Impact of ventilation tube insertion on long-term language outcomes at 6 and 10 years of age: A prospective pregnancy cohort study.

OBJECTIVE: Investigating the impact of early childhood ventilation tube insertion (VTI) on long-term language outcomes. DESIGN: Longitudinal cohort study. SETTING: A total of 2900 pregnant women participated in the Raine Study between 1989 and 1991 in Western Australia, and 2868 children have been followed up. PARTICIPANTS: Based on parental reports, 314 children had a history of recurrent otitis media but did not undergo VTI (rOM group); another 94 received VTI (VTI group); while 1735 had no history of rOM (reference group) in the first 3 years of childhood. Children with data on outcomes and confounders were included in analyses of PPVT-R at ages 6 (n = 1567) and 10 years (n = 1313) and CELF-III at 10 years (n = 1410) (approximately 5% in the VTI group and 15% in the rOM group). MAIN OUTCOME MEASURES: Peabody Picture Vocabulary Test-Revised edition and Clinical Evaluation of Language Fundamentals® Preschool-3. RESULTS: At 6 years, mean PPVT-R scores were significantly lower in the VTI group than the reference group (ß = -3.3; 95% CI [-6.5 to -0.04], p = .047). At 10 years, while the difference between the VTI and reference groups was less pronounced for PPVT-R scores, there was a small but consistent trend of lower measures, on average, across CELF-III scores (expressive: ß = -3.4 [-7.1 to 0.27], p = .069; receptive: ß = -4.1 [-7.9 to -0.34], p = .033; total: ß = -3.9 [-7.5 to -0.21], p = .038). There was no evidence to suggest that language outcomes in the rOM group differed from the reference group. CONCLUSION: Lower scores of language outcomes in school-aged children who received VTI in early childhood may suggest a long-term risk which should be considered alongside the potential benefits of VTI.

Factors that affect serum levels of ferritin in Australian adults and implications for follow-up.

BACKGROUND & AIMS: Serum levels of ferritin are commonly measured to assess iron stores but are affected by factors such as obesity and chronic disease. Published reference ranges have not changed in decades, and the number of patients whose levels exceed the upper limits has been increasing. As a result, more patients are evaluated for iron overload. METHODS: We compared serum levels of ferritin in 1188 Australian adults who participated in the 2005 Busselton Population Survey with levels from the 1995 survey. Parametric regression was used to assess the effects of body weight and biochemical parameters on serum level of ferritin to derive contemporary population-appropriate reference ranges. RESULTS: In 2005, age-adjusted levels of ferritin were 21% higher in men (P < .0001) and 10% higher in women (P = .01) than in 1995; 31% of men exceeded levels of 300 µg/L, compared with 23% in 1995. Body mass index (BMI) ≥25 kg/m(2) was associated with higher levels of ferritin in men ≥35 years old and in postmenopausal women (P ≤ .002). Serum level of γ-glutamyltransferase (GGT) correlated with serum level of ferritin (P < .0001). In men, the estimated 95th percentiles ranged from 353 to 495 µg/L (<35 years), from 350 to 511 µg/L (≥35 years, BMI <25 kg/m(2)), and from 413 to 696 µg/L (≥35 years, BMI ≥25 kg/m(2)) when GGT levels were 10-75 IU/L. In women, the 95th percentiles ranged from 106 to 235 µg/L (premenopausal), from 222 to 323 µg/L (postmenopausal, BMI <25 kg/m(2)), and from 249 to 422 µg/L (postmenopausal, BMI ≥25 kg/m(2)) when GGT levels were 8-45 IU/L. CONCLUSION: Serum levels of ferritin increased significantly between 1995 and 2005. Reference ranges that accommodate demographic and biomedical variations will assist clinicians in identifying individuals who require further evaluation for iron overload.

Correction for founder effects in host-viral association studies via principal components.

