Antibody-dependent cell-mediated cytotoxicity to β-lactoglobulin-coated cells with sera from children with intolerance of cow’s milk protein

Abstract

SUMMARY The capacity of serum antibodies against β-lactoglobulin to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) was analysed in sera from children with cow’s milk protein intolerance (CMPI). The children with CMPI were divided into three groups according to clinical features: delayed-onset CMPI with gastrointestinal symptoms (n= 8); immediate-onset CMPI with gastrointestinal and skin symptoms (n= 8); and immediate-onset CMPI with skin symptoms only (n= 8). The CMPI groups were compared with children with untreated (n= 9) or treated (n= 8) coeliac disease and a control group (n= 22). Sera from the children were examined for cytotoxic effects using lymphocytes from healthy adults as effector cells and radiolabelled β-lactoglobulincoated erythrocytes from the same donor as target cells. In addition, IgG and IgA serum antibodies against β-lactoglobulin were determined with ELISA. Sera from children with CMPI and gastrointestinal symptomatology showed a significantly increased capacity to induce ADCC reactivity as compared with controls. This increased capacity was seen in sera from those with immediate as well as delayed onset of the gastrointestinal symptoms. In contrast, sera from children who had an immediate-onset CMPI with only skin symptoms mediated no such increase in ADCC reactivity. Moreover, children with coeliac disease with a few exceptions, demonstrated low ADCC reactivity, despite the fact that they had high levels of antibodies against β-lactoglobulin. ADCC may be an immunopathogenic mechanism in certain cases of CMPI with gastrointestinal symptoms.