Monitoring of omalizumab therapy in children and adolescents.

BACKGROUND: Omalizumab is a successfully implemented supplementary therapy for improving asthma control in children aged 6 years and older with severe persistent allergic asthma. The dosage of omalizumab depends on body weight and IgE level, yet no parameter has been established to guide dosage changes during therapy. Clinical studies in patients with allergic asthma or allergic rhinitis revealed a clinically relevant improvement by using omalizumab leading to concentrations of free serum IgE reported to be lower than 50 ng/ml. Therefore, only the question concerning the concentrations of free IgE used in a therapy with omalizumab is regarded of clinical importance, while total IgE (free and omalizumab-bound IgE) increases during treatment. PATIENTS AND METHODS: Ten patients, 8 to 17 years of age, received therapy with omalizumab due to severe allergic asthma. In addition, the patients had pronounced rhinoconjunctivitis, food allergy, insect sting allergy, and/or neurodermitis. The total IgE in the serum was measured in the patients 3 - 6 months before each omalizumab injection as a potential progress parameter (Sandwich-Immunoassay ADVIA Centaur). RESULTS: Six months after beginning of the therapy with omalizumab, a significant decrease of the total IgE concentration was found, in comparison to the baseline values (p < 0.003). In all patients the tolerability of omalizumab was very good: there was a reduction in the frequency of the asthma exacerbations and rescue medications. All patients reported a clearly improved quality of life. CONCLUSIONS: A general increase in IgE was not observed in any of the children we treated with omalizumab. Apart from the development of routine assays to determine free serum IgE levels, the significance of the total serum IgE as a suitable control of an omalizumab therapy should be further investigated in controlled studies with regard to sensitivity and specificity. In order to only administer the lowest necessary dose of omalizumab especially in children and adolescents, the establishment of laboratory parameters (free IgE and/or total IgE) to adequately monitor the therapy is urgently needed. Patients undergoing an omalizumab therapy require medical supervision at close intervals.

Inhibition of phosphodiesterase 4 enhances lung alveolarisation in neonatal mice exposed to hyperoxia.

Bronchopulmonary dysplasia (BPD) is characterised by impaired alveolarisation, inflammation and aberrant vascular development. Phosphodiesterase (PDE) inhibitors can influence cell proliferation, antagonise inflammation and restore vascular development and homeostasis, suggesting a therapeutic potential in BPD. The aim of the present study was to investigate PDE expression in the lung of hyperoxia-exposed mice, and to assess the viability of PDE4 as a therapeutic target in BPD. Newborn C57BL/6N mice were exposed to normoxia or 85% oxygen for 28 days. Animal growth and dynamic respiratory compliance were reduced in animals exposed to hyperoxia, paralleled by decreased septation, airspace enlargement and increased septal wall thickness. Changes were evident after 14 days and were more pronounced after 28 days of hyperoxic exposure. At the mRNA level, PDE1A and PDE4A were upregulated while PDE5A was downregulated under hyperoxia. Immunoblotting confirmed these trends in PDE4A and PDE5A at the protein expression level. Treatment with cilomilast (PDE4 inhibitor, 5 mg.kg(-1).day(-1)) between days 14 and 28 significantly decreased the mean intra-alveolar distance, septal wall thickness and total airspace area and improved dynamic lung compliance. Pharmacological inhibition of phosphodiesterase improved lung alveolarisation in hyperoxia-induced bronchopulmonary dysplasia, and thus may offer a new therapeutic modality in the clinical management of bronchopulmonary dysplasia.

Capnovolumetry: a new tool for lung function testing in children with asthma.

In capnovolumetry, the expiratory CO2 concentration of exhaled air is plotted against the volume and thereby allows to determine functional dead space volumes. This method might offer additional information in lung function testing in children and adolescents with bronchial asthma. We aimed at determining whether a bronchospasmolysis (BSL) effect in the lower airways could also be detected by capnovolumetry as reflected by changes in the functional threshold dead space volumes (VDT). In 47 patients (aged 4-16 years) with a mild persistent bronchial asthma, VDT were determined before and after bronchodilation prior to starting therapy with inhaled steroids and after 6 months of treatment. Additionally, spirometry and body plethysmography were performed in all patients. There were significantly higher VDT values after BSL before and after 6 months of therapy (P<0.0001). VDT values before BSL were tendatively higher after 6 months of therapy compared with baseline values (P=0.07). VDT values correlated with parameters derived from conventional pulmonary function testing, i.e. vital capacity, forced expiratory volume in 1 s (FEV1), and maximum expiratory flow (MEF50). As VDT values particularly reflect the volumes of the lower bronchi this method may provide supplementary information to conventional lung function tests which are based on breathing mechanics. This seems to be especially helpful in situations where body plethysmography is not available or cooperation in forced expiration manoeuvres is insufficient.

