Genomics Links Inflammation With Neurocognitive Impairment in Children Living With Human Immunodeficiency Virus Type-1.

BACKGROUND: We identified host single-nucleotide variants (SNVs) associated with neurocognitive impairment (NCI) in perinatally HIV-infected (PHIV) children. METHODS: Whole-exome sequencing (WES) was performed on 217 PHIV with cognitive score for age (CSA) < 70 and 247 CSA ≥ 70 (discovery cohort [DC]). SNVs identified in DC were evaluated in 2 validation cohorts (VC). Logistic regression was used to estimate adjusted odds ratios (ORs) for NCI. A human microglia NLRP3 inflammasome assay characterized the role of identified genes. RESULTS: Twenty-nine SNVs in 24 genes reaching P ≤ .002 and OR ≥ 1.5 comparing CSA < 70 to CSA ≥ 70 were identified in the DC, of which 3 SNVs were identified in VCs for further study. Combining the 3 cohorts, SNV in CCRL2 (rs3204849) was associated with decreased odds of NCI (P < .0001); RETREG1/FAM134B (rs61733811) and YWHAH (rs73884247) were associated with increased risk of NCI (P < .0001 and P < .001, respectively). Knockdown of CCRL2 led to decreased microglial release of IL-1ß following exposure to ssRNA40 while knockdown of RETREG1 and YWHAH resulted in increased IL-1ß release. CONCLUSIONS: Using WES and 2 VCs, and gene silencing of microglia we identified 3 genetic variants associated with NCI and inflammation in HIV-infected children.

Genetically determined ancestry is more informative than self-reported race in HIV-infected and -exposed children.

The Pediatric HIV/AIDS Cohort Study (PHACS), the largest ongoing longitudinal study of perinatal HIV-infected (PHIV) and HIV-exposed, uninfected (PHEU) children in the United States, comprises the Surveillance Monitoring of Antiretroviral Therapy [ART] Toxicities (SMARTT) Study in PHEU children and the Adolescent Master Protocol (AMP) that includes PHIV and PHEU children ≥7 years. Although race/ethnicity is often used to assess health outcomes, this approach remains controversial and may fail to accurately reflect the backgrounds of ancestry-diverse populations as represented in the PHACS participants.In this study, we compared genetically determined ancestry (GDA) and self-reported race/ethnicity (SRR) in the PHACS cohort. GDA was estimated using a highly discriminative panel of 41 single nucleotide polymorphisms and compared to SRR. Because SRR was similar between the PHIV and PHEU, and between the AMP and SMARTT cohorts, data for all unique 1958 participants were combined.According to SRR, 63% of study participants identified as Black/African-American, 27% White, and 34% Hispanic. Using the highest percentage of ancestry/ethnicity to identify GDA, 9.5% of subjects were placed in the incorrect superpopulation based on SRR. When ≥50% or ≥75% GDA of a given superpopulation was required, 12% and 25%, respectively, of subjects were placed in the incorrect superpopulation based on SRR, and the percent of subjects classified as multiracial increased. Of 126 participants with unidentified SRR, 71% were genetically identified as Eurasian.GDA provides a more robust assessment of race/ethnicity when compared to self-report, and study participants with unidentified SRR could be assigned GDA using genetic markers. In addition, identification of continental ancestry removes the taxonomic identification of race as a variable when identifying risk for clinical outcomes.

Killer Cell Immunoglobulin-Like Receptor Alleles Alter HIV Disease in Children.

