Low neonatal Toll-like receptor 4-mediated interleukin-10 production is associated with subsequent atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) and respiratory syncytial virus lower respiratory tract infection (RSV LRTI) are common diseases during early life. Impaired Th1-cell polarizing Toll-like receptor (TLR) responses play an important role in the pathogenesis of both diseases. Neonatal TLR-mediated production of Th1-type cytokines is decreased at birth, but rapidly increases during the first month of life. OBJECTIVE: To determine whether decreased TLR-mediated production of Th1-polarizing cytokines, at the age of 1 month is associated with subsequent AD or RSV LRTI. METHODS: A prospective healthy birth cohort study was performed. Whole blood concentrations of innate immune cells and TLR-mediated cytokine responses were measured at the age of 1 month in 291 neonates. AD was determined by a physician questionnaire at the age of 1 year and RSV LRTI was defined as parent-reported respiratory symptoms and presence of RSV RNA in a nose-throat specimen. RESULTS: Of participating neonates, 45 (15%) developed AD and 41 (14%) developed RSV LRTI. Risks of AD and RSV LRTI were not associated (χ(2) , P = 1.00). AD was associated with decreased concentrations of basophils (7.6 vs. 14.0 × 10(6) /mL, P = 0.002) and plasmacytoid dendritic cells (17.0 vs. 20.5 × 10(6) /mL, P = 0.04), increased concentrations of NK-cells (79.7 vs. 45.1 × 10(6) /mL, P = 0.03), and twofold lower TLR4-mediated IL-10 production (P = 0.001). In contrast, RSV LRTI was associated neither with neonatal concentrations of innate immune cells, nor with TLR-mediated TNF-α, IL-12p70, IL-10 or IFN-α production. CONCLUSIONS AND CLINICAL RELEVANCE: Atopic dermatitis, but not RSV LRTI, is associated with distinct pre-symptomatic differences in the innate immune system. We hypothesize that decreased neonatal IL-10-mediated immune regulation during early life might play a causal role in the initiation of AD.

Influenza-associated encephalopathy: no evidence for neuroinvasion by influenza virus nor for reactivation of human herpesvirus 6 or 7.

During 2 consecutive influenza seasons we investigated the presence of influenza virus, human herpesvirus (HHV) type 6, and HHV-7 in cerebrospinal fluid samples from 9 white children suffering from influenza-associated encephalopathy. We conclude that it is unlikely that neuroinvasion by influenza virus or reactivation of either HHV-6 or HHV-7 is involved.

No evidence of Legionella infection in general practice patients presenting with acute respiratory infections in The Netherlands.

The role of Legionella spp. in the aetiology of acute respiratory infections (ARIs) is largely unknown. In this case-control study, conducted in a general practitioner setting during 2000 and 2001, nose and throat samples from patients presenting with ARIs (n = 230) and controls (n = 200) were analysed for the presence of Legionella spp. by real-time PCR. Legionella DNA was not detected in any of the cases or controls. Thus, Legionella spp. do not seem to play a role in patients presenting with ARIs, nor were they present in patients who visited their general practitioner for complaints other than ARIs.

Community-acquired pathogens associated with prolonged coughing in children: a prospective cohort study.

A 2-year prospective study was performed of children with prolonged coughing to investigate the frequency of different respiratory pathogens, the rate of mixed infections, and possible differences in severity of disease between single and mixed infections. Sera from 135 children (136 episodes of prolonged coughing lasting 1-6 weeks) were tested for antibodies to different viruses and bacteria. Swabs were taken for culture and PCR to detect different viral and bacterial pathogens. One or more pathogens were found in 91 (67%) patients. One infectious agent was found in 49 (36%) patients, two agents in 35 (26%) patients, and more than two agents in seven (5%) patients. The most frequent pathogens encountered were rhinovirus (n = 43; 32%), Bordetella pertussis (n = 23; 17%) and respiratory syncytial virus (n = 15; 11%). The most frequent mixed infection was B. pertussis and rhinovirus (n = 14; 10%). No significant differences in clinical symptoms were observed between patients with or without pathogens; however, patients with mixed infections were significantly older. There was a strong seasonal influence on the number of infections, but not on the number of mixed infections. In children with prolonged coughing, there was a high frequency of mixed infections regardless of the season. However, mixed infection was not associated with increased disease severity. No clinical symptoms were found that allowed discrimination between specific pathogens.

