Pleural fluid is a type of body fluid, specifically a transudate. It is found in the pleural space, the area between the lungs and the chest wall.
The composition of normal pleural fluid includes a variety of cells, primarily:
- Macrophages: These cells make up the majority of cells in pleural fluid, accounting for around 75%. They are responsible for engulfing and destroying foreign substances like bacteria and debris.
- Lymphocytes: These cells represent about 23% of the total white blood cell count and play a role in the immune response.
- Mesothelial cells: These cells line the pleural space and are present in small numbers (1% to 2%).
- Neutrophils: These cells are typically present in small quantities (1%) and are involved in fighting infections.
- Eosinophils: These cells are also present in very low numbers (0%) and are involved in allergic reactions and parasitic infections.
The specific cell types and their proportions can vary depending on the underlying condition. For instance, in cases of infection, the number of neutrophils may increase significantly. In cases of cancer, cancer cells may be found in the fluid, providing valuable information about the type of cancer present.
