Humoral immune response to influenza vaccine in natalizumab-treated MS patients.

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.

Chlamydia trachomatis and Mycoplasma genitalium plasma antibodies in relation to epithelial ovarian tumors.

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 (n=12), ovarian carcinoma (n=45), or other pelvic malignancies (n=11) 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 (P=.002) in women with plasma samples obtained >1 year prior to diagnosis (n=7). M. genitalium IgG antibodies were associated with borderline ovarian tumors (P=.01). 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.

Norovirus strains belonging to the GII.4 genotype dominate as a cause of nosocomial outbreaks of viral gastroenteritis in Sweden 1997--2005. Arrival of new variants is associated with large nation-wide epidemics.

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.

Sialic acid tissue distribution and influenza virus tropism.

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.

Avian influenza and sialic acid receptors: more than meets the eye?

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.

A lack of serologic evidence of transmission of Chlamydia pneumoniae by transfusion of buffy coat-depleted RBCs.

BACKGROUND: Recent studies have shown that a high percentage of blood donors harbor Chlamydia pneumoniae DNA and antigens within their PBMNCs. The aim of the present study was to investigate whether recipients of RBC transfusions who were seronegative for C. pneumoniae before transfusion showed any evidence of seroconversion after transfusion. STUDY DESIGN AND METHODS: Patients who were possible recipients of RBC transfusion and negative in a screen test for IgG antibodies against C. pneumoniae at the time of blood group determination were candidates to be included in the study. The patients were contacted 3.0 to 3.5 months after the blood group determination, and those who accepted to participate agreed that another venous blood sample could be taken. RESULTS: Among the patients who participated, 53 had become recipients of RBC transfusion (transfused group), and 51 later did not receive any RBC transfusion (control group). No significant change was found in IgG titer against C. pneumoniae between the first and the second sample from the same patient, in either the transfused group or the control group. CONCLUSION: 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.

Quantitative detection of respiratory Chlamydia pneumoniae infection by real-time PCR.

Real-time PCR was evaluated as a quantitative diagnostic method for Chlamydia pneumoniae infection using different respiratory samples. Real-time PCR had efficiency equal to or better than that of nested touchdown PCR. This study confirmed sputum as the best sampling material to detect an ongoing C. pneumoniae infection.