A Systematic, Unbiased Mapping of CD8+ and CD4+ T Cell Epitopes in Yellow Fever Vaccinees.

Examining CD8+ and CD4+ T cell responses after primary Yellow Fever vaccination in a cohort of 210 volunteers, we have identified and tetramer-validated 92 CD8+ and 50 CD4+ T cell epitopes, many inducing strong and prevalent (i.e., immunodominant) T cell responses. Restricted by 40 and 14 HLA-class I and II allotypes, respectively, these responses have wide population coverage and might be of considerable academic, diagnostic and therapeutic interest. The broad coverage of epitopes and HLA overcame the otherwise confounding effects of HLA diversity and non-HLA background providing the first evidence of T cell immunodomination in humans. Also, double-staining of CD4+ T cells with tetramers representing the same HLA-binding core, albeit with different flanking regions, demonstrated an extensive diversification of the specificities of many CD4+ T cell responses. We suggest that this could reduce the risk of pathogen escape, and that multi-tetramer staining is required to reveal the true magnitude and diversity of CD4+ T cell responses. Our T cell epitope discovery approach uses a combination of (1) overlapping peptides representing the entire Yellow Fever virus proteome to search for peptides containing CD4+ and/or CD8+ T cell epitopes, (2) predictors of peptide-HLA binding to suggest epitopes and their restricting HLA allotypes, (3) generation of peptide-HLA tetramers to identify T cell epitopes, and (4) analysis of ex vivo T cell responses to validate the same. This approach is systematic, exhaustive, and can be done in any individual of any HLA haplotype. It is all-inclusive in the sense that it includes all protein antigens and peptide epitopes, and encompasses both CD4+ and CD8+ T cell epitopes. It is efficient and, importantly, reduces the false discovery rate. The unbiased nature of the T cell epitope discovery approach presented here should support the refinement of future peptide-HLA class I and II predictors and tetramer technologies, which eventually should cover all HLA class I and II isotypes. We believe that future investigations of emerging pathogens (e.g., SARS-CoV-2) should include population-wide T cell epitope discovery using blood samples from patients, convalescents and/or long-term survivors, who might all hold important information on T cell epitopes and responses.

Adventure tourism and schistosomiasis: serology and clinical findings in a group of Danish students after white-water rafting in Uganda.

INTRODUCTION: Diagnosis of schistosomiasis in travellers is a clinical challenge, since cases may present with no symptoms or a few non-specific symptoms. Here, we report on the laboratory and clinical findings in Danish travellers exposed to Schistosoma-infested water during white-water rafting on the Ugandan part of the upper Nile River in July 2009. CASE PRESENTATION: Forty travellers were offered screening for Schistosoma-specific antibodies. Serological tests were performed 6-65 weeks after exposure. A self-reporting questionnaire was used to collect information on travel activity and health history, fresh water exposure, and symptoms. Seropositive cases were referred to hospitals where clinical and biochemical data were collected. Schistosoma-specific antibodies were detected in 13/35 (37 %) exposed participants, with 4/13 (31 %) seroconverting later than 2 months following exposure. Four of thirteen (31 %) cases reported ≥3 symptoms compatible with schistosomiasis, with a mean onset of 41 days following exposure. No Schistosoma eggs were detected in stool or urine in any of the cases. Peripheral eosinophilia (>0.45×109 cells l-1) was seen in 4/13 cases, while IgE levels were normal in all cases. CONCLUSION: Schistosomiasis in travellers is not necessarily associated with specific signs or symptoms, eosinophilia, raised IgE levels, or detection of eggs. The only prognostic factor for infection was exposure to freshwater in a Schistosoma-endemic area. Seroconversion may occur later than 2 months after exposure and therefore - in the absence of other diagnostic evidence - serology testing should be performed up to at least 2-3 months following exposure to be able to rule out schistosomiasis.

Mycobacterium intracellulare Infection Mimicking Progression of Scleroderma.

