The “low affinity” receptor for IgE, an antibody isotypeimplicated in allergy and (perhaps) parasite resistance,CD23, sometimes referred to as Fc epsilon RII, plays acrucial role in controlling IgE levels. CD23 is a C-type lectin,in contrast to numerous antibody receptors. It is present onplatelets, follicular dendritic cells, eosinophils, mature B-cells, and activated macrophages. When distinguishingCD23-positive B-CLL and B-SLLs from CD23-negativeMantle-cell Lymphomas and Small-Cleaved Lymphomas,this B-cell antibody is helpful. This antibody binds to theantigen present on EBV-transformed B-lymphoblastoid celllines, B-lymphocytes, and a subset of peripheral bloodcells. FcεRII, another name for CD23, is a C-type lectin andan IgE receptor with modest affinity. It is present on avariety of cells, including follicular dendritic cells, activatedmacrophages, and B-cells, and it helps control IgE levels.Because of its expression pattern, CD23 can be used todifferentiate between various lymphoma types, such as B-CLL and B-SLL from Mantle-cell and Small-CleavedLymphomas.