Challenge-proven Cow's Milk Allergy Research Articles

Characteristics of cow's milk allergy and sensitization in Chinese patients.

Characteristics of cow's milk allergy and sensitization in Chinese patients.

Children with cow's milk allergy following an elimination diet had normal growth but relatively low plasma leptin at age two.

To assess nutrient intake, growth and nutritional status of infants with cow's milk allergy (CMA) who follow a therapeutic elimination diet since the first few months of life. Sixty infants younger than four months of age with challenge-proven CMA and 60 healthy age-matched children were investigated. Anthropometric and body composition (BC) were assessed up to 24 months. Dietary intake was recorded by the parents for three consecutive days before visits at 6, 12, 18 and 24 months. Blood albumin, prealbumin, retinol binding protein and metabolic-related hormones were examined at 24 months. The average age at enrolment was 2.9 ± 1.0 months. At the end of the follow-up, there were no differences in daily milk consumption, nutrient intake, weight and height z scores or BC measures between the groups; however, the plasma leptin level was lower in infants with CMA (1.67 ± 1.03 vs 2.05 ± 1.48) (ng/mL) (p < 0.05) compared to healthy children. Children with CMA who followed an elimination diet could achieve a normal nutritional status, except for relatively lower plasma leptin levels, at the age of 2. Further studies with larger cohorts and research on the long-term consequences of these early differences are needed.

Early-life gut microbiome and cow’s milk allergy- a prospective case - control 6-month follow-up study

Increasing evidence suggests that perturbations in the intestinal microbiota in early infancy are implicated in the pathogenesis of food allergy (FA); existing evidence on the structure and composition of the intestinal microbiota in human beings with FA is limited and conflicting. The main object of the study was to compare the faecal microbiota between healthy and cow’s milk allergy (CMA) infants at the baseline immediately after the diagnosis, and to evaluate the changes in the faecal microbiota after 6 months of treatment of CMA infants with hypoallergenic formula (HF), compared with healthy children fed on standard milk formulae. Sixty infants younger than 4 months of age with challenge-proven CMA and 60 healthy age-matched children were investigated in this prospective case - control follow-up study. Faecal samples were collected at baseline and at 6 months of follow-up, microbial diversity and composition were characterized by high-throughput 16S rRNA sequencing. The average age (±SD) of the infants at inclusion was 2.9 ± 1.0 months. Children with CMA have lower gut microbiota diversity and an elevated Enterobacteriaceae to Bacteroidaceae (E/B ratio) in early infancy compared with healthy children (115.8 vs. 0.8, P = 0.0002). After 6 months of treatment with HF, CMA infants had a higher Lactobacillaceae (6.3% vs. 0.5%, P = 0.04) and lower Bifidobacteriaceae (0.3% vs. 8.2%, P = 0.03) and Ruminococcaceae (1.5% vs. 10.5%, P = 0.03) abundance compared with control children. Conclusion: Low gut microbiota diversity and an elevated E/B ratio in early infancy may contribute to the development of FA, including CMA. A strict elimination diet may weaken FA by reducing E/B ratio and promoting a gut microbiota that would benefit the acquisition of oral tolerance.

Incidence and natural history of challenge-proven cow's milk allergy in European children--EuroPrevall birth cohort.

