Defective NK cell activation in X-linked lymphoproliferative disease.

X-linked lymphoproliferative disease (XLP) is characterized by a selective immune deficiency to EBV. The molecular basis of XLP has been attributed to mutations of signaling lymphocytic activation molecule-associated protein, an intracellular molecule known to associate with the lymphocyte-activating surface receptors SLAM and 2B4. We have identified a single nucleotide mutation in SLAM-associated protein that affects the NK cell function of males carrying the mutated gene. In contrast to normal controls, both NK and lymphokine-activated killer cell cytotoxicity was significantly reduced in two XLP patients. In addition to decreased baseline cytotoxicity, ligation of 2B4 significantly augmented NK lytic function in normal controls but failed to enhance the cytotoxicity of NK cells from XLP patients. These findings suggest that association of SAP with 2B4 is necessary for optimal NK/lymphokine-activated killer cytotoxicity and imply that alterations in SAP/2B4 signaling contribute to the immune dysfunction observed in XLP.

Cell-mediated and antibody immune responses to AIK-C and Connaught monovalent measles vaccine given to 6 month old infants.

Measles vaccination of infants younger than 1 year of age should be successful in populations with a high proportion of measles vaccinated mothers. Infants whose mothers were vaccinated are born with less maternal antibody which can interfere with vaccination compared with infants whose mothers had measles. AIK-C or Connaught (CLL) measles vaccine was given to 300 6 month infants born to mothers who had measles (group 1) or who were vaccinated against measles (group 2). Pre- and post-vaccination measles antibody was measured by EIA and PRN and cell mediated immunity (CMI) by blast transformation and production of interferon-gamma and interleukin-10. After vaccination, mean antibody level, seroconversion and blastogenesis were significantly lower for group 1 than group 2 (p < 0.05). Post-vaccination measles IgG was significantly higher for group 2 CLL vaccinees compared with group 2 AIK-C (p < 0.05); seroconversion rates were 73 and 63%, respectively. More than 93% of group 2 infants had elevated measles IgG after vaccination. About 89% of all children had some evidence of a blastogenic response. Lymphoproliferation correlated strongly with cytokine production and weakly with IgG. Not all seroresponders had a CMI response and vice versa. AIK-C and CLL vaccines induce strong measles specific T and B immunity in most 6 month infants of vaccinated mothers.

A comparison of alternate immunization regimes for measles in vaccinated populations.

Infants today lose maternal measles antibody sooner than in the past. This is related to demographic changes in maternal immunization. Data for rates of decay of maternal antibody and seroconversion after measles vaccination for infants born to naturally immune (Group 1) or vaccinated (Group 2) mothers have been used to evaluate two vaccination schedules: Regime 1, measles-mumps-rubella (MMR) at 1 year of age and Regime 2, monovalent measles at 6 months followed by MMR at 15 months of age. Regime 2 costs less because MMR can be administered at 15 months with the last pentavalent booster. Months of protection/1000 children aged 0-15 months (child-months of protection) were estimated for infant populations ranging from 0 to 100% Group 1 for Regimes 1 and 2. Regime 1 provides more child-months of protection only for 100% Group 1 populations. For the study population Regime 2 provided at least 17% more child-months of protection than Regime 1. Regime 2 provides increased medical and financial benefits in proportion to the number of Group 2 infants in the population and thus is ever more advantageous for today's increasingly vaccinated populations.

Mutations of the CD40 ligand gene and its effect on CD40 ligand expression in patients with X-linked hyper IgM syndrome.

