Changing pattern of cow's milk protein intolerance

Non-IgE-Mediated Gastrointestinal Food Allergies in Children: An Update

Non-immunoglobulin E-mediated gastrointestinal food allergic disorders (non-IgE-GI-FA) include food protein-induced enterocolitis syndrome (FPIES), food protein-induced enteropathy (FPE) and food protein-induced allergic proctocolitis (FPIAP), which present with symptoms of variable severity, affecting the gastrointestinal tract in response to specific dietary antigens. The diagnosis of non-IgE-GI-FA is made clinically, and relies on a constellation of typical symptoms that improve upon removal of the culprit food. When possible, food reintroduction should be attempted, with the documentation of symptoms relapse to establish a conclusive diagnosis. Management includes dietary avoidance, nutritional counselling, and supportive measures in the case of accidental exposure. The prognosis is generally favorable, with the majority of cases resolved before school age. Serial follow-up to establish whether the acquisition of tolerance has occurred is therefore essential in order to avoid unnecessary food restriction and potential consequent nutritional deficiencies. The purpose of this review is to delineate the distinctive clinical features of non-IgE-mediated food allergies presenting with gastrointestinal symptomatology, to summarize our current understanding of the pathogenesis driving these diseases, to discuss recent findings, and to address currents gaps in the knowledge, to guide future management opportunities.

Non-IgE-mediated Adverse Food Reactions

PURPOSE OF REVIEW

The purpose of this review is to update what is currently known about the major non-IgE-mediated food allergies: food protein-induced enterocolitis syndrome (FPIES), food protein-induced allergic proctocolitis (FPIAP), and food protein-induced enteropathy (FPE). These conditions are similar in that symptoms are regulated to the gastrointestinal tract; therefore understanding their specific features is important for diagnosis and management.

RECENT FINDINGS

The most progress has been made in understanding FPIES with several recent large cohorts being described. The first international consensus guidelines for FPIES were published in 2017 and propose specific diagnostic criteria for acute FPIES as well as guidance for diagnosing chronic FPIES. Recent studies in FPIAP have challenged our thinking about the recommended duration of food avoidance and that cow's milk avoidance is the primary management with reports of self-resolution without dietary management. FPE continues to appear to be on the decline. FPIES, FPIAP, and FPE are distinguished from one another by their main clinical features: delayed repetitive vomiting in FPIES, benign blood in stool in FPIAP, and chronic diarrhea in FPE. Due to the risk of nutritional deficiencies with food avoidance in both infant and maternal diets if breastfeeding, confirmation of diagnosis with challenges is encouraged. Additional studies are needed for these conditions to elucidate pathophysiology, search for diagnostic markers, and understand natural history.

Non-IgE-mediated gastrointestinal food allergy

Non-IgE-mediated gastrointestinal food-induced allergic disorders (non-IgE-GI-FAs) account for an unknown proportion of food allergies and include food protein-induced enterocolitis syndrome (FPIES), food protein-induced allergic proctocolitis (FPIAP), and food protein-induced enteropathy (FPE). Non-IgE-GI-FAs are separate clinical entities but have many overlapping clinical and histologic features among themselves and with eosinophilic gastroenteropathies. Over the past decade, FPIES has emerged as the most actively studied non-IgE-GI-FA, potentially because of acute and distinct clinical features. FPIAP remains among the common causes of rectal bleeding in infants, while classic infantile FPE is rarely diagnosed. The overall most common allergens are cow's milk and soy; in patients with FPIES, rice and oat are also common. The most prominent clinical features of FPIES are repetitive emesis, pallor, and lethargy; chronic FPIES can lead to failure to thrive. FPIAP manifests with bloody stools in well-appearing young breast-fed or formula-fed infants. Features of FPE are nonbloody diarrhea, malabsorption, protein-losing enteropathy, hypoalbuminemia, and failure to thrive. Non-IgE-GI-FAs have a favorable prognosis; the majority resolve by 1 year in patients with FPIAP, 1 to 3 years in patients with FPE, and 1 to 5 years in patients with FPIES, with significant differences regarding specific foods. There is an urgent need to better define the natural history of FPIES and the pathophysiology of non-IgE-GI-FAs to develop biomarkers and novel therapies.

HLA-DQA1 and HLA-DQB1 genetic markers and clinical presentation in celiac disease

BACKGROUND

Patients with celiac disease are diagnosed at any age and can exhibit a wide range of clinical manifestations. The reasons for this are unclear. The aim of this study was to investigate a possible correlation between the HLA-DQA1 and HLA-DQB1 genetic markers and clinical features of celiac disease.

METHODS

A total of 133 patients with celiac disease were tested for the HLA-DQA1 and HLA-DQB1 genes. Their corresponding allele and haplotype frequency distributions were estimated from the phenotypes found. The results were correlated with data from the clinical records.

RESULTS

The DQ2 molecule was found in 93% of the patients, and DQ2 or DQ8 was found in 98%. The DQA1*0201-DQB1*0202 haplotype showed strong linkage disequilibrium. DQ2 homozygosis was significantly associated with female sex, earlier age at diagnosis, and shorter delay between onset of symptoms and diagnosis. Double-dose DQB1*02 (01-02) allele was more frequent in patients with the classic presentation of the disease.

CONCLUSIONS

The genetic markers investigated may prove useful for diagnosing and managing celiac disease. With some clinical variables, correlations not previously described were found. These correlations have a moderate strength and, therefore, must be confirmed by other studies.