BACKGROUND: HLA class I molecules are ligands for killer cell immunoglobin like receptors (KIR) that control the antiviral response of natural killer (NK) cells. However, the effects of KIR and HLA (KIR/HLA) alleles on HIV disease of children have not been studied. METHODS: 993 antiretroviral naïve children with symptomatic HIV infection from PACTG protocols P152 and P300 were genotyped for KIR and HLA alleles using the Luminex platform. Linear regression was used to test the association between genotypes and baseline pre-ART HIV RNA, CD4+ lymphocyte count, and cognitive score, adjusting for age, race/ethnicity and study. The interaction between genetic markers and age was investigated. To account for multiple testing the false discovery rate (FDR) was controlled at 0.05. RESULTS: Children with the KIR2DS4*ALL FULL LENGTH (KIR2DS4*AFL) allele had higher CD4+ lymphocyte counts. Among children ≤2 years of age, the KIR2DS4*AFL was associated with lower plasma HIV RNA and higher cognitive index scores. KIR Cent2DS3/5_1 had lower CD4+ lymphocyte counts in children ≤2 years of age, while the presence of Tel1, Tel2DS4_2, Tel2DS4_4, Tel8, Tel2DS4_6 had higher CD4+ lymphocyte counts in all children. Presence of Cent2, Cent4 and Cent8 was associated with increased HIV RNA load in children ≤2 years. Presence of KIR3DL1+Bw4 was associated with higher CD4+ lymphocyte counts in all children. Among children >2 years old, KIR3DS1+Bw4-80I was associated with higher plasma HIV RNA, and Bw6/Bw6 was associated with lower plasma HIV RNA compared to children with KIR3DS1+Bw4-80I. CONCLUSIONS: Presented data show for the first time that specific KIR alleles independently or combined with HLA ligands are associated with HIV RNA and CD4+ lymphocyte counts in infected, antiretroviral naive children; and many of these effect estimates appear to be age dependent. These data support a role for specific KIR alleles in HIV pathogenesis in children.

Associations of Genetically Determined Continental Ancestry With CD4+ Count and Plasma HIV-1 RNA Beyond Self-Reported Race and Ethnicity.

BACKGROUND: Ancestry informative markers (AIMs) measure genetic admixtures within an individual beyond self-reported racial/ethnic (SRR) groups. Here, we used genetically determined ancestry (GDA) across SRR groups and examine associations between GDA and HIV-1 RNA and CD4 counts in HIV-positive children in the United States. METHODS: Forty-one AIMs, developed to distinguish 7 continental regions, were detected by real-time PCR in 994 HIV-positive, antiretroviral naive children. GDA was estimated comparing each individual's genotypes to allele frequencies found in a large set of reference individuals originating from global populations using STRUCTURE. The means of GDA were calculated for each category of SRR. Linear regression was used to model GDA on CD4 count and log10 RNA, adjusting for SRR and age. RESULTS: Subjects were 61% black, 25% Hispanic, 13% white, and 1.3% Unknown. The mean age was 2.3 years (45% male), mean CD4 count of 981 cells per cubic millimeter, and mean log10 RNA of 5.11. Marked heterogeneity was found for all SRR groups with high admixture for Hispanics. In adjusted linear regression models, subjects with 100% European ancestry were estimated to have 0.33 higher log10 RNA levels (95% CI: 0.03 to 0.62, P = 0.028) and 253 CD4 cells per cubic millimeter lower (95% CI: -517 to 11, P = 0.06) in CD4 count, compared to subjects with 100% African ancestry. CONCLUSION: Marked continental admixture was found among this cohort of HIV-infected children from the United States. GDA contributed to differences in RNA and CD4 counts beyond SRR and should be considered when outcomes associated with HIV infection are likely to have a genetic component.

Complement Component 3 Is Associated with Metabolic Comorbidities in Older HIV-Positive Adults.

Our objective was to evaluate the association of plasma inflammatory biomarkers with MetS in an older population of treated HIV-infected (HIV(+)) as compared to age-matched HIV-negative (HIV(-)) adults. This was done in a retrospective observational study. Plasma concentrations of complement component 3 (C3), cystatin C, fibroblast growth factor 1, interleukin 6, oxidized LDL, soluble RAGE, soluble CD163, soluble CD14, and osteopontin were measured in 79 HIV(+) participants on combination antiretroviral treatment (cART) with a suppressed HIV viral load and 47 HIV(-) participants with a median age of 59 (range 50 to 79). Outcomes were individual MetS components (hypertension, type II diabetes, dyslipidemia, and obesity) and MetS. Covariates were screened for inclusion in multivariable models. Odds ratios are reported per 50 mg/dl increase in C3. In the HIV(+) group, higher C3 levels were associated with MetS (OR 3.19, p = 0.004), obesity (OR 2.02, p = 0.01), type II diabetes (OR 1.93, p = 0.02), and at a trend level with dyslipidemia (OR 1.87, p = 0.07) and hypertension (OR 1.66, p = 0.09). C3 levels were significantly higher in HIV(+) participants with MetS compared to those without MetS (p = 0.002). C3 was higher among HIV(+) patients with three or four MetS components as compared to those with one or two (p = 0.04) and those with none (p = 0.002). No associations were found between C3 and the outcomes for HIV(-) participants. C3 is strongly associated with both MetS and MetS components in an older HIV(+) sample on cART compared to HIV(-) controls. C3 warrants further investigation as a marker of cardiometabolic risk among persons aging with HIV.