Cow's milk allergy (CMA) is one of the most commonly reported childhood food problems. Community-based incidence and prevalence estimates vary widely, due to possible misinterpretations of presumed reactions to milk and differences in study design, particularly diagnostic criteria. Children from the EuroPrevall birth cohort in 9 European countries with symptoms possibly related to CMA were invited for clinical evaluation including cows' milk-specific IgE antibodies (IgE), skin prick test (SPT) reactivity and double-blind, placebo-controlled food challenge. Across Europe, 12049 children were enrolled, and 9336 (77.5%) were followed up to 2years of age. CMA was suspected in 358 children and confirmed in 55 resulting in an overall incidence of challenge-proven CMA of 0.54% (95% CI 0.41-0.70). National incidences ranged from 1% (in the Netherlands and UK) to <0.3% (in Lithuania, Germany and Greece). Of all children with CMA, 23.6% had no cow's milk-specific IgE in serum, especially those from UK, the Netherlands, Poland and Italy. Of children with CMA who were re-evaluated one year after diagnosis, 69% (22/32) tolerated cow's milk, including all children with non-IgE-associated CMA and 57% of those children with IgE-associated CMA. This unique pan-European birth cohort study using the gold standard diagnostic procedure for food allergies confirmed challenge-proven CMA in <1% of children up to age 2. Affected infants without detectable specific antibodies tocow's milk were very likely to tolerate cow's milk one year after diagnosis, whereas only half of those with specific antibodies in serum 'outgrew' their disease so soon.

The role of food allergy in the atopic march

Cite this as: K. J. Allen and S. C. Dharmage, Clinical &amp; Experimental Allergy, 2010 (40) 1439–1441.

Concurrent cereal allergy in children with cow's milk allergy manifested with atopic dermatitis.

There is increasing consensus about the significance of food allergens in the pathogenesis of atopic dermatitis (AD) in infancy and childhood, with cow's milk and egg accounting for most of the reactions. Previous studies have indicated that multiple food sensitization, such as cereals, is very common in patients with cow's milk allergy (CMA). Evidence is lacking, however, as to its clinical relevance. The purpose of this study was to determine the concurrent occurrence of cereal allergy among children with challenge-proven CMA who have residual symptoms, such as AD and/or gastrointestinal symptoms, during cow's milk elimination diet. Further, we sought to evaluate the utility of patch testing in prescreening foods other than cow's milk behind allergic symptoms in children. The study population comprised 90 children, aged from 2.5 to 36 months (mean 1.1 years), with challenge-proven CMA. As a result of residual symptoms during meticulous cow's milk elimination diet (AD: n=80, and gastrointestinal: n=10), the children were put on a cereal elimination diet (oats, wheat, rye, and barley) and skin prick tests (SPT) and patch testing with cereals were performed. Open cereal challenge was performed to confirm cereal allergy. Cereal challenge was positive in 66 (73%) of the children with CMA. Of them, 17% reacted with immediate reactions and delayed-onset reactions were seen in 83% of the children. SPT was positive in 23%, patch test in 67%, and either SPT or patch test was positive in 73% of the children with cereal allergy. SPT gave the best positive predictive value, whereas SPT together with patch test gave the best negative predictive value. Residual symptoms, such as eczema or gastrointestinal symptoms in CMA children may be a sign of undetected allergy to other food antigens. SPT with cereals aids in diagnosing cereal allergy in small children, especially when used together with patch testing.

Low frequency of CD4+, but not CD8+, T cells expressing interferon-gamma is related to cow's milk allergy in infancy.

Low interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) production in peripheral blood mononuclear cells (PBMC) from patients with atopic dermatitis and food allergy have been reported previously. However, it remains unclear whether the weak cytokine production is caused by the imbalance of specific T-cell subsets or by dysregulation of T-cell function. In the present study we investigated the intracellular expression of these cytokines at a single-cell level to clarify the background of the disruption. Twelve of 27 breast-fed infants (0.1-8.8 months of age) had challenge-proven cow's milk allergy (CMA), and 15 infants were studied as a healthy control group. PBMC were stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin. The frequencies of the cells expressing intracellular IL-4, IFN-gamma, and TNF-alpha were assessed using flow cytometry. In addition, at this time-point leucocyte subsets from the milk of mothers of these infants were evaluated using light microscopy. A lower number of CD8+ T cells and the defective capability of CD4+ T cells to express IFN-gamma in infant's peripheral blood co-existed with a lower number of macrophages in their mother's milk.

Defective tumor necrosis factor-alpha production in infants with cow's milk allergy.

