Perinatal Human Immunodeficiency Virus Type 1 Infection Research Articles

Toll-like receptor 9 polymorphisms influence mother-to-child transmission of human immunodeficiency virus type 1

BackgroundToll-like receptors (TLRs) recognize pathogen-associated molecular patterns and play a crucial role in the host's innate immune response. Genetic variations in TLR genes may influence host-viral interactions and might impact upon the risk of mother-to-child transmission (MTCT) of Human Immunodeficiency Virus type 1 (HIV-1). The aim of this study was to investigate the influence of genetic variants of TLR 9 gene on MTCT.MethodsThree hundred children (118 HIV-1-infected and 182 HIV-1-uninfected) born to HIV-1-infected mothers were studied. Single nucleotide polymorphisms (SNPs) NM_017442.2: c.4-44G > A (rs352139) and c.1635A > G (rs352140) of the TLR9 gene were genotyped by TaqMan allelic discrimination assay. Statistical analyses were performed using SNPStats program.ResultsWhen considered separately, neither of the two SNPs was significantly associated with risk of HIV-1 infection. However, the [A;A] and [G;G] haplotypes were associated with a higher risk of HIV-1 infection compared to the prevalent [G;A] haplotype [odds ratio (OR) = 3.16, 95% confidence interval (CI) 1.24-8.03, p = 0.016, and OR = 5.54, 95% CI 1.76-17.50, p = 0.004, respectively].ConclusionsOverall, results demonstrate a significant correlation between specific genetic variants of the TLR9 gene and risk of MTCT of HIV-1, thus confirming a critical role of innate immunity in perinatal HIV-1 infection. Strategies aimed at modulating innate immunity might be useful for future treatment of pediatric HIV-1 infection and AIDS.

A universal real-time PCR assay for the quantification of group-M HIV-1 proviral load

Quantification of human immunodeficiency virus type-1 (HIV-1) proviral DNA is increasingly used to measure the HIV-1 cellular reservoirs, a helpful marker to evaluate the efficacy of antiretroviral therapeutic regimens in HIV-1-infected individuals. Furthermore, the proviral DNA load represents a specific marker for the early diagnosis of perinatal HIV-1 infection and might be predictive of HIV-1 disease progression independently of plasma HIV-1 RNA levels and CD4(+) T-cell counts. The high degree of genetic variability of HIV-1 poses a serious challenge for the design of a universal quantitative assay capable of detecting all the genetic subtypes within the main (M) HIV-1 group with similar efficiency. Here, we describe a highly sensitive real-time PCR protocol that allows for the correct quantification of virtually all group-M HIV-1 strains with a higher degree of accuracy compared with other methods. The protocol involves three stages, namely DNA extraction/lysis, cellular DNA quantification and HIV-1 proviral load assessment. Owing to the robustness of the PCR design, this assay can be performed on crude cellular extracts, and therefore it may be suitable for the routine analysis of clinical samples even in developing countries. An accurate quantification of the HIV-1 proviral load can be achieved within 1 d from blood withdrawal.

Changed bone status in human immunodeficiency virus type 1 (HIV‐1) perinatally infected children is related to low serum free IGF‐I

