Copyright ©2013 Baishideng Publishing Group Co.
World J Gastroenterol. Jun 21, 2013; 19(23): 3534-3542
Published online Jun 21, 2013. doi: 10.3748/wjg.v19.i23.3534
Table 1 Function of the spleen
Red pulp
Extramedullary hematopoiesis if required
Facilitating an environment wherein erythrocytes rid themselves of solid waste material
Blood filter for foreign material and damaged and senescent blood cells
Storage site for iron, erythrocytes, platelets, plasmablasts and plasma cells
Rapid release of antigen-specific antibodies into the circulation produced by red pulp plasma cells Defense against bacteria using iron metabolism by its macrophages
White pulp
T cell zone (periarterial lymphatic sheath) and B cell zone (follicles)
Storage site for B and T lymphocytes
Development of B and T lymphocytes upon antigenic challenge
Release of immunoglobulins upon antigenic challenge by B lymphocytes
Production of immune mediators involved in clearance of bacteria such as complement, opsonins, properdin and tuftsin
Marginal zone
Phagocytosis of circulating microorganisms and immune complexes by MZ macrophages
Development of marginal zone B lymphocytes upon TI-2 antigenic challenge
Blood trafficking of B and T lymphocytes
Release of immunoglobulins upon antigenic challenge by splenic B lymphocytes
Table 2 Main topics
Congenital asplenia in humans
There are two types of congenital asplenia: with or without other clinically evident abnormalities
Tcf21, Bapx1, Pbx1 and Tlx1 are crucial for spleen development
The molecular mechanisms and the etiology of spleen development are still unknown
How the anatomical and histological composition of the spleen can guarantee its function?
The phagocytosis of old and damaged cells, particles and blood-borne microorganisms from local macrophages takes place in the red pulp
The spleen is fundamental in the recycling of iron
Exercise in splenectomized individuals can decrease splanchnic flow and increase blood viscosity
Most important differences between mice and humans in the spleen organization and functionality are revealed in the immune response
Role of spleen in limiting bacterial infection
Splenectomized and asplenic patients are more susceptible to infections, especially caused by Haemophilus influenzae
Subjects with functional asplenia develope the same type of infections
The spleen and natural antibodies
B cells may be divided in two main subpopulations on the basis of life development (fetal or adult), superficie markers and functions
Spleen might be central to the generation or survival of the B-1a population and therefore splenectomy would lead to their depletion
Other functions of the spleen
There is a probable relationship among GALT and spleen in humans
The spleen also has important hematological functions
In the spleen were found stem cells with several differentiation properties: haematological, osteogenic and maybe pancreatic
Assessment of spleen function
Hematologycal and immunological parameters should be used in the assessment of spleen function
The best approach to gauge all the facets of the splenic function is the radioisotope method
Spleen as a new player
There is an association between spleen enlargement and NAFLD
SLD could be used as new marker for assessing splenic function
Initial data have shown that SLD is more sensitive than IL-6 and VEGF in discriminating NASH from FL, and the optimal cut-off value for SLD is 116 mm
Infections tendency in obesity and the possible link with the spleen
Obese subjects have an increased risk to develop malignancies and infections
The pathophysiological mechanisms by which cellular immune functions are affected by obesity are still under investigation but the spleen may have an important role