Effects of Lactobacillus GG treatment during pregnancy on the development of fetal antigen-specific immune responses

BACKGROUND

Several clinical trials suggest that probiotics may have a role in the prevention of eczema. The optimal timing and mechanisms underlying this intervention are not clear. In particular it is not known whether such treatment works during pregnancy or whether postnatal exposure is important.

OBJECTIVE

We investigated whether the probiotic Lactobacillus rhamnosus strain GG (LGG) influences fetal immune responses when administered to pregnant women, as a possible mechanism for its protective effects against the development of eczema.

METHODS

Peripheral blood mononuclear cell from 11 adults treated with LGG, and cord blood mononuclear cells (CBMCs) from 73 women participating in a randomized controlled trial of LGG treatment were cultured with heat-killed LGG, ovalbumin (OVA) or without stimulus. Cells were analysed by flow cytometry and real-time PCR for markers of dendritic cell (DC) phenotype, T cell proliferation and regulation. Cytokine secretion was analysed in culture supernatants by multiplex cytokine assay.

RESULTS

LGG treatment of adults led to systemic immune responses suggestive of antigen-specific tolerance including reduced CD4(+) T cell proliferation to heat-killed LGG (30% reduction; P=0.03). LGG treatment of pregnant women did not influence CD4(+) T cell proliferation, forkhead box P3 expression, DC phenotype or cytokine secretion in CBMCs cultured with heat-killed LGG or OVA.

CONCLUSION

LGG treatment of pregnant women fails to influence fetal antigen-specific immune responses. This suggests that modulation of fetal immune responses may not be a major mechanism by which probiotics such as LGG prevent eczema.

The clinical syndrome of specific antibody deficiency in children

Specific antibody deficiency (SAD) is an immune deficiency which has been reported in adults and children with recurrent respiratory tract infections; however, the clinical features of SAD are not well described. This study evaluated formally the clinical syndrome of SAD, by comparing the clinical features of children with SAD and those of children with recurrent infection but normal immune function tests. SAD was defined as an adequate IgG antibody response to less than 50% of 12 pneumococcal serotypes tested following 23-valent unconjugated pneumococcal immunization. An adequate IgG antibody response was defined as a post-immunization titre of >or= 1.3 microg/ml or >or= four times the preimmunization value. Seventy-four children with recurrent infection were evaluated where immune deficiencies other than SAD had been excluded. Eleven (14.9%) of these children had SAD. Clinical features differed between the group with SAD and the group with normal antibody responses. A history of otitis media, particularly in association with chronic otorrhoea was associated with SAD [relative risk (RR) of SAD in those with chronic otorrhoea 4.64 (P = 0.02)]. SAD was associated with allergic disease, particularly allergic rhinitis [RR of SAD in those with allergic rhinitis 3.77 (P = 0.04)]. These two clinical associations of SAD were independent in this study [RR of chronic otorrhoea in those with allergic rhinitis 0.85 (P = 0.28)]. SAD was not an age-related phenomenon in this population. SAD has a distinct clinical phenotype, presenting as recurrent infection associated with chronic otorrhoea and/or allergic disease, and the condition should be sought in children with these features.

Can allergic diseases be prevented prenatally?

Allergic diseases continue to increase in prevalence, and now affect over a third of the population in many countries. There is evidence that the increase in such diseases has its origins in early life exposures. Pregnancy or early childhood may therefore be critical periods for preventing the onset of allergic disease, and prenatal interventions are an attractive possibility for a population-based preventive approach. Here we review the data suggesting that prenatal exposures are important in the development of allergic disease, and that interventions during this time might be effective in prevention. We find evidence from both animal and human studies that prenatal interventions can influence the future development of allergic disease. There are a number of mechanisms through which such interventions may act to prevent allergic sensitization. We conclude that prenatal interventions have the potential to reduce the burden of allergic disease, and merit continued investigation. Further research in this area may lead to significant public health initiatives.

The role of probiotics in the management of allergic disease

Probiotics have recently been advocated for the prevention and treatment of allergic disease (AD). In clinical practice they are increasingly being used for these purposes. Here we review the evidence base for the use of probiotics in the management of AD. We find support for their use in the treatment of childhood eczema, but the clinical significance of any treatment effect is uncertain. There is also evidence to support the use of probiotics in the prevention of childhood eczema. However the available evidence suggests that probiotics are not an effective treatment for allergic airway diseases. Probiotics may be more effective when used early in life, and they may have a particular role in gastrointestinal AD. The relative efficacy of different probiotic strains in the management of AD is not well established, and further work is needed to establish their mechanisms of action. In summary probiotics are likely to play a part in the management of childhood eczema in the future, and further studies are warranted to precisely define their role.