Adults and children affected by human immunodeficiency virus type-1 (HIV-1) infection show bone demineralization. Little is known about skeletal status using a quantitative high-frequency ultrasound (QUS) technique in these patients. To evaluate the bone quality and assess the role of the IGF system in the bone metabolism and skeletal status of HIV-1 perinatally infected children. Serum free and total IGF-I, IGFBP-3, serum osteocalcin level, urinary deoxypyridinoline concentration, spontaneous interleukin-6 (IL-6) release and broadband ultrasound attenuation (BUA) were evaluated in 44 prepubertal children who had perinatal HIV-1 infection. The patients were divided into two groups depending on the severity of their clinical condition: group 1 (23 children with no or mild clinical symptoms, mean age 8.0 +/- 2.9 years) and group 2 (21 children with severe clinical symptoms, mean age 8.58 +/- 2.47 years). Fifty-five healthy age- and sex-matched controls were analysed for comparison. Compared with group 1 and the controls, group 2 patients showed a significantly reduced BUA Z-score (P < 0.001), and significantly reduced concentrations of serum osteocalcin (P < 0.001) and urinary deoxypyridinoline (P < 0.001 and P < 0.05, respectively). Group 2 patients also showed significantly reduced serum free IGF-I (P < 0.001) and total IGF-I (P < 0.05) levels compared with the controls, but not with group 1. No statistically significant differences were found between the three groups with regard to IGFBP-3. Group 2 patients showed significantly higher spontaneous IL-6 release than group 1 patients and controls (P < 0.001). BUA Z-scores displayed a significant correlation with free IGF-I in group 2 (r = 0.96; P < 0.001), group 1 (r = 0.56; P = 0.005) and controls (r = 0.50; P < 0.001). Our study shows that only patients affected by perinatal HIV-1 infection with severe clinical manifestations present significant changes in bone quality and bone metabolism. Our data also show that impairment of skeletal status is related to reduction in serum total and free IGF-I. Children with perinatal HIV-1 infection, because of a considerable improvement in life expectancy, seem at great risk of not obtaining an optimal bone mass. A possible therapeutic approach should be considered in these children.

Genetic Determinants of Pediatric HIV-1 Infection: Vertical Transmission and Disease Progression Among Children

It is very likely that perinatal human immunodeficiency virus type 1 (HIV-1) infection is influenced by a combination of virologic and host factors. A greater understanding of the role played by various risk factors for HIV-1 infection is crucial for the design of new preventive and therapeutic strategies. In recent years, a number of studies have suggested that host genetic factors are important determinants of both the susceptibility to perinatal HIV-1 infection and the subsequent pathogenesis of acquired immunodeficiency syndrome (AIDS). Control of HIV-1 infection involves the processing of specific viral peptides and their presentation to cells of the immune system by highly polymorphic human leukocyte antigen (HLA) alleles. The contribution of multiple HLA class I and II alleles in modulating pediatric HIV/AIDS outcomes has now been confirmed by several independent groups. Penetration of HIV-1 into cells is mediated by interaction between CD4 and chemokine receptors that serve as entry coreceptors. Genetic polymorphisms in chemokine ligand and chemokine receptor genes have recently been associated both with mother-to-child HIV-1 transmission and disease progression in children. These observations suggest a key role for genetic factors in pediatric HIV-1 infection. This article describes the current state of knowledge regarding host genetic influences on pediatric HIV-1 infection and discusses the role of these genes in HIV/AIDS pathogenesis.

The HLA A2/6802 supertype is associated with reduced risk of perinatal human immunodeficiency virus type 1 transmission.

Certain HLAs may, in part, account for differences in human immunodeficiency virus type 1 (HIV-1) susceptibility by presenting conserved immunogenic epitopes for T cell recognition. The HLA supertype A2/6802 is associated with decreased susceptibility to HIV-1 among sex workers. The alleles in this supertype present the same HIV-1 peptide epitopes for T cell recognition in some cases. This study sought to determine whether the HLA A2/6802 supertype influenced HIV-1 transmission in a prospective cohort of HIV-1-infected mothers and children in Kenya. Decreased perinatal HIV-1 infection risk was strongly associated with possession of a functional cluster of related HLA alleles, called the A2/6802 supertype (odds ratio, 0.12; 95% confidence interval, 0.03-0.54; P=.006). This effect was independent of the protective effect of maternal-child HLA discordance. These data provide further evidence that HLA supertypes are associated with differential susceptibility to HIV-1 transmission.

