The efficacy and immunogenicity of Pneumo-23 and ACT-HIB in patients undergoing splenectomy

The objective of this prospective study is to validate the efficiency of Streptococcus pneumoniae and Haemophilus influenzae vaccines in splenectomized patients via the demonstration of seroconversion and uninterrupted ability for opsonization.

Thirty-two adult patients (18 males, 14 females; mean age 46.1 years; range 18 to 79 years) who underwent elective or urgent splenectomy for various benign and malignant hematological disorders, splenic trauma and splenic masses were reviewed. Pneumo-23 and Act-HIB were administered to all patients on routine basis. In order to demonstrate the ongoing opsonizing capacity of the immune system and the seroconversion of immunoglobulins after vaccination, antibody titers of IgG and IgM and plasma C3 and C4 levels were quantitatively measured.

The operative morbidity was 9% and overall mortality was 16%, with no early postoperative death in this series. Five patients with various malignant disorders died due to dissemination of their primary tumor. None of the patients with benign hematological disorders or those with splenic trauma died during the mean follow-up of 427 days. Furthermore, death from overwhelming postsplenectomy infection was nil in our clinical survey. All of the patients including those with malignancy had normal IgG (mean: 1383.1 mg/dL) and IgM levels (mean: 80.9 mg/dL) during discharge and at the last follow-up. Among the patients with benign hematological disorders, splenic trauma and splenic masses necessitating splenectomy, C3 and C4 levels were entirely within normal limits with a mean of 108.8 mg/dL and 21.4 mg/dL, respectively.

This preliminary study reveals adequate seroconversion of immunoglobulins in all patients and normal C3 and C4 levels in patients with benign hematological disorders and splenic trauma. Moreover, none of the patients in the latter group had S. pneumoniae or H. influenzae infection nor did they expire due to overwhelming sepsis during the follow-up period. Long-term follow-up is required to determine the continuation of this immunologic response and the necessity of repeated vaccination.