Associations of host genetic variants on CD4⁺ lymphocyte count and plasma HIV-1 RNA in antiretroviral naïve children.

BACKGROUND: CD4 T-lymphocyte (CD4) counts and HIV plasma RNA concentration (RNA) are 2 key HIV disease markers. The complex interplay between virus and host genetics may contribute to differences in viral set point and CD4 status. Determining the effects of host genetic variation on HIV disease markers is often complicated by the use of antiretroviral therapy. In this study, the association between genetic variants and baseline HIV RNA and CD4 counts was examined in a large cohort of antiretroviral naïve children. METHODS: Specimens from 1053 HIV-infected children were screened for single nucleotide polymorphisms in 78 regions from 17 genes. Linear regression with a robust variance estimator was used to test the association between genetic markers with HIV RNA and CD4 count, controlling for age, race/ethnicity and study. False discovery rate (FDR) controlling was used to adjust for multiple testing. RESULTS: The study population was 60% black, 26% Hispanic and 13% white; median age 2.35 years; 55% female. Baseline median CD4 count was 780/mm; median log10 HIV RNA was 5.17 copies/mL. For analyses of the associations of genetic makers with baseline CD4 count, 6 HLA and 4 additional markers exhibited P < 0.05, but none met the criteria for statistical significance with FDR controlled at 0.05. For baseline HIV RNA, HLA DRB1*15, DRB1*10, B-27/57, B-14, Cw-8, B-57 were statistically significant with FDR controlled at 0.05. CONCLUSIONS: These results provide strong evidence that HLA DRB1*15, DRB1*10, B-27/57, B-14, Cw-8, B-57 are associated with HIV RNA and play a role in HIV pathogenesis in infected children.

Vitamin D-related host genetic variants alter HIV disease progression in children.

BACKGROUND: Vitamin D deficiency is common in HIV infection and has been associated with advanced disease. This study investigated whether vitamin D-related genetic variants were associated with disease progression in HIV-infected children. METHODS: The Fok-I (C/T), Bsm-I (G/A), GC (A/C), DHCR7 (G/T) and CYP2R1 (G/A) genetic variants were detected by real-time polymerase chain reaction in HIV-infected children who participated in the Pediatric AIDS Clinical Trials Group P152 and P300 protocols, which predated the availability of effective combination antiretroviral therapy. The primary endpoints included time to progression to the first HIV-related disease endpoint (≥2 opportunistic infection, weight growth failure) or death, which constituted the progression-free survival. Analyses were performed for age>2 years and ≤2 years separately adjusting for race and treatment effect. RESULTS: Of the 998 children evaluated, 139 experienced HIV disease progression. For children>2 years, rapid disease progression was associated with the DHCR7 G allele compared with the T allele (G/G vs. T/T: hazard ratio [HR]=5.0, P = 0.035; G/T vs. T/T: HR=4.5, P=0.042; G/G+G/T vs. T/T: HR=4.8, P=0.036) and the Bsm-I A allele compared with the G allele (A/G vs. G/G: HR=2.2, P=0.014 and A/G+A/A vs. G/G: HR=2.0, P=0.026). In children≤2 years, the Bsm-I A allele increased the risk of disease progression in Hispanics (A/A vs. G/A+G/G: HR=2.8, P=0.03 and A/A vs. G/G: HR=2.8, P=0.046) and whites (A/A vs. G/G: HR=6.6, P=0.025 and A/A vs. G/A+G/G: HR=3.6, P=0.038). CONCLUSIONS: Vitamin D-related host genetic variants that alter the availability and activity of vitamin D are associated with risk of HIV disease progression in children and may vary by age and race.

Genetic variants in toll-like receptor 2 (TLR2), TLR4, TLR9, and FCγ receptor II are associated with antibody response to quadrivalent meningococcal conjugate vaccine in HIV-infected youth.

