Christopher Conlon

Disseminated Penicillium marneffei infection presenting as a right upper lobe mass in an HIV positive patient

A 35 year old HIV positive patient from Hong Kong presented with a fever, cough and a skin rash in association with a lung mass, all of which were due to disseminated Penicillium marneffeiinfection. He made a good response to antifungal therapy. The lung mass is a previously undescribed pulmonary manifestation of disseminated Penicillium marneffei infection. Infections with this fungus should be suspected in any patient with HIV and respiratory symptoms who has visited southeast Asia.

Immune Activation and CD8+ T-Cell Differentiation towards Senescence in HIV-1 Infection

Progress in the fight against the HIV/AIDS epidemic is hindered by our failure to elucidate the precise reasons for the onset of immunodeficiency in HIV-1 infection. Increasing evidence suggests that elevated immune activation is associated with poor outcome in HIV-1 pathogenesis. However, the basis of this association remains unclear. Through ex vivo analysis of virus-specific CD8+ T-cells and the use of an in vitro model of naïve CD8+ T-cell priming, we show that the activation level and the differentiation state of T-cells are closely related. Acute HIV-1 infection induces massive activation of CD8+ T-cells, affecting many cell populations, not only those specific for HIV-1, which results in further differentiation of these cells. HIV disease progression correlates with increased proportions of highly differentiated CD8+ T-cells, which exhibit characteristics of replicative senescence and probably indicate a decline in T-cell competence of the infected person. The differentiation of CD8+ and CD4+ T-cells towards a state of replicative senescence is a natural process. It can be driven by excessive levels of immune stimulation. This may be part of the mechanism through which HIV-1-mediated immune activation exhausts the capacity of the immune system.

A Systematic Review of the Antifungal Effectiveness and Tolerability of Amphotericin B Formulations

OBJECTIVE A systematic review was performed to compare the effectiveness and tolerability of lipid-based amphotericin B (AmB) formulations and conventional AmB in the treatment of systemic fungal infections. METHODS The literature and unpublished studies were searched using MEDLINE, EMBASE, Biological Abstracts, AIDSLINE, CANCERLIT, CRD database, Cochrane Controlled Trials Register, and other databases. Search terms included: amphotericin, liposom*, lipid*, colloid*, antifungal agents, and mycoses. Studies were selected according to predetermined criteria. The outcome measures reviewed were efficacy, mortality, renal toxicity, and infusion-related reactions. Meta-analyses and number-needed-to-treat (NNT) analyses were performed. RESULTS Seven studies (8 publications) met the entry criteria. Meta-analysis showed that lipid-based formulations significantly reduced all-cause mortality risk by an estimated 28% compared with conventional AmB (odds ratio [OR], 0.72; 95% CI, 0.54 to 0.97). There was no significant difference in efficacy between the lipid-based formulations and conventional AmB (OR, 1.21; 95% CI, 0.98 to 1.49). AmB lipid complex (ABLC) and liposomal AmB (L-AmB) significantly reduced the risk of doubling serum creatinine by an estimated 58% (OR, 0.42; 95% CI, 0.33 to 0.54). There was no significant reduction in risk of infusion-related reactions with lipid-based formulations, although this was difficult to interpret given the lack of consistent control of confounding factors. Comparing the lipid-based formulations with conventional AmB, the overall NNT to prevent 1 death was 31. The NNT to prevent a doubling of serum creatinine for both ABLC and L-AmB compared with conventional AmB was 6. CONCLUSIONS This study demonstrates advantages with lipid-based formulations over conventional AmB in terms of reduced risk of mortality and renal toxicity. Future trials in patients with proven fungal infection should control for factors such as premedication, infusion rates, fluid preloading, sodium/potassium supplementation, and concomitant medication.

HIV-specific cytotoxic T cells from long-term survivors select a unique T cell receptor.