X-linked hyper IgM syndrome (XHIM) is a primary immunodeficiency disorder caused by mutations of the gene encoding CD40 ligand (CD40L). We correlated mutations of the CD40L gene, CD40L expression, and the clinical manifestations observed in XHIM patients from 30 families. The 28 unique mutations identified included 9 missense, 5 nonsense, 9 splice site mutations, and 5 deletions/insertions. In 4 of 9 splice site mutations, normally spliced and mutated mRNA transcripts were simultaneously expressed. RNase protection assay demonstrated that 5 of 17 mutations tested resulted in decreased levels of transcript. The effect of the mutations on CD40L expression by activated peripheral blood mononuclear cells (PBMC) and T-cell lines or clones was assessed using one polyclonal and four monoclonal antibodies and a CD40-Ig fusion protein. In most patients, the binding of at least one antibody but not of CD40-Ig was observed, suggesting nonfunctional CD40L. However, activated PBMC from three patients and activated T-cell lines from two additional patients, each with different genotype, bound CD40-Ig at low intensity, suggesting functional CD40L. Thus, failure of activated PBMC to bind CD40-Ig is not an absolute diagnostic hallmark of XHIM and molecular analysis of the CD40L gene may be required for the correct diagnosis. Patients with genotypes resulting in diminished expression of wild-type CD40L or mutant CD40L that can still bind CD40-Ig appear to have milder clinical consequences.

Cerebellar hypoplasia and frontal lobe cognitive deficits in disorders of early childhood.

A developmental chronometry hypothesis of early brain damage is suggested in which regions of the brain with a protracted course of postnatal development will be more vulnerable than earlier maturing areas to deleterious effects of early insult and, therefore, may become common sites of abnormality across many disorders originating in early childhood. Initial investigations of the cerebellum and frontal lobes are presented using MRI and neuropsychological measures. Planimetric measures of the cerebellar vermis (lobuli I-V and VI-VII) and pons, and neuropsychological frontal lobe measures were obtained from high functioning individuals with autism (A), survivors of acute lymphoblastic leukemia (ALL) with brain sequelae following radiation and chemotherapy, and from rigorously selected healthy controls (C). The neuropsychological results were clustered according to functions commonly related to frontal brain, posterior brain, and left and right hemispheres. The A and ALL groups, as compared to C, yielded modest but consistently reduced MRI measures for vermal lobuli I-V and VI-VII. Hypoplasia of lobuli VI-VII was more marked than I-V. Performance on neuropsychological tests for frontal lobe functions was generally depressed in both groups, with more severe deficits in A. Between-group differences in verbal, visual-spatial, and emotional-social skills are discussed. The cerebellar and frontal brain deficits that are present in both clinical groups (A and ALL) may be common to other developmental and acquired disorders of early childhood. Such joint manifestation of cerebellar and frontal lobe abnormalities is in agreement with the concept of cerebellar significance for the development of higher cognitive functions.

Kinetics of immunologic responses after primary MMR vaccination.

To study the kinetics of humoral as well as cellular immunity to measles and to test for associated immunosuppression 124 12 month old children were studied twice, before routine MMR and either 14, 22, 30, or 38 days after vaccination. Plaque reduction neutralization (PRN) titres were determined at these time points and lymphocytes were evaluated to identify changes in proportions of phenotype, their capacity to generate cytokines and to respond to blast transformation (BT) to measles hemagglutinin (HA), tetanus toxoid and Candida antigen. The PRN titre and BT to HA plateaued at 30 days and CD8+ and NK cells increased after immunization. Interleukin 2, 4, and 10 showed no significant changes. There was mild suppression of BT at 14 and 22 days post-immunization Interferon-gamma was the principal cytokine produced after primary measles immunization, suggesting primary measles immunization induces predominantly a TH1 type response.

Differential modulation of the immune response by breast- or formula-feeding of infants.

Spontaneous integrin expression on CD4+, CD8+ and CD19+ lymphocytes at 6 months was significantly lower in breastfed than formula-fed infants (p < 0.05). In another study of 59 formula-fed and 64 breastfed 12-month-old children blast transformation and cytokine production by lymphocytes, and T cell changes were measured before and after measles-mumps-rubella vaccination (MMR). Before vaccination, lymphocytes of breastfed children had lower levels of blast transformation without antigen (p < 0.001), with tetanus toxoid (p < 0.02) or Candida (p < 0.04), and lower interferon-gamma production (p < 0.03). Fourteen days after the live viral vaccination, only the breastfed children had increased production of interferon-gamma (p < 0.02) and increased percentages of CD56+ (p < 0.022) and CD8+ cells (p < 0.004). These findings are consistent with a Th1 type response by breastfed children, not evident in formula-fed children. Feeding mode has an important long-term immunomodulating effect on infants beyond weaning.

Perinatal vitamin A (retinol) status of northern Canadian mothers and their infants.

