Comparison of the Lewis phenotypes among the different population groups of Taiwan

In Caucasians, three red cell Lewis phenotypes are observed, namely Le (a+b-), Le (a-b+) and Le (a-b-). For Chinese living in Taiwan the Le (a+b-) phenotype is replaced by the Le (a+b+) phenotype so that the three red cell Lewis phenotypes observed in Chinese are Le (a+b+), Le (a-b+) and Le (a-b-). In addition, Chinese individuals with Le (a-b-) red cells can be subdivided into two groups, namely those who secrete both ABH and Lewis substances in saliva and those who secrete only ABH substances in saliva. However, four red cell Lewis phenotypes Le (a+b-), Le (a+b+), Le (a-b+) and Le (a-b-) are observed among some of the indigenous groups living in Taiwan. Red cell Le (a+b-) individuals among these indigenous groups can also be subdivided into at least two groups, namely those with Le(a) and Le(b) in saliva (plus varying amounts of ABH substances) and those with just Le(a) in saliva. The former are most likely a weak form of the red cell Le (a+b+) phenotype while the latter appear to be similar to the Caucasian red cell Le (a+b-) phenotype. There was also one red cell Le (a+b-) individual whose saliva had a small amount of A substance as well as Le(a) substance and therefore appeared to be intermediate between the above two forms of the Le (a+b-) phenotype.