Tumor growth stimulatory macrophages induced by a subclinical bacterial infection in vivo.

Nonelicited peritoneal macrophages obtained from normal mice from our animal house unexpectedly expressed a strong tumor growth stimulatory effect in vitro. Macrophages expressing this stimulatory effect had an aberrant morphology compared to the morphology of normal macrophages as observed by electron microscopy. The results of immunization of these affected mice with tumour cells led to the usual lymphocyte sensitization. No external symptoms were observed, and the mice looked healthy. Treatment of the affected macrophage donors with antibiotics resulted in the abolishment of the tumor growth stimulatory effect by the macrophages. Thus, this tumor cell growth stimulation by macrophages was probably due to a subclinical infection of the mice.

Influence of rheumatoid synovial fluid and cells on proteoglycans in human cartilage explants. Modulation by piroxicam.

We have studied the effects of cell-free rheumatoid synovial fluid (RASF) and the conditioned medium (CM) from these cells on the proteoglycans (PGs) of normal human cartilage and the influence which piroxicam might have on these processes. Both RASF and the CM from RASF cells enhanced the PG release from the cartilage explants. The effects of the above mentioned fluids on the cartilage PG content depended on the metabolic state of the cartilage i.e. correlated inversely with the PG synthesis. Whether this was due to the presence of anabolic and catabolic factors in these fluids is discussed. Piroxicam had no adverse effect on the PGs of human cartilage in vitro. Piroxicam prevented the cartilage PG depletion when it was induced by the CM from RASF cells.

Surveillance of respiratory pathogens and influenza-like illnesses in general practices - The Netherlands, winter 1997-98.

The Netherlands Institute of Primary Health Care (NIVEL) has coordinated the activities of a sentinel surveillance network of 43 general practices since 1970. These practices care for 1% of the Dutch population, a sample representative of the national pop

[The 2003/2004 influenza season in the Netherlands with a limited epidemic of the virus variant A/Fujian, and the vaccine composition for the 2004/2005 season]. / Het influenzaseizoen 2003/'04 in Nederland met een beperkte epidemie door de virusvariant A/Fujian, en de vaccinsamenstelling voor het seizoen 2004/'05.

In contrast to the three previous influenza seasons, the influenza epidemic of the 2003/2004 season started early in week 49 of 2003. The epidemic was predominantly caused by influenza-A viruses of the H3N2 subtype. All isolated influenza-A viruses were antigenically related to influenza virus A/Fujian/411/02, which was already detected in the influenza season 2002/2003 and that deviated from the vaccine-reference strain A/Moscow/10/99 to a certain extent. The magnitude of the epidemic was limited despite the fact that it was caused by influenza-A H3N2-virus-drift variants. Immunity caused by natural infection with influenza viruses during previous seasons or vaccination has possibly provided sufficient cross protection against these new H3N2-drift variant. No influenza-A viruses of the H1N1 or H1N2 subtypes were detected in the influenza season 2003/2004. Only a small number of influenza-B viruses were isolated, which all belonged to the B/Yamagata/16/88 lineage, which was temporarily replaced by the B/Victoria2/87 lineage in the previous influenza season. On the basis of epidemiological and serological data the World Health Organization has recommended the following vaccine composition for the 2004/2005 influenza season: A/Fujian/411/02 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Shanghai/361/02.

[The 2002/2003 influenza season in the Netherlands and the vaccine composition for the 2003/2004 season]. / Het influenzaseizoen 2002/'03 in Nederland en de vaccinsamenstelling voor het seizoen 2003/'04.