Vitamin A (retinol) status was determined in two groups living in the northern part of Canada: native (Indian and Inuit) and non-native (Caucasian). The dietary intake of vitamin A and its plasma concentration were measured prenatally, at delivery and postnatally in mothers. Plasma concentrations were also measured at birth and postnatally in their infants. The mean vitamin A intake of native mothers was significantly lower than that of non-native mothers, 661 +/- 485 versus 1,377 +/- 1,418 retinol equivalents (p < 0.00005), with a higher risk of deficiency without supplementation, 35% versus 8%. Plasma retinol concentrations, although not in the deficient range, were significantly lower in native than non-native mothers prenatally and postnatally. Infant mean plasma retinol concentrations at birth averaged only 52% of those of their mothers and were significantly lower among native than non-native infants although no clinical evidence of vitamin A deficiency was noted. We speculate that vitamin A supplementation in native Northern Canadian mothers during pregnancy and in their neonates during infancy may have a role to play in the prevention of vitamin A deficiency. We also postulate that plasma retinol concentrations of 50-60% of maternal levels and between 0.7 and 2.5 mumol/l represent a 'normal' range for newborn infants.

A novel immunosuppressive factor in human colostrum.

Human colostrum contains a factor that inhibits the induction of interleukin 2 (IL2) in T lymphocyte cell lines (colostrum inhibitory factor, CIF). In PMA-stimulated EL4.E1 cells, inhibition is the result of blocking the accumulation of IL2 mRNA. Human colostrum contains on the order of 100 U/ml of CIF activity, where 1 U/ml inhibits 50% of the IL2 response. Transient acidification to pH 3.0 increased CIF activity severalfold. Although it resembles TGF beta in some respects, antisera against TGF beta neutralized 10% or less of the CIF activity in human colostrum. Furthermore, whereas authentic TGF beta blocked the induction of IL2 by PMA-plus-calcium-stimulated cells by only about 50%, CIF inhibited it completely. A similar CIF activity was also detected in bovine colostrum, but not in normal bovine milk.

Measles vaccination of infants in a well-vaccinated population.

During outbreaks of measles, measles vaccine is recommended for infants considered to be at risk who are 6 months of age and older. In a prospective trial the serologic response to early measles immunization has been evaluated in 125 infants given monovalent measles vaccine at 6 to 8.5 months of age and measles-mumps-rubella at 15 months. The response to vaccination was measured by plaque reduction neutralization (PRN) assay and enzyme immunoassay. Infants were grouped by the mother's immunization history: natural immunity (n = 60, Group 1); killed followed by live, further attenuated vaccine (n = 22, Group 2); and live, further attenuated vaccine only (n = 43, Group 3). The prevaccination geometric mean titer (GMT) by PRN for Group 1 (GMT = 69) was significantly higher than that of Group 2 (GMT = 18) or 3 (GMT = 13). Seroconversion (4-fold increase in PRN titer) rates after monovalent vaccine were 31, 71 and 76% for Groups 1, 2 and 3, respectively. Seroconversion percentages were higher when measured 6 to 8 weeks after vaccination compared with 4 to 5 weeks. After measles-mumps-rubella > or = 97% of all infants had PRN titers > 120 and were measles IgG-positive by enzyme immunoassay. These data show that as demographics shift to a well-vaccinated maternal population and susceptibility in younger infants, measles vaccination before the currently recommended age will be effective.

Familial enteropathy with villous edema and immunoglobulin G2 subclass deficiency.

We describe a familial form of recurrent acute, life-threatening secretory diarrhea associated with distinctive jejunal histologic changes and IgG2 subclass deficiency. Symptoms begin abruptly with anorexia and vomiting, and progress within hours to massive secretory diarrhea and shock with profound neutropenia and hypoproteinemia, including hypoalbuminemia and hypogammaglobulinemia. Affected survivors recover quickly and thereafter grow and develop normally. Biopsy specimens obtained during remission from 3 adults and 11 children show club-shaped jejunal villi broadened by edema and histiocytes with imbibed fluid; the overlying intestinal epithelium and brush border appear normal, but the basement membrane is interrupted in some areas. No characteristic microorganisms have been identified in association with the syndrome. Clinical manifestations cease in the second decade, but the abnormal jejunal histologic pattern persists into adult life. Female and male patients are equally affected, although all fatal cases have been in female subjects. Inheritance appears dominant with variable penetrance: one family member without a history of diarrhea has characteristic biopsy findings and another appears to be an obligate carrier with normal biopsy findings. Affected individuals have a reduced serum concentration of IgG2. We believe that this familial enteropathy is a unique entity, not previously described.