As an aid to clarifying the role of immune mechanisms in the development of cow's milk allergy (CMA) in suckling infants, we studied the capacity of peripheral blood mononuclear cells (PBMC) to produce tumor necrosis factor-alpha(TNF-alpha) in vitro. The study population consisted of 43 infants, aged 0.12-11.2 months; of these, 31 had challenge-proven cow's milk allergy manifested with either skin or gastrointestinal symptoms or both. In addition, 12 healthy infants were studied as controls. The spontaneous, unstimulated and mitogen-induced production of TNF-alpha and interferon-gamma (IFN-gamma) by isolated peripheral blood leukocytes was evaluated. TNF-alpha and IFN-gamma production of PBMC was significantly lower in infants with cow's milk allergy than in healthy children. Our results indicate that, in infants with CMA, the function of TNF-alpha-producing cells is defective. This might disturb the development of oral tolerance and thereby lead to cow's milk allergy. These results may help to clarify the etiopathology of CMA.

Relation between Weak HLA-DR Expression on Human Breast Milk Macrophages and Cow Milk Allergy (CMA) in Suckling Infants

The precise role of breast milk leukocytes is unknown. We therefore studied the cellular composition of breast milk and the activation of breast milk macrophages in mothers with a cow milk-allergic infant and in those with a healthy infant. Further, we sought to determine the influence of the cellular composition of mother's milk on the infant's risk of developing cow milk allergy. Thirty-six asymptomatic mothers (26 with atopic constitution) whose babies had challenge-proven cow milk allergy and 24 asymptomatic mothers (17 with atopic constitution) with healthy infants were recruited. Geometric mean ages of the infants were 3.2 mo (95% confidence interval [CI], 2.3 to 4.4) and 2.4 mo (95% CI, 1.6 to 3.7), respectively. After separation of the fat layer, breast milk cells were incubated with fluorescein-labeled MAb to CD antigens (CD14, 45, 3, 4, 8, 19, 23, and HLA-DR) and analyzed by flow cytometry. Breast milk samples, collected with a breast pump, were processed immediately. Cytospin preparations of milk samples, made after separation of the fat layer, were stained with May-Grunwald-Giemsa and examined with a light microscope. HLA-DR expression on breast milk macrophages was significantly lower in the mothers whose infant was allergic to cow milk, 58.3% (95% CI, 44.9 to 75.6), than in the mothers of a healthy infant, 86.9% (95% CI, 78.7 to 96.1), p=0.012 (ANOVA). There was also a significant difference in the total number of breast milk leukocytes between the mothers with an allergic child, 0.17 x 10(6)/mL (95% CI, 0.12 to 0.25), and those with a healthy child, 0.08 x 10(6)/mL (95% CI, 0.05 to 0.14), p=0.019 (Mann-Whitney U test). These results suggest impaired function of breast milk macrophages in mothers whose infants had cow milk allergy. They may also reflect decreased antigen presentation to the inexperienced T cells in the gut or on other mucosal surfaces of the suckling infant, leading to subsequent development of food or respiratory allergies, e.g. asthma.

Large number of CD19+/CD23+ B cells and small number of CD8+ T cells as early markers for cow's milk allergy (CMA).

Assessment of activation of immune mechanisms is valuable in the early diagnosis of cow's milk allergy (CMA). The purpose of this study was to evaluate peripheral blood lymphocyte subclasses in children suspected of having CMA and healthy infants in order to detect an early marker for food allergy. Altogether 47 breast-fed infants, aged from 0.4 to 10 months were followed-up prospectively from birth because of atopic heredity. Twenty-three of the infants were healthy and 24 infants had a strong suspicion of and later challenge-proven cow's milk allergy. Leucocyte subsets were determined from peripheral blood mononuclear cells by flow cytometry. In response to a clinical cow's milk challenge, seven infants developed urticaria, 11 infants had eczema, three patients had loose stools, diarrhoea or vomiting and three infants had eczema and diarrhoea, loose stools or vomiting. The total percentage of B cells and also the proportion of B cells bearing a low-affinity IgE receptor as a marker for activation were significantly higher, whereas the percentage of CD8+ T cells was significantly lower in infants with challenge-proven CMA than in healthy controls. These results imply that infants with active CMA have a defect in regulation of B-cell function. Further, they suggest that imbalance of the ratio of suppressor and helper T cells might be an important factor in the etiopathogenesis of CMA. Our results show that large numbers of activated CD19+ B cells and low numbers of CD8+ T cells could be considered as early markers for food allergy since they are already detectable in peripheral blood during the earliest symptoms of CMA.

