potential problem associated with gene product

A potential problem associated with gene product
replacement is the initiation of an immunological reaction to
the administered protein by the recipient. In haemophilia, the
effectiveness of factor VIII injections is greatly reduced in the
10–20% of patients who develop factor VIII antibodies. The
efficiency of replacement therapy is, however, demonstrated by
the increase in documented life expectancy for haemophiliacs
from 11 years in the early 1900s to 60–70 years in 1980. The
reduction in life expectancy to 49 years between 1981 and 1990
reflects the transmission of the AIDS virus in blood products
during that time period, when 90% of patients requiring
repeated treatment became HIV positive. