CD23 expression in non-Hodgkin lymphoma: immunohistochemical demonstration using the antibody BU38 on paraffin sections.

The leucocyte antigen CD23 is upregulated in the early stages of B-cell activation by Interleukin-4 (IL-4), and functions as an IgE receptor and lymphocyte growth factor. We have studied the expression of CD23 in 68 cases of non-Hodgkin lymphoma (NHL) using the antibody BU38. This new antibody has the great advantage of being applicable to routinely-processed paraffin sections. CD23 was expressed in tumour cells in 27 out of 36 cases of low grade NHL and 3 out of 32 cases of high grade NHL. Follicular dendritic cells were strongly positive and were seen in follicular lymphomas. Macrophages were also positive and were numerous in high grade lesions.