(2) All I system antibody reactions are enhanced if enzyme-treated red
blood cells are used. Many of them are also enhanced in the presence of albumin.
(3) Small amounts of complement may be bound to red blood cells at room
temperature, causing a subsequent antiglobulin test at 37C to be weakly positive.
(4) If interpretation of results at 37C is to be relied upon, pre-warmed tests
should be set up strictly at 37C, including centrifugation procedures, if possible.
2-32. KELL BLOOD GROUP SYSTEM
a. The Kell (K) antigen was first demonstrated by an antibody that caused
hemolytic disease of the newborn. Its associated gene (K) is present in approximately
9confirmed when an antithetical relationship was established between K and k antigens
using anti-Cellano (k), which reacted with the red blood cells of over 99% of the
b. Subsequently, four additional antigens were found to be related to the Kell
system. The first two were shown to be allelic and were termed Kpa and Kpb. As with K
and k, Kpa has a low frequency and Kpb a high frequency (see Table 2-18). Jsa is found
in about 20 percent of Blacks, but very rarely in Whites or Orientals. In antithetical antigen,
Jsb, has a high frequency. The paired antigens K and k, Kpa and Kpb, and Jsa and Jsb
are inherited as if they were controlled by 3 pairs of allelic genes, analogous to the
situation in the Rh system; however, unlike the latter system, not all theoretically
possible gene complexes have been found for the Kell system.
Table 2-18. Some phenotype frequencies in the Kell system.