UMLS:C0029713 - FACTA Search

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Query: UMLS:C0029713 (immaturity)
4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The approach of providing passive protection to young infants by immunizing pregnant women can bypass the problems of immunological immaturity in the neonate, avoid or delay active immunization of the infant in the first year of life, and prevent transmission of an infection from the mother to the neonate. Optimal vaccines for this approach should induce high immunoglobulin G antibody titers that quickly reach their maximum level after immunization and persist at protective levels for several years, thus providing passive protection in subsequent pregnancies. Specific applications of this approach include the worldwide practice of maternal immunization with tetanus toxoid vaccine and ongoing studies of maternal immunization to prevent Haemophilus influenzae type b, group B streptococcal, pneumococcal, meningococcal, and human immunodeficiency virus infection in the infant. Addressing the cultural, sociological, and legal aspects of maternal immunization will be required to ensure the success of this approach.
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PMID:Maternal immunization to prevent infectious diseases in the neonate or infant. 815 47

The importance of the EEG for the investigation of neurological diseases in the neonatal period has been largely discussed, since it is often the only way to approach cerebral function in newborns with severe pathologies or under drug effect. The present study was carried out with 85 newborns (NB) who presented perinatal dysfunctions and were submitted to neurological and electroencephalogram (EEG) or polysomnography (PS) evaluation. EEG/PS alterations, pathologies and prognosis were reported. The EEG were classified according to basal activity alterations, presence of paroxysmal activity and sleep stages organization and maturity. The most frequent pathology was perinatal asphyxia (40%) followed by intraventricular hemorrhage (HIV, 16%). The most frequent complaint for exam indication was apnea (71%) followed by convulsion (19%). Fifty-five percent of the exams exclusively required because apnea complaint were considered normal and out of all exams required because seizures only 31% were normal. The EEG alteration most frequently related to perinatal asphyxia, HIV and intrauterine growth delay was immaturity and in the NB with seizures immature EEG and abnormal paroxysms. Many different alterations were registered in the NB with nervous system infection. The EEG findings more correlated with unfavorable prognosis were isoelectricity and abnormal paroxysmal activity including positive sharp waves (100%).
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PMID:[Value of EEG in the characterization and prognosis of neurological diseases in premature infants]. 858 21

We characterized the surface phenotype of B cells from HIV+ children in order to better understand the biology of B cell dysregulation. Twenty-nine HIV-infected, twenty-one exposed, and nineteen age-matched control children were studied for expression of CD5, CD10, CD21, CD23, CD25, CD62L, CD71, and CD69. We conclude that, despite persistent high immunoglobulin levels, total B cells decreased as HIV disease progressed, with selective decreases in CD62L+ and CD23+ B cells. This resulted in an increased proportion of usually minor subpopulations of CD62L- and CD23-negative B cells. We did not find significantly altered B cell expression of other activation/immaturity antigens. This suggests an absolute decrease in a subset of antigen-responsive B cells and a disproportionate increase in a subset of hyperstimulated B cells. These findings provide a biological basis for the paradoxical generalized B cell hyperactivity and specific immune unresponsiveness that are characteristic of HIV infection in children.
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PMID:HIV disease in children is associated with a selective decrease in CD23+ and CD62L+ B cells. 890 51

The early development of symptoms and the rapid progression of disease in some vertically infected infants are thought to reflect in part the immaturity of their immune systems. We examined the relationship between HIV-specific CTL activity and the profile of cytokine production induced by mAb to CD3 and HIV envelope (env) peptides P18 and T1 in PBMC derived from 0.6- to 3.6-yr-old children with perinatal HIV infection. Cellular immunity against HIV was demonstrated only during early stages of disease, whereas the responses were either undetectable or at background levels in HIV-infected children with rapidly progressing disease and in uninfected children of HIV+ and HIV- mothers. Levels of IL-2 mRNA in anti-CD3 mAb- and env peptide-induced PBMC varied and were increased in the infected children with high frequencies of HIV-specific CTL precursors. Analysis of IFN-gamma and IL-4 production by CD4+ T cell clones obtained from cultures stimulated with anti-CD3 mAb or the env peptides showed an increased proportion of Th2 and Th0 clones in HIV-infected children with lower HIV-specific CTL activity, whereas children with high CTL activity had increased numbers of Th1 clones. The results of these studies suggest that decreases in CTL activity to the virus might be associated with the induction of a type 2 cytokine response. These findings underline the role of cytokines in the generation of HIV-specific CTL responses and may be important for the development of immunomodulatory and vaccine strategies to interrupt vertical transmission of HIV.
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PMID:Diminished HIV-specific CTL activity is associated with lower type 1 and enhanced type 2 responses to HIV-specific peptides during perinatal HIV infection. 919 Sep 58

Children born to HIV-1 infected mothers present a more severe clinical evolution than adults or children infected by other routes. The physiologic immaturity of the fetal and neonatal immune systems at the time of the infection probably plays an essential role in the progression of HIV-1 infection in these children. This paper describes the development of the normal human immune system and its correlation with the immunopathogenicity of vertical acquired immunodeficiency syndrome (AIDS).
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PMID:[Immunologic fetal and neonatal immaturity: influence on the clinical course of HIV-1 infection in children]. 922 89

