Anna Plebani

HIV-1 transmission through breast-milk: appraisal of risk according to duration of feeding.

ObjectivesTo estimate the risk of HIV-1 transmission through breast-milk in children born to infected mothers, and to determine the relationship between duration of breast-feeding and risk. Design and methodsThe study population included 168 breast-fed and 793 bottle-fed children born to seropositive mothers. All subjects were enrolled and followed-up in the Italian Register for HIV Infection in Children; HIV serostatus was defined in all children. Multivariate analysis was performed using a logistic regression model. Independent variables included biological factors (duration of breast-feeding, gestational age, clinical condition of mother at delivery, mode of delivery, birth-weight and sex). Year of birth and age when HIV infection was diagnosed were also considered in the analysis attempting to control for possible selection biases. ResultsBreast-feeding increased the risk of HIV-1 transmission. The estimated adjusted odds ratio for 1 day of breast- versus bottle-feeding was 1.19 (95% confidence interval, 1.10–1.28). The infection odds ratio of breast- versus bottle-feeding increased with the natural logarithm of the duration of practice. ConclusionsThese results are the first to provide an appraisal of the additional risk of HIV-1 transmission associated with a seropositive mother breast-feeding her child. Biological significance of this route of transmission was supported by demonstration of a relationship between duration of breast-feeding and risk of HIV-1 transmission.

Onset of clinical signs in children with HIV-1 perinatal infection

Objective: To investigate the timing of onset of each clinical sign in infants and children with HIV‐1 perinatal infection. Design and methods: A total of 200 HIV‐1‐infected children followed‐up from birth were studied. Failure and conditional probabilities were estimated by the Kaplan‐Meier product‐limit method. Cox proportional hazard analysis was used to evaluate independently associated factors. Results of 934 seroreverters were used to calculate reference values of CD4+ cell counts and predictivity of early signs. Results: Median age at the onset of any sign was 5.2 months (range, 0.03‐56 months). The probability of remaining asymptomatic was 19% [95% confidence interval (CI), 14‐25.1] at 12 months and 6.1% (95% Cl, 2.6‐11.7) at 5 years. Lymphadenopathy (69.5%), splenomegaly (62.4%) and hepatomegaly (58.4%) were the most common signs in the first year of life. Peculiar to the first year of life (compared with subsequent ages) was the onset of primary HIV‐1 hepatitis and diarrhoea (rate ratios, 23.3 and 15.2, respectively). When CD4+ cell counts in the asymptomatic stage (age, 2 months; range, 0.03‐5.9 months) were below rather than above the fifth percentile in seroreverters, onset of signs was earlier [3 (range, 0.03‐19) versus 5 (range, 0.03‐56) months]. Children manifesting signs before the 5.2‐month breakpoint had a lower survival rate [74% (range, 65.9‐82%) at 12 months and 45% (range, 32.9‐57%) at 5 years] than children manifesting signs later 198% (range, 92.2‐100%) at 12 months and 74% (range, 60.3‐87.7%) at 5 years]. Children whose birthweight was ≤2400g had an earlier onset (24 months; range, 1‐57 months) of severe conditions than children with higher birthweight (71 months; range, 1‐71 months). Development of lymphadenopathy or hepatosplenomegaly within 3 months of life were reliable indicators of infection. Conclusions: This study describes the sequence of onset of signs in perinatal HIV‐1 infection. Infection is shown to progress faster than in adults and in a different manner. Low birthweight, early decreased CD4+ cell counts, and early onset of signs are predictive of rapid progression. AIDS 1995, 9:455‐461

Polymerase chain reaction, virus isolation and antigen assay in HIV-1-antibody-positive mothers and their children