Antiviral Therapy Reduces Viral Burden but Does Not Prevent Thymic Involution in Young Cats Infected with Feline Immunodeficiency Virus

The thymus is a major target organ in human immunodeficiency virus type 1 (HIV-1)-infected children and feline immunodeficiency virus (FIV)-infected young cats (G. A. Dean and N. C. Pedersen, J. Virol. 72:9436-9440, 1998; J. L. Heeney, Immunol. Today 16:515-520, 1995; S. M. Schnittman et al., Proc. Natl. Acad. Sci. USA 87:7727-7731, 1990; T. A. Seemayer et al., Hum. Pathol. 15:469-474, 1984; H.-J. Shuurn et al., Am. J. Pathol. 134:1329-1338, 1989; J. C. Woo et al., J. Virol. 71:8632-8641, 1997; J. C. Woo et al., AIDS Res. Hum. Retrovir. 15:1377-1388, 1999). It is likely that the accelerated disease process in children and cats is due to infection of the thymus during the time when generation of naive T lymphocytes is needed for development of the mature immune system. Zidovudine (ZDV) monotherapy, which is used to prevent and treat perinatal HIV-1 infection (R. Sperling, Infect. Dis. Obstet. Gynecol. 6:197-203, 1998), previously had been shown to reduce viral burden in FIV-infected young cats (K. A. Hayes et al., J. Acquir. Immune Defic. Syndr. 6:127-134, 1993). The purpose of this study was to evaluate the effect of drug-induced reduction of viral burden in the thymus on virus-mediated thymic involution and peripheral blood CD4 decline using FIV-infected cats as a model for pediatric HIV-1 infection. Eight-week-old cats were randomly assigned to uninfected, saline-treated; uninfected, ZDV-treated; FIV-infected, saline-treated; and FIV-infected, ZDV-treated groups. Parameters measured included blood lymphocyte numbers, viral load in blood and thymic tissue, and thymic histopathology. While the viral burden was significantly reduced by ZDV monotherapy in peripheral blood lymphocytes, plasma, and thymus, thymic lesions were similar for the treated and untreated FIV-infected cats. Further, markedly lowering the viral burden did not increase blood CD4 lymphocyte numbers or prevent their decline. The data suggest that an inflammatory process continued in spite of reduced virus replication. These observations imply that reducing virus load and limiting thymic inflammation are separate factors that must be addressed when considering therapeutic strategies aimed at preserving thymic function.

Reduction in mortality with availability of antiretroviral therapy for children with perinatal HIV-1 infection. Italian Register for HIV Infection in Children and the Italian National AIDS Registry.

Since the introduction of combined antiretroviral therapy, mortality rates in adults with human immunodeficiency virus type 1 (HIV-1) infection have decreased. However, little information is available outside the setting of controlled trials on survival of perinatally HIV-infected children treated with antiretroviral therapy. To assess effect of availability of antiretroviral therapy on decreasing mortality in perinatally HIV-infected children. Population-based, multicenter longitudinal study involving data collected by the Italian Register for HIV Infection in Children. A network of 106 pediatric clinical centers. A total of 1142 children born between November 1980 and December 1997 with perinatally acquired HIV infection with a median follow-up of 5.9 years. Time to HIV-related death calculated for birth cohort and calendar period and grouped by distribution of predominant type of antiretroviral therapy administered over time. Survival was longer in the 1996-1997 birth cohort (crude relative hazard [RH] of death, 0.39; 95% confidence interval [CI], 0.15-0.96) and 1996-1998 calendar period (crude RH of death, 0.65; 95% CI, 0.45-0.95) than in birth cohort and calendar period 1980-1995, but not when adjusted for maternal antiretroviral treatment during pregnancy and clinical condition at time of delivery, gestational age, and birth weight (adjusted RH of death, 0.55; 95% CI, 0.20-1.50, for birth cohort; and adjusted RH of death, 0.71, 95% CI, 0.43-1.16, for calendar period). In a multivariate model with 1980-1995 as comparison, the 1996-1997 birth cohort had an RH of 0.57 (95% CI, 0.22-1.47; P=.27) but RH for calendar period 1996-1998 was 0.63 (95% CI, 0.47-0.85; P<. 01). When the effects of birth cohort, calendar period, and type of antiretroviral therapy were evaluated simultaneously in the same model, the RH of death was not significantly different from 1.0 for the 1996-1997 birth cohort (P=.19) and calendar period 1996-1998 (P=. 83) suggesting a causal relationship between decreased risk of death and use of combination therapy. The RH of death in children receiving monotherapy or double or triple combination therapy was 0. 77 (95% CI, 0.55-1.08), 0.70 (95% CI, 0.42-1.17), and 0.29 (95% CI, 0.13-0.67), respectively, vs no antiretroviral therapy. Survival of perinatally HIV-infected children improved in 1996-1998 as a result of the introduction of combined antiretroviral therapies. JAMA. 2000;284:190-197

Thyroid function in children with perinatal human immunodeficiency virus type 1 infection.