Potential anti-inflammatory and anti-infectious effects of human milk oligosaccharides.

There is increasing evidence of the local effects within the gastro intestinal tract and the systemic functions of human milk oligosaccharides (HMO). In addition to the vast majority of in vitro data, animal studies underline the high potential of HMO to influence very different processes. HMO probably influence the composition of the gut microflora through effects on the growth of bifidus bacteria. Whether the concomitant low number of pathogenic microorganisms in breastfed infants is also caused by HMO is an intriguing question that still has yet to be proven. Due to the similarity of HMO to epithelial cell surface carbohydrates, an inhibitory effect on the adhesion of pathogens to the cell surface is most likely. If this could be shown in humans, HMO would provide a new way to prevent or treat certain infections. It would also indicate supplementing infant formula based on cow's milk with HMO, as those oligosaccharides are either not detectable or present only in low numbers in bovine milk. As some HMO can be absorbed and circulate in blood, systemic effects may also be influenced. Due to their similarities to selectin ligands, HMO have been tested in in vitro studies demonstrating their anti-inflammatory abilities. For example, it has been shown that sialic acid-containing oligosaccharides reduce the adhesion of leukocytes to endothelial cells, an indication for an immune regulatory effect of certain HMO. We cover these topics after a short introduction on the structures of HMO, with a particular emphasis on their blood group and secretor specificity.

Hypoxia-induced intrauterine growth retardation: effects on pulmonary development and surfactant protein transcription.

BACKGROUND AND OBJECTIVES: Preterm infants with intrauterine growth retardation (IUGR) reveal an increased risk for the development of acute and chronic pulmonary disorders, i.e. bronchopulmonary dysplasia (BPD). In order to investigate the effect of IUGR on pulmonary development, an easily reproducible animal model for fetal growth restriction has been established using hypoxia as a sole intervention in the last third of pregnancy. METHODS: Date-mated mice were randomly assigned to either being kept at a fraction of inspired oxygen (FiO2) of 0.10 (hypoxic group) starting at day 14 or under normoxic conditions until day 17.5 of gestation (control group). Variables of somatic growth were assessed and standardized histomorphometric analyses of pulmonary tissue were performed. Expression of surfactant proteins (SP)-A, -B, -C and -D was determined by quantitative rt-PCR as biochemical indicators for lung development and maturation. RESULTS: Fetuses were delivered preterm at 0.87 of gestation. Those grown under hypoxic conditions revealed significantly lower birth weights (median: 0.69 vs. 0.97 g in controls; p < 0.001), body lengths (median: 17.5 vs. 20.2 mm in controls; p < 0.001) and fronto-occipital diameters (median: 9.4 vs. 10.1 mm in controls; p < 0.001) compared to controls. Histomorphometric analyses were found to be without significant differences between both groups. On the transcriptional level, however, mRNA expression of SP-A, -B and -C but not SP-D could be shown to be significantly reduced in hypoxic fetuses compared to normoxic controls. CONCLUSIONS: In conclusion, hypoxic conditions from day 14 to 17.5 led to IUGR in preterm mice and to significant alterations of the developing surfactant system. We speculate restricted development of SP gene expression to be a causal factor for the increased risk of acute and chronic pulmonary disorders in preterm infants with IUGR.

Renal excretion of calcium and phosphorus in premature infants with incipient late metabolic acidosis.