This study examined the association of host genetic variants with the antibody response to the quadrivalent meningococcal conjugate vaccine (MCV4) in HIV-infected youth. Genetic variants associated with severity of meningococcal disease, including the IgG Fc receptor (FCγRII)-A484T, interleukin-10 (IL-10)-A1082G, -C819T, and -C627A, IL-4-C589T, mannose binding lectin-2 (MBL2)-A/O, -H/L, -P/Q, and -X/Y, toll-like receptor 2 (TLR2)-G2408A, TLR4-A12874G and -C13174T, and TLR9-T1237C and -T1486C were determined by real-time PCR (RT-PCR) for 271 HIV-infected subjects (median, 17 years). Response was defined as a ≥4-fold increase from entry in bactericidal antibody titers to each serogroup. Generalized estimating equation (GEE) models were used to evaluate the association of allelic variants with the immunologic response to all serogroups within each subject with and without adjusting for CD4 percentage and HIV viral load. At week 4, but not after, subjects with TLR2-2408-G/A versus -G/G genotypes and the TLR4-12874-A/A genotype were more likely to achieve a ≥4-fold increase overall in the four serogroups (unadjusted P of 0.006 and adjusted P of 0.008 and unadjusted P of 0.008 and adjusted P of 0.019, respectively). At week 28, the TLR9-1237 T allele was associated with enhanced antibody response (T allele versus C/C, unadjusted P of 0.014 and adjusted P of 0.009), which was maintained at week 72 (unadjusted and adjusted P of 0.008). At week 72, the FcγRII-131Arg allotype was associated with a ≥4-fold increase in antibody titer versus those with His/His (unadjusted P of 0.009; adjusted P of <0.001). These findings suggest that for HIV-infected youth, the initial antibody response to MCV4 is associated with variants in TLR2 and TLR4 while the long-term response is associated with genetic polymorphisms in TLR9 and FcγRIIa.

Genetic variants in the host restriction factor APOBEC3G are associated with HIV-1-related disease progression and central nervous system impairment in children.

BACKGROUND: Apolipoprotein B mRNA editing catalytic polypeptide 3G (APOBEC3G) protein is incorporated into nascent virus particles and mediates cytidine deamination (C-to-U) of first-strand reverse transcripts of HIV-1 in target cells resulting in G-to-A hypermutation of the coding strand and premature degradation. We investigated the effects of APOBEC3G genetic variants on HIV-1-related disease in children. METHODS: APOBEC3G variants were detected using real-time polymerase chain reaction in HIV-1-infected children from Pediatric AIDS Clinical Trials Group (PACTG) protocols P152 and P300 that evaluated the effectiveness of 3 mono- or dual-nucleoside reverse transcriptase inhibitor treatments. RESULTS: Of the 1049 children evaluated, 60% were non-Hispanic black, 26% Hispanic, 13% non-Hispanic white, and 1% other or unknown race/ethnicity. Age ranged from 42 days to 18 years; 45% were males. APOBEC3G-H186R homozygous G/G genotype was associated with more rapid HIV-1 disease progression [hazard ratio (HR): 1.69; P = 0.01] and central nervous system (CNS) impairment (HR: 2.00; P = 0.02) compared with the wild-type A/A or heterozygous A/G genotype in a recessive model. In both additive and dominant models, APOBEC3G-F119F-C allele was associated with protection against disease progression (HR [additive]: 0.69; P = 0.002 and HR [dominant]: 0.60; P = 0.001, respectively) and CNS impairment (HR [additive]: 0.65; P = 0.02 and HR [dominant]: 0.54; P = 0.007, respectively). These associations remained significant in multivariate analyses controlling for baseline characteristics or previously identified genetic variants known to alter HIV-1-related disease in this cohort of children. CONCLUSIONS: APOBEC3G-H186R and F119F variants are associated with altered HIV-1-related disease progression and CNS impairment in children.

The influence of HLA on HIV-associated neurocognitive impairment in Anhui, China.

