The Basophil (on the left) is another of the three varieties of blood granulocyte (1-2% of total WBC), also has a multi-lobed nucleus, but has abundant basophilic cytoplasmic granules. Very similar to tissue-bound "mast cells", it bears high affinity Fc receptors for IgE, and can be triggered to release histamine and other pharmacologically active agents during allergic reactions (also in response to the vasoactive complement components C3a and C5a).
A PMN can be seen at the right.