BACKGROUND: Premature infants receiving alimentation with cow milk-based formulas run a considerably high risk of incipient late metabolic acidosis, an early stage developing of manifest late metabolic acidosis. Is bone metabolism involved in pathophysiologic mechanisms characterizing this early stage of retention acidosis? METHODS: Urinary ionography was performed in 10 premature infants with spontaneous development of incipient late metabolic acidosis (indicated by urine pH < 5.4 on 2 consecutive days) and 10 pair-matched premature infants with normal values of urine pH; both groups were receiving full oral nutrition with the same standard formula. Moreover, in 37 premature infants with incipient late metabolic acidosis who were randomly allocated to oral therapy with 2 mmol. kg(-1). d(-1) of either NaHCO 3 or NaCl over a period of 7 days, urinary excretion of calcium and phosphorus was assessed on day 1 and day 7. RESULTS: Incipient late metabolic acidosis was accompanied by increased phosphaturia in premature infants receiving full oral nutrition. Seventeen premature infants receiving NaCl therapy (19 treatment periods) showed increased calciuria from day 1 to day 7, whereas, in 20 premature infants receiving NaHCO 3 therapy (23 treatment periods), calcium or phosphorus excretion in urine did not increase. CONCLUSIONS: The data of urinary calcium and phosphorus excretion in premature infants support the hypothesis that bone mineralization may already be impaired in the early stage of incipient late metabolic acidosis.

Investigations of the in vitro transport of human milk oligosaccharides by a Caco-2 monolayer using a novel high performance liquid chromatography-mass spectrometry technique.

Complex lactose-derived oligosaccharides belong to the main components of human milk and are believed to exert multiple functions in the breast-fed infant. Therefore, we investigated the transepithelial transport of human milk oligosaccharides over Caco-2 monolayers. Main human milk oligosaccharides (HMOs) in the apical, basolateral, or intracellular compartment were separated by high performance liquid chromatography using a Hypercarb(TM) column and analyzed on line by mass spectrometry. This method allowed the identification and quantification of these components in intra- and extracellular fractions without prior purification. Using this technique we were able to show that acidic and neutral HMOs cross the epithelial barrier. The transepithelial flux of neutral, but not acidic, oligosaccharides was temperature-sensitive and partly inhibited by brefeldin A and bafilomycin A. Furthermore, net flux from the apical to the basolateral compartment was only observed for the neutral components. Similarly, apical cellular uptake was only found for neutral components but not for acidic oligosaccharides. Intracellular concentrations of neutral HMOs were significantly increased by inhibitors of transcytosis such as brefeldin A, N-ethylmaleimide, or bafilomycin A. The cellular uptake was saturable, and an apparent K(m) for lacto-N-fucopentaose I of 1.7 +/- 0.1 mmol/liter and for lacto-N-tetraose of 1.8 +/- 0.4 mmol/liter was determined. Furthermore, the uptake of lacto-N-fucopentaose I could be inhibited by the addition of the stereoisomer lacto-N-fucopentaose II but not by lacto-N-tetraose. These findings suggest that neutral HMOs are transported across the intestinal epithelium by receptor-mediated transcytosis as well as via paracellular pathways, whereas translocation of acidic HMOs solely represents paracellular flux.

Human milk oligosaccharides are minimally digested in vitro.

In examining the functional aspects of human milk oligosaccharides (HMO), it is not known whether they are digested during the passage through the infant's gastrointestinal tract. HMO were prepared from individual milk samples (n = 6) and separated into neutral and acidic compounds by chromatography. These oligosaccharide fractions were studied for their digestibility by human salivary amylase, porcine pancreatic amylase and brush border membrane vesicles (BBMV) isolated from porcine small intestine; we also examined the effect of low pH on these structures. The characterization of HMO and their digestion products was performed by high-pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) as well as TLC. It was shown that neither salivary amylase nor pancreatic amylase cleaved HMO. Only after a 2-h incubation with BBMV were slight modifications of the HMO observed. HPAEC-PAD analysis revealed two new components within the neutral oligosaccharide fractions; these were characterized by mass spectrometric analysis as lacto-N:-triose and galactose. Only lacto-N:-triose was present within digestion assays of oligosaccharides, which did not contain fucosyl or N:-acetylneuraminic acid residues. These results suggest that <5% of the HMO are digested in the intestinal tract. Hence, HMO may play a role as prebiotics or as factors influencing the local immune system of the intestine in breast-fed infants.

Endotoxin-reduced milk oligosaccharide fractions suitable for cell biological studies.

