Establishing a cut-off for the serum levels of specific IgE to milk and its components for cow's milk allergy: results from a specific population.
BACKGROUND
Cow's milk allergy diagnosis many times requires double-blind placebo-controlled food challenge (DBPCFC), which presents high accuracy but involves risks, specifically in infants and anaphylactic patients. The identification of the cut-off values for specific IgE to milk or its components would contribute to cow's milk allergy (CMA) diagnosis. The aim of this study was to compare discriminating concentration of a cow's milk specific IgE and its fractions (α-lactoalbumin, β-lactoglobulin, casein) in children for the CMA diagnosis.


METHODS
this study included 123 patients (M:F=1.3:1) median age at diagnosis=1.91 years, (3.5m to 13.21y) with CMA diagnosis via DBPCFC (n=26), proven anaphylaxis due to cow's milk (n=46) or a suggestive clinical history associated with a positive skin prick test (n=51) and open oral food challenge. The control group included 61 patients (1 male:1.1 female) ages ranging from 0.66 to 16.7 years (median=6.83 years). Receiver operator characteristics (ROC) curves were constructed to determine the best cut-offs that guarantees high specificity (>95%) for cow's milk and its components.


RESULTS
considering 98% specificity, cut-off points were: 3.06 kU/L for cow's milk, 2.06 kU/L for α-lactalbumin, 1.85 kU/L for β-lactoglobulin and 1.47kU/L for casein. The best ROC curve (area under the curve=0.929) was obtained evaluating cow's milk.


CONCLUSIONS
this study showed that the cut-off point detected for whole cow's milk revealed a better discriminatory capacity for CMA diagnosis without the necessity of the milk components testing.
Department of Pediatrics, Faculty of Medicine, University of Sao Paulo, Brazil. Electronic address: moschione@uol.com.br.
A P
AP
Castro
Department of Pediatrics, Faculty of Medicine, University of Sao Paulo, Brazil. Electronic address: acpastorino@uol.com.br.
A C
AC
Pastorino
Department of Pediatrics, Faculty of Medicine, University of Sao Paulo, Brazil. Electronic address: agushken@uol.com.br.
A K F
AK
Gushken
Division of Clinical Immunology and Allergy, University of São Paulo School, Brazil. Electronic address: cmkokron@usp.br.
C M
CM
Kokron
Department of Pediatrics, Faculty of Medicine, University of Sao Paulo, Brazil. Electronic address: udoria@hotmail.com.
U D
UD
Filho
Department of Pediatrics, Faculty of Medicine, University of Sao Paulo, Brazil. Electronic address: miuki55@uol.com.br.
C M A
CM
Jacob
D000293:Adolescent; D000707:Anaphylaxis / Q000209:etiology / Q000517:prevention & control*; D000818:Animals; D002417:Cattle; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007114:Immunization; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007223:Infant; D008297:Male; D008892:Milk / Q000276:immunology; D016269:Milk Hypersensitivity / Q000150:complications / Q000175:diagnosis*; D044382:Population Groups; D012015:Reference Standards; D012016:Reference Values; D012680:Sensitivity and Specificity
D007073:Immunoglobulin E
Cow's milk hypersensitivity; Diagnosis, Immunoglobulin E; Food hypersensitivity; Milk proteins, ImmunoCAP