A New Example of Anti‐LW and Further Studies on Heterogeneity of the System

Abstract
A case is reported in which an LW3 woman formed anti-LW. It is shown that the case represents the "genetic" and not the "transient" type of red blood cell LW antigen depletion. Studies have confirmed the quantitative difference of LW antigen on LW3 and LW4 red blood cells and the fact that Rhnull individuals produce the only totally LW-negative red blood cells. The difficulties encountered in the identification of anti-LW, because of the LW3 and LW4 states, are described. It is clear, from this study, that if random donors are typed for LW using anti-LW made by an LW4 indvidual, those who are LW3 will be classed as unremarkable LW-positives.