Background: The liability to overwhelming infection of children lacking a s
pleen either as a result of its congenital absence or because of splenectom
y, has been frequently documented. Although there have been numerous studie
s of the consequences of experimental splenectomy in postnatal animals, thi
s is the first study of the effects of this operation in early fetal life.
Methods: A technique is described for microsurgical removal of the spleen f
rom fetal lambs approximately one-third of the way through gestation, when
the fetus is approximately the size of a mouse. Lambs that had been splenec
tomized in utero were submitted to haematological examination in postnatal
life and were challenged with pneumococcal polysaccharide to test their imm
unological competence.
Results: Lambs in which splenectomy had been performed close to the gestati
onal age of initiation of the splenic contribution to differentiation of im
mune and haemopoietic systems, exhibited insignificant deviations from norm
ality in postnatal life.
Conclusion: Provided the spleen is removed from the fetal lamb sufficiently
early in gestation, it is possible for other lymphoid tissues to compensat
e for most of the deficiencies that would be anticipated in animals lacking
a spleen. In this experiment, splenectomy was performed at approximately t
he developmental stage equivalent to that at which the spontaneous interrup
tion of development that leads to human congenital asplenia occurs. The abs
ence of major postnatal abnormalities observed in these lambs reinforces th
e significance of the associated abnormalities in the development of the cl
inical deficits observed in children with spontaneous asplenia.