Reactive lymphocyte

Reactive lymphocytes or variant lymphocytes are lymphocytes that become large as a result of antigen stimulation. Typically they can be more than 30 µm in diameter with varying size and shape.

The nucleus of a reactive lymphocyte can be round, elliptic, indented, cleft or folded. The cytoplasm is often abundant and can be basophilic. Vacuoles and/or azurophilic granules are also sometimes present. Most often the cytoplasm is gray, pale blue or deep blue in colour.