The response to Heinz bodies in the rat.

Irregular refractile granules which occur within red blood cells were first described by Heinz in 1890. The precise nature of these bodies is unknown. The present work was undertaken in order to help to assess the significance of the presence of Heinz bodies in the blood over a considerable period. Heinz bodies have been produced in the red blood cells of intact and splenectomized rats over relatively long periods by continuous feeding of azo geranine. The proportion of Heinz-body red blood cells quickly rose to a peak and then fell to fluctuating lower values; there was a concurrent fall in the red blood cell count and reticulocytosis. There were more Heinz-body red blood cells and a greater fall in the red blood cell count in the splenectomized animals. Large deposits of haemosiderin were present in the livers of the splenectomized animals fed the dye. Little or no haemosiderin was found in the livers of intact animals fed the dye or in those of splenectomized animals not receiving dye. Splenic hyperplasia accompanied the initial increase in Heinz-body red blood cells and remained undiminished after the level had fallen. The half-time survival of Heinz-body red blood cells transfused into normal rats was approximately one day compared with over five days in splenectomized animals. The anaemia associated with the appearance of Heinz bodies was found to be hypochromic: the mean cell haemoglobin concentration fell from 35·7% before feeding dye to 26·7% at the time of peak Heinz-body red blood cell concentration after seven days of dye feeding. With the subsequent fall in Heinz-body red blood cell level, approximately half of the deficiency in the mean cell haemoglobin concentration was replaced, despite a substantial recovery in the packed cell volume without an increase in the red cell count. Twenty days after feeding the dye had been stopped, no Heinz-body red blood cells were found, and all values had returned to normal.