Histiocytes are cells of the immune system that ingest foreign antigens to protect against infection. They are fixed, meaning they remain in one part of the body rather than traveling through the bloodstream. Histiocytes are found in many organs and connective tissues:
Spleen Lymph nodes Brain Liver (Kupffer cells) Breast tissue Alveoli Tonsils Serous cavities Placenta Histiocytosis involves an abnormal number of histiocytes and may affect the lungs (alveoli), the bones, or the lymphatic system.