Viruses such as HIV and Hepatitis C (HCV) replicate rapidly and with high transcription error rates, which may facilitate their escape from immune detection through the encoding of mutations at key positions within human leukocyte antigen (HLA)-specific peptides, thus impeding T-cell recognition. Large-scale population-based host-viral association studies are conducted as hypothesis-generating analyses which aim to determine the positions within the viral sequence at which host HLA immune pressure may have led to these viral escape mutations. When transmission of the virus to the host is HLA-associated, however, standard tests of association can be confounded by the viral relatedness of contemporarily circulating viral sequences, as viral sequences descended from a common ancestor may share inherited patterns of polymorphisms, termed 'founder effects'. Recognizing the correspondence between this problem and the confounding of case-control genome-wide association studies by population stratification, we adapt methods taken from that field to the analysis of host-viral associations. In particular, we consider methods based on principal components analysis within a logistic regression framework motivated by alternative formulations in the Frisch-Waugh-Lovell Theorem. We demonstrate via simulation their utility in detecting true host-viral associations whilst minimizing confounding by associations generated by founder effects. The proposed methods incorporate relatively robust, standard statistical procedures which can be easily implemented using widely available software, and provide alternatives to the more complex computer intensive methods often implemented in this area.

The association between otitis media in early childhood with later behaviour and attention problems: A longitudinal pregnancy cohort.

OBJECTIVES: The present study aims to investigate the association between an early history of recurrent otitis media (OM) with or without ventilation tube insertion (VTI) and later behavioural problems in childhood and adolescence. METHODS: Parental reports in a longitudinal pregnancy cohort were used to classify children into three groups; recurrent OM without VTI (rOM group; n = 276), recurrent OM with VTI (VTI group; n = 62), and no history of early-life recurrent OM as a reference group (n = 1485). The Child Behaviour Checklist (CBCL) was administered at ages 5, 8, 10, and 13 years and data were analysed for psychological wellbeing. Mixed-effects regression modelling was used to investigate the associations between a history of rOM and CBCL T-scores across all ages for rOM and VTI groups compared to the reference group. All analyses were controlled for a wide range of confounding variables. RESULTS: The analyses revealed a significant association between recurrent OM and behavioural problems. While there was a general decline in scores (i.e. improvement) observed over the duration of the follow-up period, children in the rOM group displayed significantly higher scores for internalising and externalising behaviours at ages five, eight and 10 years. Attention scores were significantly higher across all ages in the rOM group. A transient increase in internalising behaviour was observed in the VTI group at ages eight and 10 years. Logistic regression models showed an increased overall likelihood for the rOM group only to fall within the abnormal clinical range for internalising and externalising behaviours. CONCLUSION: Early-life recurrent OM with and without VTI was associated with increased behavioural and attention problems in early and late childhood. This suggests that recurrent OM can have a significant impact on children's behaviour and attention that can persist into early adolescence.

Allogeneic hematopoietic stem cell transplantation recipients have defects of both switched and igm memory B cells.

Allogeneic hematopoietic stem cell transplant (HSCT) recipients were assessed to elucidate memory B cell defects underlying their increased susceptibility to infections, particularly by encapsulated bacteria. Circulating IgM memory B cells (CD19+, CD27+, IgM+) and switched memory B cells (CD19+, CD27+, IgM(-)) were enumerated in allogeneic HSCT recipients (n = 37) and healthy controls (n = 35). T lymphocyte subpopulations and serum levels of immunoglobulins, including IgG subclasses, and antibodies to pneumococcal polysaccharides were also assayed. Allogeneic HSCT recipients were deficient in both switched memory and IgM memory B cells compared to healthy controls (both P < .0001), irrespective of time post-HSCT. Switched memory B cell deficiency correlated with CD4+ T cell deficiency, and both correlated with serum levels of IgG1 (P < .0001), possibly reflecting impaired B cell isotype switching in germinal centres. "Steady-state" serum levels of antibodies to pneumococcal polysaccharides did not correlate with circulating memory B cells. Graft-versus-host disease (GVHD) was associated with lower IgM memory B cell counts and lower serum levels of IgG2, IgG4, IgA, and pneumococcal antibodies. The increased susceptibility of allogeneic HSCT patients to infection may reflect a combination of memory B cell defects, which are most common in patients with a history of GVHD.

Novel HLA Class I Alleles Outside the Extended DR3 Haplotype Are Protective against Autoimmune Hepatitis.