Ethics of refusing parental requests to withhold or withdraw treatment from their premature baby

In the United Kingdom women have access to termination of pregnancy for maternal reasons until 24 weeks' completed gestation, but it is accepted practice for children born at or beyond 25 weeks' gestation to be treated according to the child's perceived best interests even if this is not in accordance with parental wishes. The authors present a case drawn from clinical practice which highlights the discomfort that parents may feel about such an abrupt change in their rights over their child, and argue that parents should have greater autonomy over treatment decisions regarding their prematurely born children.

Gamete retrieval in terminal conditions

There has been a growing interest and requests by patients facing intensive chemotherapy or surgically ablative procedures for gamete retrieval and preservation for future procreative efforts. There are technical difficulties in this area but little ethical discomfort. More troubling are the issues that arise with a terminally ill, incapable patient-one who is in a persistent vegetative state or who is declared brain dead or who is neurologically devastated with no hope for recovery, but not yet in either of the above states-or with a person who has suddenly died. In these cases, the surviving spouse, partner, or family members may request gamete retrieval for future reproductive efforts. Discussion of this topic within the Ethics Consultation Service at the University of Virginia demonstrated a need for development of insight derived from facts and ethical deliberation to help formulate a policy that would apply to such cases. A group was assembled with the expertise to explore the issue and to help formulate a policy that could be suggested for adoption by the hospital administration. The group consisted of a urologist with experience in sperm retrieval from terminally ill patients; the director of the laboratory supporting the assisted reproductive facility in the Department of Obstetrics and Gynecology; the chairperson of the Ethics Consultation Service (who is also a neonatologist); and 2 members of the Ethics Consultation Service, one a genetic counselor and the other an obstetrician-gynecologist with a master's degree in biomedical ethics. Current literature was reviewed, the expertise of the urological member and the reproductive laboratory director was explored, and the insight of the members of the Ethics Consultation Service was added. We explored the technical aspects of both male and female gamete retrieval and preservation and the reproductive potential of these stored gametes. We present a review of the current literature on both the technical and ethical aspects of the topic. Finally, we present a policy that we deem acceptable for adoption and that should be of value to other practitioners and facilities as they contemplate facing requests for gamete retrieval.

Ethical considerations in neonatal resuscitation: clinical and research issues

The recent publication of guidelines for ethical decision making for resuscitation of infants has highlighted the problems inherent in using the currently available data to define those situations in which resuscitation should be or might be withheld or withdrawn. Prior selection criteria for resuscitation, criteria for inclusion into the study group, incomplete resuscitation, gestational age determination, intrauterine growth restriction, subjective assessment of 'poor' outcome, and other factors make setting specific parameters for acting or not acting difficult, if not dangerous, and possibly impossible. Research in neonatal resuscitation poses some potential ethical obstacles, but national and international regulations and guidelines are available to assist investigators in study design.

Ethical issues surrounding resuscitation

Difficult delivery room situations concerning resuscitation can pose major ethical, legal, and professional problems. As with any medical decision, careful and timely acquisition and analysis of the data and frank, open discussion among all the decision makers, including parents, pediatric staff, obstetrical staff, and consultants will allow optimal decisions to be made. Recognizing the problem of uncertainty before and even at birth is essential to these discussions.

Parental rights at the birth of a near-viable infant: conflicting perspectives

OBJECTIVE

Our purpose was to clarify the roles of parents and caregivers in making decisions for resuscitation of near-viable infants.

STUDY DESIGN

We present two cases and review ethical and legal issues involved in making decisions for near-viable infants.

RESULTS

Medical responsibility for the infant shifts at birth from obstetrics to neonatology. Neonatologists will "opt for life" when prognosis is uncertain. As surrogate decision makers, parents have rights to make decisions about initiation of resuscitation, but these parental rights are limited by the infant's best interests. If caregivers believe parents are not acting in the infant's best interests, they may persuade parents, challenge parental refusal by petitioning the courts, or treat without consent with possible legal risk.

CONCLUSIONS

Effective communication is essential to prevent misunderstanding and conflicts. In most instances parents are the best decision makers for a near-viable infant. Parental rights are limited by best interests of the infant.