Iron status and pregnancy in a northern Canadian population: relationship to diet and iron supplementation.

To determine the extent of iron deficiency, the prognostic value of prenatal ferritin levels and the desirability of prenatal iron supplementation in the western Canadian arctic, dietary iron intake was determined in 171 women and ferritin levels determined in 121 women during pregnancy, 79 at delivery and 77 postnatally, as well as in 65 of their infants at birth and 74 postnatally. Iron deficiency (ferritin < 15 ng/ml) was present in 34% of women during the first two trimesters, 25% (20/79) at delivery and in 51.7% (15/29) of mothers and 31% (9/29) of infants beyond four months after delivery. Maternal follow-up ferritin levels correlated poorly with dietary iron intake but well with prenatal ferritin levels, which appeared to be good predictors of the effectiveness of supplementation. Mean infant follow-up ferritin levels were 105.6 +/- 115.2 ng/ml with, and 46.7 +/- 63.5 without maternal prenatal supplementation (p = 0.03); maternal, 45.5 +/- 40.9 ng/ml with, and 12.8 +/- 9.2 without (p < 0.001). Measurement of prenatal ferritin levels to determine risk of iron deficiency and routine prenatal iron supplementation are recommended.

Reduced measles immunity in infants in a well-vaccinated population.

The recommended age for measles vaccination is based in part on information gathered when most mothers had natural measles. Nowadays many mothers have received measles vaccine. To assess this change measles antibody neutralization titers (NT) were determined for 278 mother-infant pairs. One hundred sixty-four mothers, born before 1958, likely had had natural measles (Group 1). Sixty mothers received one to three killed plus one attenuated measles vaccination (Group 2) and 54 received 1 attenuated measles vaccination only (Group 3). NT were determined for the mother and for the infant at birth and in the infant during the fourth and sixth months. Group 1 mothers and infants at every age had higher geometric mean NT than those in Groups 2 or 3 (P less than 0.05). By 7 months 65% of Group 1 infants and greater than 90% of Group 2 and 3 infants had an NT less than 1:10. The rate of antibody decay was significantly faster for Group 1 infants (P less than 0.05). Earlier vaccination in the infant should be considered.

Smoking and caffeine and alcohol intake during pregnancy in a northern population: effect on fetal growth.

OBJECTIVES: To assess the prevalence of smoking and of caffeine and alcohol intake during pregnancy in a northern population and to determine the relation of these factors to birth weight, length and head circumference. DESIGN: Questionnaire survey and collection of maternal and newborn measurements. SETTING: Ten communities in the Inuvik Zone, NWT. PATIENTS: A total of 162 women (56 Inuit, 38 Indian, 37 white and 31 mixed race) who presented for prenatal care in their community and gave birth in Inuvik between September 1987 and January 1990 and their newborns. RESULTS: In all, 64% (101/159) of the women smoked, 57% (88/154) ingested more than 300 mg of caffeine daily, and 34% (50/145) drank alcohol during their pregnancy. Smoking, caffeine intake and binge drinking were most frequent among the Inuit and Indian mothers. Smoking was significantly associated with decreased birth weight (p less than 0.001) and length (p less than 0.05). Alcohol intake, especially binge drinking, was significantly associated with decreased head circumference (p less than 0.05). Caffeine was found not to be related to any of the outcome variables after smoking was controlled for through stepwise multiple regression. CONCLUSIONS: The marked prevalence of smoking and alcohol intake during pregnancy and their effects on the newborn are public health concerns in the Northwest Territories and warrant intensive countermeasures.

Human colostrum contains an activity that inhibits the production of IL-2.