Endotoxins (ET) are able to activate leukocytes and other cell types and thus affect cell adhesion studies with regard to biological functions of human milk oligosaccharides (HMO). In our HMO preparations we detected ET in concentrations of 1.1 to 32.7 ng/mg. However, as we found in previous tests, an ET concentration of less than 100 pg/ml was necessary in order to avoid effects on the expression of CD11b and CD62L on human neutrophil granulocytes. Therefore, we used affinity chromatography with a detoxifying gel (polymixin B) which reduces the ET concentration of 414.9 +/- 121.5 (mean +/- SEM) and 47.9 +/- 5.9 pg/mg for the acidic and the neutral HMO, respectively. As only about 50 - 100 microg HMO per ml test solution are usually used in biological assays, the residual ET concentration does not interfere with cellular functions. We conclude that despite structural similarities between ET as lipopolysaccharides and complex HMO, a one step purification of HMO preparations was sufficient to get HMO material that can be used in cell culture systems.

Oligosaccharides in human milk: structural, functional, and metabolic aspects.

Research on human milk oligosaccharides (HMOs) has received much attention in recent years. However, it started about a century ago with the observation that oligosaccharides might be growth factors for a so-called bifidus flora in breast-fed infants and extends to the recent finding of cell adhesion molecules in human milk. The latter are involved in inflammatory events recognizing carbohydrate sequences that also can be found in human milk. The similarities between epithelial cell surface carbohydrates and oligosaccharides in human milk strengthen the idea that specific interactions of those oligosaccharides with pathogenic microorganisms do occur preventing the attachment of microbes to epithelial cells. HMOs may act as soluble receptors for different pathogens, thus increasing the resistance of breast-fed infants. However, we need to know more about the metabolism of oligosaccharides in the gastrointestinal tract. How far are oligosaccharides degraded by intestinal enzymes and does oligosaccharide processing (e.g. degradation, synthesis, and elongation of core structures) occur in intestinal epithelial cells? Further research on HMOs is certainly needed to increase our knowledge of infant nutrition as it is affected by complex oligosaccharides.

Inflammation markers and cytokines in breast milk of atopic and nonatopic women.

BACKGROUND: Breast milk is thought to contain its own complex immune system. Whether or not this is altered in allergic individuals is not yet known. METHODS: By ELISA techniques, inflammatory markers (MIP-1alpha, sICAM-1) and T(H)1 (interferon-gamma [IFN-gamma]), as well as T(H)2 cytokines (interleukin [IL]-4, IL-10), were investigated in serum and milk samples from nonallergic (n = 23) lactating women and those with respiratory allergies (n = 19) during the first week postpartum. RESULTS: IFN-gamma was not detected in either serum or milk. IL-10 was more often found to be above the detection limit in both milk and serum samples from allergic mothers. IL-4 was detected in almost all serum samples with a wide variation. In milk, IL-4 was found in about 20% of the samples. MIP-1alpha was not detected in the serum but was detected in the milk of 23% of the nonatopic and 53% of the allergic mothers. Soluble ICAM-1 was present in all samples. Surprisingly, serum levels of sICAM-1 in allergic mothers (271+/-97 ng/ml) were significantly lower (P<0.001) than in nonatopic subjects (375+/-86 ng/ml). Concentrations of sICAM-1 in milk were similar in both groups. CONCLUSIONS: The concentrations of proinflammatory markers and cytokines in breast milk did not differ significantly between allergic and nonatopic mothers. In some individuals, high levels of MIP-1alpha, IL-10, and sICAM-1 could be found. However, the significance of these components for the breastfed infant is still unclear.

Secretion of 13C-labelled oligosaccharides into human milk and infant's urine after an oral [13C]galactose load.