This case report describes a patient with scleroderma who developed Mycobacterium intracellulare infection, which for more than a year mimicked worsening of her connective tissue disorder. The patient was diagnosed with scleroderma based on puffy fingers that developed into sclerodactyly, abnormal nail fold capillaries, interstitial lung disease, Raynaud's phenomenon, esophageal dysmotility, and positivity for rheumatoid factor and anti-SSA antibodies. She developed massive inflammatory changes of the cutis, the subcutis, and the muscle fasciae of the right leg, that after several failed attempts of immunosuppressive treatments were found to be caused by Mycobacterium intracellulare. While she was receiving high-dose prednisolone, as worsening of her connective tissue disease was suspected to be the cause of the inflammatory changes, she had Listeria monocytogenes meningitis and was hospitalized for several weeks, but she recovered from this without sequelae. After Mycobacterium intracellulare infection was diagnosed, she was treated with clarithromycin and rifampicin. Her skin manifestations, arthralgias, and fatigue improved considerably, and the wounds of the right leg healed, unfortunately with significant scarring. Immunodeficiency testing was unremarkable. In summary, an infection with Mycobacterium intracellulare was mistaken for an unusually severe progression of scleroderma.

Adaptive immune responses to booster vaccination against yellow fever virus are much reduced compared to those after primary vaccination.

Outbreaks of Yellow Fever occur regularly in endemic areas of Africa and South America frequently leading to mass vaccination campaigns straining the availability of the attenuated Yellow Fever vaccine, YF-17D. The WHO has recently decided to discontinue regular booster-vaccinations since a single vaccination is deemed to confer life-long immune protection. Here, we have examined humoral (neutralizing antibody) and cellular (CD8 and CD4 T cell) immune responses in primary and booster vaccinees (the latter spanning 8 to 36 years after primary vaccination). After primary vaccination, we observed strong cellular immune responses with T cell activation peaking ≈2 weeks and subsiding to background levels ≈ 4 weeks post-vaccination. The number of antigen-specific CD8+ T cells declined over the following years. In >90% of vaccinees, in vitro expandable T cells could still be detected >10 years post-vaccination. Although most vaccinees responded to a booster vaccination, both the humoral and cellular immune responses observed following booster vaccination were strikingly reduced compared to primary responses. This suggests that pre-existing immunity efficiently controls booster inoculums of YF-17D. In a situation with epidemic outbreaks, one could argue that a more efficient use of a limited supply of the vaccine would be to focus on primary vaccinations.

Immune response after one or two doses of pandemic influenza A (H1N1) monovalent, AS03-adjuvanted vaccine in HIV infected adults.

INTRODUCTION: Continued research is needed to evaluate and improve the immunogenicity of influenza vaccines in HIV infected patients. We aimed to determine the antibody responses after one or two doses of the AS03-adjuvanted pandemic influenza A (H1N1) vaccine in HIV infected patients. METHOD: Following the influenza season 2009/2010, 219 HIV infected patients were included and divided into three groups depending on whether they received none (n=60), one (n=31) or two (n=128) doses of pandemic influenza A (H1N1) vaccine. At inclusion, antibody titers for all patients were analyzed and compared to pre-pandemic antibody titers analyzed from serum samples in a local storage facility. RESULTS: 4-9 months after a single immunization, we found a seroprotection rate of 77.4% and seroconversion rate of 67.7%. After two immunizations the rates increased significantly to seroprotection rate of 97.7% and seroconversion rate of 86.7%. CONCLUSION: A single dose of AS03-adjuvanted pandemic influenza A (H1N1) vaccine created an adequate immune response in HIV infected patients lasting as long as 4-9 months. Two doses improved the immunogenicity further.

Cystic echinococcosis of the liver: experience from a Danish tertiary reference center (2002-2010).

