Red Cell Resistance to Lysins in Pernicious Anemia

Since there is evidence that there is an in vivo hemolytic process involved in pernicious anemia, 1 we have carried out measurements of the resistance, to saponin and other lysins, of red cells from cases of pernicious anemia in relapse and in remission.

The methods used were those described by Ponder. 2 Suspensions of red cells from normal oxalated blood and from the oxalated blood of cases of pernicious anemia are made by suspending the thrice-washed cells in sufficient 1% NaCl (or buffered Ringer at pH 7.0) to give 2.5 (10⁸) cells/cc. A series of dilutions of saponin, or of another lysin, is then prepared in 1% NaCl, and time-dilution curves for complete hemolysis are plotted at 25°C up to times as long as 300 minutes, and in some cases 600 minutes. Under these circumstances, the resistance of the cells from the blood of cases of pernicious anemia, relative to the resistance of the normal cells, is simply and properly expressed by a constant R∞, obtained by dividing the asymptotic concentration of lysin for the cell suspension whose resistance is sought, by the asymptotic concentration for the cell suspension from the normal control (R∞ = 1.0). The resistance of suspensions of normal red cells varies remarkably little. 3

In 6 cases of clinically ascertained pernicious anemia in relapse, we have found the red cell resistance to saponin to be greatly decreased, so that the time-dilution curve for the abnormal blood rises to an asymptote much higher than that for the normal blood. Frequently the 2 curves cross each other, as shown in Fig. 1, curves A and C, the times for complete lysis in high lysin concentrations being longer for the abnormal blood than for the normal, but the times in higher dilutions of lysin being very much shorter for the abnormal cells.