To study thyroid function in children with perinatal HIV-1 infection retrospectively and determine whether thyroid abnormalities are correlated with clinical condition, disease progression, immunological impairment, and viral load. Total (TT4) and free (FT4) thyroxine, total (TT3) and free (FT3) triiodothyronine, reverse triiodothyronine (rT3), thyrotropin (TSH), thyroglobulin (TG), and thyroid binding globulin (TBG) were measured twice in 56 children with perinatal human immunodeficiency virus type 1 (HIV-1) infection. Median age at first determination was 13.5 (range: 0.03-127.0) months; median age at second determination was 66.2 (range 3.42-147.4) months. Antithyroglobulin, antimicrosomal, thyroid peroxidase, and thyrotropin receptor antibodies were also evaluated. Fifty-three healthy children were selected as controls. TT3, TT4, FT4, and TG were significantly reduced and rT3, TBG, and TSH increased in children with HIV-1 infection when compared with controls. Thyroid dysfunction correlated with severe immunosuppression and high viral load early in life preceded the onset of the disease and worsened over time. Autoantibodies were negative in all children with HIV-1 infection in all determinations. Thyroid abnormalities are observed early in the course of perinatal HIV-1 infection; thyroid dysfunction is particularly pronounced in children with severe immunosuppression and high viral load. Modifications of thyroid function precede worsening of clinical course in HIV-1 infected children.

Interleukin-6 Release by Cultured Peripheral Blood Mononuclear Cells Inversely Correlates with Height Velocity, Bone Age, Insulin-like Growth Factor-I, and Insulin-like Growth Factor Binding Protein-3 Serum Levels in Children with Perinatal HIV-1 Infection

Spontaneous and phytohemagglutinin (PHA)-stimulated interleukin (IL)-6 release by cultured peripheral blood mononuclear cells was related to height velocity, bone age, insulin-like growth factor-I (IGF-I), and IGF binding protein-3 (IGFBP-3) serum level standard deviation scores (SDS) of 32 children [aged 91 (median; range 13–151) months] with human immunodeficiency virus-type 1 (HIV-1) perinatal infection and severe disease. Spontaneous and PHA-stimulated IL-6 release inversely correlated with height velocity, bone age, IGF-I, and IGFBP-3 SDS. Ten children with height velocity SDS ≤ −2, compared to 22 children with height velocity SDS > −2, showed higher spontaneous and PHA-stimulated IL-6 release and lower IGF-I and IGFBP-3 SDS (irrespective of CD4-positive T-lymphocyte counts, viral load, liver disease, or nutrition status). IL-6 overproduction may be a mechanism of IGF-I and IGFBP-3 down-regulation and impaired linear growth in children with perinatal HIV-1 infection. Growth-promoting strategies, including targeted anticytokine treatments, could be devised for such children.

Maternal and infant factors predicting disease progression in human immunodeficiency virus type 1-infected infants. Women and Infants Transmission Study Group.