INTRODUCTION: HLA class II allele, DRB1*03:01, is the most common genetic risk factor for autoimmune hepatitis (AIH), but other unrecognized HLA related risks exist. METHODS: We compared the HLA class I (A, B, C) and class II (DR, DQ, DP) typing between patients with well-characterized AIH and healthy controls by high resolution sequencing of the HLA region. Seventy-three patients with AIH and 87 healthy controls were included. Association between HLA alleles and AIH was considered singly and in clusters and adjusted for age, gender, and DRB1*03:01. RESULTS: DRB1*03:01 was singly associated with AIH among whites (odds ratio [OR]: 3.09, P = 0.002) and carriers of DRB1*03:01 also carried DQA*05:01 and DQB1*02:01. Significant HLA class I alleles were associated with AIH including those belonging to the A03 (OR: 0.4, P = 0.01) and B44 supertype (OR: 0.44, P = 0.03). Further refinement of HLA-A by binding pocket structure revealed that the sequence Y(F/T)AVMENV(H/Q)Y, corresponding to HLA-A alleles A*03:01-02; *31:01; *32:02, was protective for AIH (OR: 0.3, P = 0.002). A protective association also existed for alleles belonging to the HLA-B binding pocket structure Y(H/Y)TVKEISNY (OR: 0.35, P = 0.01), corresponding to HLA-B alleles: B*40:01-02; *41:02; *44:02-03; *45:01; *49:01; *50:01-02. Associations with specific class I alleles belonging to the 8.1 ancestral haplotype (HLA-A*01:01, HLA-B*08:01, HLA-C*07:01) were not significant when considered jointly with DRB1*03:01 and reported protective class I alleles. DISCUSSION: Our study identified novel supertypes and HLA-A and B peptide binding structures protective against AIH. Further risk assessment of class I molecules remains important in AIH as they are key mediators of adaptive immunity.

Circulating memory B-cell subpopulations are affected differently by HIV infection and antiretroviral therapy.

OBJECTIVE: To determine if the depletion of IgM memory B cells might contribute to the increased susceptibility of HIV patients to pneumococcal infection, memory B-cell subpopulations were investigated in HIV patients, including patients receiving antiretroviral therapy (ART). METHODS: Blood B cells with the phenotype of IgM memory B cells (CD27, IgM) and switched memory B cells (CD27, IgM) were measured in antiretroviral-treated (n = 32) and untreated (n = 24) HIV patients and non-HIV controls (n = 35). Serum levels of IgG and IgG2 antibodies to pneumococcal polysaccharides, IgG, IgG subclasses, IgM and IgA were also assayed in HIV patients. RESULT: Switched memory B-cell counts were lower than controls in HIV patients (P < 0.01) irrespective of antiretroviral status and correlated with CD4 T-cell counts (r = 0.56, P = 0.001) in treated patients. In untreated patients, IgM memory B-cell counts correlated with CD4 T-cell counts (r = 0.73, P < 0.0001) reflecting higher values than controls in patients with CD4 T-cell counts greater than 300 cells/microl (P = 0.004) and lower values than controls in patients with CD4 T-cell counts below 300 cells/microl (P = 0.0001). There was no relationship between serum levels of pneumococcal antibodies and IgM or switched memory B cells. CONCLUSION: The depletion of IgM memory B cells in untreated HIV patients with a CD4 T-cell count below 300 cells/microl might be a risk factor for pneumococcal infection. The depletion of switched memory B cells is a complication of HIV infection irrespective of ART and might contribute to impaired IgG antibody responses. Memory B-cell subpopulations might predict the risk of pneumococcal sepsis more accurately than the CD4 T-cell count or pneumococcal antibody levels.

Shared peptide binding of HLA Class I and II alleles associate with cutaneous nevirapine hypersensitivity and identify novel risk alleles.

Genes of the human leukocyte antigen (HLA) system encode cell-surface proteins involved in regulation of immune responses, and the way drugs interact with the HLA peptide binding groove is important in the immunopathogenesis of T-cell mediated drug hypersensitivity syndromes. Nevirapine (NVP), is an HIV-1 antiretroviral with treatment-limiting hypersensitivity reactions (HSRs) associated with multiple class I and II HLA alleles. Here we utilize a novel analytical approach to explore these multi-allelic associations by systematically examining HLA molecules for similarities in peptide binding specificities and binding pocket structure. We demonstrate that primary predisposition to cutaneous NVP HSR, seen across ancestral groups, can be attributed to a cluster of HLA-C alleles sharing a common binding groove F pocket with HLA-C*04:01. An independent association with a group of class II alleles which share the HLA-DRB1-P4 pocket is also observed. In contrast, NVP HSR protection is afforded by a cluster of HLA-B alleles defined by a characteristic peptide binding groove B pocket. The results suggest drug-specific interactions within the antigen binding cleft can be shared across HLA molecules with similar binding pockets. We thereby provide an explanation for multiple HLA associations with cutaneous NVP HSR and advance insight into its pathogenic mechanisms.

