Allergen-specific IgE antibodies have not only been demonstrated in the serum, but also in the nasal secretions of allergic patients by means of the radio-allergosorbent test (RAST). In this preliminary study we adapted the technique of crossed radioimmunoelectrophoresis (CRIE) to nasal secretions in order to obtain further insight into the specificity of locally collected antibodies. Based on RAST results we compared CRIE patterns in serum, nasal secretions in 13 out of 23 grass pollen allergic subjects and two out of three house dust mite allergic subjects. In the nasal secretions the same IgE specificities were found as in the corresponding serum of the individual subject and as in a reference serum pool. These data indicate that the same specificity of IgE antibody can be found in the serum and the target organ. From these data there is no evidence for a local mucosal immune response that differs in specificity from the serum response.