Infants with perinatally acquired human immunodeficiency virus type 1 (HIV-1) infection have widely variable courses. Previous studies showed that a number of maternal and infant factors, when analyzed separately, are associated with infant HIV-1 disease progression. In this study, clincal, virologic, and immunologic characteristics in the mothers and infants were examined together to determine the predictors of disease progression by 18 months of age and the associations with rapid progression during the first 6 months of life. One hundred twenty-two HIV-1-infected women whose infants were HIV-1 infected were identified from the Women and Infants Transmission Study (WITS) cohort. WITS is a longitudinal natural history study of perinatal HIV-1 infection carried out in 6 sites in the continental United States and in Puerto Rico. The women were enrolled during pregnancy and their infants were enrolled at the time of delivery and followed prospectively by a standardized protocol. Virologic and immunologic studies were performed in laboratories certified by National Institutes of Health-sponsored quality assurance programs. Maternal factors in pregnancy were used as potential predictors of infant disease progression (progression to Centers for Disease Control and Prevention [CDC] Clinical Class C disease or death by 18 months of age) or as correlates of progression at <6 months of age. Infant factors defined during the first 6 months of life were used as potential predictors of progression during 6 to 18 months of age and as correlates of progression at <6 months of age. Progression by 18 months of age occurred in 32% of infants and by 6 months of age in 15%. Maternal characteristics that, by univariate analysis, were significant predictors of infant disease progression by 18 months of age were elevated viral load, depressed CD4(+)%, and depressed vitamin A. CD8(+)%, CD8(+) activation markers, zidovudine (ZDV) use, hard drug use, and gestational age at delivery were not. When examined in a combined multivariate analysis of maternal characteristics, only vitamin A concentration independently predicted infant progression. Infant characteristics during the first 6 months of life that, by univariate analysis, were associated with disease progression included elevated mean viral load at 1 to 6 months of age, depressed CD4(+)%, CDC Clinical Disease Category B, and growth delay. Early HIV-1 culture positivity (<48 hours), CD8(+)%, CD8(+) activation markers, and ZDV use during the first month of life did not predict progression. Multivariate analysis of infant characteristics showed that the only independent predictors were progression to CDC Category B by 6 months of age (odds ratio [OR], 5.80) and mean viral load from 1 to 6 months of age (OR, 1.99). The final combined maternal and infant analysis included the significant maternal and infant characteristics in a multivariate analysis. It showed that factors independently predicting infant progression by 18 months of age were progression to CDC Category B by 6 months of age (OR, 5.80) and elevated mean HIV-1 RNA copy number at 1 to 6 months of age (OR, 1.99). The characteristics associated with rapid progression to CDC Category C disease or death by 6 months of age were also examined. The only maternal characteristic associated with progression by 6 months in multivariate analysis was low maternal CD4(+)%. The infant characteristics associated with progression by 6 months of age in multivariate analysis were depressed mean CD4(+)% from birth through 2 months and the presence of lymphadenopathy, hepatomegaly, or splenomegaly by 3 months. Infant ZDV use was not assocciated with rapid progression. The strongest predictors of progression by 18 months are the presence of moderate clinical symptoms and elevated RNA copy number in the infants in the first 6 months of life. In contrast, progression by 6 months is associated with maternal and infant immun

Interleukin-6 synthesis and IgE overproduction in children with perinatal human immunodeficiency virus-type 1 infection.

Unbalanced interleukin network and elevated IL-6 synthesis are suggested mechanisms of immunoglobulin overproduction in children with perinatal human immunodeficiency virus-type 1 (HIV-1) infection. To investigate whether elevated IL-6 synthesis is a general mechanism of immunoglobulin overproduction in perinatal HIV-1 infection. In vitro spontaneous and phytohaemoagglutinin (PHA)-stimulated IL-6 and IL-2 synthesis, serum IgE, IgG, IgA, and IgM levels, CD4+ T-lymphocyte counts, and HIV-1 RNA copy numbers were cross-sectionally determined in 31 children with perinatal HIV-1 infection. Children with immunoglobulin z-scores in the highest quartile were defined as children with high immunoglobulin level. Relationships between interleukin synthesis, high immunoglobulin levels, and HIV-1 related disease were studied. Children with high IgE levels had higher spontaneous IL-6 synthesis (1337 +/- 138 pg/mL) compared with those without high IgE levels (861 +/- 194 pg/mL; P < .001). By contrast, spontaneous IL-6 synthesis was similar in children with or without high IgG, IgA, or IgM levels. Decreased PHA-stimulated IL-2 synthesis, low CD4+ lymphocyte counts, elevated HIV-1 RNA copy numbers, and severe disease correlated with high IgE (but not IgG, IgA, and IgM) levels. IgG, IgA, and IgM levels correlated with each other, but not with IgE levels. The increased IL-6 synthesis in HIV-1+ children may affect IgE rather than other immunoglobulin isotype levels. Overall results suggest that IgE and IgG, IgA, IgM overproduction have distinct underlying mechanisms.