Various authors have reported a high rate of human papillomavirus (HPV) infection and HPV-related neoplasias in human immunodeficiency virus (HIV)-seropositive women. On the other hand, young women are most susceptible to cervical infection because of immaturity of the cervix, as it appears that HPV has more access to the basal cells of the differentiating epithelium. The purpose of the present work was to study cervical smears of 82 adolescent HIV-seropositive women (13-21 years of age) to search for cytological evidence of cervical intraepithelial neoplasias. Twenty-one cases showed characteristic features of HPV infection and squamous intraepithelial lesions (SIL; 25.6%). Sixteen cases aged from 17 to 21 years (mean age 19.5 years) had low-grade SIL (LSIL; 19.5%) and five cases aged from 18 to 21 years (mean age 20.2 years) had high-grade SIL (HSIL; 6.1%). There was no significant difference between the mean age of patients with LSIL and HSIL. Two cases had atypical squamous cells of undetermined significance (ASCUS). In the present work it was found that HIV-seropositive adolescents have a high risk for preneoplastic lesions of the cervix (25.6%) as well as a high incidence of more aggressive lesions (6.1% of HSIL) when compared to the general population of adolescents. As it can be assumed that, if the age of acquisition of the infection in both groups (in the general population and HIV-seropositive women) is the same, it is probable that HIV infection in adolescents not only increases the frequency of HPV infections but also facilitates the evolution to more aggressive preneoplastic lesions of the cervix due to HPV.
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PMID:Squamous intraepithelial lesions in cervical smears of human immunodeficiency virus-seropositive adolescents. 948 35

The increased susceptibility of neonates to infections has been ascribed to the immaturity of their immune system. More particularly, T cell-dependent responses were shown to be biased towards a Th2 phenotype. Our studies on the in vitro maturation of umbilical cord blood T cells suggest that the Th2 bias of neonatal response cannot be simply ascribed to intrinsic properties of neonatal T cells. Phenotypically, neonatal CD4+ T cells are more immature than their adult CD45RO-/RA+ naive counterparts and they contain a subset (10-20%) of CD45RO-/RA+ CD31- cells which is very low in adults and displays some unique functional features. The activation and maturation of neonatal CD4+ T cells is particularly dependent upon the strength of CD28-mediated cosignal which dictates not only the cytokine profile released upon primary activation but also the response to IL-12. Activation of adult as well as neonatal CD4+ T cells in the context of low CD28 costimulation yields to the production of low levels of only one cytokine, i.e. IL-2. In contrast, strong CD28 costimulation supports the production of high levels of type 1 (IL-2, IFN gamma and TNF beta) and low levels of type 2 (IL-4 and IL-13) cytokines by neonatal T cells. The low levels of naive T cell-derived IL-4 are sufficient to support their development into high IL-4/IL-5 producers by an autocrine pathway. The ability of IL-12 to prime neonatal CD4+ T cells for increased production of IL-4 (in addition to IFN gamma) is observed only when CD28 cosignal is minimal. Under optimal activation conditions (i.e. with anti-CD3/B7.1 or allogenic dendritic cells) the response and the maturation of neonatal and adult naive T cells are similar. Thus the Th2 bias of neonatal immune response cannot be simply ascribed to obvious intrinsic T cell defect but rather to particular conditions of Ag presentation at priming. Unlike CD4+ T cells, neonatal CD8+ T cells strictly require exogenous IL-4 to develop into IL-4/IL-5 producers. Most importantly, anti-CD3/B7-activated neonatal CD8 T cells coexpress CD4 as well as CCR5 and CXCR4 and are susceptible to HIV-1 infection in vitro.
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PMID:Maturation of human neonatal CD4+ and CD8+ T lymphocytes into Th1/Th2 effectors. 971 81

The reduced incidence of graft-vs.-host disease following umbilical cord blood (CB) transplantation may be related to the functional immaturity of newborn T cells expressing mainly the naive CD45RA phenotype. Expansion of CD4(+) CD45RA(+) T cells using cytokines may benefit neonates and infants with human immunodeficiency virus (HIV) infection, as a preferential decline in CD4(+) CD45RA(+) cells has been noted as HIV disease progresses. The aim of the study was to investigate the effect of interleukin (IL)-15, a novel cytokine similar to IL-2 in biological activities, on CD45RA/RO expression and apoptosis in umbilical cord blood (CB) and adult peripheral blood (APB) mononuclear cells (MNCs). Prior to culture, CB MNCs contained a greater number of CD4(+) CD45RA(+) cells and fewer CD4(+) CD45RO(+) cells than did APB MNCs. When incubated with RPMI-1640 containing 10% fetal calf serum for 7 days, the percentage of CD45RA(+) cells within CD4(+) T cells (%CD45RA(+)/CD4(+)) significantly decreased compared to that of fresh CB MNCs. IL-15 exerted a dose-dependent increase of %CD45RA(+)/CD4(+) and a corresponding decrease of %CD45RO(+)/CD4(+) in CB MNCs, an effect not observed with APB MNCs treated with IL-15. The percentages of CD45RA(+) and CD45RO(+) expression within CD8(+) cells, however, were not influenced by IL-15, in either CB or APB MNCs. A greater number of CB MNCs underwent apoptosis than did APB MNCs after 7 days of culture in RPMI-1640 containing 10% fetal calf serum. IL-15 did not inhibit apoptosis but induced proliferation comparable to that achieved in APB MNCs. The ability of IL-15 to preferentially enhance the proliferation of CD4(+) CD45RA(+) cells in CB MNCs suggests a role for immunomodulative therapy in HIV-infected newborns and infants.
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PMID:Interleukin-15 enhances CD4(+) CD45RA(+) expression on umbilical cord blood mononuclear cells. 1155 15