As in the 2000/2001 and 2001/2002 seasons, the influenza epidemic in the 2002/2003 season started late (week 7 of 2003) and was only moderate in size. Influenza A (H3N2) and B viruses were detected in equal numbers among patients of general practitioners and these two viruses were therefore equally responsible for the epidemic. However, H3N2 viruses dominated isolates taken from hospitals. In haemagglutination-inhibition (HI) assays most of the H3N2 viruses proved highly reactive with antiserum to the vaccine-reference strain A/Moscow/10/99. This was also true for a number of isolates, including those obtained from nursing home residents, closely related to the reference strain A/Finland/170/03. However, an estimated 4% of the H3N2 isolates belonged to the variant A/Fujian/411/02 from China, which constituted the majority of the H3N2 viruses isolated in Europe in the later phase of the season. This variant reacted poorly with antiserum to A/Moscow/10/99. In H1 tests all influenza A(H1N1)-virus isolates and all B-virus isolates were closelyrelated to the corresponding vaccine-reference strains. Taking this data into consideration, the World Health Organization has advised the same vaccine composition for the 2003/2004 season as for the 2002/2003 season, namely: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Hong Kong/330/01. There is the possibility of a mismatch occurring between the H3N2-vaccine strain and the circulating H3N2 viruses in the coming influenza season. In March and April 2003 there was an outbreak of influenza-A (H7N7) fowl plague in the Netherlands. A special monitoring survey revealed that 91 people who had handled infected poultry became infected with the H7N7 virus. One of these later died as a result of this. None of the avian and human H7N7-virus isolates examined contained human or porcine influenza-A virus genes.

[The 2001/2002 influenza season and the vaccine composition for the 2002/2003 season]. / Het influenzaseizoen 2001/'02 en de vaccinsamenstelling voor het seizoen 2002/'03.

The epidemic in the influenza season 2001/2002 was of moderate activity just like in 2000/2001. The influenza epidemic started in week 2 of 2002 when the clinical influenza activity reported by the general practitioner network of the Netherlands Institute of Primary Health Care (NIVEL) increased. This was caused by influenza A viruses of the H3N2 subtype in particular. All influenza A viruses of this subtype were closely related to the vaccine strain for this subtype, A/Moscow/10/99. Influenza B viruses and influenza A/H1 viruses isolated this season had surprising features. The influenza B viruses originated from two lineages. Viruses of the B/Yamagata/16/88 lineage have been circulating for more than twelve years. The vaccine reference strain B/Sichuan/379/99 belongs to this lineage. The B/Victoria/2/87 lineage reappeared again after an absence in Europe of more than ten years and accounted for 50% of the influenza B viruses that were isolated in the Netherlands. Therefore the vaccine will have provided only partial protection against influenza B. The only influenza A/H1 virus that was isolated appeared to be of a new subtype H1N2. The H1 hemagglutinin of this virus was closely related to that of the vaccine strain A/New Caledonia/20/99. The N2 neuraminidase originated from recent human influenza A/H3N2 viruses. Therefore the vaccine probably provided good protection against the new H1N2 subtype. Based in part on these data, the World Health Organization has advised that the vaccines for the season 2002/2003 should contain the following or comparable influenza-virus strains: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Hong Kong/330/01, the latter being an influenza B virus of the B/Victoria/2/87 lineage.

[2000/01 influenza season and the vaccine composition for the season 2001/'02]. / Het influenzaseizoen 2000/'01 en de vaccinsamenstelling voor het seizoen 2001/'02.

