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OBJECTIVES: Natalizumab is a drug with documented efficacy in relapsing?remitting multiple sclerosis (RRMS). The mechanism of action of natalizumab has immunosuppressive properties and it is not yet investigated if treatment with natalizumab affects the immunological response to vaccination. This study aims to investigate the humoral immune response to influenza vaccine while undergoing treatment with natalizumab.

METHODS: A cohort of 17 RRMS patients treated with natalizumab and 10 healthy controls received trivalent influenza A/B vaccine. Influenza-specific immunoglobulin G (IgG) levels were determined at baseline and after 4, 8, and 12 weeks.

RESULTS: Both groups experienced a significant increase in anti-influenza B IgG after the vaccination. Both groups also experienced a smaller increase in anti-influenza A IgG, but this was only significant for the natalizumab group. The IgG titers compared between the groups did not differ significantly at any of the time points.

DISCUSSION: These results indicate that vaccination against influenza in patients treated with natalizumab yields a humoral immune response comparable to that achieved in healthy individuals.

Objective: To assess associations of Chlamydia trachomatis and Mycoplasma genitalium antibodies with epithelial ovarian tumors.

Methods: Plasma samples from 291 women, undergoing surgery due to suspected ovarian pathology, were analyzed with respect to C. trachomatis IgG and IgA, chlamydial Heat Shock Protein 60-1 (cHSP60-1) IgG and M. genitalium IgG antibodies. Women with borderline tumors (), ovarian carcinoma (), or other pelvic malignancies () were matched to four healthy controls each.

Results: Overall, there were no associations of antibodies with EOC. However, chlamydial HSP60-1 IgG antibodies were associated with type II ovarian cancer () in women with plasma samples obtained >1 year prior to diagnosis (). M. genitalium IgG antibodies were associated with borderline ovarian tumors ().

Conclusion: Chlamydial HSP60-1 IgG and M. genitalium IgG antibodies are in this study associated with epithelial ovarian tumors in some subsets, which support the hypothesis linking upper-genital tract infections and ovarian tumor development.

BACKGROUND: In recent years an increase of the incidence of nosocomial outbreaks caused by noroviruses has been observed throughout Sweden, with high peaks noted in the winter seasons 2002/2003 and 2004/2005, respectively. OBJECTIVES: To phylogenetically characterize norovirus strains causing nosocomial outbreaks from 1997 to 2005 and estimate the impact of norovirus-like disease on the Swedish health care system during the peak season 2002/2003 when a new variant of norovirus occurred. STUDY DESIGN: Stool samples from 115 randomly selected nosocomial outbreaks occurring during 1997--2005 throughout Sweden were studied by RT-PCR and sequencing. In addition, to investigate the impact on the health-care system, a questionnaire was distributed to infection control units (n=90) serving all Swedish hospitals, nursing homes and other health-care institutions during the largest epidemic of nosocomial outbreaks. RESULTS: Sequencing of 279 nucleotides of the norovirus RNA polymerase gene in stools containing norovirus RNA showed that strains belonging to the GII.4 genotype dominated. Each of the two large epidemics was due to a new variant within this cluster. The questionnaire revealed that 30,000-35,000 episodes of nosocomial norovirus-like infections occurred in 80 of 82 major Swedish hospitals affected in 2002/2003. CONCLUSION: New norovirus variants within the cluster GGII.4 may have a major impact on the health-care system.

Avian influenza A viruses exhibit a strong preference for using alpha2,3-linked sialic acid as a receptor. Until recently, the presumed lack of this receptor in human airways was believed to constitute an efficient barrier to avian influenza A virus infection of humans. Recent zoonotic outbreaks of avian influenza A virus have triggered researchers to analyse tissue distribution of sialic acid in further detail. Here, we review and extend the current knowledge about sialic acid distribution in human tissues, and discuss viruses with ocular tropism and their preference for alpha2,3-linked sialic acid.