Transfusion-acquired human immunodeficiency virus infection in twelve neonates: epidemiologic, clinical and immunologic features

Twelve neonates in 3 cohorts received blood transfusions from two donors who were infected with human immunodeficiency virus (HIV). All 12 infants developed laboratory and/or clinical evidence of HIV infection, usually in the first year of life. Ten of 12 infants had serum antibody to HIV when tested between 9 and 42 months of age. The two seronegative infants were severely hypogammaglobulinemic when they were tested. Nine infants developed a variety of illnesses attributable to HIV infection, but only 2 fulfilled criteria for the diagnosis of acquired immunodeficiency syndrome. In follow-up ranging from 2 1/2 to 4 years 5 patients (42%) have died. Four patients had HIV-associated illnesses but recovered and now have few if any symptoms attributable to HIV infection. Three children have never had signs or symptoms attributable to HIV. Immunologic abnormalities were present in all patients; the most consistent finding was a decrease in the proportion of T helper cells. Three patients had severe panhypogammaglobulinemia. The hypogammaglobulinemic infants had significantly lower numbers and percentages of T helper cells compared to the remaining patients (P less than 0.01). We conclude that exposure to HIV via transfusion in the neonatal period results in an extremely high rate of infection with substantial mortality and morbidity, but clinical recovery occurs in some patients. Also hypogammaglobulinemia may be more common in infants with HIV infection than previously appreciated.

Prophylactic treatment of asymptomatic patent ductus arteriosus in premature infants with respiratory distress syndrome

Early treatment of premature infants with indomethacin has been proposed as a means of reducing the morbidity associated with respiratory distress syndrome complicated by symptomatic patent ductus arteriosus. We identified 26 infants less than 48 hours old with severe respiratory distress syndrome who had an asymptomatic patent ductus arteriosus. These infants were treated with either indomethacin or placebo. There was a significant difference in the frequency of ductal closure after receiving indomethacin treatment. No significant difference was observed in the time required for mechanical ventilation, time receiving supplemental oxygen, or time in the hospital, and there were no significant differences in the incidence of bronchopulmonary dysplasia, intraventricular hemorrhage, retinopathy of prematurity, or death between the two groups.

Thrombocytopenia as the presenting manifestation of human T-lymphotropic virus type III infection in infants

Three infants between 8 and 9 months of age developed thrombocytopenia resulting from immune-mediated platelet destruction, as evidenced by the presence of serum antibody to platelets and elevated platelet-associated immunoglobulin G in two patients, and abundant bone marrow megakaryocytes in all patients. The patients had a satisfactory response to corticosteroid therapy, and platelet counts have remained normal during observation after therapy. All patients had serum antibody to human T-lymphotropic virus type III, and HTLV-III was isolated from the peripheral blood lymphocytes in two patients. The HTLV-III infections were presumably acquired via blood transfusions in the neonatal period; none of the patients' mothers belonged to a risk group for HTLV-III infection, and all were HTLV-III seronegative. Although thrombocytopenia was the major clinical manifestation, the patients had a number of immunologic abnormalities characteristic of HTLV-III infection; these included hyperimmunoglobulinemia, a decreased proportion of peripheral blood T cells, and a marked reduction in the proportion of peripheral blood T helper-inducer lymphocytes. We conclude that the patients had immune-mediated thrombocytopenia caused by HTLV-III infection.

Intralipid infusion in neonates: effects on polymorphonuclear leukocyte function

In vivo and in vitro studies were done to assess the effects of Intralipid (IL) on neonatal polymorphonuclear leukocyte (PMNL) function. No significant abnormalities of chemotactic (CT) or chemiluminescent (CL) activities were noted in cord or adult PMNLs incubated with IL (10 mg/ml) when compared with paired controls incubated with buffer. In 14 premature and term neonates, IL was infused at 1 g/kg/24 h. Postinfusion CL activity of PMNLs was not significantly different from preinfusion CL activity. Although previous animal and human studies have shown abnormalities of PMNL function using higher infusion rates, slow infusion of IL at 1 g/kg/24 h produced no detectable alteration in PMNL oxidative function. The safety of long-term therapy with higher doses of IL remains to be proven.

Hypernatremia with choroid plexus hematomas and elevated CSF protein level

A 3-month-old infant had hypernatremia, neurologic dysfunction, and an unusually high level of cerebrospinal fluid protein. The autopsy findings included cerebral edema, intravascular coagulation, and bilateral choroid plexus hematomas. Extensive destruction of the choroid plexus, in combination with diffuse intravascular coagulation may explain the much greater elevation of CSF protein than previously described with hypernatremia.

Nonketotic hyperglycinemia. Effects of therapy with strychnine

Nonketotic hyperglycinemia was diagnosed in identical twins with lethargy and respiratory failure in the neonatal period. Therapy with strychnine (0.32 mg/kg/day) resulted in great reductions in CSF and plasma glycine levels and improvement in muscle tone, respiration, and ability to suck. Myoclonic seizures were partially controlled by therapy with clonazepam. Higher dosages of strychnine (up to 2.0 mg/kg/day) were needed to counteract the increased lethargy following administration of clonazepam. At 5 months of age, the twins' developmental performance remained below the 1-month level despite adequate somatic growth. The twins died suddenly of status epilepticus at 6 1/2 months of age.