IMMUNOGENETIC ANALYSIS OF THE HEAVY-CHAIN VARIABLE REGIONS OF IGE FROM PATIENTS ALLERGIC TO PEANUTS

Peanuts are one of the most allergenic of the foods, and hypersensitiv ity responses to peanut allergens can be fatal. Although the nature of the antigenic components of peanuts is being defined at the molecular level, there is little information on the induced IgE antibodies, whi ch are central to the allergic reaction. Recognition sites of IgE anti body molecules arise from the variable regions of heavy and light chai ns (V-H and V-L). By using nested polymerase chain reactions with spec ific primers for the available repertoire of V-H genes, together with primers in the constant epsilon region, we have amplified V-H sequence s of IgE from blood lymphocytes of two patients with peanut allergy. A fter cloning and sequencing the products, we found a predominance of V (H)1 family use in both patients, which was not found in control IgM-s pecific primers. The IgE V-H sequences were highly somatically mutated , but in only six of 17 cases was there clear evidence for clustering of amino acids indicative of antigen selection. Previous results from patients with allergy to house dust mites have indicated predominance of V(H)5 use and little evidence for antigen selection. Although resul ts from two patients allergic to peanuts must be regarded as prelimina ry, they do suggest that the IgE response to peanuts may have a differ ent V-H bias, with a similar mutational pattern.