BACKGROUND: HLA-DR*04 was identified as a predictor of HIV-Associated neurocognitive disorder (HAND), low CD4 T-cell responses to HIV, and low plasma HIV RNA levels in a U.S. cohort. We hypothesized that low CD4 T-cell activation leads to poor immune control of HIV in the CNS, predisposing to HAND, but also provided fewer target (activated CD4 T-cells) for HIV replication. To assess the consistency of these HLA Class II associations in a new cohort and extend analysis to HLA Class I, HLA types, neurocognitive, and virologic status were examined in a cohort of former plasma donors in China. METHODS: 178 HIV infected individuals in Anhui China, were HLA typed and underwent neurocognitive evaluations (using locally standardized norms), neuromedical, treatment and virologic assessments at baseline and at 12 months. RESULTS: HLA DR*04 was associated with a higher rate of baseline neurocognitive impairment (p = 0.04), neurocognitive decline (p = 0.04), and lower levels of HIV RNA in plasma (p = 0.05). HLA Class I alleles (B*27,57,58,A*03,33) that specify a CD8 T-cell response to conserved HIV sequences were neuroprotective, associated with less impairment at baseline (p = 0.037), at month 012 (p = 0.013) and less neurocognitive decline (p = 0.023) in the interval. Consistent with the theory that effective CD8 T-cell responses require CD4 T-cell support, the HLA DR*04 allele reduced the neuroprotective effect of the Class I alleles. The presence of HLA-DR*04 and the Alzheimer associated allele ApoE4 in the same individual had a synergistic negative effect on cognition (p = 0.003). CONCLUSIONS: Despite major background differences between U.S. and Anhui China cohorts, HLA DR*04 predicted neurocognitive impairment and lower plasma HIV RNA levels in both populations. HLA Class I alleles associated with CD8 T-cell control of HIV were associated with protection from HAND, but protection was reduced in the presence of HLA-DR*04.

Sensitive CSF ELISAs for the detection of MBL, MASP-2 and functional MBL/MASP-2.

Mannose binding lectin (MBL) mediated complement pathway is an important constituent of innate immune response in several infections including neuroinflammatory and neurodegenerative diseases. Although there are Enzyme-Linked Immunosorbent Assays (ELISAs) for estimating MBL, MBL-associated serine protease-2 (MASP-2) and functional MBL-MASP-2 (fMBL) proteins for the plasma, serum and cell supernatants there are no established methods for their estimation in the cerebrospinal fluid (CSF). We developed sensitive ELISAs for the detection of MBL, fMBL and MASP-2 in the CSF. First, we adapted standard ELISAs for the detection of these proteins in the CSF. Second, we used a biotinyl-tyramide based horseradish peroxidase (HRP) signal amplification for the sensitive detection of these proteins in the CSF. In summary, using modified ELISA and biotinyl-tyramide based HRP signal amplification, we successfully detected MBL, fMBL and MASP-2 proteins in the CSF samples with high sensitivity and reproducibility.

Mannose binding lectin mediated complement pathway in multiple sclerosis.

Role of mannose binding lectin (MBL) complement activation pathway, an arm of innate immunity in multiple sclerosis (MS) was evaluated by analyzing the expression of MBL, MBL-associated serine protease-2 (MASP-2), and functional MBL/MASP-2 mediated C4 cleavage (fMBL) in 87 plasma and cerebrospinal fluid (CSF) samples from MS patients and non-MS controls. Median fMBL and MASP-2 plasma levels were higher in MS vs. non-MS cases. These associations remained in an analysis of subtypes of MS disease. These findings suggest a potential activation of MBL complement pathway in MS that may possibly alter the risk or progression of MS disease.

Expression of mannose binding lectin in HIV-1-infected brain: implications for HIV-related neuronal damage and neuroAIDS.

Mannose binding lectin (MBL) activates complement pathway that leads to pathogen opsonization and phagocytosis. MBL deficiency is linked to HIV transmission and disease progression. We sought to determine the role of MBL in HIV encephalitis (HIVE) by evaluating its presence and distribution in the HIV-1-infected brain and by assessing its association with monocyte chemoattractant protein-1 (MCP-1) expression. This retrospective study utilized archived post-mortem brain tissues obtained from 35 individuals enrolled in a longitudinal study as part of the California NeuroAIDS Tissue Network. MBL, MCP-1 and brain cell markers in post-mortem brain tissues with or without HIVE were evaluated using immunocytochemistry, immunofluorescence, confocal microscopy, and western blots. MBL was expressed in neurons, astrocytes, microglia, and oligodendrocytes of the frontal cortex of the HIV-1-infected brain. Overall, there were 30% to 40% more MBL-positive brain cells in HIVE vs non-HIVE cases (P = 0.01, paired t-test). Specifically, there was an increased MBL expression in the neuronal axons of HIVE cases. Also, western blots showed 3- to 4-fold higher levels of 78 kD MBL trimers in HIVE vs non-HIVE cases. This MBL-HIVE link was further confirmed by MBL associated higher MCP-1 expression in HIVE vs non-HIVE cases. HIV negative healthy individuals and normal or the gp120 transgenic mice did not show any differential MBL expression. Increased MBL expression in the major brain cell types, specifically in the neuronal axons of HIVE brain, and MBL associated higher MCP-1 expression in HIVE suggest that MBL could cause neuroinflammation and neuronal injury through MBL complement activation pathway.