Diagnosis of perinatal HIV-1 infection is complicated by the persistence of maternal antibodies and the conflicting reports on polymerase chain reaction (PCR) reactivity in children born to HIV-1-seropositive mothers. We have compared PCR with other diagnostic methods for perinatal HIV-1 infection and have attempted also to identify maternal markers which correlate with risk of transmission. PCR was the most sensitive method for early diagnosis of perinatal transmission of HIV-1, but the PCR-positive children (n = 11) developed at least one additional sign of infection. The PCR-negative children (n = 76) were clinically healthy, virus isolation negative, and their serum was HIV-1-antigen-negative. All children who had become seronegative (n = 36) were both PCR- and isolation-negative. Antigenaemia in the mothers correlated significantly with higher risk of perinatal transmission of HIV-1, while no other parameters (clinical stage, lymphocyte subsets, PCR and isolation) showed such a correlation. This indicates that the level of virus expression may be of key importance for the risk of vertical transmission of HIV-1 infection.

Mode of delivery and gestational age influence perinatal HIV-1 transmission

Some data suggest that cesarean section reduces mother-to-child HIV-1 transmission. To assess the influence of mode of delivery and other maternal and infant factors on the rate of transmission, we analyzed the data of 1,624 children prospectively followed from birth. Of these, at the last visit 1,033 were > 18 months of age or would have been had they not died of HIV-related illness. Among the 975 first singleton children, 180 [18.5%; 95% confidence limits (CL), 16.1-20.9] acquired infection, as did 8 of 56 (14.3%; 95% CL, 5.1-23.5) second-born children. Multivariate stepwise analysis showed that vaginal delivery and development of symptoms in the mother were significantly and independently associated with a higher transmission rate (vaginal delivery; odds ratio, 1.69; 95% CL, 1.14-2.5; symptoms: odds ratio, 1.61; 95% CL, 1.12-2.3). In contrast, a history of maternal drug use, birth weight, breast-feeding (only 37 infants were breast-fed), and childs sex did not have a significant impact on viral transmission. The percentage of infected children was highest (30.7%) among very premature infants (< or = 32 weeks of gestation); this significant trend subsequently decreased to 11.9% at the week 42 (p < 0.001), suggesting a parallel reduction in peripartum transmission. The reduced rate of infection observed in infants born by cesarean section underlines the urgent need for randomized controlled trials to evaluate the protective role of surgical delivery in preventing perinatal HIV-1 transmission.

Rapid disease progression in HIV-1 perinatally infected children born to mothers receiving zidovudine monotherapy during pregnancy The Italian Register for HIV Infection in Children*

OBJECTIVE To investigate the outcome in children perinatally infected with HIV-1 whose mothers received zidovudine (ZDV) monotherapy in pregnancy. DESIGN Observational retrospective study of a prospectively recruited cohort. SETTING Italian Register for HIV Infection in Children. PATIENTS A group of 216 children perinatally infected with HIV-1, born in 1992-1997 and derived prospectively from birth: 38 children had mothers receiving ZDV monotherapy and for 178 children the mothers received no antiretroviral treatment during pregnancy. MAIN OUTCOME MEASURES The estimated probability of developing severe disease or severe immune suppression, survival probability [95% confidence interval (CI)] within 3 years, and the hazard ratio (95% CI), adjusted for year of birth, maternal clinical condition at delivery, birthweight and treatments (Pneumocystis carinii pneumonia chemoprophylaxis and/or antiretroviral therapy before the onset of severe disease, severe immune suppression or death) were compared. RESULTS Comparison of HIV-1-infected children whose mothers were treated with ZDV with children whose mothers were not treated showed that the former group had a higher probability of developing severe disease [57.3% (95% CI 40.9-74.3) versus 37.2% (95% CI 30.0-45.4); log-rank test 7.83, P = 0.005; adjusted hazard ratio 1.8 (95% CI 1.1-3.1)] or severe immune suppression [53.9% (95% CI 36.3-73.5) versus 37.5% (95% CI 30.0-46.2); log-rank test 5.58, P = 0.018; adjusted hazard ratio 2.4, (95% CI: 1.3-4.3)] and a lower survival [72.2% (95% CI 50.4-85.7) versus 81.0% (95% CI 73.7-86.5); log-rank test 4.23, P = 0.039; adjusted hazard ratio of death 1.9 (95% CI 1.1-3.6)]. CONCLUSIONS This epidemiological observation could stimulate virologic studies to elucidate whether this rapid progression depends on in utero infection or transmission of resistant virus. Findings may suggest a need to hasten HIV-1 diagnosis in infants of ZDV-treated mothers and undertake an aggressive antiretroviral therapy in those found to be infected.

