Reticulocyte and red cell volume in HS and AIHA.

Mean cell volume of reticulocytes (left panel) and of mature red cells (middle panel) in blood samples from 37 adult control individuals, 25 nonsplenectomized individuals with HS, 23 splenectomized individuals with HS, and 13 nonsplenectomized individuals with AIHA. MCV of both reticulocytes and of mature red blood cells in HS blood samples was decreased compared with controls (P  < .0001). No significant differences were noted between splenectomized or nonsplenectomized HS samples. In contrast, in AIHA, blood samples MCV of reticulocytes was modestly increased compared with controls (P = .03) whereas the MCV of mature red blood cells was similar to that of controls. The extent of difference in cell volume between reticulocytes and mature red cells (ΔMCV) in AIHA was not different from the control (right panel), whereas it was significantly decreased in HS (P < .0001).