The effect of human colostrum on T cell immune function was investigated. Colostrum inhibited the proliferation of human T cells activated by allogeneic, concanavalin A (Con A) or phytohaemagglutinin (PHA) stimulation. Colostrum also inhibited the production of IL-2 by Con A-activated human peripheral blood T cells and by Con A-activated Jurkat cells, a human T lymphoma line. Similarly, human colostrum inhibited the production of IL-2 by EL4 cells, a murine thymoma line, when stimulated with phorbol myristate acetate. The inhibitory activity was not cytotoxic and could not be neutralized by antibody to transforming human growth factor beta.

Beta 1 integrin (CD29) expression on human postnatal T cell subsets defined by selective CD45 isoform expression.

The integrin beta 1 (CD29) is a marker for total very late activation Ag integrins on cells, and exhibits considerable fluctuation in cell surface density at various stages of T cell development. We have analyzed beta 1 integrin expression on subsets of human thymus, and on T cells from healthy babies and children, in comparison to healthy adults aged 26 to 75. T cells from adult peripheral blood include a CD29-, a CD29lo, and a CD29hi set. Compared with adults, PBMC T cells from children have reduced numbers of both CD29lo and CD29hi subsets but equivalent numbers of CD29- T cells. The number of CD29hi T cells increases gradually with age, achieving adult levels only at about 26 yr of age; in aged adults (69 to 75 yr), nearly all T cells have a CD29hi phenotype. Most thymocytes and cord blood T cells, in contrast, have a single peak of CD29 staining that is intermediate to the two peaks seen in adults. Multi-negative progenitor and CD45RO- thymocytes (presumptive thymic generative line-age) are 98% CD29hi. Progenitor thymocytes and adult PBMC T cells express equivalent amounts of beta 1 and alpha 4, but progenitors are alpha 5hi, whereas PBMC T cells are alpha 5lo. T cells from children have reduced beta 1hi and alpha 5lo, but nearly comparable numbers of alpha 4hi. This suggests that the major very late activation Ag integrins during childhood may be alpha 5 beta 1 and alpha 4 complexed with an alternate beta chain. In children, the majority of CD29hi cells are also CD45RAhi, in contrast to the pattern in adults, in whom the majority of CD29hi T cells are CD45RA-. This suggests that in children, the main defense against infection may reside in the CD29hi45RAhi T cells, which have not yet made the transition to CD45RO and to bona fide memory status. The proliferative response to tetanus toxoid of 4- to 6-mo-old babies correlates with the number of CD29hi45RAhi T cells, suggesting that it derives at least in part from cells that do not express a "memory" phenotype. These observations show a pattern of alternating high and low density CD29 during T cell development, which is consistent with the idea that CD29 is a marker for functionally defined T cell sets. Analysis of the CD29 expression of CD29hi thymocytes developing in vitro supports this view. We suggest that the intensity of CD29 expression on a T cell varies, dependent upon the microenvironmental interactions required by a differentiating T cell.

Measles virus specific antibody in infants in a highly vaccinated society.

Measles virus specific antibody levels were measured in infants from 2 to 12 months of age. The sera were tested by hemagglutination-inhibition (HI), neutralization (NT), and enzyme immunoassay (EIA) methods. The results of this study indicate that in the population examined, infants at an early age have very low or no immunity of maternal origin to measles virus-93% of the infants were without detectable neutralizing antibody (NT titer less than or equal to 10) at 6 months of age, and by the end of the first year of life 100% had no neutralizing antibody.

Effect of breast-feeding on antibody response to conjugate vaccine.

Infants were immunised at the ages of 2, 4, and 6 months with conjugate Haemophilus influenzae type b vaccine, and their responses to the vaccine were evaluated by feeding method (breast or formula). There were no significant differences between the groups in antibody levels at early ages. However the antibody levels were significantly higher in the breast-fed (57 infants) than the formula-fed group (24 infants) at 7 months (mean [SD] 29.8 [32.0] vs 17.5 [14.8] micrograms/ml) and at 12 months (55 vs 26 infants; 4.8 [4.4] vs 3.0 [2.3] micrograms/ml). These findings are strong evidence that breast-feeding enhances the active immune response in the first year of life, and therefore the feeding method must be taken into account in the evaluation of vaccine studies in infants.