Rapid method for screening dried blood samples on filter paper for human immunodeficiency virus type 1 DNA.

PCR is a highly sensitive method for the detection of human immunodeficiency virus type 1 (HIV-1) nucleic acids in blood mononuclear cells and plasma. However, blood separation techniques require extensive laboratory support systems and are difficult when a limited volume of blood is available, which is often the case for infants. The use of blood samples stored on filter paper has many advantages for the detection of perinatal HIV-1 infection, but current methods require extraction and purification of target DNA prior to PCR amplification. We report a highly sensitive and rapid method for the extraction and detection of HIV-1 DNA in infant blood samples stored on filter papers. Because this rapid protocol does not involve steps for the removal of potential inhibitors of the PCR, the highest sensitivity is achieved by testing the filter paper lysate in quadruplicate. Assays for HIV-1 DNA were done by using nested PCR techniques that amplify HIV-1 gag DNA from blood spot samples on filter paper and from corresponding viably frozen mononuclear cells separated from venous blood samples obtained from 111 infants born to HIV-1-seropositive mothers. PCR results with blood from filter papers showed 100% specificity (95% confidence internal [CI] 93.1 to 100%) and 96% (95% CI, 88.65 to 98.9%) and 88% (95% CI, 79.2 to 94.5%) sensitivity (for quadruplicate and duplicate tests, respectively) compared to PCR results with blood mononuclear cells. Moreover, this method could detect HIV-1 sequences of multiple subtypes.

Airway resistance and spirometry in children with perinatally acquired human immunodeficiency virus-type 1 infection

Airway resistance was measured by the interrupter technique in 54 children [aged 63.8 months (range: 9.1-131.6 months)], with perinatal human immunodeficiency virus-type 1 (HIV-1) infection and in a control group of 315 gender, height, and race-matched healthy children. In addition, 14 HIV-infected children, aged 75-131 months, had spirometry performed. Resistance was significantly higher in infected children than in controls (0.84 +/- 0.3 vs 0.64 +/- 0.08 kPa x l(-1) x s; t = 9.991; P < 0.0001). Resistance decreased with age in controls (r = -0.95; P < 0.001), but not in infected children (r= -0.22; P = 0.105). Resistance did not correlate with mothers' intravenous drug addiction, perinatal data, T-cell subset numbers, treatment, clinical course, or presence of respiratory complications. Resistance was higher (t = 3.103; P < 0.003) in p24 antigen-positive than in negative children. Thirty-nine children underwent a second evaluation 12.3 months (range 11.1-14 months) after the first. Resistance was higher (t = 3.960; P < 0.0001) at the second evaluation compared to the first. Eight of 14 children had abnormal spirometric measurements. We conclude that perinatal HIV-1 infection is associated with increased airway resistance and often abnormal spirometry. The degree of abnormalities in resistance depends on the duration of the infection rather than on HIV-1-related respiratory complications.

Acellular pertussis vaccine in children with perinatal human immunodeficiency virus-type 1 infection

The immunogenicity of an acellular pertussis vaccine containing genetically detoxified pertussis toxin, filamentous haemoagglutinin and pertactin was studied in 12 children [median age: 45 (6–107) months] with perinatal human immunodeficiency virus-type 1 (HIV-1) infection. Antibody response to all antigens was observed in six cases and another children 3 reacted to two or one antigen(s), but titres were lower than those from healthy controls. Antibody titre fold-rise correlated with preimmunization CD4-positive cell counts. Significant titres were still detectable 4 months after the third dose. The acellular vaccine is immunogenic in a portion of children with perinatal HIV-1 infection but early vaccination might be more effective, taking advantage of still adequate CD4-positive cell numbers.

