Time course of total and food specific IgE antibodies (Rast Fx5) in the developing allergic child.
OBJECTIVE
To analyze the evolution of total and food specific IgE (Rast Fx5) titers in the course of food allergy in children.


METHODS
925 children, mean age 8.9 + 9.1 years (15 days-18 years), 455 girls and 470 boys, investigated for food allergy in year 1997, underwent serum samples assay for total IgE and of Rast Fx5, Cap System, Pharmacia & Upjohn Diagnostics AB, Uppsala, Sweden, a mix test detecting specific IgE to 6 major food allergens in children, cow's milk proteins (CMP), egg white, peanut, soy, wheat and fish and analyzed as a function of reference values by age.


RESULTS
Total IgE titers increased significantly with age, r0.22, p0.0001. The percentage of children with a total IgE level above normal range first increased with age, from 10.3 % at 0-6 months, reaching 38.2 % at 1-2 years and peaking at 56.9% at 4-6 years, then leveled off, 48.1% at 8-12 years (ns vs 4-6 years) and 41.3% above 12 years (ns). Detectable Rast Fx5 increased in a parallel manner until age 4-6 years and then exhibited a progressive decrease from age 6-8 years, differing significantly from total IgE: 31.9% vs 52.9%, p0.01 (6-8 years), 32.2% vs 48.1%, p0.03 (8-12 years), 21.8% vs 41.3%, p0.05 (> 12 years).


CONCLUSIONS
In these outpatient children investigated for food allergy, the increase with age of the percentage of high total IgE contrasted with the progressive decrease of Rast Fx5 from age 4-6 yr. This biological finding correlates timely with the clinical spontaneous decrease of food allergy in the developing child.
Kalach
Nicolas
N
Department of Pediatrics, Neonatology, Pediatric Gastroenterology & Nutrition Unit, Hôpital Cochin-Saint Vincent de Paul, Paris, France. kalach.nicolas@ghicl.net
Soulaines
Pascale
P
Guerin
Sylvie
S
de Boissieu
Delphine
D
Dupont
Christophe
C
D000293:Adolescent; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D021181:Egg Hypersensitivity / Q000097:blood / Q000276:immunology; D005260:Female; D005396:Fish Products; D005512:Food Hypersensitivity / Q000097:blood* / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016269:Milk Hypersensitivity / Q000097:blood / Q000276:immunology; D021183:Peanut Hypersensitivity / Q000276:immunology; D011852:Radioallergosorbent Test; D013025:Glycine max / Q000276:immunology; D013997:Time Factors; D021182:Wheat Hypersensitivity / Q000276:immunology
D007073:Immunoglobulin E