Streptococcus pneumoniae is the most frequent cause of otitis media, sinusitis, and pneumonia in children. It is also one of the most common causes of invasive bacterial infections in children including bacteremia and meningitis. One of the current issues regarding S. pneumoniae is the emergence of pneumococcal strains resistant to penicillin and other antibiotics. Children less than two years of age suffer an increased incidence of invasive pneumococcal disease but fail to respond to the 23-valent polysaccharide vaccine because of the immaturity of the T-cell independent immune function. Covalently conjugating the polysaccharide antigen to a carrier protein improves the immune response by permitting the host to utilize a T-cell dependent immune response that is adequately mature in children less than two years of age. Immunogenicity studies of the currently licensed heptavalent conjugated polysaccharide vaccine, (Prevnar, marketed by Wyeth Lederle Vaccines) demonstrated that infants vaccinated with three doses 2 months apart at 2, 4, and 6 months of age successfully developed antibodies to all 7 serotypes; booster doses at 12-15 months demonstrated an amnestic response for each serotype. Immunogenicity studies have similarly demonstrated successful responses in children with sickle cell disease and human immunodeficiency virus infection. An efficacy trial involving nearly 38,000 subjects demonstrated the vaccine's effectiveness in healthy children against invasive pneumococcal disease as well as against pneumonia and otitis media. Currently the US Advisory Committee on Immunization Practices (ACIP) recommends that all infants and children under 24 months of age receive the vaccine. The ACIP recommends that infants receive the vaccine routinely at 2, 4 and 6 months with a fourth dose at 12 to 15 months of age. Infants may receive the first dose as early as 6 weeks of age. The vaccine is also indicated for children 24 to 59 months of age who are at high risk for pneumococcal infection. Adverse events include local reactions in the first two days following vaccination such as approximately 10% reporting erythema, 10% induration, and 20% tenderness. Fever of 38 degrees C or higher occurred in 15% to 25% of children in the first two days following vaccination. Follow-up studies should address important questions regarding the use of pneumococcal conjugate vaccine and other age groups.
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PMID:The pneumococcal conjugate vaccine. 1213 65

The major results are presented of a study of adolescent sexuality in five Sahel countries: Burkina Faso, Gambia, Mali, Niger, and Senegal. Because of strong taboos on discussing sexuality, most studies of reproductive health in the region have paid little attention to adolescents, who constitute over one-fifth of reproductive-age women. Awareness of problems in adolescent reproductive health is limited. Marriage age in the five countries is among the lowest in the world. In urban areas marriage age is increasing, but premarital sex is becoming more common. 51% of uneducated rural girls in Niger are married by age 15, as are 26% who are educated. But at age 20, 38% in Ouagadougou, 52% in Niamey, and 71% in Dakar are still single. Early marriage in the Sahel is usually followed rapidly by a pregnancy in an immature adolescent. The medical consequences of early pregnancy are a public health problem: spontaneous abortion, premature or difficult deliveries, high cesarean rates, infections, fistulas, trauma to the newborn, and low birth weight. Premarital sexual activity carries the same risks of early pregnancy, with the additional social and economic consequences inherent in non-marital fertility. Unwanted pregnancy, illegal abortion, or even infanticide may occur. The proportion of single mothers under age 20 varies from 9% to 18% in the large cities of the Sahel. Adolescents appear to be especially vulnerable to sexually transmitted diseases and HIV infection in case of unprotected sex, possibly because of their physical immaturity. Knowledge of sexually transmitted diseases is limited among girls, and most do not know that seemingly healthy persons can be HIV seropositive. Friends and the media are the most common sources of information about sex, and health agents, family members, and teachers are among the least frequent sources. Most older respondents agreed that premarital sexual activity has increased. Various explanations including later marriage and economic problems were advanced. Some parents implicitly approve of contraceptive use by adolescents, but others feel that it would encourage sexual activity. According to adolescents themselves, the disapproving attitude of health workers prevents them from seeking contraception and other needed reproductive health services.
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PMID:[Sexuality of adolescents in the Sahel]. 1217 12

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