BACKGROUND: Cystic echinococcosis (CE) of the liver can be treated with ultrasound-guided puncture, aspiration, injection, and re-aspiration (PAIR), with surgery and with benzimidazole derivatives. The aim of this study was to review available data concerning treatment modality and outcome for patients treated for CE of the liver in a Danish tertiary reference center. METHODS: A search was made for patients treated for CE infection between January 1, 2002 and January 1, 2010. All relevant patient records and radiology exams were scrutinized and all cysts were re-classified according to the WHO-IWGE, blinded as to which treatment the patient had received. PAIR was performed as a first choice treatment and surgery was reserved for cases where PAIR was impossible. Inactive cyst stages received medical treatment only. RESULTS: The search revealed 26 cases with confirmed CE of the liver. Nine patients underwent PAIR and nine patients surgery as a first choice treatment. Three patients were treated with PAIR secondary to surgery and one patient was treated with surgery secondary to PAIR. For all PAIR treatments, the success rate was 58% regardless of cyst stage and for surgery the success rate was 70%. The difference between the rates was not statistically significant (p = 0.67). CONCLUSION: CE is a rare disease in Denmark and our study is the first describing clinical management of CE in our institution.

[African Tick Bite Fever upon game hunting in South Africa]. / African tick bite fever efter storvildtjagt i Sydafrika.

The incident of spotted fever imported to Denmark is unknown. We present a classic case of African Tick Bite Fever (ATBF) to highlight a disease, which frequently infects wildlife enthusiasts and hunters on vacation in South Africa. ATBF has a good prognosis and is easily treated with doxycycline. The treatment should be given upon the clinical picture alone, since antibodies only reveal half of infected cases.

High rate of failure in treatment of imported schistosomiasis.

BACKGROUND: There is an increasing number of imported cases of schistosomiasis in Europe, but there are only few studies on the efficacy of praziquantel for the treatment of schistosomiasis in non-endemic settings. METHODS: Patients treated for schistosomiasis in 2003 to 2008 were offered reexamination with serology, eosinophil count, IgE, microscopy of 24 h urine samples and/or rectal biopsies >3 months after treatment. All patients had been treated with at least one dose of praziquantel 40 to 60 mg/kg >12 weeks after exposure and had not been reexposed to schistosomiasis after treatment. RESULTS: Twenty-eight traveler (15 tourists and 13 expatriates) and two immigrants were reexamined after treatment. Viable ova were detected in six traveler (20%). Ova were found in 5/23 (22%) rectal biopsies and in 2/12 (17%) urine samples. Treatment failure was suspected in a symptomatic patient who 2 years after treatment had eightfold rise in antibody titer and elevated IgE but no detectable ova in urine or rectal biopsies. Additional 13 patients had one or more parameters, which could indicate persistent infection. There were no significant differences in eosinophil count, IgE or, change in antibody titer between patients with versus without detectable ova after treatment. CONCLUSIONS: In traveler with a low parasite burden, assessment of treatment results can be difficult because of the low sensitivity of microscopy and persistence of antibodies for several years after treatment. We found a high rate of treatment failure among traveler, indicating that nonimmune patients may need more than the recommended single day of treatment for eradication of parasites. Until more sensitive and specific methods for detection of persistent, active infection are available, repeated treatment should be considered in patients with continuous symptoms or other indications of treatment failure even when viable ova cannot be detected by microscopy.

[Schistosomiasis in Danish travellers and immigrants]. / Schistosomiasis hos danske rejsende og immigranter.

INTRODUCTION: The purpose of the study was to describe symptoms and diagnosis of schistosomiasis in travellers and immigrants based on patients diagnosed and treated at the State University Hospital in Copenhagen in 2003-2008. MATERIAL AND METHODS: Retrospective review of patient records. RESULTS: A total of 49 patients (39 travellers and ten immigrants) were diagnosed with schistosomiasis. All patients except one were infected in Africa. There was considerable variation in clinical manifestations between travellers and immigrants. Eggs were detected in urine, faeces and/or biopsy from 18 patients, whereas 31 patients were diagnosed solely by serology. DISCUSSION: Travellers with schistosomiasis are often asymptomatic or have unspecific symptoms, while immigrants may present with severe complications to the infection. Because symptoms can develop years after the infection and due to the risk of severe complications, even asymptomatic patients should be treated. Treatment is simple and has few side effects.