HIV-specific cytotoxic T lymphocytes (CTL) are important in controlling HIV replication, but the magnitude of the CTL response does not predict clinical outcome. In four donors with delayed disease progression we identified Vβ13.2 T cell receptors (TCRs) with very similar and unusually long β-chain complementarity determining region 3 (CDR3) regions in CTL specific for the immunodominant human histocompatibility leukocyte antigens (HLA)-B8–restricted human immunodeficiency virus-1 (HIV-1) nef epitope, FLKEKGGL (FL8). CTL expressing Vβ13.2 TCRs tolerate naturally arising viral variants in the FL8 epitope that escape recognition by other CTL. In addition, they expand efficiently in vitro and are resistant to apoptosis, in contrast to FL8–specific CTL using other TCRs. Selection of Vβ13.2 TCRs by some patients early in the FL8-specific CTL response may be linked with better clinical outcome.

Assessment of Mycobacterium tuberculosis transmission in Oxfordshire, UK, 2007-12, with whole pathogen genome sequences: an observational study.

Summary Background Patients born outside the UK have contributed to a 20% rise in the UK’s tuberculosis incidence since 2000, but their effect on domestic transmission is not known. Here we use whole-genome sequencing to investigate the epidemiology of tuberculosis transmission in an unselected population over 6 years. Methods We identified all residents with Oxfordshire postcodes with a Mycobacterium tuberculosis culture or a clinical diagnosis of tuberculosis between Jan 1, 2007, and Dec 31, 2012, using local databases and checking against the national Enhanced Tuberculosis Surveillance database. We used Illumina technology to sequence all available M tuberculosis cultures from identified cases. Sequences were clustered by genetic relatedness and compared retrospectively with contact investigations. The first patient diagnosed in each cluster was defined as the index case, with links to subsequent cases assigned first by use of any epidemiological linkage, then by genetic distance, and then by timing of diagnosis. Findings Although we identified 384 patients with a diagnosis of tuberculosis, country of birth was known for 380 and we sequenced isolates from 247 of 269 cases with culture-confirmed disease. 39 cases were genomically linked within 13 clusters, implying 26 local transmission events. Only 11 of 26 possible transmissions had been previously identified through contact tracing. Of seven genomically confirmed household clusters, five contained additional genomic links to epidemiologically unidentified non-household members. 255 (67%) patients were born in a country with high tuberculosis incidence, conferring a local incidence of 109 cases per 100 000 population per year in Oxfordshire, compared with 3·5 cases per 100 000 per year for those born in low-incidence countries. However, patients born in the low-incidence countries, predominantly UK, were more likely to have pulmonary disease (adjusted odds ratio 1·8 [95% CI 1·2–2·9]; p=0·009), social risk factors (4·4 [2·0–9·4]; p<0·0001), and be part of a local transmission cluster (4·8 [1·6–14·8]; p=0·006). Interpretation Although inward migration has contributed to the overall tuberculosis incidence, our findings suggest that most patients born in high-incidence countries reactivate latent infection acquired abroad and are not involved in local onward transmission. Systematic screening of new entrants could further improve tuberculosis control, but it is important that health care remains accessible to all individuals, especially high-risk groups, if tuberculosis control is not to be jeopardised.

Expansion and Diversification of Virus-Specific T Cells following Immunization of Human Immunodeficiency Virus Type 1 (HIV-1)-Infected Individuals with a Recombinant Modified Vaccinia Virus Ankara/HIV-1 Gag Vaccine

ABSTRACT Affordable therapeutic strategies that induce sustained control of human immunodeficiency virus type 1 (HIV-1) replication and are tailored to the developing world are urgently needed. Since CD8+ and CD4+ T cells are crucial to HIV-1 control, stimulation of potent cellular responses by therapeutic vaccination might be exploited to reduce antiretroviral drug exposure. However, therapeutic vaccines tested to date have shown modest immunogenicity. In this study, we performed a comprehensive analysis of the changes in virus-specific CD8+ and CD4+ T-cell responses occurring after vaccination of 16 HIV-1-infected individuals with a recombinant modified vaccinia virus Ankara-vectored vaccine expressing the consensus HIV-1 clade A Gag p24/p17 sequences and multiple CD8+ T-cell epitopes during highly active antiretroviral therapy. We observed significant amplification and broadening of CD8+ and CD4+ gamma interferon responses to vaccine-derived epitopes in the vaccinees, without rebound viremia, but not in two unvaccinated controls followed simultaneously. Vaccine-driven CD8+ T-cell expansions were also detected by tetramer reactivity, predominantly in the CD45RA− CCR7+ or CD45RA− CCR7− compartments, and persisted for at least 1 year. Expansion was associated with a marked but transient up-regulation of CD38 and perforin within days of vaccination. Gag-specific CD8+ and CD4+ T-cell proliferation also increased postvaccination. These data suggest that immunization with MVA.HIVA is a feasible strategy to enhance potentially protective T-cell responses in individuals with chronic HIV-1 infection.