Use of alcohol, nicotine and other drugs in the Western Australian HIV Cohort study.

Self-report questionnaires on alcohol, nicotine and other drugs were administered to assess the current prevalence of alcohol, drug and nicotine use in our tertiary HIV service and inform the establishment of effective interventions. Many respondents reported use of alcohol over the preceding month (111 out of 152, 73%), and recent drug use (48 out of 137, 35%) and frequently both. Sessional alcohol consumption was prevalent among drinkers (52 out of 111, 47%), and correlated with both early treatment phase (P=0.009) and non-adherence (P=0.03). Encouraged by a notable proportion of patients expressing interest in clinic-based smoking cessation counselling, we recommend a targeted education strategy to motivate patients in health-seeking behaviours.

Low CD4+ T-cell counts in HIV patients receiving effective antiretroviral therapy are associated with CD4+ T-cell activation and senescence but not with lower effector memory T-cell function.

The adverse effects of immune activation on CD4(+) T-cell recovery and the relationship between CD4(+) T-cell counts and effector T-cell function were examined in HIV-1 patients receiving long-term effective ART. Patients with nadir CD4(+) T-cell counts <100/microl, > 12 months on ART and >6 months with <50 HIV RNA copies/ml were stratified by current CD4(+) T-cell counts and patients from the lowest (n = 15) and highest (n = 12) tertiles were studied. We assessed proliferation (Ki67), activation (HLA-DR, CD38) and replicative senescence (CD57) by flow cytometry and CD4(+) T-cell responses to CMV by IFN-gamma ELISpot. Proportions of CD4(+) T-cells expressing HLA-DR or CD57 were strong univariate predictors of total (P = 0.0002 and P = 0.002) and naive (P < 0.0001 and P < 0.0001, respectively) CD4(+) T-cell counts, suggesting that CD4(+) T-cell activation drives the depletion of naive CD4(+) T-cells. This was clearest in patients with a small/undetectable thymus. IFN-gamma responses to CMV were similar in patients with low or high CD4(+) T-cell counts.

A T2 cytokine environment may not limit T1 responses in human immunodeficiency virus patients with a favourable response to antiretroviral therapy.

Low-level production of interferon-gamma (IFN-gamma) marks human immunodeficiency virus (HIV)-induced immunodeficiency and has been ascribed to a bias towards T2 cytokines. This was investigated in two cross-sectional studies of HIV patients who were immunodeficient when they began antiretroviral therapy (ART) and had stable increases in CD4 T-cell counts. Blood leucocytes were assessed unstimulated or after stimulation with cytomegalovirus (CMV), anti-CD3 or mitogen. IFN-gamma and interleukin (IL)-5 responses were initially assessed by enzyme-linked immunosorbent spot-forming cell assay (ELISPOT) and enzyme-linked immunosorbent assay (ELISA). We then adopted a sensitive reverse transcription-polymerase chain reaction (RT-PCR) system to assess IFN-gamma, IL-5, IL-4 and IL-4delta2 (an inhibitory splice variant of IL-4) mRNA. The results were correlated with putative serological markers of a T1 [lymphocyte activation gene-3 (LAG-3), CD26] or a T2 [CD30, immunoglobulin E (IgE)] cytokine environment. IL-5 production and IgE levels were elevated in patients. IgE levels did not correlate with IFN-gamma, but showed an inverse correlation with IL-5 released in culture (P = 0.05). The levels of IL-4, IFN-gamma, IL-5 and IL-4delta2 mRNA were correlated after anti-CD3 stimulation, where IL-5 was the best predictor of IFN-gamma mRNA (P = 0.006). Weak positive correlations were evident between CD30 and cytokine mRNA levels, whilst IgE correlated inversely with IL-4, IL-4delta2, IL-5 and IFN-gamma mRNA levels. These analyses provide no evidence for an inverse relationship between T1 and T2 cytokine responses in HIV patients, but suggest that the elevation of IgE marks low cytokine responses.

Tissue-specific associations between mitochondrial DNA levels and current treatment status in HIV-infected individuals.

