Antibody to Chlamydia trachomatis proteins, TroA and HtrA, as a biomarker for Chlamydia trachomatis infection.

We studied whether antibody to two chlamydial proteins (TroA and HtrA) could be used as biomarkers of Chlamydia trachomatis infection. METHODS: Recombinant proteins C. trachomatis TroA and HtrA were used as antigens in enzyme immunoassay (EIA). Both IgG and IgA antibody responses were studied. RESULTS: IgG or IgA antibody to either protein was infrequently detected in sera from healthy blood donors or virgin girls. Patients attending the STI Clinic and patients with perihepatitis had often IgG antibody against TroA (25 and 50 % respectively) and HtrA (21 and 38 % respectively). Especially in sera from patients with chlamydial perihepatitis, the A450nm values with TroA were high (mean 1.591). A positive correlation between C. trachomatis MIF antibody and TroA (r  = 0.7) as well as HtrA (r  = 0.5) antibody was observed in sera from STI clinic patients and perihepatitis patients. Individuals with C. trachomatis infection and positive serology already when seeking medical attention had higher A450nm values for TroA (0.638) and HtrA (0.836) than patients with no marker of previous exposure or with no infection (0.208 and 0.234 respectively). Diagnosis of genital C. trachomatis infection is often NAAT-based, whereas serology has little value in testing for uncomplicated genital C. trachomatis infection. TroA and HtrA antibodies are potential biomarkers for evaluation of ascending and repeated C. trachomatis infection.

A new quantitative PCR for human parvovirus B19 genotypes.

Parvovirus B19 (B19V) is a minute ssDNA virus associated with a wide range of diseases from childhood erythema to fetal death. After primary infection, the viral genomes persist lifelong in solid tissues of most types. Quantification of the viral DNA is important in the timing of primary infection, assessment of tissue persistence and screening of blood donor plasma. In this study, we present a new PCR assay for detection and quantification as well as for differentiation of all three B19V genotypes. A new B19V qPCR was designed to target a 154-bp region of the NS1 area. Serum, plasma and solid tissue samples were suitable for testing in the assay. The WHO International Reference Panel for Parvovirus B19 Genotypes was utilized to validate the assay for detection of different genotypes of B19V in clinical material. Each panel member yielded, by the new qPCR, a quantity similar to the one reported by National Institute for Biological Standards and Control (NIBSC). The qPCR was specific for B19V and amplified and quantified all three genotypes with detection sensitivities of ≤10 copies/reaction. The differentiation of B19V genotypes was performed by Sanger sequencing of the amplified products.

Human parvoviruses B19, PARV4 and bocavirus in pediatric patients with allogeneic hematopoietic SCT.

Among the immunocompetent, infections with parvovirus B19 (B19V) and human bocavirus (HBoV) 1 range clinically from asymptomatic to severe, while following allogeneic hematopoietic SCT (HSCT) B19V can cause a persistent severe illness. The epidemiology and clinical impact of HBoV1 and the other emerging parvovirus 4 (PARV4) among immunocompromised patients have not been established. To determine the occurrence and clinical spectrum of B19V, PARV4 and HBoV1 infections, we performed a longitudinal molecular surveillance among 53 allogeneic HSCT recipients for pre- and post-HSCT DNAemias of these parvoviruses. Quantitative real-time PCR showed B19V DNA in sera of 16 (30%) patients, at mean levels of 4.6 × 10(3), 9.9 × 10(7), 1.1 × 10(10) and 1.6 × 10(2) B19V DNA copies/mL pre-HSCT (9/53), and at 1 (6/53), 2 (4/53) and 3 months (1/25) post HSCT, respectively. However, no clinical manifestation correlated with the presence of B19V viremia. All B19V sequences were of genotype 1. None of the sera investigated contained PARV4 or HBoV1 DNAs. Our data demonstrate B19V viremia to be frequent among pediatric allogeneic HSCT recipients, yet without apparent clinical correlates. PARV4 or HBoV1 viremias were not seen in these immunocompromised patients.

No evidence for an association between infections with WU and KI polyomaviruses and respiratory disease.

BACKGROUND: WU virus (WUV) and KI polyomavirus (KIPyV) are newly discovered related human polyomaviruses detected in respiratory samples. To investigate their potential role in respiratory disease, we determined their frequencies of detection, clinical presentations and epidemiological characteristics among samples referred for diagnostic respiratory virus testing. METHODS: Anonymised samples and accompanying study subject information were obtained from the Edinburgh respiratory specimen archive. Samples were screened by nested PCR using two sets of primers conserved between WUV and KIPyV, as well for other respiratory viruses (respiratory syncytial virus [RSV], adenoviruses [AdV], influenza A/B and parainfluenza viruses 1-3, human bocavirus, B19). RESULTS AND CONCLUSIONS: WUV and KIPyV were detected in 10 and 14 samples, respectively from 983 specimens (from 9 to 10 different individuals from 612 study subjects). Infections occurred in two types of study subject; those who were young (<2 years) with lower respiratory tract infections (n=8), and almost invariably co-infected with other respiratory viruses (RSV, AdV), and a second, generally older group either without respiratory disease (n=6) or with mild upper respiratory tract infections (n=5) but who were generally clinically severely immunosuppressed from leukaemia or transplant therapy. Findings from either group do not support an aetiological link between infection with WUV or KIPyV and respiratory disease.