Does low IgA in human milk predispose the infant to development of cow's milk allergy?

We sought a relationship between total and cow's milk-specific IgA levels in colostrum and human milk and subsequent development of cow's milk allergy (CMA) in the breast-fed infant. The study included 87 nursing mothers and their infants (age, 2 d to 7 mo), followed prospectively up to 1 y. At 1 y, 48 mothers (69% with an atopic constitution) had an infant with CMA, verified by clinical cow's milk challenge, eight (38% with an atopic constitution) had a baby who had had protracted infantile colic but no CMA (disease control group), and 31 (23% with an atopic constitution) had a healthy infant. Total breast-milk IgA was measured by radial immunodiffusion, and IgA antibodies to cow's milk were measured by ELISA during the breast-feeding period. The levels of total and cow's milk-specific IgA antibodies in colostrum and human milk were significantly lower in the mothers whose baby later developed CMA [estimated third day value, 0.38 g/L (95% confidence interval, 0. 24-0.82)] than in the ones whose infant remained healthy or had had infantile colic but not CMA [0.82 g/L (95% confidence interval, 0. 99-1.51); p < 0.05]. The infants developed CMA significantly more often if the concentration of total IgA antibodies in milk was <0.25 g/L, when measured between 6 d and 4 wk postpartum [sensitivity, 0. 55; specificity, 0.92; odds ratio, 14.7 (95% confidence interval, 3. 1-70.2); p < 0.001]. The levels of cow's milk-specific IgA positively correlated with the levels of total IgA but not with the development of CMA in the infant. The levels of total or cow's milk-specific IgA did not correlate with maternal atopy. IgA antibodies in colostrum and human milk may prevent antigen entry at the intestinal surface of the breast-fed infant. A low IgA content in human milk may lead to defective exclusion of food antigens and thus predispose an offspring to develop food allergies.

The effect of proctocolectomy on serum antibody levels against cow's milk proteins in patients with chronic ulcerative colitis, with special reference to liver changes.

BACKGROUND: The levels of antibodies against cow's milk proteins in ulcerative colitis (UC) were used to study whether mucosal inflammation leads to immune recognition, as a marker of enhanced permeability, of dietary proteins. A further purpose was to study the effect of proctocolectomy on the serum antibody levels against cow's milk proteins and their relation to biochemical and histologic liver abnormalities associated with ulcerative colitis. METHODS: Serum antibody levels against six cow's milk proteins, alpha-casein, alpha-lactalbumin (LA), beta-lactoglobulin A (LGA), beta-lactoglobulin B (LGB), bovine serum albumin (BSA), and whole milk powder (MP) were determined before and after (mean, 24 months) proctocolectomy in 15 patients with ulcerative colitis. Simultaneously, serum liver enzymes were analyzed. A liver biopsy specimen was also obtained at proctocolectomy. RESULTS: Before proctocolectomy IgA antibody levels were significantly increased against all antigens except BSA. Increased levels of IgM antibodies against LGA, LGB, and BSA were also detected. IgG antibodies were significantly increased only against LGA. After proctocolectomy IgA and IgM antibody levels decreased significantly (p < 0.05) against LGA, LGB, and LA, whereas IgG antibodies increased significantly (p < 0.01). In the patient group with abnormal liver histology (n = 9) the IgA antibodies to all cow's milk proteins were significantly higher (p < 0.02) than in the group with normal liver histology both before and after proctocolectomy. The IgA antibody levels showed a significant positive correlation with alanine amino-transferase and gamma-glutamyltransferase (r value from 0.460 to 0.721, p value from < 0.05 to < 0.01), but not with alkaline phosphatase. CONCLUSIONS: These results suggest that the inflamed mucosa in UC allows the antigenic contents of the bowel to escape. Proctocolectomy alters the antibody levels against certain milk proteins, which may serve as a model to suggest that proctocolectomy, probably by eliminating inflammation, may have positive effects by reducing the foreign pathogenic antigen and immune complex load.

Evaluation of the new Behring Nephelometer in the measurement of M proteins.

The Behring Nephelometer is a new automatic analyzer designed for the measurement of specific proteins. The authors evaluated the nephelometer in the determination of M proteins as compared with immunodiffusion and cellulose acetate electrophoresis. In addition, the effects of sample dilution and antigen excess on the nephelometric measurement of M proteins were studied in 24 patient samples containing a single monoclonal IgG, IgA, or IgM M component. Immunodiffusion cannot be recommended for the determination of M proteins. Nephelometry and protein electrophoresis gave similar results with few exceptions. Sera with immunoglobulin monomer-oligomer pairs involve difficulties in serum electrophoresis. In certain cases, special care must be taken to adjust the nephelometric measurement of the M protein to the most accurate part of the calibration curve. All in all, the new Behring Nephelometer proved precise and reliable in M protein determination without risk of antigen excess.