Elimination diet in cow's milk allergy: risk for impaired growth in young children.

The objective of this study was to evaluate the nutritional impact of therapeutic elimination diets and to identify risk factors predisposing infants with food allergy to poor growth. We studied 100 children (mean age 7 months) with atopic dermatitis and challenge-proven cow's milk allergy and evaluated their growth during the symptomatic period before diagnosis and during the therapeutic elimination diet. Clinical control of symptoms was achieved in all patients. The mean length SD score and weight-for-length index of patients decreased compared with those in healthy age-matched children, p < 0.0001 and p = 0.03, respectively. Low serum albumin was present in 6% of the patients, 24% had an abnormal urea concentration, and 8% had a low serum phospholipid docosahexaenoic acid. The delay in growth was more pronounced in a subgroup of patients with early onset than in those with later of symptoms (F = 6.665, p < 0.0001). The duration of breast-feeding correlated positively with the sum of n-3 polyunsaturated fatty acids (r = 0.39, p = 0.001) and with the relative amount of docosahexaenoic acid (r = 0.36, p = 0.002). A delicate balance exists between the benefits and the risks of elimination diets.

Lymphocyte response to cow's milk proteins in patients with cow's milk allergy: relationship to antigen exposure.

The cellular immune response to cow's milk was measured in patients with challenge-proven cow's milk allergy (CMA), manifested with either gastrointestinal or skin symptoms. After 2-4 weeks on milk elimination, 44 children, mean (SD) age 15.7 (9.4) months, were challenged, and cow's milk-induced lymphocyte transformation was measured before the clinical challenge (Day 1) and/or one week later (Day 8). During the clinical challenge period, 17 (39%) patients showed gastrointestinal reactions, 9 (20%) had urticarial or eczematous skin eruptions, and 18 (41%) were negative to challenge. On Day 1, the mean [95% confidence interval] stimulation index for lymphocytes in patients manifesting CMA with gastrointestinal symptoms, 2.60 [1.60, 4.10], was significantly higher than that in patients with skin symptoms, 1.15 [0.60, 2.30], or patients with negative clinical challenge, 0.83 [0.64, 1.08], F = 9.0, p = 0.001. After the clinical challenge (Day 8), this cow's milk-induced lymphocyte proliferation response was abrogated. At the same time, CMA patients evidenced a significantly higher spontaneous lymphocyte proliferation response in RPMI medium-containing control cultures than those with negative clinical challenge. We conclude that in patients with CMA, the number of circulating cow's milk-sensitized lymphocytes is depleted or their function is impaired after clinical exposure to cow's milk antigens.

Evidence for eosinophil activation in cow's milk allergy

To assist in identifying pathogenetic mechanisms in different clinical manifestations of cow's milk allergy (CMA), the involvement of eosinophil cells in immunoinflammatory reactions was evaluated. The study population comprised 28 patients, aged from 5.8 to 43.0 months, who had challenge-proven CMA, manifested either cutaneously (n = 17) or gastrointestinally (n = 11). A clinical cow's milk challenge was performed in hospital after a 4 week cow's milk elimination period. Eosinophil activation in vivo was studied by measuring the serum level of eosinophil cationic protein (ECP) before the oral cow's milk challenge, mean (SD) 27 (12) hours after commencing the challenge and one week later. These results were compared to those of 80 non-allergic age-matched controls. During the challenge, the level of ECP increased from 6.2 (4.5, 8.0) micrograms/L to 20.0 (9.5, 30, 4) micrograms/L in CMA patients with skin manifestations but not in those with gastrointestinal symptoms. The increase was shown to be transient. We conclude that eosinophil degranulation is an important immunologic mechanism leading to allergic inflammation in cutaneously manifested CMA.