In the 2000/01 season, the size of the influenza epidemic in the Netherlands was exceptionally small. Since the start of the Continuous Morbidity Registration of the Netherlands Institute of Primary Health Care (NIVEL) in 1970, the peak incidence of influenza-like illnesses has never been so low. The aetiology of the epidemic was also unusual. Most remarkable was the relatively extensive circulation of subtype H1N1 and the low activity of subtype H3N2. The epidemic started in week 1 of 2001 and ended in week 8. The antigenic properties of the influenza A (H1N1) viruses closely resembled those of the vaccine strain A/New Caledonia/20/99. This new variant of subtype H1N1 was first isolated in Asia in 1995 and was only (sporadically) detected in the Netherlands in the 1999/2000 season. Phylogenetic analysis showed that these viruses represent a new line of subtype H1N1. Following the influenza-activity caused by H1N1 viruses in the 2000/01 season, a small number of B and H3N2 viruses were also isolated up to week 19. Antigenically, these viruses were identical to those obtained in the previous years. On the basis of the antigenetic analyses presented, it can be concluded that the vaccine provided good protection against the circulating influenza viruses in the 2000/01 season. The World Health Organization recommends that influenza vaccines intended for use in the 2001/02 season of the northern hemisphere should contain the following, or antigenically similar, strains: A/Moscow/10/99 (H3N2), A/New Caledonia/20/99 (H1N1), and B/Sichuan/379/99.

Long time trends in influenza-like illness and associated determinants in The Netherlands.

We analysed long-term epidemiological trends in influenza-like illness (ILI) in The Netherlands and used an ecological analysis to estimate its relationship with age, influenza vaccination, and virological aspects. This study used data from weekly ILI consultation reports from sentinel general practitioners (1986/1987 to 2006/2007), virological data from sentinel ILI patients (1992/1993 to 2006/2007), and data for influenza vaccine uptake (1991-2005). The incidence of ILI consultations, although varying during the study period, was estimated to decrease in the total population by 12.2/10 000 persons each season (95% CI 8.6-15.9). Uptake of influenza vaccination in people aged > or = 65 years (elderly) increased from 28% in 1991 to >70% since 1997. ILI incidence in the elderly declined by 1.7/10 000 persons (P=0.05) per percentage vaccine uptake per season. The decline in ILI incidence over the last 20 years could be related to the increased vaccine uptake. However, insufficient data were present to assess the impact of other potential contributing factors, such as diminished fitness of influenza viruses and changes in consulting behaviour.

Structural and functional comparison of anchorin CII (cartilage annexin V) and muscle annexin V.

Annexin V has been isolated from chicken muscle and cartilage either by EDTA extraction or by plasma membrane purification and solubilization with detergent to obtain the hydrophilic and hydrophobic variants. The hydrophobic variant of the cartilage annexin V associated with phosphatidylserine-containing liposomes in a Ca(2+)-independent manner, whereas the EDTA-extracted molecule required Ca2+ for association with the liposomes. The collagen-binding assay used is based on the principle of a cell attachment assay using mildly pepsinized collagen type II or intact collagen type I as the solid-phase substrate. Soluble intact collagen type I or II was added as competitive inhibitor. The lipophilic and the EDTA-extracted anchorins CII from cartilage were inhibited to the same extent by collagen type II on pepsinized collagen type II as the solid-phase substrate. The EDTA-extracted muscle annexin V exhibited a fivefold lower affinity to collagen type II than its counterpart from cartilage. Peptide mapping studies and amino acid sequencing of selected peptides from the hydrophobic cartilage annexin V and the hydrophilic cartilage and muscle annexin V revealed 100% identity to the established chicken annexin V protein sequence in the corresponding amino acids 7-29 and 118-126. These results indicate that annexin V may occur in multiple pools within one cell type and/or tissue and that its biological function may depend on the subcellular distribution as well as the microenvironment in the tissue.

Human osteoarthritic cartilage is synthetically more active but in culture less vital than normal cartilage.

The proteoglycan turnover of human osteoarthritic (OA) cartilage was compared to that of normal (N) cartilage. The cartilage was obtained postmortem from human femoral knee condyles. Short term cultures were compared to longterm cultures, and proteoglycan synthesis rate, content and release determined. Proteoglycan synthesis rate, determined shortly after collection of the cartilage, was higher in OA cartilage than in N cartilage. After longterm culture, the initially higher proteoglycan synthesis rate of OA cartilage became lower than that of N cartilage. An increased percentage release of proteoglycans from OA cartilage compared to N cartilage was apparent both shortly after collection of the cartilage and after culture. Thus, although OA cartilage in vivo is synthetically more active, in vitro it has an increased catabolic and a decreased anabolic activity, from which we conclude that OA cartilage is less vital than N cartilage.

