Functional Hyposplenism in Long-Standing Renal Transplant Recipients

Background. A nephrologist with expertise in ultrasonography noticed that patients with longstanding renal grafts had smaller spleens than subjects undergoing initial post-transplantation imaging. This putative finding prompted us to pursue a further investigation into splenic function based on Doppler ultrasound and hematologic parameters. Methods. We enrolled 47 patients with functioning long-standing kidney grafts, measuring longitudinal diameter of the spleen, hilar and intrasplenic peak systolic velocities (PSV), and hilar and intrasplenic resistivity indices of the splenic artery as well as mean arterial blood pressure (MAP). Giemsa-stained peripheral blood smears were examined for the presence of Howell-Jolly bodies (HJBs) using light microscopy. The patients were then divided into HJB present (HJ(+)) or absent (HJ(-)) groups for further comparison. Results. The overall mean age of 21 females and 26 males was 47.8 +/- 12.0 years, and the mean time after transplantation was 2750 +/- 1818 days (range, 208-6446). HJBs were detected in 23/47 patients (48.9%). The intrasplenic artery PSV was significantly lower and MAP higher in the HJ(+) group (P < .05). There was no difference in spleen size between the groups. Discussion. HJBs in peripheral blood red cells, an indicator of hyposplenism, was associated with reduced intrasplenic artery PSV, suggesting dysfunction, which may play a role in the known vulnerability of renal transplant recipients to infections.