Aim To determine associations between specific sensitization and featurе of the intestinal microbiota composition in children with food allergy during nutrition diversification.

Material and Method This is a cross-sectional, single-center study of 90 children with food allergy in groups: 6–12 (I, n=56) and 13–18 months old (II, n=34). The levels of total IgE (TIgE) and sIgE were studied using ALEX2 allergochip; the intestinal microbiota composition - by bacteriological method.

Results Complementary foods were introduced to children of both groups at the age of 5.5 [5–6] months old. At 13–18 months children received 10–12 groups of products. Group I - M TIgE=54.0 kE/L. A moderate/high level of sensitization was detected in 25 children: egg (Gal d1, d2, d3) - 11, cow’s milk protein (CMP) (Bos d6) – 5, cat (Fel d1, 7) – 4. Monosensitization was detected in 12 children: wheat, birch pollen, egg white, cat, CMP. 7 children had polyvalent sensitization to food, respiratory and epidermal allergens. Group II - M TIgE=105.3 kE/l. A moderate/high level of sensitization was detected in 6 children: CMP (Bos d4, Bos d5, Bos d8), egg (Gal d1, 2, 3), wheat, soy, potato, shrimp, mackerel, cod, cashew, walnut. Sensitization to respiratory allergens was detected in 6 children: birch pollen (Bet v1, Mal d1), cat (Fel d1, 4, 7), dog (Can f1, 4, 6), house dust mite. The following correlations were revealed: positive – Proteus spp. & TIgE; Proteus spp. & sIgE to Gal d1, d2, d3, cashew, cod (R=0,30, 0,22, 0,23, 0,38, 0,38, 0,38); Clostridium spp. & sIgE to sheep’s milk, Gal d4, cashew, fenugreek, cod, Fel d1 (R=0,22, 0,22, 0,22, 0,30, 0,22, 0,23); negative - Bifidobacterium spp. & sIgE to Gal d2 (R= - 0,59).

Conclusions The obtained results indicate association between Proteus spp. and Clostridium spp. of the intestinal microbiota with progrediency of atopy in the period of nutrition diversification.