HLA alleles are associated with altered risk for disease progression and central nervous system impairment of HIV-infected children.

OBJECTIVE: To examine the effects of human leukocyte antigen (HLA) alleles on HIV-1-related disease progression and central nervous system (CNS) impairment in children. DESIGN: Five hundred seventy-two HIV-1-infected children, identified as disease progressors or nonprogressors, were selected from PACTG P152 and P300 through a case-cohort sampling scheme. Study endpoints were HIV-1-related disease progression-free survival and time to CNS impairment. METHODS: DNA was genotyped for HLA alleles using a Luminex 100 platform. Weighted Kaplan-Meier methods, and Cox proportional hazards models were used to assess the effects of HLA alleles on study endpoints. RESULTS: Presence of the B-27 allele (n = 20) was associated with complete protection against disease progression and CNS impairment over the median follow-up of 26 months (P < 0.0001 for both). These findings held in multivariate analyses controlling for baseline covariates including race, gender, age, log HIV-1 RNA, CD4 lymphocyte count and percent, weight for age z score and treatment, and for other genotypes shown to affect HIV-1-related disease progression. Also, although the Cw-2 allele protected against disease progression [Hazard ratio (HR), 0.48; 95% confidence interval (CI): 0.28 to 0.81; P = 0.006], the A-24 allele was associated with more rapid CNS impairment (HR: 2.01; 95% CI: 1.04 to 3.88; P = 0.04). The HLA class II DQB1-2 allele was associated with a delayed disease progression (HR: 0.66; 95% CI: 0.47-0.92; P = 0.01) and CNS impairment (HR: 0.58; 95% CI: 0.36 to 0.93; P = 0.02). CONCLUSIONS: Presence of B-27, Cw-2, or DQB1-2 alleles was associated with delayed HIV-1 disease progression, while B-27, A-24, and DQB1-2 alleles were associated with altered progression to CNS impairment in children.

APOE epsilon4 and MBL-2 O/O genotypes are associated with neurocognitive impairment in HIV-infected plasma donors.

BACKGROUND: Host genetic factors are important determinants for risk of HIV-1 infection and disease progression. This study examined associations of host genetic variants and neurocognitive impairment in Chinese individuals infected through contaminated blood products. METHODS: Two hundred and one HIV-infected patients from Anhui, China, had neuropsychological tests at baseline and 12 months. DNA was genotyped for APOE epsilon2, epsilon3 and epsilon4 alleles; MBL2-A/O; CCR5-wt/Delta32; CCR5-59029-G/A; CCR2-180-G/A; SDF-1-G/A; IL4-589-C/T; MCP-1-2518-A/G; CX3CR1-745-G/A; -849-C/T polymorphisms and CCL3L1 copy number variants using real-time PCR. Univariate and multivariate analyses were performed. RESULTS: The cohort included 61% men, with mean education 5.5 years, AIDS diagnosis 113 (55%), on antiretrovirals 114 (56%), mean baseline CD4(+) cell count 349 cells/microl and mean log10 RNA 4.09. At baseline, 37% had global neuropsychological impairment increasing to 44% after 12 months. Of 43 patients with the APOE epsilon4 allele, 58% were cognitively impaired compared with 31% without the epsilon4 allele (P = 0.001, odds ratio 3.09, 95% confidence interval 1.54-6.18). The mean global deficit score (GDS) for epsilon4-positive participants on antiretrovirals for 12 months was 0.88 (0.55) compared with 0.63 (0.54) for epsilon4-negative participants (P = 0.053, 95% confidence interval -0.004 to 0.51). For MBL2, 52% of patients with the O/O genotype declined in cognitive function over 12 months compared with 23% with A/A (odds ratio 3.62, 95% confidence interval 1.46-9.03, P = 0.004). No associations were observed for the other genetic variants. CONCLUSION: The APOE epsilon4 allele was associated with increased risk for cognitive deficits, whereas the MBL2 O/O genotype was associated with increased risk for progressive cognitive decline in Chinese individuals infected with HIV through contaminated blood products.