Immunologic disturbances in cow's milk allergy, 2: Evidence for defective interferon-gamma generation.

We have investigated the role of interferon-gamma (IFN-gamma) in the regulation of antigen-specific T-cell function in patients with cow's milk allergy. The study population consisted of 22 patients, aged from 7.6 to 56.9 months, who had challenge-proven cow's milk allergy (CMA) manifested with either skin (n = 9) or gastrointestinal (n = 13) symptoms. In addition, 11 age-matched children and 6 adults, mean (SD) age 31 (7) years, were studied as controls. Patients with challenge-proven CMA were rechallenged to establish whether they had acquired clinical tolerance to cow's milk. The spontaneous and mitogen-induced IFN-gamma and interleukin-4 (IL-4) generation of isolated lymphocytes was evaluated in vitro with commercial ELISA Kits at diagnosis and at reassessment. At diagnosis, the IFN-gamma production was not detectable in patients with CMA as compared with control children. IL-4 production was almost undetectable in all subjects in this study. However, at reassessment the CMA patients who had acquired clinical tolerance to cow's milk (n = 16) showed enhanced IFN-gamma production, when compared with that of control children, but still lower when compared with that of healthy adults. Our results indicate that the maturation of IFN-gamma producing T-cells is delayed in CMA, which could lead to a disturbance in the regulation of T-cell function. This defect might be an important etiologic factor for CMA.

Immunologic disturbances in cow's milk allergy, 1: delayed maturation of suppressor activity

To assist in identifying pathogenetic mechanisms in different subtypes of cow's milk allergy (CMA), the function of immunoregulatory T-lymphocytes was studied. The study population consisted of 23 patients, mean [95% confidence interval] age of 25.6 [19.5, 33.6] months, who had challenge-proven cow's milk allergy manifested with either skin (n = 9) or gastrointestinal (n = 14) symptoms; in addition, 13 age-matched disease controls were studied. Patients with challenge-proven CMA were rechallenged to establish whether they had acquired clinical tolerance to cow's milk. The suppressor activity of isolated lymphocytes was measured in vitro by a cell coculture at rechallenge and in 10/23 patients at diagnosis. At diagnosis, patients with CMA (n = 10) showed a decreased mean [95% CI] suppressor activity, induced by either Concanavalin A, 7[-2,15]%, or cow's milk, 3[-8,14]% as compared with disease controls (n = 13), 19[15,24]% and 24[17,31]%; F = 7.1, p = 0.004 and F = 6.7, p = 0.005, respectively. At rechallenge the suppressor activity, induced both by Concanavalin A and cow's milk, reached the level of disease controls only in patients who had acquired clinical tolerance to cow's milk (n = 13/23), but not in those retaining CMA (n = 10/23). Our results indicate that the maturation of suppressor function is delayed in CMA, which might be of primary importance in the etiopathogenesis of CMA.

Natural history of cow milk allergy: Clinical outcome

Of an initial cohort of 100 children with challenge-proven cow milk allergy, 97 were reviewed after 5 years to determine the effect of prolonged cow milk avoidance on clinical features, the reported frequency of adverse reactions to other foods, and the reported emergence of other atopic disorders. The mean age at diagnosis was 16 months, and at final follow-up 99 months. Cow milk tolerance by challenge was demonstrated in 28% of patients by 2 years of age, 56% by 4 years, and 78% by 6 years. Only 25% of children were allergic to cow milk alone; parents reported associated adverse reactions to many other foods, including egg (58%), soy milk (47%), and peanut (34%). Exclusion of cow milk from the diet of infants and young children with cow milk allergy did not prevent the subsequent development of atopic disorders. At final follow-up, 40% of patients reportedly had asthma, 21% atopic eczema, and 43% allergic rhinitis. It is unclear whether independent mechanisms control the development of cow milk allergy and other atopic conditions.