Correlation of lymphocyte proliferating cell nuclear antigen expression with dietary cow's milk antigen load in infants with allergy to cow's milk.
BACKGROUND
Controversial results have been reported on the participation and diagnostic value of lymphocyte reactivity in cow's milk (CM) allergy. In this study, we used a specific nuclear marker to evaluate lymphocyte proliferation in IgE-mediated CM allergy in infants, and examine its relation with diets containing different CM antigen loads.


METHODS
Infants with IgE-mediated CM allergy, as assessed by open provocation and RAST, were grouped according to their exclusive diet, either CM formulae, breast feeding, or hydrolysed whey formulae. A group of non-atopic infants receiving CM was also examined. Lymphocyte proliferation to beta-lactoglobulin was evaluated by quantitation of the proliferating cell nuclear antigen (PCNA) expression in peripheral blood mononuclear cells, by flow cytometry. Immunophenotypic surface markers were also examined.


RESULTS
A marked difference of PCNA expression between CM-fed allergic infants and healthy controls was observed (p<0.001). In this setting, PCNA expression >/=10% was highly specific and sensitive as a marker of CM allergy in CM-fed infants. Moreover, a significant correlation (p<0.001) between antigen load and PCNA was established in CM-allergic infants under different diets, higher values obtained with increasing antigen loads. In addition, within the group fed hydrolyzed formulae, low-molecular-weight products resulted in marginally lower PCNA expression than higher-molecular-weight formulae. No differences in immunophenotype were found, with the exception of a higher CD23 expression in the breast-fed group.


CONCLUSIONS
PCNA could be a useful marker in the assessment of lymphocyte proliferation to CM antigens. Low CM antigen diets are related with reduced lymphocyte reactivity, which may partly explain the clinical benefit observed with such diets.
Papadopoulos
N G
NG
Allergy and Clinical Immunology Laboratory, 2nd Department of Pediatrics, University of Athens, Greece. ngp@soton.ac.uk
Syrigou
E I
EI
Bossios
A
A
Manou
O
O
Gourgiotis
D
D
Saxoni-Papageorgiou
P
P
D000818:Animals; D000941:Antigens / Q000276:immunology*; D001942:Breast Feeding; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D016130:Immunophenotyping; D007223:Infant; D007782:Lactoglobulins / Q000378:metabolism; D008213:Lymphocyte Activation; D008892:Milk / Q000009:adverse effects*; D016269:Milk Hypersensitivity / Q000276:immunology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011852:Radioallergosorbent Test
D000941:Antigens; D007782:Lactoglobulins; D018809:Proliferating Cell Nuclear Antigen; D007073:Immunoglobulin E