CYP2C19 genetic variants affect nelfinavir pharmacokinetics and virologic response in HIV-1-infected children receiving highly active antiretroviral therapy.

BACKGROUND: The objective of this research was to identify the impact of genetic variants of P-glycoprotein (ABCB1) and cytochrome P450 (CYP) on nelfinavir pharmacokinetics and response to highly active antiretroviral therapy (HAART) in HIV-1-infected children. METHODS: HIV-1-infected children (n = 152) from Pediatric AIDS Clinical Trial Group 366 or 377 receiving nelfinavir as a component of HAART were evaluated. Genomic DNA was assayed for ABCB1 and CYP genetic variants using real-time polymerase chain reaction Nelfinavir oral clearance (CL/F), M8 to nelfinavir ratios, CD4 T cells, and HIV-1-RNA were measured during HAART. RESULTS: Nelfinavir CL/F and M8 to nelfinavir ratios were significantly associated with the CYP2C19-G681A genotypes (P < 0.001). Furthermore, the CYP2C19-G681A genotype was related to virologic responses at week 24 (P = 0.01). A multivariate analysis demonstrated that age (P = 0.03), concomitant protease inhibitor use (P < 0.001), and the CYP2C19-G681A genotype (P < 0.001) remained significant covariates associated with nelfinavir CL/F. CONCLUSIONS: CYP2C19 genotypes altered nelfinavir pharmacokinetics and the virologic response to HAART in HIV-1-infected children. These findings suggest that CYP2C19 genotypes are important determinants of nelfinavir pharmacokinetics and virologic response in HIV-1-infected children.

Human metapneumovirus associated with central nervous system infection in children.

BACKGROUND: Human metapneumovirus (hMPV) is an established pathogen of the respiratory tract of children and adults. hMPV is related to other paramyxoviruses known to cause encephalitis. Reports suggest that hMPV may cause disease of the central nervous system (CNS). METHODS: Two groups of patients were studied. The first group consisted of children between birth and 18 years from whom nasal scrapings were obtained between January 2004 and October 2005. hMPV RNA amplification by PCR was done and records were reviewed for clinical and demographic data. The second group consisted of patients with encephalitis referred to the California Encephalitis Project (CEP) for comprehensive diagnostic testing between November 2004 and June 2006. RESULTS: In group 1, 1474 specimens were examined for hMPV RNA. Sixty-three evaluable patients were infected with hMPV of whom 4 (6.3%) had seizures, compared with 145 patients infected with RSV of whom 1 had seizures (0.7%, P = 0.031). Comparing respiratory syncytial virus (RSV) and hMPV infections, there was no significant difference in the occurrence of fever. All children with hMPV infections and seizures were hospitalized and 3 were intubated because of status epilepticus. Group 2 consisted of 205 pediatric cases referred to CEP between November 2004 and June 2006 who had hMPV testing done. hMPV was detected in nasopharyngeal swabs of 5 patients. Neither hMPV RNA nor antihMPV specific IgM were detectable in the CSF from the 5 patients for whom CSF was available. CONCLUSION: Nine cases of CNS illness temporally associated with the presence of hMPV nucleic acid in the upper airway are described. Compared with children infected with RSV, children with hMPV were significantly more likely to have had a seizure. Our data, in conjunction with previously reported cases suggest that hMPV may be associated with a spectrum of CNS disease ranging from febrile seizures to severe, fatal encephalitis.

Host genetic determinants of human immunodeficiency virus infection and disease progression in children.

