Evaluation of serological methods for diagnosis of Puumala hantavirus infection (nephropathia epidemica).

Nephropathia epidemica (NE), Puumala (PUU) virus infection, is a febrile disease which is commonly associated with acute renal impairment. To differentiate NE from other acute febrile illnesses, a rapid and reliable serological diagnosis is important, and a number of different protocols have recently been introduced. In the present report we describe a comparative evaluation of six PUU virus immunoglobulin M (IgM) and seven IgG enzyme-linked immunosorbent assay (ELISA) protocols based on native, Escherichia coli-expressed, or baculovirus-expressed nucleocapsid protein (N). Neutralization and immunofluorescence assays were included for comparison. Equally high sensitivities and specificities were obtained with three mu-capture-based IgM ELISAs using native, baculovirus-expressed, and E. coli-expressed N antigens, respectively, and by an ELISA based on purified E. coli-expressed full-length N adsorbed to solid phase. The assays based on truncated amino-terminal N proteins, including a commercially available PUU virus IgM ELISA, all showed lower sensitivities. For detection of PUU virus-specific IgG, ELISAs based on monoclonal antibody-captured native or baculovirus-expressed N antigens showed optimal sensitivities and specificities, while the assays based on E. coli-expressed N did not detect all PUU virus IgG-positive serum samples. A commercially available PUU virus IgG ELISA based on E. coli-expressed amino-terminal N showed a significantly lower sensitivity than those of all other IgG assays.     

Blood Lymphocyte Proliferation Response to Pollen Extract as a Monitor of Immunotherapy

In a study of immunotherapy 41 children with seasonal rhinoconjunctivitis due to deciduous tree pollen allergy were monitored by means of symptom scoring, patient self-evaluation, conjunctival provocation tests and lymphocyte proliferation in vitro to the allergen. The lymphocyte responsiveness to birch pollen decreased significantly during the first year of immunotherapy. However, neither the lymphocyte responsiveness before treatment nor changes in lymphocyte reactivity during the immunotherapy correlated with the clinical efficacy of the therapy as evaluated by changes in symptom scores, self-evaluation or conjunctival provocation test changes in the individual patients. The results indicate the lymphocyte responsiveness to an allergen cannot be used to select patients for immunotherapy, i.e. to predict whether a patient would benefit from immunotherapy or not, or to evaluate the effects of immunotherapy after beginning the treatment. However, lymphocyte proliferation response to an allergen indicates clinical sensitivity.     

High prevalence of undiagnosed coeliac disease in adults: a Swedish population-based study

OBJECTIVE: To determine the prevalence of coeliac disease in a population-based sample of Swedish adults. DESIGN: Population-based cross-sectional study. SETTING: Northern Sweden. SUBJECTS: A total of 1894 adults (76%) out of 2500 invited, randomly selected from the population register after stratification for age and sex. MAIN OUTCOME MEASURES: Prevalence of biopsy verified coeliac disease, symptoms of undiagnosed cases, and results of antiendomysium and antigliadin serum antibody tests. RESULTS: Coeliac disease was confirmed by intestinal biopsy showing enteropathy in 10 individuals (seven women and three men), corresponding to a prevalence of 5.3 per 1000 (95% CI = 2.5-9.7). The majority of cases (eight out of 10) had not been diagnosed prior to the screening, although many had symptoms compatible with coeliac disease. All individuals with antiendomysium antibody positivity who were subjected to a small intestinal biopsy had enteropathy. Furthermore, all of them also had elevated levels of antigliadin antibodies type IgA and/or IgG. CONCLUSIONS: Coeliac disease is common, albeit mostly undiagnosed, in Swedish adults. It is likely that the situation is no better in other countries. This highlights the importance of keeping coeliac disease in mind, and of promptly investigating individuals with unexplained, even mild, symptoms compatible with the disease. Serological markers, e.g. antigliadin and antiendomysium antibodies, are useful tools within this active case-finding strategy, although the final diagnosis should be based on an intestinal biopsy demonstrating enteropathy.     

Puumala hantavirus genetic variability in an endemic region (Northern Sweden)