Human milk oligosaccharides seem to play an important role in the infant's defense against bacterial and viral infections of the gastrointestinal and the urogenital tract. In this study, we investigated the influence of dietary carbohydrates on the biosynthesis of lactose and oligosaccharides in the human mammary gland and their renal excretion by the human milk-fed infant. For this purpose, a lactating woman was given 27 g galactose (Gal) containing 2 g [13C] Gal (1-13C/99%) immediately after breakfast. In the following 36 h, milk (5-10 ml) was collected before each nursing. Infant's urine was collected over a period of 24 h. 13C-enrichment was measured in total milk, milk fat and protein, in the carbohydrate fraction as well as in urine by isotope ratio mass spectrometry (IRMS). Milk carbohydrates and deproteinized urine samples were fractionated by Sephadex G25 gel filtration and further analyzed by IRMS, high performance thin layer chromatography and and high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). IRMS revealed that in milk a maximal delta 13CPDB was reached within 8 h after Gal intake which then rapidly declined in the following 8 h. The cumulative 13C-elimination over this first peak was 6.9% of the oral 13C-dose. The highest 13C-enrichment was detectable in the carbohydrate fraction, mainly in lactose and neutral oligosaccharides. Compared to the enrichment of human milk, the delta 13CPDB of infant's urine was delayed. In urine, the highest amount of 13C was found in the Sephadex G25 fractions which mainly contained lactose, fucosyl-lactose, lacto-N-tetraose (LNT), fucosyl-LNT and difucosyl-LNT. For further characterization, individual components were separated by HPAEC-PAD and subsequently analyzed by fast atom bombardment mass spectrometry and IRMS. The data show, that orally applied Gal is incorporated in milk, especially in lactose and neutral oligosaccharides. Obviously, some of these components were absorbed by the infant and then excreted with urine. There, oligosaccharides may serve as analogous receptors for bacterial or viral adhesion molecules, and, hence, may prevent urogenital infections in breastfed infants.

Lactose-derived oligosaccharides in the milk of elephants: comparison with human milk.

Human milk is commonly considered to be unique when compared with the milk of other species with regard to its high content of complex fucosylated and sialylated lactose-derived oligosaccharides. We describe the application of high-pH anion-exchange chromatography with pulsed amperometric detection and TLC to characterize and quantitate neutral and sialylated lactose-derived oligosaccharides in milk from three Asian elephants and human milk. The lactose contents of elephant and human milks were 25-30 g/l and about 66 g/l respectively, whereas total oligosaccharide concentration was about three times higher in elephant milk and comprised up to 40% (10% in human milk) of the carbohydrate content. The ratio neutral: acidic components was different in the milk of the two species; in elephant milk, the N-acetylneuraminic acid-containing oligosaccharides made up almost half of the total amount v. 30% in human milk. Most oligosaccharides in elephant milk were more fucosylated and/or sialylated compared with human milk components. By mild acid hydrolysis, fucose and N-acetylneuraminic acid were cleaved off from complex components, and this resulted in increased amounts of fucose, galactose, N-acetylneuraminic acid, lactose and lacto-N-neo-tetraose. Unique to elephant milk are the high levels of 3'-galactosyllactose (up to 4 g/l) and lacto-N-neo-tetraose which are present in human milk only in trace amounts. Elephant and human milks have high levels and unique patterns of oligosaccharides which may reflect the relative importance of these components in neonatal host defence, in endothelial leucocyte interactions or in brain development.

Glycosylphosphatidylinositol-anchored proteins in human and pig's milk.

Glycosylphosphatidylinositols (GPIs) are a recently discovered class of glycoconjugates that anchor either proteins, polysaccharides or small oligosaccharides to cellular membranes via a covalent linkage. To investigate the presence of soluble GPIs, individual human milk samples and mature pig's milk were defatted and casein removed by acid precipitation and ultracentrifugation. Soluble proteins were subjected to FPLC gel filtration (Superdex 200) and high molecular weight proteins were separated into fractions I-V. Immunological studies have been performed using Western blotting of whole milk, casein and whey fractions, and Superdex fractions I-V followed by incubation with a monoclonal antibody against the purified GPI anchor of the variant surface glycoprotein from Trypanosoma brucei brucei. We found that significant amounts of GPI-anchored proteins are secreted into human milk and pig's milk. The antibody which reacted only with components in the whey fractions bound to 5 different human milk proteins with a molecular weight of >/=200 (at least 3 components), 90 and 80 kD. In pig's milk, the staining pattern was found to be different from human milk. Similar to other GPI-anchored cell structures the functions of GPI-containing proteins in human milk and pig's milk as well as the specific components carrying these anchors remain to be investigated.

Modified cow's milk formula with reduced renal acid load preventing incipient late metabolic acidosis in premature infants.