Strongyloidiasis--the most neglected of the neglected tropical diseases?

Soil-transmitted helminths of the genus Strongyloides (S. fuelleborni and the more prevalent S. stercoralis) are currently believed to infect an estimated 30-100 million people worldwide. The health consequences of S. stercoralis infections range from asymptomatic light infections to chronic symptomatic strongyloidiasis. Uncontrolled multiplication of the parasite (hyperinfection) and potentially life-threatening dissemination of larvae to all internal organs is found among individuals with compromised immune system functions. This paper provides an overview of the current state of the art in relation to diagnostic methods for detecting the infection, the morbidity caused by the infection and the recommended treatment. It further discusses some of the reasons why this infection is so neglected and the consequence of this for the estimated global prevalence. The paper finally points to the gaps in our knowledge and future research needs related to this infection. As Strongyloides infections have the potential to develop into severe disease in certain population subgroups, untreated infections could cause serious problems in the community. Therefore, we need to carefully investigate this parasite in order to develop and implement effective control programmes.

[Ebola--haemorrhagic fever]. / Ebola--haemoragisk feber.

This review presents the latest findings on ebola. Ebola presents one of the highest case-fatality rates of all infectious diseases, and in 2007 outbreaks were observed first in the Democratic Republic of Congo and later in Uganda with a new subtype. Accumulating evidence suggests that fruit bats are a likely reservoir for the ebola virus. The frequency of filovirus outbreaks in Central Africa is increasing and the potential for introduction and patient care in Denmark is evaluated.

[Hemorrhagic Rift Valley fever]. / Haemoragisk Rift Valley Fever.

A case of fatal hemorrhagic Rift Valley fever during an epidemic in Kenya's North Eastern Province in January 2007 is described.

[Ocular complications of dengue fever]. / Øjenmanifestationer af denguefeber.

We report a case of a 32-year-old Danish woman with ocular complications of (IgM-verified) dengue fever. After having returned from a trip to Thailand, she became ill with fever and symptoms suggestive of dengue. On the tenth day, when the fever had subsided, she suddenly experienced visual disturbances and was admitted to hospital. Ophthalmologic examination revealed retinal oedema, probably immunologically mediated. Months later, her visual symptoms had still not completely disappeared. Ocular complications of dengue are rarely reported, but in the Third World they are probably common.

[Screening of apparently healthy people returning from "the tropics"]. / Undersøgelse af tilsyneladende raske personer, som er vendt hjem fra "de varme lande".

Screening for imported parasites and infections in apparently healthy travellers and immigrants from the tropics is made more difficult by the lack of specificity and sensitivity of the standard investigations of blood and stools. Investigations must focus on parasites and infections prevalent in the area where the person has been. In the majority of people returned from the tropics, no infections or parasites are detected. However, some parasites, such as schistosomiasis, amoebae, and strongyloides, persist for many years and must be treated to prevent the development of serious complications at a later stage. The possibility of HIV infection and hepatitis should also be kept in mind when screening.

[Screening of people with fever returning to Denmark from "the tropics"]. / Undersøgelse af febrile personer, som er vendt hjem til Danmark fra "de varme lande".

A number of febrile diseases imported from the tropics, above all malaria, may, if left untreated, endanger the life of the patient. Microscopy of malaria slides without delay is by far the most important diagnostic tool in all patients who may have been exposed to infection. An accurate, detailed travel history, a knowledge of infections prevalent in areas where the patient has been and a thorough physical examination are essential. However, the majority of persons with fever after travel have a cosmopolitan etiology to their disease. If investigations suggest a possibly exotic yet not clear-cut cause of the febrile condition, it may be desirable to consult a physician with expertise in tropical medicine.