Structural defects and variations in the HIV-1 nef gene from rapid, slow and non-progressor children.

Objectives: Evaluation of sequence evolution as well as structural defects and mutations of the human immunodeficiency virus‐type 1 (HIV‐1) nef gene in relation to disease progression in infected children. Design: We examined a large number of nef alleles sequentially derived from perinatally HIV‐1‐infected children with different rates of disease progression: six non‐progressors (NPs), four rapid progressors (RPs), and three slow progressors (SPs). Methods: Nef alleles (182 total) were isolated from patients’ peripheral blood mononuclear cells (PBMCs), sequenced and analysed for their evolutionary pattern, frequency of mutations and occurrence of amino acid variations associated with different stages of disease. Results: The evolution rate of the nef gene apparently correlated with CD4+ decline in all progression groups. Evidence for rapid viral turnover and positive selection for changes were found only in two SPs and two RPs respectively. In NPs, a higher proportion of disrupted sequences and mutations at various functional motifs were observed. Furthermore, NP‐derived Nef proteins were often changed at residues localized in the folded core domain at cytotoxic T lymphocytes (CTL) epitopes (E105, K106, E110, Y132, K164, and R200), while other residues outside the core domain are more often changed in RPs (A43) and SPs (N173 and Y214). Conclusions: Our results suggest a link between nef gene functions and the progression rate in HIV‐1‐infected children. Moreover, non‐progressor‐associated variations in the core domain of Nef, together with the genetic analysis, suggest that nef gene evolution is shaped by an effective immune system in these patients.

Correlation between HIV sequence evolution, specific immune response and clinical outcome in vertically infected infants

Objective:To evaluate sequence evolution in relation to different rates of disease progression in infants infected with HIV-1. Design:Variability in the gp120 V3 region was analysed in HIV-1-infected children with different clinical courses, slow progression (n = 2) versus progressive disease (n = 3). Methods:Cloning and sequencing of virus-derived DNA from uncultured peripheral blood mononuclear cells was performed at two to three timepoints from birth and up to the fifth year of life. Sequence variability was estimated by calculating the genetic distance and the proportion and ratio of synonymous and non-synonymous nucleotide substitutions over time. Results:Genetic distances were significantly shorter in children with fast progression to disease, a predominance of synonymous nucleotide substitutions also being detected at later timepoints. Conversely, a preferential accumulation of non-synonymous nucleotide substitutions was apparent in children with slow disease progression. Furthermore, a positive correlation between a decreased ratio of synonymous/non-synonymous nucleotide substitutions and the ability of childrens sera to react with synthetic peptides representing the autologous virus sequence was determined. Conclusion:Data suggest that an antigenically more diverse virus population emerges in infected children with slower progression to disease as a result of a stronger immune pressure.

Diagnostic implication of specific immunoglobulin G patterns of children born to HIV-infected mothers.

