Spleen autotransplantation provides restoration of functional splenic lymphoid compartments and improves the humoral immune response to pneumococcal polysaccharide vaccine

After splenectomy, patients have an increased risk of overwhelming post-spl enectomy infection (OPSI) or sepsis involving encapsulated bacteria such as pneumococs. The value of spleen autotransplantation after splenectomy beca use of trauma has long been questioned. Much attention has been given to th e restoration of mononuclear phagocyte system (MPS) function, which appeare d to be similar to that of splenectomized individuals. The presence of spec ific anti-pneumococcal antibodies may enhance phagocytosis of opsonized bac teria by other parts of the MPS, as present in the liver. Therefore, in the present study we have evaluated the restoration of the humoral immune resp onse after spleen autotransplantation, especially to pneumococcal capsular polysaccharides (PPS). Wistar rats were divided into three groups which wer e operated as follows:splenectomy, splenectomy followed by autotransplantat ion, and sham operation. After 12 weeks the rats were vaccinated with 23-va lent pneumococcal vaccine. Blood samples were taken after 3 days, 3 and 6 w eeks for anti-PPS IgM and IgG ELISA against types 3, 4, 6, 9, 14 and 23. In addition, immunohistological studies were performed on the autotransplants . Significant antibody titre rises were found in a main proportion of the a utotransplanted rats, comparable to sham-operated rats. Splenectomized rats showed as well a significantly lower increase in immunoglobulin levels, as significant differences in the proportion of rats showing a minimum two-fo ld increase of antibody level, considered to represent an adequate response . The titres were highest 3 days after vaccination. Immunohistochemical stu dies demonstrated structurally functional autotransplants, including an int act marginal zone. Considering this significant antipneumococcal antibody r esponse, spleen autotransplants can be expected to enable an improved humor al response to PPS, and to contribute to protection against OPSI after sple nectomy.