Outcomes and costs of single-step hepatitis C testing in primary care, Birmingham, United Kingdom.

OBJECTIVES: In UK laboratories, the diagnostic algorithm for chronic hepatitis C (HCV) infection commonly requires two serological assays to confirm anti-HCV-antibody positivity in a serum sample followed by HCV RNA detection in a second whole-blood sample (two-step testing algorithm). A single-step algorithm (both anti-HCV antibodies and RNA tested on an initial serum specimen) has been advocated to reduce attrition rates from the care pathway. STUDY DESIGN: To investigate the feasibility, clinical impact and relative costs of switching from a two-step to single-step testing algorithm in the laboratory, a pilot study on unselected primary care requests was undertaken. METHODS: All primary care patients tested for HCV infection from December 2013 to April 2016 were included. The single-step testing algorithm was introduced in March 2015. Before this, the two-step algorithm was used. Patients were followed up until August 2016. RESULTS: RNA quantitation in plasma was within one log of serum values for 21 paired samples. Although all patients in the single-step algorithm received an RNA test, only 70% completed the two-step testing algorithm; differences in referral rates to specialist care was due to 30% of HCV antibody-positive patients in the two-step algorithm not having follow-up whole-blood sampling for HCV RNA testing. Costs per new diagnosis and new diagnosis referred to specialist care were lower in single-step testing by £94.32 and £144.25, respectively. CONCLUSION: This study provides further evidence that a single-step testing algorithm, as recommended in the UK Standards for Microbiology Investigation, works in practice and should be the standard of care for screening for chronic HCV.

Cytomegalovirus replication kinetics in solid organ transplant recipients managed by preemptive therapy.

After allotransplantation, cytomegalovirus (CMV) may be transmitted from the donor organ, giving rise to primary infection in a CMV negative recipient or reinfection in one who is CMV positive. In addition, latent CMV may reactivate in a CMV positive recipient. In this study, serial blood samples from 689 kidney or liver transplant recipients were tested for CMV DNA by quantitative PCR. CMV was managed using preemptive antiviral therapy and no patient received antiviral prophylaxis. Dynamic and quantitative measures of viremia and treatment were assessed. Median peak viral load, duration of viremia and duration of treatment were highest during primary infection, followed by reinfection then reactivation. In patients who experienced a second episode of viremia, the viral replication rate was significantly slower than in the first episode. Our data provide a clear demonstration of the immune control of CMV in immunosuppressed patients and emphasize the effectiveness of the preemptive approach for prevention of CMV syndrome and end organ disease. Overall, our findings provide quantitative biomarkers which can be used in pharmacodynamic assessments of the ability of novel CMV vaccines or antiviral drugs to reduce or even interrupt such transmission.

Pancreas allograft thrombosis following intravenous immunoglobulin administration to treat parvovirus B19 infection.

Pancreas graft thrombosis is one of the commonest non-immunological causes for early graft loss after transplantation. This case report describes a patient who developed graft thrombosis after intravenous immunoglobulin administration to treat acute parvovirus B19 infection. The potential role of hypercoagulability in graft thrombosis and the implications for immunoglobulin therapy in transplant patients with hypercoagulable states is discussed.

Natural measles causes prolonged suppression of interleukin-12 production.

Among vaccine-preventable diseases, measles is the preeminent killer of children worldwide. Infection with measles virus (MV) is associated with prolonged suppression of cell-mediated immune responses, a phenomenon that is thought to underlie the susceptibility to secondary infections that accounts for most measles-related mortality. Interleukin (IL)-12 is critical for the orchestration of cellular immunity. MV specifically ablates IL-12 production by monocyte/macrophages in vitro through binding to CD46, a complement regulatory protein that is an MV receptor. To address the effect of MV on IL-12 responses in vivo, cytokine production was examined in Gambian patients with measles. IL-12 production by peripheral blood monocytes from such patients is markedly suppressed, which provides a unifying mechanism for many of the immunologic abnormalities associated with measles. This suppression is prolonged, with significant, stimulus-specific inhibition of IL-12 production demonstrable months after recovery from acute infection. However, despite this suppression, IL-12 responsiveness remains intact.

Identification of an immunodominant neutralizing and protective epitope from measles virus fusion protein by using human sera from acute infection.

Polyclonal sera obtained from African children with acute measles were used to screen a panel of 15-mer overlapping peptides representing the sequence of measles virus (MV) fusion (F) protein. An immunodominant antigenic region from the F protein (p32; amino acids 388 to 402) was found to represent an amino acid sequence within the highly conserved cysteine-rich domain of the F protein of paramyxoviruses. Epitope mapping of this peptide indicated that the complete 15-amino-acid sequence was necessary for high-affinity interaction with anti-MV antibodies. Immunization of two strains of mice with the p32 peptide indicated that it was immunogenic and could induce antipeptide antibodies which cross-reacted with and neutralized MV infectivity in vitro. Moreover, passive transfer of antipeptide antibodies conferred significant protection against fatal rodent-adapted MV-induced encephalitis in susceptible mice. These results indicate that this epitope represents a candidate for inclusion in a future peptide vaccine for measles.