We analysed HIV-specific immunoglobulin G (IgG) responses to gag and env peptides in infants born to HIV-positive mothers. Questions of interest were whether there are early specific markers for prognosis, and whether any specific IgG is related to the prevention of vertical transmission of infection. Fifty-three children, 0-24 months old and born to HIV-1-infected mothers, were retrospectively divided into two groups based on HIV seroreactivity or non-reactivity at 15 months of age. Their sera were used to find reactivities important in diagnosis and/or prediction of the putative HIV disease. Three important findings emerged. First, a low IgG titer against the very immunodominant penv9 in newborns was found to be associated with rapid progression to AIDS. This difference was clearly reflected in the reactivity to a small peptide representing amino acid (aa) 598-606. The second interesting finding was the putative hypervariable loop on gp120 (especially aa 324-338), reactivity to which was found only in the uninfected group, and was seen in six out of 19 uninfected children under 6 months of age. This specific response was not caused by a generally high total anti-HIV reactivity, and may indicate a role of protective antibodies against vertical transmission. The response to this region in the infected group, on the other hand, was directed to the amino terminal half of the putative loop, in particular peptide 53, aa 304-318. Finally, response to a part of the amino terminal end of P17 was seen in seven out of eight infected children over 6 months of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of nutritional rehabilitation on intestinal function and on CD4 cell number in children with HIV

Background A complex interplay of malnutrition, intestinal dysfunction, and immune impairment increases the progression of human immunodeficiency virus (HIV) disease in children. The authors tested the hypothesis that nutritional support improves intestinal and immune functions in children infected with human immunodeficiency virus (HIV). Methods A questionnaire was circulated through reference centers for pediatric HIV infection to evaluate the effects of nutritional rehabilitation, total parenteral nutrition (TPN) and enteral nutrition (EN), in children. Information included changes in body weight, CD4 cell numbers, and intestinal absorption—as judged by the xylose load—before and after clinical nutritional support and the outcome of children. Results Sixty-two children underwent nutritional support: 46 received TPN and 16 received EN. All but three had full-blown acquired immunodeficiency syndrome, and all were severely malnourished. Baseline clinical conditions were worse in children receiving TPN than in those receiving EN. Intestinal dysfunction was detected in all children who received xylose oral load. A significant increase in CD4 cell count, xylose levels, and body weight followed EN. A similar pattern was observed after TPN, but none of the parameters significantly changed. Twenty-seven children who received TPN and three who received EN eventually died. Fourteen who received TPN and eight who received EN were shifted to oral feeding, and five who received TPN and five who received EN continued with clinical nutritional support at the end of the observation period. Conclusions Nutritional intervention may restore intestinal absorption and increase CD4 cell numbers. The efficacy of nutritional intervention is enhanced if provided before a terminal stage of HIV infection. These data provide evidence of a close association among nutritional condition, intestinal absorption, and immune impairment.

Pandemic influenza A/H1N1 vaccine administered sequentially or simultaneously with seasonal influenza vaccine to HIV-infected children and adolescents.

In order to evaluate the immunogenicity, safety and tolerability of the 2009 A/H1N1 MF59-adjuvanted influenza vaccine administered sequentially or simultaneously with seasonal virosomal-adjuvanted influenza vaccine to HIV-infected children and adolescents, 36 HIV-infected children and adolescents, and 36 age- and gender-matched healthy controls were randomised 1:1 to receive the pandemic vaccine upon enrollment and the seasonal vaccine one month later, or to receive the pandemic and seasonal vaccines simultaneously upon enrollment. Seroconversion and seroprotection rates against the pandemic influenza A/H1N1 virus were 100% two months after vaccine administration in both groups, regardless of the sequence of administration. Geometric mean titres against pandemic and seasonal antigens were significantly higher when the seasonal and pandemic vaccines were administered simultaneously than when the seasonal vaccine was administered alone. Local and systemic reactions were mild and not increased by simultaneous administration. In conclusion, the 2009 pandemic influenza A/H1N1 MF59-adjuvanted vaccine is as immunogenic, safe and well tolerated in HIV-infected children and adolescents as in healthy controls. Its simultaneous administration with virosomal-adjuvanted seasonal antigens seems to increase immune response to both pandemic and seasonal viruses with the same safety profile as that of the pandemic vaccine alone. However, because this finding cannot be clearly explained by an immunological viewpoint, further studies are needed to clarify the reasons of its occurrence.