Spleen transplantation is the transfer of
spleen
The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes . or its fragments from one individual to another. It is under research for induction of
immunological tolerance
Immune tolerance, or immunological tolerance, or immunotolerance, is a state of unresponsiveness of the immune system to substances or tissue that would otherwise have the capacity to elicit an immune response in a given organism. It is induced by ...
for other
transplanted organs. Success has been achieved in
rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...
models. Recently, evidence has been obtained for a tolerogenic effect of a spleen transplant in
miniature swine. Also, the spleen harbors primitive
hematopoietic progenitor cell
Hematopoietic stem cells (HSCs) are the stem cells that give rise to other blood cells. This process is called haematopoiesis. In vertebrates, the very first definitive HSCs arise from the ventral endothelial wall of the embryonic aorta within t ...
s. Spleen transplantation has been performed on humans with mixed results.
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Autotransplantation
Splenic tissue can be deliberately autotransplanted after splenectomy, as some tissue will still be viable, to attempt to preserve some splenic function (with the goal of preventing
OPSI). Usually this involves leaving parts of splenic parenchyma in pouches of
omentum. This is not without risk or complication. This was performed after
splenosis Splenosis is the result of spleen tissue breaking off the main organ and implanting at another site inside the body. This is called '' heterotopic autotransplantation'' of the spleen. It most commonly occurs as a result of traumatic splenic ruptu ...
was understood; splenosis is the spontaneous reimplantation of splenic tissue elsewhere in the body (usually the abdomen) after it has broken off from the spleen due to trauma or surgery.
According to a 2020 review of 18 experimental studies, the transplanted spleen appears functional, with 95% of re-implanted tissue undergoing regeneration (by
scintigraphy
Scintigraphy (from Latin ''scintilla'', "spark"), also known as a gamma scan, is a diagnostic test in nuclear medicine, where radioisotopes attached to drugs that travel to a specific organ or tissue ( radiopharmaceuticals) are taken internally an ...
) and 90% of patients having a normalized
blood film
A blood smear, peripheral blood smear or blood film is a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically. Blood smears are examined in the ...
(suggesting functional blood filtration). All studies also report restoration of antibody levels. There is insufficient evidence to draw conclusions about OPSI rates. Of patients, 3.7% suffer from complications.
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See also
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References
Lymphatic organ surgery
Organ transplantation
Spleen (anatomy)
Transplantation medicine
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