Dietary fat affects plasma prolactin in female F344 rats under conditions of ether stress.

The influence of amount and type of dietary fat on circulating concentrations of prolactin and estradiol-17 beta in female F344 rats from which blood was sampled by decapitation under ether anesthesia was compared with that in rats from which blood was collected without anesthesia. The animals were fed isonutrient (adjusted for differences in energy density) semipurified diets containing 5% or 20% (by weight) sunflower seed oil or lard. Blood was sampled by decapitation with or without standardized ether anesthesia during the afternoon of proestrus-estrus or the morning of metestrus-diestrus, as determined by examination of vaginal smears. Plasma hormone concentrations were measured by radioimmunoassay. Prolactin levels were lower during proestrus-estrus in rats fed a low-fat diet than in animals fed a high-fat diet, statistically independent of the type of dietary fat, but only when blood was sampled by decapitation under ether anesthesia [p = 0.0384, 2-way analysis of variance (ANOVA)]. No such difference was found in rats decapitated without anesthesia. This effect of amount of dietary fat on prolactin in proestrus-estrus animals anesthetized with ether was predominantly present in animals fed polyunsaturated fat (p < 0.05, 1-way ANOVA and Tukey's test) and was statistically not significant in rats fed saturated fat diets. During metestrus-diestrus, prolactin levels were significantly lower in animals fed a high-saturated fat diet than in those fed low-saturated fat, low-unsaturated fat, or high-unsaturated fat diets, independent of the blood sampling conditions (p < 0.05, 2-way ANOVA and Tukey's test). No consistent effects on estradiol-17 beta levels were found in type or amount of dietary fat or in presence or absence of ether anesthesia before decapitation. Growth, apparent digestibility of fat, and caloric intake were similar in all four dietary groups, but food consumption was higher and food conversion efficiency was lower in animals fed low-fat diets than in those fed high-fat diets. This study confirms the hypothesis that effects of dietary fat, particularly polyunsaturated fat, on circulating prolactin occur only during (ether) stress. Because stress is a frequent and normal phenomenon, this observation implies that the mammary glands of animals with a high dietary intake of polyunsaturated fat are frequently exposed to higher circulating prolactin concentrations than rats fed a low-fat diet, which may be a major mechanism by which dietary fat enhances rat mammary carcinogenesis.

The effect of human interleukin 1 on proteoglycan metabolism in human and porcine cartilage explants.

Human interleukin 1 (IL-1), up to 100 pg/ml, causes a decrease of the proteoglycan content of human (old and young) as well as porcine cartilage explants, without stimulating the proteoglycan release from the cartilage. The proteoglycan depletion is stronger in young than in old human cartilage and stronger in human than in porcine cartilage. The proteoglycan synthesis is considerably more inhibited by IL-1 in young than in old human cartilage. Our data suggest that an IL-1 induced inhibition of the proteoglycan synthesis, rather than a stimulation of proteoglycan breakdown causes the proteoglycan depletion of the cartilage. The data furthermore suggest a clear difference between young and old human cartilage, with respect to their sensitivity for IL-1. IL-1 in a concentration of 500 pg/ml causes in all 3 kinds of cartilage explants chondrocyte damage that might be relevant in the cartilage destruction during rheumatoid arthritis.

Mycoplasma pneumoniae P1 type 1- and type 2-specific sequences within the P1 cytadhesin gene of individual strains.