Food-induced malabsorption syndromes

A syndrome of chronic diarrhea, vomiting, and failure to thrive was described 35 years ago. The syndrome was caused by damage in the jejunum after ingestion of cow's milk. Symptoms appeared in young infants shortly after introduction of cow's milk formula. Patients had moderate steatorrhea, decreased absorption of D-xylose, and, often, iron-deficiency anemia and hypoproteinemia. They had strong IgA and IgG antibodies to cow's milk. IgE antibodies to cow's milk were negative, as a rule. Indicators of cell-mediated immune reaction to cow's milk proteins were often positive. Patients were tolerant to cow's milk by the age of 3 years. Malabsorption was due to damage to the jejunal mucosa: Varying villus atrophy was associated with inflammation in surface epithelium and lamina propria. The epithelial cell renewal rate increased. Surface epithelial cells decreased in height, with short, furry microvilli and large aggregates of lysozymes. The number of intraepithelial lymphocytes was markedly increased, but normalized during cow's milk elimination. Most of these lymphocytes had alpha/beta T-cell receptors, and many were cytotoxic. Some specimens had an increase in gamma/delta T-cell receptor-bearing cells. In the lamina propria, CD4+ cells predominated, and some of them were activated. IgA- and IgM-containing cells were markedly increased during cow's milk exposure, but IgE cells were not abnormal. The density of eosinophils was moderately increased. Secretion of interferon-gamma by cells isolated from patients' intestines was markedly increased. Morphologic and immunologic findings suggest that T-cell-mediated reaction to proteins in cow's milk is present in the small intestines of patients with this syndrome and causes this enteropathy.

Cow's milk protein intolerance in infants under 1 year of age: a prospective epidemiological study

Incidence and clinical manifestation of cow's milk protein intolerance (CMPI) were studied in 1158 unselected newborn infants followed prospectively from birth to 1 year of age. No food changes were required in 914 infants who were used as healthy controls. When CMPI was suspected (211 infants), diagnostic dietary interventions according to a standard protocol were performed. After exclusion of lactose intolerance, two positive cow's milk elimination/challenge tests were considered diagnostic of CMPI. Two hundred and eleven symptomatic infants were examined for possible CMPI. A large group of 80 infants improved on a lactose reduced formula. In 87/211 infants CMPI was excluded (sick controls). Finally CMPI was proven in 26 infants. The calculated incidence rate for CMPI was 2.8%. The principal symptoms in infants with CMPI were gastrointestinal, dermatological and respiratory in 50%, 31% and 19% respectively. A positive family history for atopy (first or second degree relatives) was more frequent in either CMPI infants (65%), or sick controls (63%) when compared to either healthy controls (35%) or infants improving on a low lactose formula (51%). Differences between patients with CMPI and sick controls were only found for the presence of atopy in at least 2 first degree relatives [(5/26 in CMPI infants and 4/87 in sick controls (P < 0.05)] and for multiorgan involvement [10/26 infants with CMPI as opposed to 12/87 in the sick control group (P < 0.02)]. These statistical differences are too weak to be of clinical value.

The role of cow's milk protein intolerance in steroid-resistant nephrotic syndrome

The role of cow's milk protein intolerance in steroid-resistant nephrotic syndrome was evaluated in 17 children. Cow's milk was excluded from the diet for at least 14 days without changing previously ineffective prednisone dosage. Six patients with minimal change or mesangial proliferation went into remission 3 to 8 days after elimination of cow's milk. After a period of 2-3 weeks of remission, cow's milk challenge was positive in three patients. After one year on a cow's milk-free diet, two of six patients became milk tolerant and are in remission of NS, one of six became steroid-dependent, two of six are still unable to tolerate cow's milk and are in remission on a cow's milk-free diet and one of six children was lost from observation. The role of cellular mechanisms in steroid-resistant nephrotic syndrome is suggested.

Cow milk-sensitive enteropathy: predisposing factors and treatment

Cow milk-sensitive enteropathy is a temporary disorder of infancy characterized by a variably abnormal small intestinal mucosa while milk is in the diet. This abnormality is reversed by a cow milk-free diet, only to recur on challenge. Important predisposing factors are age (< 3 years), transient IgA immunodeficiency, atopy, and early bottle feeding. The disorder is diagnosed histologically by evidence of mild-to-moderate partial villous atrophy with thin, often patchy mucosa. For an accurate clinical diagnosis, challenge with the offending food after a demonstrated response to cow milk elimination is critical. When available, serial small intestinal bowel biopsies related to elimination and challenge are also important. Treatment is elimination of cow milk and all foods based on cow milk, and substitution of cow milk feedings with commercially available formulas free of cow milk protein. Five types of cow milk substitutes are described; only nutritionally complete formulas are recommended. Later, a milk challenge will determine the timing of safe reintroduction of cow milk to the diet, at a time when the child is gaining weight, thriving, and symptom free. This dietary treatment is always temporary; reintroduction of a normal diet is nearly always possible between 1 and 2 years of age.

Increasing incidence of childhood coeliac disease in Sweden. Results of a national study

A survey of the incidence of coeliac disease was carried out by asking all 43 paediatric departments in Sweden to report the number of children born between 1978 and 1987 in whom coeliac disease had been diagnosed. Thirty-four departments representing a population of 7.18 million reported 1944 cases of coeliac disease among 804,935 children born between 1978 and 1987. The cumulative incidence of coeliac disease was 1.7 per 1000 live births in children born between 1978 and 1982 and doubled to 3.5 per 1000 live births in children born after 1982. The highest incidence was found in the southern and south-eastern regions of the country. The observed increase may have been influenced by changes in infant feeding practices such as the postponed age of introduction of gluten from four to six months of age and an increase in gluten content of proprietary baby foods.