BACKGROUND: Tissue mitochondrial DNA (mtDNA) levels have been proposed as a marker of nucleoside analouge reverse transcriptase inhibitor (NRTI) toxicity. However, clinical studies have yielded conflicting data regarding possible associations with mtDNA levels. This study examined mtDNA levels in matched samples of peripheral blood mononuclear cells (PBMCs) and subcutaneous fat from a large Australian cohort to examine treatment, clinical, and demographic associations with mtDNA depletion. METHODS: mtDNA was quantified by real-time polymerase chain reaction. Results were compared across patient treatment and demographic details using linear mixed models. RESULTS: One hundred sixty-three PBMCs and 161 fat samples were available from 61 individuals. Current NRTI exposure was the major determinant of mtDNA levels. Both ddI (didanosine) and d4T (stavudine) exposures were associated with mtDNA depletion in fat (P < or = 0.0001 vs. those not on NRTIs). DdI exposure (P = 0.003), but not d4T exposure (P = 0.5), was associated with mtDNA depletion in PBMCs. No association between patient demographics or time on current therapy and mtDNA was observed. CONCLUSIONS: Current NRTI exposure is the major determinant of tissue mtDNA, but the precise determinants are tissue specific. Both ddI and d4T exposure are associated with fat mtDNA depletion, whereas ddI exposure was the only observed association with mtDNA depletion in PBMCs.

Viral load detectability profiles for HIV infection.

The introduction of potent antiretroviral therapies for treatment of HIV infection typically results in a dramatic reduction in plasma HIV RNA concentration, often to levels undetectable by current measurement practices. However, although a high proportion of patients achieve 'undetectability', many then experience a return to a state of detectability at a later date. As evaluation of virologic response provides a useful measure of therapy efficacy, it is of interest to estimate the proportions of cases with undetectable viral load over time following commencement of treatment. These proportions depend on the rates of transition from detectability to undetectability and subsequent return to detectability, and may be related to covariates or risk factors, possibly differing in both transitions. We consider construction of detectability profiles as estimates of these proportions, based on parametric modelling of the component survival distributions. The method is applied to an examination of the effects of baseline CD4 T-cell lymphocyte counts on virologic response to therapy amongst patients of the Western Australian HIV Cohort Study.

Randomized, controlled, 48-week study of switching stavudine and/or protease inhibitors to combivir/abacavir to prevent or reverse lipoatrophy in HIV-infected patients.

OBJECTIVE: HIV-1 protease inhibitors (versus no protease inhibitors) and stavudine (versus zidovudine) are independently associated with a higher risk of lipoatrophy in HIV-infected patients. We sought to determine whether the revision of stavudine and/or protease inhibitor-containing regimens to combivir/abacavir would result in prevention and/or reversibility of lipoatrophy in HIV-1-infected patients. DESIGN: The investigation was a prospective, randomized, controlled, open-label study. SUBJECTS: The subjects included 37 HIV-1-infected individuals with stable undetectable HIV-1 loads who were taking a regimen containing either stavudine or zidovudine with lamivudine and a protease inhibitor. INTERVENTION: Subjects were randomized to continue therapy or switch stavudine to zidovudine and protease inhibitor to abacavir, such that the universal switch regimen was combivir (zidovudine/lamivudine) and abacavir. MAIN OUTCOME MEASURES: Total body, leg, and arm fat mass was measured at baseline, 24 weeks, and 48 weeks using whole-body dual-energy x-ray absorptiometry. Single-cut L4 computed tomography and assays of multiple metabolic parameters were also performed. RESULTS: There was an average gain in fat mass of 0.009 kg/(leg.mo) in switch patients versus a loss of 0.010 kg/(leg.mo) in controls (p =.04, on-treatment analysis) over 48 weeks. Significant arm fat restoration was observed in patients who switched regimens, with an average gain of 0.014 kg/(arm.mo) (p =.004), whereas controls did not have a significant change from baseline. Analyses of percentage changes in arm and leg fat masses showed similar findings. No significant effects on intraabdominal fat, blood lipid levels, glycemic indices, and lactate levels were detected, although most baseline mean values were normal in study subjects. Combivir/abacavir maintained virological control in all but one case, and three (13.6%) of 22 individuals had adverse reactions to abacavir therapy. CONCLUSIONS: A switch to combivir/abacavir therapy was associated with objective evidence of limb fat-sparing and fat restoration compared with continued treatment with stavudine and/or protease inhibitor.