Mycoplasma pneumoniae strains traditionally are divided into two types, based on sequence variation in the P1 gene. Recently, however, we have identified 8 P1 subtypes by restriction fragment length polymorphism analysis. In the present study the P1 gene sequences of three P1 type 1 and two P1 type 2 M. pneumoniae strains were analyzed. A new P1 gene sequence in a type 1 strain with partial similarity to a recently reported variable region in the P1 gene of an M. pneumoniae type 2 strain (T. Kenri, R. Taniguchi, Y. Sasaki, N. Okazaki, M. Narita, K. Izumikawa, M. Umetsu, and T.Sasaki, Infect. Immun. 67:4557-4562, 1999) was identified. In addition, the P1 gene of the type 1 strain contained another region with nucleotide polymorphisms identical to a stretch in the P1 gene of one of our type 2 strains. These findings indicate that recombination between sequences specific for P1 type 1 and type 2 had occurred and that P1 type 1 and type 2 hybrid sequences can be present within the P1 gene of an individual strain. Identical or nearly identical variable P1 gene sequences were present in several repetitive regions outside the P1 gene locus in the genome of M. pneumoniae strain M129, implying recombination as a mechanism for generation of the P1 gene variation. Additionally, in the P1 gene sequences of four of the five strains studied, single-nucleotide polymorphisms different from the previously reported P1 type 1 and 2 characteristic sequences were identified. The polymorphic sites are candidate targets for genotyping of M. pneumoniae by direct sequencing of amplicons from clinical specimens.

In vitro influence of ketoprofen on the proteoglycan metabolism of human normal and osteoarthritis cartilage.

We investigated the influences of ketoprofen on the proteoglycan (PG) turnover of human articular cartilage explants in three groups: normal young with a high basal PG synthesis, normal adult and osteoarthritis cartilage, both with a low basal PG synthesis. Ketoprofen had no influence on the mean PG synthesis rate of normal adult and OA cartilage after 4 days of culture nor on the cartilage PG content after 8 days of culture. There was no relation between the histological grade of OA and effects of ketoprofen. In normal young cartilage ketoprofen induced an increase of the PG synthesis rate when added to the culture in a concentration of 10(-4) M. No correlation existed between the effect of ketoprofen and the basal PG synthesis of normal cartilage.

Role of TNF alpha, in relation to IL-1 and IL-6 in the proteoglycan turnover of human articular cartilage.

In both young and old human articular cartilage explants, TNF alpha induced a concentration-dependent, reversible suppression of the proteoglycan (PG) synthesis. Young cartilage was more sensitive to TNF alpha than old cartilage: 50% suppression of PG synthesis was reached at a TNF alpha concentration of 5 U/ml for young and 30 U/ml for old cartilage, whereas at 10(3) U/ml the PG synthesis of young cartilage was blocked and that of old cartilage suppressed by 80%. These inhibition levels of PG synthesis resulted in 25% PG depletion of the explants after 8 days of culture. The release of cartilage PG was not enhanced. TNF alpha induced no detectable amounts of IL-1 (less than 0.01 U) in young or old cartilage but did induce IL-6 production. The induced amounts of IL-6 were higher in young than in old cartilage but no dose-dependency was evident. Antibodies to neither IL-1 nor IL-6 had any influence on the TNF alpha-induced suppression of PG synthesis. The combination of TNF alpha and IL-1 led to an additive inhibition of PG synthesis which had no relationship to induced IL-6. TNF alpha was about 100-fold less active than IL-1.

Contrasting in vitro effects of retinol and mononuclear cell factor on young and old human cartilage.

Studies with young animal cartilage have shown that retinol and mononuclear cell-factor (MCF) cause in vitro breakdown of the cartilage, mediated by the living chondrocyte (indirect degradation). We studied the effects of retinol and MCF on healthy human articular cartilage of different ages, measuring the effects on proteoglycan (PG) content of the cartilage, and on PG synthesis during 8 days of culture. This study shows: Retinol and MCF induce indirect degradation of young, but not of old human cartilage of the humeral head; Both retinol and MCF suppress PG synthesis of young and stimulate PG synthesis of old cartilage; The effects of retinol and MCF on cartilage PG content and on PG synthesis are related to the metabolic state of the chondrocyte; Therefore mononuclear cell-factor may have a destructive or beneficial effect on cartilage depending on whether proteoglycan synthesizing activity is high or low, respectively.