Intra-erythrocytic haemoglobin crystals.

When investigating a newly discovered haemoglobin L, using Itano's solubility test (Itano, 1953), a resemblance to sickle cell haemoglobin was noticed inasmuch as solubility was not complete in 2.24 M phosphate buffer. This was later realized to be due to an artefact (see Ager and Lehmann, 1957), but at that time the cells containing haemoglobin L were tested for sickling by incubation with reducing agents (Daland and Castle, 1948; Williams and Mackey, 1949). On prolonged immersion of the erythrocytes in isotonic sodium metabisulphite or bisulphite, it was observed that many contained one or more crystals. This effect had been reported in haemoglobin C disease, sickle cell-haemoglobin C disease, and haemoglobin C-thalassaemia on immersion of cells in 3% sodium citrate (Diggs, Kraus, Morrison, and Rudnicki, 1954; Kraus and Diggs, 1956). These authors suggested that further work was needed to evaluate whether or not their findings could be used for diagnostic purposes. Since the erythrocytes used by the present authors contained 71 % of normal adult haemoglobin, investigation of erythrocytes containing other types of haemoglobin was undertaken.