BACKGROUND: Premature infants receiving alimentation with cow's milk formulas are at a considerably high risk of developing incipient late metabolic acidosis, an early stage in the development of manifest late metabolic acidosis. Is it possible to reduce this risk by modification of the composition of a standard formula? METHODS: The mineral composition of a cow's milk preterm formula A was modified (formula B) with the aim of reducing the alimentary load to that of human milk. 160 premature infants were fed either mother's milk (n = 50) or the modified formula B (enriched with sodium and potassium) (n = 110), and their urine pH was tested twice a week. Randomly collected subgroups of infants were studied in detail for nutrient balances. The results were compared with earlier observations of 282 premature infants fed either mother's milk (n = 28) or the standard formula A (n = 254). RESULTS: Incipient late metabolic acidosis was observed in nine of 78 premature infants receiving mother's milk, 53 of 254 premature infants receiving the standard formula A, and only one of 110 premature infants fed the modified formula B. Net acid excretion was 0.58 mmol/kg/day in 11 premature infants receiving alimentation with the modified formula B compared with 1.73 mmol/kg/day in 23 premature infants fed formula A. This reduction was mainly due to an increased alkali excess (sodium + potassium-chloride) in intake and urine. CONCLUSIONS: Reduction of renal acid load with the modified formula B had a preventive effect on the rate of development of incipient late metabolic acidosis in premature infants.

High-pH anion-exchange chromatography with pulsed amperometric detection and molar response factors of human milk oligosaccharides.

A method is described to separate and characterize neutral and acidic lactose-derived oligosaccharides without prior derivatization or reduction by high-pH anion-exchange chromatography and pulsed amperometric detection (HPAEC-PAD). This method has been applied to human milk oligosaccharides from donors with different blood group specificity (A, Le(a) and A, Le(b). Neutral and acidic components were separated from each other by anion-exchange chromatography. A distinct separation of individual components was obtained by size-exclusion chromatography on Fractogel TSK HW 50S (acidic oligosaccharides) or Fractogel TSK HW 40S (neutral oligosaccharides containing up to 6 monomers) and Bio-Gel P-4 size exclusion (neutral oligosaccharides containing more than 6 monomers). Furthermore the moral response factors after HPAEC-PAD have been determined for 28 components.

Urinary excretion of lactose and oligosaccharides in preterm infants fed human milk or infant formula.

At present, not much is known about the absorption and metabolism of human milk (HM) oligosaccharides in term and preterm infants. We investigated the renal excretion of lactose and complex oligosaccharides in preterm infants fed HM (n = 9, mean actual body weight 2290 g) or a cow's milk-based infant formula (n = 9, mean actual body weight 2470 g). We found that the renal excretion of lactose in HM-fed infants was slightly lower than in formula-fed infants (14.0 +/- 7.4 versus 20.4 +/- 8.7 mg kg-1 day-1, mean +/- SD). The excretion of neutral sugars deriving from oligosaccharides was similar in HM-fed and formula-fed infants (3.8 +/- 2.1 versus 2.9 +/- 0.9 mg kg-1 day-1); the difference between means was not statistically significant. The separation and characterization of oligosaccharides by high-pH anion exchange chromatography with pulsed amperometric detection (HPAE-PAD) and subsequent analysis by fast atom bombardment-mass spectrometry (FAB-MS) revealed a more complex pattern in HM-fed infants compared to the formula-fed group. Lactose-derived oligosaccharides characteristic for HM (e.g. lacto-N-tetraose, and lacto-N-fucopentaoses I and II) were excreted in HM-fed but not in formula-fed infants. These results indicate that nutrition has a significant impact on the oligosaccharide composition in urine of preterm infants.

[Structural and functional aspects of oligosaccharides in human milk]. / Strukturelle und funktionelle Aspekte von Oligosacchariden in Frauenmilch.

About a century ago, pediatricians observed that in feces of breast-fed infants, compared to those of bottle-fed infants, Bifidobacterium bifidum was the predominant microorganism. It was shown thereafter that aminosugar-containing oligosaccharides are growth factors for a specific strain of Bifidobacterium. Meanwhile, more than 130 lactose-derived oligosaccharides have been identified in human milk. Some of these oligosaccharides like Lacto-N-Tetraose and Lacto-N-Fucopentaose I and II do not occur in minute amounts but in concentrations up to 1-2 g/L. As the total amount of complex oligosaccharides is between 3-6 g/L those components have to be considered as major human milk constituents. There is striking evidence that human milk oligosaccharides are potent inhibitors of bacterial adhesion to epithelial surfaces, an initial stage of infective processes. Therefore, these oligosaccharides are considered to be soluble receptor analogues of epithelial cell surfaces participating in the non-immunological defense system of human milk-fed infants.