Predicting perinatal human immunodeficiency virus infection by antibody patterns

The evolution of human immunodeficiency virus type 1 (HIV-1) antibody titers determined by enzyme-linked immunosorbent assay between birth and 18 months of age was investigated in 118 babies born to HIV-1-seropositive South African mothers. By 18 months 41 (34.7%) children were diagnosed as HIV-1-infected by standard criteria. All 77 uninfected babies cleared maternal antibodies by 15 months; 94.5% of these babies seroreverted by 12 months. By 9 months of age a significant difference (P < 0.05) was noted between antibody decay rates in infected and uninfected children. Of the children subsequently shown to be uninfected, 95.8% demonstrated > or = 50% decay in antibody titers between 6 and 9 months; only 1 in the infected group showed a similar pattern (sensitivity, 97.8%; specificity, 93.8%). The approach of assessing the progression of antibody decay in infected and uninfected babies makes it a feasible and useful tool for estimating vertical transmission rates and diagnosis of perinatal HIV-1 infection earlier than standard practice.

Human cord blood mononuclear cells are preferentially infected by non-syncytium-inducing, macrophage-tropic human immunodeficiency virus type 1 isolates.

Identification of the factors which impact on the transmission of human immunodeficiency virus type 1 (HIV-1) from an infected mother to her infant is essential for the development of effective strategies to prevent perinatal HIV-1 infection. The current study was designed to determine if unstimulated human neonatal cord blood mononuclear cells (CBMC) differ from adult peripheral blood mononuclear cells (PBMC) in susceptibility to HIV-1 infection. Both cell populations were challenged with two laboratory and two clinical HIV-1 isolates with different phenotypic properties. Infection was evaluated by quantitation of p24 antigen production and p24 antigen expression by an enzyme immunoassay and immunofluorescence, respectively. T-cell markers were determined by flow cytometry. Unstimulated CBMC were preferentially infected by macrophage-tropic, non-syncytium-inducing (non-SI) laboratory and clinical isolates, whereas PBMC were more susceptible to T-lymphotropic, SI HIV-1 strains. The macrophage-tropic strain HIV-1Ba-L replicated to 100-fold higher titers in CBMC than a similar inoculum of the SI isolate HIV-1LAI. The opposite occurred in unstimulated PBMC, which replicated HIVLAI to eightfold higher titers than the macrophage-tropic isolate. These findings indicate that a selection of viral phenotype may occur with unstimulated CBMC displaying a predominant susceptibility to infection by macrophage-tropic, non-SI HIV-1 strains and that this selection may influence mother-infant transmission of HIV-1.

Use of polimerase chain reaction for neonatal diagnosis of human immunodeficiency virus type 1 (HIV-1) perinatal infection

The polymerase chain reaction (PCR) was evaluated for its ability to diagnose perinatal HIV-1 infection before the development of signs or symptoms of the disease in thirty-seven infants (median age of 5.5 days) born to HIV-1 infected women. Of 30 children with complete follow up (median of 25 months), 9 (30%) had serological and clinical features of HIV-1 infection and 21 (70%) were uninfected. Among the infected infants, 5/9 (56%) had positive neonatal PCR tests and 4/9 (44%) had negative PCR tests. None of the 21 uninfected children had positive PCR tests. The prognosis of HIV-1 disease in infected infants with a positive neonatal PCR positive test was similar to that of infected infants with a negative PCR test. In spite of not identifying all the infected infants, the PCR test is a useful tool for early diagnosis of HIV-1 perinatal infection, detecting infected newborns during gestation.