Puumala hantavirus (PUUV), naturally harboured and shed by bank voles (Myodes [Clethrionomys] glareolus), is the etiological agent to nephropathia epidemica (NE), a mild haemorrhagic fever with renal syndrome. Both host and virus are found throughout much of the European continent and in northern Sweden NE is the second most prevalent serious febrile viral infection after influenza. The reliability of diagnostics by PCR depends on genetic variability for the detection of viral nucleic acids in unknown samples. In the present study we evaluated the genetic variability of PUUV isolated from bank voles in an area of northern Sweden highly endemic for NE. Genetic variability among bank voles was also investigated to evaluate co-evolutionary patterns. We found that the viral sequence appeared stable across the 80km study region, with the exception of the southernmost sampling site, which differed from its nearest neighbour by 7%, despite a geographical separation of only 10km. The southernmost sampling site demonstrated a higher degree of genetic similarity to PUUV previously isolated 100km south thereof; two locations appear to constitute a separate PUUV phylogenetic branch. In contrast to the viral genome, no phylogenetic variance was observed in the bank vole mtDNA in this study. Previous studies have shown that as a result of terrestrial mammals' postglacial re-colonization routes, bank voles and associated PUUV of a southern and a northern lineage established a dichotomous contact zone across the Scandinavian peninsula approximately 100-150km south of the present study sites. Our observations reveal evolutionary divergence of PUUV that has led to dissimilarities within the restricted geographical scale of the northern host re-colonization route as well. These results suggest either a static situation in which PUUV strains are regionally well adapted, or an ongoing process in which strains of PUUV circulate on a geographical scale not yet reliably described.     

Nasal mucosal histamine reactivity among teachers six years after working in a moisture-damaged school

OBJECTIVES: The objective of this study was to determine whether verified increased nasal mucosal reactivity among teachers, who had been working in a school with severe moisture problems, still persisted 6 years after remedial measures had been taken. The increased nasal mucosal reactivity, measured as the mucosal swelling reaction upon histamine provocation, had earlier been shown both 1 and 3 years after the renovation. METHODS: Twenty-four teachers in the target school and sixteen teachers in the control school, who participated in all the investigations (1995, 1997 and 2000), answered a standardized questionnaire and underwent a nasal histamine provocation test. In addition to the registration of mucosal swelling, the microcircular reaction to histamine provocation was measured with laser-Doppler flowmetry. RESULTS: The nasal histamine reactivity among the teachers, measured as the mucosal swelling reaction, was no longer increased. However, the laser-Doppler flowmetry showed that the teachers in the target school had significantly divergent microcircular perfusion (P = 0.0022) and a concentration of moving blood cells (P=0.0009) in the histamine provocation when compared with the teachers in the control school; this finding indicates more-pronounced plasma leakage and edema from the nasal mucosa. CONCLUSIONS: Restored nasal histamine reactivity, measured as mucosal swelling reaction, was observed among the teachers 6 years after an obviously successful renovation of the school environment. However, changes in microcirculation indicate a remaining effect on the nasal mucosa.     

Airway reactivity and exhaled NO following swine dust exposure in healthy volunteers

Short-time exposure to swine dust causes an intense inflammation of upper and lower airways and induces increased bronchial responsiveness to methacholine in previously non-exposed healthy volunteers. The objective to this study was to investigate the nasal inflammatory response and mucosal reactivity to swine dust exposure and whether nitric oxide metabolism is involved in the inflammatory process. Nitric oxide in expired air, nasal histamine test (NH), nasal lavage (NAL) and bronchial histamine challenges were studied before and after a 3 h exposure to swine dust in a swine confinement building in 17 non-smoking healthy subjects not previously exposed to farm dust. To detect any interference between NAL and NH, the subjects were divided into two groups: in group 1, NAL was performed after NH and in group 2, NAL preceded NH. Nasal histamine response increased significantly in group 1, but not in group 2 (P=0.012). Albumin levels in NAL were higher before as well as after dust exposure in group 1 compared to group 2 (P=0.036 and 0.015 respectively). Bronchial histamine responsiveness increased following exposure (P= 0.045). Nitric oxide in expired air decreased following bronchial histamine challenge at baseline (P=0.013) but was otherwise unaltered. Short-time exposure to swine dust increases non-specific reactivity of both nose and bronchi. Nasal lavage procedure interferes with nasal histamine test when performed with connection to each other. The inflammatory reaction may involve NO metabolism.     

Outbreak of Puumala Virus Infection, Sweden

An unexpected and large outbreak of Puumala virus infection in Sweden resulted in 313 nephropathia epidemica patients/100,000 persons in Västerbotten County during 2007. An increase in the rodent population, milder weather, and less snow cover probably contributed to the outbreak.     

Treatment of infantile atopic dermatitis with a strict elimination diet

Of twenty-one infants with atopic dermatitis, twenty were treated with a strict elimination diet for a period of up to 6 weeks. Seven infants healed and twelve improved. The infants who healed were less than 6 months old and had had a short duration of dermatitis. For one infant the skin condition was unchanged. Another infant was breast-fed throughout the period with dermatitis. Blood eosinophilia and/or elevated serum IgE commonly found on admission decreased significantly (P less than 0.01) during the diet period. On challenge with cows' milk, twelve infants were considered as intolerant. At the age of 2 years the dermatitis had cleared in all but four children. Of these four children, two were still cows' milk intolerant. Another two infants were also cows' milk intolerant, but without dermatitis.