BACKGROUND: The objective of this study was to evaluate whether serum Chlamydia trachomatis immunoglobulin-A (IgA), IgM and C. trachomatis heat shock protein 60 (CHSP60) IgG are of additional value to C. trachomatis IgG regarding the impact on fecundity in infertile couples, and to relate C. trachomatis serum antibodies to semen characteristics, diagnoses and pregnancy outcome.

METHODS: A total of 226 infertile couples, previously tested for C. trachomatis IgG, were tested for C. trachomatis IgA, IgM and CHSP60 IgG, and semen samples from all men were analysed.

RESULTS: Chlamydia trachomatis serum IgA in men (but not in women) correlated with reduced chances of achieving pregnancy [p = 0.021, relative risk (RR) =0.65, 95% confidence interval (CI) 0.42-1.005] and in combination with C. trachomatis IgG the chance was further reduced (p =0.001, RR = 0.35, 95% CI 0.15-0.84). Chlamydia trachomatis serum IgA was also significantly correlated with reduced motility of the spermatozoa (-8.7%, p = 0.023), increased number of dead spermatozoa (+10.5%, p = 0.014) and higher prevalence of leucocytes in semen (+122%, p = 0.005), and in combination with C. trachomatis IgG positivity, there was also a decrease in sperm concentration (-35%, p = 0.033), the number of progressive spermatozoa (-14.8%, p = 0.029) and a rise in the teratozoospermia index (+4.4%, p = 0.010). CHSP60 IgG correlated with reduced motility (-5.6%, p = 0.033), and in the women to tubal factor infertility (p = 0.033), but no correlations of C. trachomatis serum IgM or CHSP60 IgG with pregnancy rates were found.

CONCLUSIONS: Chlamydia trachomatis serum IgA in the male partner of the infertile couple has an additive value to IgG in predicting pregnancy chances, and serum IgA and IgG are associated with subtle negative changes in semen characteristics.

Given our recent discoveries that the ocular human pathogens adenovirus serotype 37 and enterovirus serotype 70 use sialic acid linked to galactose via alpha2,3 glycosidic bonds as a cellular receptor, we propose that the presence of this receptor in the eye also explains the ocular tropism exhibited by zoonotic avian influenza A viruses such as subtype H5N1 in Hong Kong in 1997, H7N7 in the Netherlands in 2003, H7N2 in the USA in 2003, and H7N3 in Canada in 2004. We also draw attention to the implications this hypothesis may have for epizootic and zoonotic influenza, and the initiation of future pandemics.

BACKGROUND: The objective of this study was to determine the prevalence of Chlamydia trachomatis among both men and women seeking help at an infertility clinic, and to prospectively follow the effect of previous infection on pregnancy rates and pregnancy outcome after a long follow-up period (mean 37 months). 

METHODS: A total of 244 infertile couples was tested for C. trachomatis IgG antibodies, and IgG(+) couples were also tested for C. trachomatis DNA by PCR in a first-void urine sample. Study parameters were serology, PCR results, clinical diagnoses, treatments, pregnancy rates and pregnancy outcome. As controls, age-matched and spontaneously pregnant women were also tested with serology. 

RESULTS: The prevalence of IgG antibodies was 24.2, 20.1 and 15.6% among infertile women, infertile men and control women respectively. The prevalence of C. trachomatis DNA was 6.8 and 7.1% among tested women and men respectively. The presence of C. trachomatis IgG antibodies in women was related to tubal factor infertility (TFI) (P = 0.002). Decreased pregnancy rates were seen in couples where the man was IgG(+) (P = 0.005) with no relationship to TFI. Among women who achieved pregnancy, there was no difference in pregnancy outcome between IgG(+) or negative couples. 

CONCLUSIONS: C. trachomatis IgG antibodies in the man of the infertile couple was related to decreased pregnancy rates and to the presence of IgG antibodies in the woman. There was a high prevalence of asymptomatic persistent infections among infertile couples.

In our study, which was limited to 53 seronegative recipients of RBC units from seropositive donors, we found no serologic evidence that C. pneumoniae could be transmitted by RBC transfusion.