechanisms in chronic neuroborreliosis, we investigated which cell types that secrete IFN-gamma. Blood mononuclear cells from 13 patients with neuroborreliosis and/or acrodermatitis chronicum atrophicans were stimulated with Bb antigen and the phenotypes of the induced IFN-gamma-secreting cells were analyzed with three different approaches. Cells expressing CD8 or TCRgammadelta, which both have cytolytic properties, were the main phenotypes of IFN-gamma-secreting cells, indicating that tissue injury in chronic neuroborreliosis may be mediated by cytotoxic cells.

Juvenile polyposis syndrome (JPS) is a rare genetic disorder characterized by juvenile polyps of the gastrointestinal tract. We present a new pathogenic mutation of theSMAD4gene and illustrate the need for a multidisciplinary health care approach to facilitate the correct diagnosis. The patient, a 47-year-old Caucasian woman, was diagnosed with anaemia at the age of 12. During the following 30 years, she developed numerous gastrointestinal polyps. The patient underwent several operations, and suffered chronic abdominal pain, malnutrition, and multiple infections. Screening of theSMAD4gene revealed a novel, disease-causing mutation. In 2012, the patient suffered hypoalbuminemia and a large polyp in the small bowel was found. Gamma globulin was given but the patient responded with fever and influenza-like symptoms and refused more treatment. The patient underwent surgery in 2014 and made an uneventful recovery. At follow-up two months later albumin was 38 g/L and IgG was 6.9 g/L. Accurate diagnosis is essential for medical care. For patients with complex symptomatology, often with rare diseases, this is best provided by multidisciplinary teams including representatives from clinical genetics. Patients with aSMAD4mutation should be followed up both for JPS and haemorrhagic hereditary telangiectasia and may develop protein loosing enteropathy and immunodeficiency.

Lyme borreliosis is a tick-borne disease caused by the bacteriumBorrelia burgdorferi. The most frequent clinical manifestation is a rash called erythema migrans. Changes in antibody reactivity toB. burgdorferi3 months after a tick bite are measured using enzyme-linked immunosorbent assays (ELISAs). One assay is based on native purified flagellum antigen (IgG), and the other assay is based on a recombinant antigen called C6 (IgG or IgM). Paired samples were taken at the time of a tick bite and 3 months later from 1,886 persons in Sweden and the Åland Islands, Finland. The seroconversion or relative change is defined by dividing the measurement units from the second sample by those from the first sample. The threshold for the minimum level of significant change was defined at the 2.5% level to represent the random error level. The thresholds were a 2.7-fold rise for the flagellar IgG assay and a 1.8-fold rise for the C6 assay. Of 1,886 persons, 102/101 (5.4%) had a significant rise in antibody reactivity in the flagellar assay or the C6 assay. Among 40 cases with a diagnosis of Lyme borreliosis, the sensitivities corresponding to a rise in antibodies were 33% and 50% for the flagellar antigen and the C6 antigen, respectively. Graphical methods to display the antibody response and to choose thresholds for a rise in relative antibody reactivity are shown and discussed. In conclusion, 5.4% of people with tick bites showed a rise inBorrelia-specific antibodies above the 2.5% threshold in either ELISA but only 40 (2.1%) developed clinical Lyme borreliosis.

Objectives - The existence of chronic neuroborreliosis is controversial. The aim of our study was to investigate the existence and kind of persistent symptoms in patients previously treated because of neurological symptoms as a result of neuroborreliosis. Material and methods - A total of 106 patients with neuroborreliosis, according to established criteria, and a control group of 123 patients with Borrelia induced erythema migrans diagnosed in a general practitioner office were studied. A questionnaire was sent to patients and controls concerning their health situation. Time from onset of neurological symptoms to the questionnaire sendout was 32 months (mean) for the patients with neuroborreliosis and 33 months (mean) for the controls. Results - Fifty per cent of the individuals in the patient group compared with 16% of the individuals in the control group showed persistent complaints after their Borrelia infection (P

As regards clinical studies performed on hepatocyte growth factor (HGF) during recent years, we have aimed in the present study to investigate the eventual differences in sample handling of this cytokine that might influence the results of serum concentrations. Venous blood from patients with current infectious diseases and controls was used in different sub-studies. Compared with samples separated within one hour, no significant changes in serum HGF levels were observed when whole blood stayed 4, or 24h at 6 degrees C before or 6h in room temperature after separation but HGF levels were significantly higher (P0.01) when whole blood was kept at room temperature 4 and 24h before separation. Serum HGF was stable up to 20 freeze-thaw cycles. The serum concentrations of HGF were significantly higher than levels in the plasma (19%; P0.05). A significant increase in serum HGF levels (12%, P0.05) was observed after shaking the whole blood sample to a visible haemolysis, although the HGF concentration in blood cells was around half of that in serum. HGF tolerated storage at -70 degrees C for at least 4 months. We conclude that standardized methods in sample handling are important in the study of HGF concentrations in blood samples.

A prospective study was carried out in which brain, core and skin temperatures were studied in children with cerebral malaria (n = 23), uncomplicated malaria (n = 12) and normal children (n = 9) using the zero heat flow method. Patients with cerebral or uncomplicated malaria were admitted to the paediatric wards (mean age, 6 years 8 months +/- 2 years 8 months). Normal children, children of the investigators, of the same age group, served as controls. Parasitaemia levels were similar in the cerebral and uncomplicated malaria cases. Higher brain than core temperatures would have been expected in cerebral malaria but not in uncomplicated malaria but this was not the case in this study. There was no statistical difference in brain, core and skin temperature between cerebral and uncomplicated malaria patients. However, there was a highly significant difference between normal children and cerebral and uncomplicated malaria patients. Brain temperature was 0.02-0.2 degrees C below core temperature in all the groups with larger differences during the febrile period. Mean differences of brain minus core, brain minus skin and core minus skin between the two groups of patients were not statistically significant. There was no correlation between temperature and the level of coma or parasitaemia for cerebral and uncomplicated malaria patients. There was a positive correlation between brain and core temperature in both groups of patients during the febrile phase. Brain temperature remained lower than core temperature in cerebral and uncomplicated malaria as in normal children. Normal thermoregulation appears to be maintained in cerebral malaria.

The risk of tick-borne encephalitis virus (TBEV) infection after a tick bite remains largely unknown. To address this, we investigated the presence of TBEV in ticks detached from humans in an attempt to relate viral copy number, TBEV subtype, and tick feeding time with the serological and clinical response of the tick-bitten participants. Ticks, blood samples, and questionnaires were collected from tick-bitten humans at 34 primary health care centers in Sweden and in the Aland Islands (Finland). A total of 2167 ticks was received from 1886 persons in 2008-2009. Using a multiplex quantitative real-time PCR, 5 TBEV-infected ticks were found (overall prevalence 0.23%, copy range