Preservation of Splenic Immunocompetence After Splenic Artery Angioembolization for Blunt Splenic Injury

Background: Splenic artery angioembolization (SAE) is increasingly being used as an adjunct to nonoperative management for stable patients with blunt splenic injury (BSI). However, little is known about splenic immunocompetence after SAE. This study aims at assessing splenic immunocompetence after SAE for BSI. Methods: Peripheral blood was obtained from BSI patients (n = 8) who had SAE >6 months prior. Splenic immunocompetence was assessed by isolating mononuclear cells and incubating with CD4 super(+) and CD45RA super(1) and CD45RO super(+) antibody to analyze the proportion of T-cells expressing CD4 receptor, or coexpressing CD4 and either CD45RA or CD45RO receptors. Cells were counted by fluorescence-activated cell sorting and compared with trauma patients that had splenectomy for BSI also >6 months prior (n = 4, negative controls) and normal healthy volunteers with intact spleens (n = 4, positive controls). Results: The test was discriminatory for the asplenic state. %CD4 super(+) cells were significantly lower in splenectomized patients (16 plus or minus 1) versus normal (40 plus or minus 2), p < 0.05. This was due to significant decrease (8 plus or minus 2 vs. 26 plus or minus 4, p < 0.05) in %CD4 super(+)CD45RA super(+) cells whereas the proportion of CD4 super(+)CD45RO super(+) cells were maintained similar to normal. SAE patients had values (CD4 super(+), 36 plus or minus 2, and CD4 super(+)CD45RA super(+), 24 plus or minus 2) comparable to normal (p > 0.05) and significantly higher than splenectomized patients (p < 0.05). When the SAE group was subdivided into main (total, n = 4) and branch vessel (partial, n = 4) SAE, results were the same for both types of SAE. Conclusion: Splenic immune function, measured by T-cell subset, generated only in the presence of an immunocompetent spleen, is preserved after SAE for BSI, main or partial.