Immunological factors in milk from Brazilian mothers delivering small-for-date term neonates.

Breast milk samples from three groups of Brazilian women were evaluated: G1, mothers delivering term babies of low birth weight (n = 16); G2, mothers delivering preterm babies of appropriate birth weight (n = 20); G3, mothers delivering term babies of appropriate birth weight (n = 30). Milk samples were obtained at 48 h and on the 7th, 15th, 30th and 60th days after delivery and they were analyzed for lysozyme and total IgA levels and for the presence of specific antibodies against Poliovirus types I, II, III, Rotavirus, Herpes simplex virus, Varicella zoster and Cytomegalovirus. The groups were not statistically different in relation to mother's age, parity, type of delivery or socio-economic levels. IgA levels were higher in both low-birth-weight groups (G1 & G2) compared to the control group (G3) throughout the study period. Lysozyme levels decreased up to the 15th day, increasing thereafter up to the 60th day in all groups. Specific antibodies were detected throughout the study period, with no differences among groups. We conclude that breast milk composition of mothers delivering low-birth-weight babies (G1 & G2) was similar despite the different gestational ages.

Frequency of selective IgA deficiency among Brazilian blood donors and healthy pregnant women.

Selective IgA deficiency (SIgAD) is the most common primary immunodeficiency, with frequencies ranging from 1:300 to 1:3,000 in populations surveyed in Europe and the US. In the present study we tested 11,576 clinically healthy persons (blood donors and pregnant women) for SIgAD (serum IgA less than 5 mg%). Serum samples were screened by double immunodiffusion with a sheep anti-human alpha-chain (minimal detection level of 30 mg%). Samples showing negative or doubtful reactions were submitted to the radial immunodiffusion test (minimal detection level of 0.5 mg%). For the samples with low or undetectable IgA levels, IgG and IgM concentrations were also determined. We found 12 individuals with SIgAD and 2 with deficiency of the 3 immunoglobulin classes. The prevalence of SIgAD in this Brazilian population (1:965) is equivalent to values reported for other countries.