Increased Susceptibility of Neonatal Monocyte/Macrophages to HIV-1 Infection

The relative susceptibility of neonatal/cord blood monocyte/macrophages to productive infection with human immunodeficiency virus type 1 (HIV-1) was investigated. In addition, the effect of HIV-1 infection of cord blood monocyte/macrophages in various stages of maturation/differentiation as represented by differing ages of monocytes in culture was examined. Monocyte/macrophages were infected with two viral strains isolated and cloned from primary clinical isolates, each with different cell tropisms. Cord blood and adult monocyte/macrophages were infected with either the macrophage-tropic strain HIV-1(JR-FL) or the predominantly lymphocyte-tropic strain HIV-1(JR-CSF). p24gag antigen levels were measured in supernatants by ELISA. Cord monocyte/macrophages at three different ages in culture (4, 7, and 11 days) were more productively infected by both viral strains than were adult monocyte/macrophages infected in parallel. In addition, the less differentiated cells (cord and adult monocyte/macrophages infected after growing 4 days in culture) were more productively infected than were the more differentiated monocyte/macrophages (cells infected after growing 7 or 11 days in culture). The mechanism for this increased susceptibility of cord monocyte/macrophages to HIV-1 infection as compared to adult cells was also investigated. A measurable increase in DNA synthesis was found in the infected cord cells when compared to infected adult cells and to uninfected adult or cord cells as represented by increased [3H]thymidine incorporation, suggesting that increased cell proliferation of cord monocyte/macrophages may enhance the permissivity of infection. This article suggests that cord monocyte/macrophages may play an important role in the pathogenesis of perinatal HIV-1 infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Ontogeny of anti-human immunodeficiency virus (HIV) antibody production in HIV-1-infected infants.

The early serologic response of infants to infection with human immunodeficiency virus type 1 (HIV-1) is normally obscured by the presence of transplacentally acquired maternal HIV antibody. By measuring HIV antibody produced in vitro by lymphocytes isolated from peripheral blood of infants and children of HIV-1-infected mothers, we have been able to study the natural acquisition of humoral immunity to perinatal HIV-1 infection. One hundred ninety-seven infants of HIV-1-infected women were studied prospectively and longitudinally from birth. In the neonatal period, infected infants produced only small amounts of HIV-specific IgG antibodies to a restricted number of antigens. The amount of immunoglobulin to HIV-1 and the number of HIV-1 antigens recognized increased with age. After 6 months of life 85% of infected infants made detectable antibody to two or more viral proteins. Antibody to gp160 appeared first and was the most frequently found at all ages, followed by antibody to the envelope proteins gp120 and gp41. The amount of HIV antibody produced correlated positively with the percentage of CD4+ T lymphocytes in peripheral blood. This assay provides a method of studying the immunogenicity of vaccines against HIV-1 in HIV-1-infected infants and of assessing the effect of early therapeutic interventions on the humoral response to HIV-1.

Prognostic factors and survival in children with perinatal HIV-1 infection

The signs that may arise after perinatal infection with human immunodeficiency virus type 1 (HIV-1) have been classified by the Centers for Disease Control, but the clinical usefulness of the classification system and the prognostic importance of each disease pattern have not been established. We sought to address these issues by analysing data from the Italian Register for HIV infection in children. We studied 1887 children born to HIV-1-seropositive mothers. 1045 were identified at birth and the others were registered later (median age 4·8 [range 0·4-72] months). HIV-1-associated signs developed in 433 (81·8%) of 529 seropositive infected children at a median age of 5 (0·03-84) months. These signs appeared significantly earlier in the 102 children who died of HIV-1-related illness than in those who are still alive (median 3 [0·03-55] vs 6 [0·03-84] months; p<0·001). The cumulative proportion surviving at age 9 years was 49·5% (95% confidence interval 27-65%) and the median survival time was 96·2 months. Separate analysis of the 112 seropositive infected children followed from birth and older than 15 months gave similar results. Hepatomegaly, splenomegaly, lymphadenopathy, parotitis, skin diseases, and recurrent respiratory tract infections formed the mildest disease pattern. Lymphoid interstitial pneumonitis and thrombocytopenia were signs of intermediate disease. By contrast, in multivariate analysis specific secondary infectious diseases, severe bacterial infections, progressive neurological disease, anaemia, and fever were significant and independent negative predictors of survival. Growth failure, persistent oral candidosis, hepatitis, and cardiopathy were associated in univariate analysis with significantly shorter survival. Our findings suggest that the outlook for children with perinatal HIV-1 infection is better than previously thought and that a new clinical staging system of single disease patterns is needed. Lancet 1992; 339: 1249-53.