The ethics of research related to health care in developing countries

A report by the Nuffield Council on Bioethics, contrary to the Declaration of Helsinki, permits most important research initiatives in developing countries. The Ethics of Research Related to Health Care in Developing Countries by the Nuffield Council on Bioethics makes a number of innovative recommendations that depart from codes such as the Declaration of Helsinki. It recommends that standards of care might be relativised to the standard of that nation. It recommends that very good reasons need to be given for not giving post-trial access to medications but recognises that there may be justifiable instances of this. It is the view of the authors that these and other recommendations of the report are sensible pieces of advice given the complexities of the developing world.

Impaired IFN-γ-secreting capacity in mycobacterial antigen-specific CD4 T cells during chronic HIV-1 infection despite long-term HAART

Objective:To determine whether long-term HAART in chronic HIV-1 infection restores fully functional Mycobacterium tuberculosis (MTB)-specific CD4 T-cell responses. Design:A cross-sectional study of HIV-1-seropositive subjects on continuous HAART for over one year with CD4 cell counts greater than 300 cells/μl and undetectable viraemia, antiretroviral-naive individuals with primary HIV-1 infection (PHI), and healthy bacillus Calmette–Guérin-vaccinated low-risk controls. Methods:Purified protein derivative (PPD)-specific cytokine-secreting CD4 T cells were quantified ex vivo by enzyme-linked immunospot assay and intracellular cytokine staining. Lymphoproliferation was detected by [3H]-thymidine incorporation. Results:PPD-specific IFN-γ-secreting CD4 T cells were markedly reduced in chronic HAART-treated HIV-1-positive and PHI subjects compared with healthy controls [medians 30, 155 and 582 spot-forming cells/million peripheral blood mononuclear cells (PBMC), respectively, P < 0.0001 and P < 0.002], but the frequency of these cells was, nonetheless, significantly greater in viraemic PHI subjects than in aviraemic chronic HIV-1-positive subjects (P < 0.01). In the latter, low frequencies of PPD-specific IL-2 and IL-4-secreting CD4 T cells were also observed. However, lymphoproliferation was evident after the in-vitro stimulation of PBMC with PPD, indicating that MTB-specific T cells were present. The defect in IFN-γ secretion could be overcome by culture with IL-12. Conclusion:Despite an improvement in CD4 T-cell counts after HAART, MTB-specific CD4 T cells from chronically infected patients have impaired IFN-γ-secreting capacity. The early initiation of HAART might preserve functional CD4 T-cell responses to MTB, and warrants evaluation in populations with a high risk of dual infection.

Acute Pulmonary Schistosomiasis in Travelers Returning from Lake Malawi, Sub-Saharan Africa

We describe four cases of acute schistosomiasis presenting to the Infectious Diseases Unit of John Radcliffe Hospital (Oxford, England) during a 2-month period in autumn 1997. All four patients had swum in Lake Malawi, a freshwater lake in sub-Saharan Africa that is associated with Schistosoma haematobium and, less commonly, Schistosoma mansoni infections. All four patients had a severe acute illness and had prominent pulmonary involvement, both clinically and radiologically. This represents a change in the recognized pattern of presentation and could possibly reflect a new parasite variant in the lake.

Cutaneous Tuberculosis of the Penis and Sexual Transmission of Tuberculosis Confirmed by Molecular Typing

A case of culture-positive primary cutaneous Mycobacterium tuberculosis infection of the penis was diagnosed in a male patient; 1 year later, endometrial tuberculosis was diagnosed in the patients wife. These organisms were confirmed to be indistinguishable by use of molecular techniques.