From the Guidelines
The spleen plays a crucial role in the human body, primarily functioning as a blood filter, immune system component, and storage site for platelets and red blood cells, with its main functions including removing old or damaged red blood cells, producing antibodies, and storing lymphocytes and monocytes. The spleen's functions can be broken down into several key areas, including:
- Filtering the blood to remove old or damaged red blood cells and recycling their components like iron 1
- Acting as part of the immune system to help fight infections by producing antibodies and removing bacteria from the bloodstream 1
- Storing platelets and a small reserve of blood that can be released during emergencies such as significant blood loss
- Producing lymphocytes and monocytes, which are crucial for immune responses
- Producing red blood cells during fetal development, though this function typically ceases after birth It is essential to note that while the spleen's functions are vital, humans can survive without a spleen if necessary, as other organs can compensate for its functions, though this may lead to increased susceptibility to certain infections, such as those caused by encapsulated bacteria like Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis 1. In the context of splenectomy or hyposplenia, it is crucial to consider the risk of overwhelming post-splenectomy infection (OPSI) and take preventive measures, such as vaccination against encapsulated bacteria and influenza, as well as providing antibiotic prophylaxis in certain situations 1.
From the Research
Functions of the Spleen
The spleen is a vital organ that performs several important functions in the body, including:
- Filtering blood of pathogens and abnormal cells 2
- Facilitating low-probability interactions between antigen-presenting cells (APCs) and cognate lymphocytes 2
- Regulating the T and B cell response to antigenic targets in the blood 2
- Initiating immune reactions to blood-borne antigens 3
- Filtering the blood of foreign material and old or damaged red blood cells 3
- Hosting a wide range of immunologic functions alongside its roles in hematopoiesis and red blood cell clearance 2
Immunologic Functions
The spleen's immunologic functions are carried out by its two main compartments: the white pulp and the red pulp 3. These compartments have different architectures, vascular organizations, and cellular compositions, which enable them to perform distinct functions. The white pulp, including the marginal zone, plays a key role in initiating immune reactions to blood-borne antigens 3. The red pulp, on the other hand, is involved in filtering the blood of foreign material and old or damaged red blood cells 3.
Cellular Composition and Organization
The spleen's cellular composition and organization are critical to its functions. The spleen hosts a wide range of cell types, including APCs, T cells, and B cells 2. The physical organization of the spleen allows for interactions between these cells, which is essential for initiating adaptive immunity to systemic blood-borne antigens 2.