| Abstract:
The blood specimen of a 42-year-old male donor was targeted for detailed study at the Iranian
National Blood Transfusion Services as the ABO blood grouping of his cells and serum did not
match. Preliminary results suggested that his group was “Bombay” (Oh) phenotype. For
confirmation, his blood specimen was air-shipped to Bombay, where detailed studies revealed the
presence of depressed A antigens on his red cells that were detectable with variable strength with
anti-A+B reagents prepared from group O individuals. His red cells failed to show agglutination by
anti-H reagents from “Bombay” phenotype, lectin from Ulex europaeus, and immunized chicken.
The donor’s serum agglutinated group B red cells showing a titer of up to 1:32 at room
temperature, but reacted with A and O red cells only at 4°C in a low titer of 1:4 – 8. The reactivity
against group A and O cells was partially inhibited by saliva from individuals secreting A/H
antigens and was characterized as anti-I. The donor was classified as para-Bombay of AHw
phenotype. The anti-I antigen strength on the donor’s red cells, as determined by titration of anti-I
and anti-i reagents, was comparable to normal adult individuals but not to the “Bombay”
phenotype, thus supporting his phenotype as para-Bombay. This case provides another example
of the para-Bombay phenotype that serologically differs from the one reported earlier in Iran.
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