The Spleen: An Underrated Organ Essential for Health and Immunity

The spleen, an organ often overlooked or viewed as non-essential, is being recognized for its critical role in maintaining human health and immunity. While historically relegated to a secondary status in medical perception, research highlights its function as the largest secondary lymphoid organ in the body.

Reporting from outlets including Nieuwsblad, VRT, and De Morgen indicates that the effect of the spleen on immunity has been long underestimated, with descriptions of the organ as essential for overall health.

Immune System Functions and Blood Filtration

The spleen serves as a sophisticated filter for the blood. According to the Cleveland Clinic, the organ stores and filters blood while producing white blood cells that protect the body from infection.

Beyond basic filtration, the spleen is central to the initiation of adaptive immunity against systemic blood-borne antigens. Research published via PubMed explains that the physical organization of the spleen allows it to filter pathogens and abnormal cells from the blood.

This organization facilitates interactions between cognate lymphocytes and antigen-presenting cells (APCs). Specifically, APCs within the spleen regulate the responses of T cells and B cells to antigenic targets found in the bloodstream.

In addition to its immunologic functions, the spleen is involved in hematopoiesis and the clearance of red blood cells.

Anatomy and Physical Characteristics

The spleen is a fist-sized organ, roughly the size of an avocado in adults, located inside the left rib cage just above the stomach. NPR describes its appearance and consistency as being similar to an orange wedge that is squishy and full of blood.

The internal architecture of the human spleen includes a perifollicular zone (PFZ) and specific zones for T cells and B cells, which are necessary for its immune functions.

While most individuals have a single spleen, some may possess accessory spleens. In one instance reported by NPR, a patient discovered a bunch of extra spleens during surgery to repair a splenic tear.

Medical Risks and Clinical Considerations

Because the spleen contains a significant volume of blood and is relatively fragile, injuries to the organ can be severe. The Cleveland Clinic notes that a ruptured or torn spleen can be fatal.

There is a common misconception that the spleen is unnecessary for survival. While healthcare providers can remove the organ through a procedure called a splenectomy when necessary, the organ’s role in filtering pathogens and regulating the immune response is substantial.

The spleen, shown in the 19th-century French anatomy atlas, Traite Complet de L’Anatomie de L’Homme… Has been relegated to the organ bargain-basement, something to be cut out and discarded along with the appendix and wisdom teeth.

NPR

Modern imaging technology and medical research have shifted this perspective, confirming that the spleen is not a redundant organ but a vital component of the lymphatic and immune systems.