Systemic lupus erithematosus (SLE)

About one-third of patients with SLE develop a pleural or pericardial effusion, or less commonly a peritoneal effusion.

The characteristic cell is the lupus erythematosus (LE) cell, a neutrophil or macrophage containing an ingested cytoplasmic particle called hematoxylin body. The hematoxylin body can be green, blue or purple with the Papanicolaou stain and has a glassy, homogeneous appearance. The nucleus is pushed to one side and indented into a crescent-like space.