Increasing data support host genetic factors as an important determinants of human immunodeficiency virus type-1 (HIV-1) susceptibility, mother-to-child transmission (MTCT), and disease progression. Of these genetic mediators, those impacting innate and adaptive immune responses seem to play a critical role in viral infectivity and pathogenesis. During primary infection, CCR5 using virus is predominantly transmitted and polymorphisms that affect the expression of CCR5 alter the risk for MTCT and rate of disease. Chemokines that naturally bind to coreceptors alter infectivity and viral pathogenesis. Additional genes that affect innate immunity including those encoding for MBL2 and those modulating the adaptive immune response including CX3CR1 and human leukocyte antigen types can significantly modify susceptibility and response to HIV-1 infection. As young children develop, the dependence on certain arms of the immune system varies and can alter the effect of genetic variants. Additionally, host genetic factors may alter the response to antiretrovirals. Finally, because HIV-infected children progress more rapidly than adults and have fewer background cofactors, such as drug use and coinfections, the effects of host factors on HIV-1 disease may be more clearly identified. In this review, we summarize available data on the impact of host genetics on MTCT and disease progression of HIV-infected children.

Associations of chemokine receptor polymorphisms With HIV-1 mother-to-child transmission in sub-Saharan Africa: possible modulation of genetic effects by antiretrovirals.

BACKGROUND: HIV-1 mother-to-child transmission (MTCT) remains an important route of infection in sub-Saharan Africa. METHODS: Genetic variants in CCR5 promoter, CCR2, CX3CR1, and Stromal cell-derived factor-1 (SDF-1) genes were determined in 980 infants from sub-Saharan Africa using real-time polymerase chain reaction to determine association with MTCT. RESULTS: In antiretroviral-naive mother-infant pairs (n = 637), CCR5 promoter polymorphisms at positions 59029: A allele vs. G/G [odds ratio (OR): 1.61, 95% confidence interval (CI): 1.04 to 2.48; P = 0.032] and 59356: T allele vs. C/C (OR: 0.63, 95% CI: 0.41 to 0.96; P = 0.033) and CCR2-180: G allele vs. A/A (OR: 3.32, 95% CI: 1.13 to 9.73; P = 0.029) were associated with risk of MTCT. Treatment of HIV-1-infected mothers and infants with single-dose nevirapine or perinatal zidovudine altered but did not eliminate the association of genetic variants with MTCT. CONCLUSIONS: CCR5 promoter, CCR2, and CX3CR1 polymorphisms were associated with risk of MTCT likely through their role as an HIV-1 coreceptor or by modulating the early immune response. Host genetics may continue to alter MTCT when short-course interventions that only partially suppress virus are used. These findings will need to be confirmed in validation cohorts with a large number of infected infants.

An age-dependent association of mannose-binding lectin-2 genetic variants on HIV-1-related disease in children.

BACKGROUND: Mannose-binding lectin (MBL) is part of the lectin pathway of complement activation against various pathogens; however, its role in innate immune responses against HIV-1 infection in children is unknown. OBJECTIVE: This study evaluated the effects of mannose-binding lectin-2 (MBL2) alleles on HIV-1 disease progression and central nervous system (CNS) impairment in children. METHODS: A cohort of 1037 HIV-1-infected children enrolled in Pediatrics AIDS Clinical Trial Group protocols P152 and P300 before the availability of effective antiretroviral therapy was genotyped for MBL2 and evaluated for disease progression. RESULTS: Children with the homozygous variant MBL2-O/O genotype were more likely to experience rapid disease progression and CNS impairment than those with the wild-type AA genotype. The effects were predominantly observed in children younger than 2 years. In unadjusted Cox proportional hazards models, children younger than 2 years with MBL2-O/O experienced more rapid disease progression (O/O vs AA: relative hazard [RH], 1.54; 95% CI, 1.07-2.22; P = .02; O/O vs A/O: RH, 2.28; 95% CI, 1.09-4.79; P = .029). Similarly, children with MBL2-O/O were more likely to experience rapid progression to CNS impairment (O/O vs A/A: RH, 2.78; 95% CI, 1.06-2.69, P = .027; O/O vs A/O: RH, 1.69; 95% CI, 1.07-7.21; P = .035). The effects remained significant after adjustment for CD4(+) lymphocyte count, plasma HIV-1 RNA, and other genotypes. CONCLUSIONS: MBL2-O/O genotypes, which result in lower expression of MBL, are associated with more rapid HIV-1-related disease progression, including CNS impairment, predominantly in children younger than 2 years. These data suggest that MBL2 variants are associated with altered HIV-1 disease progression, particularly in young children.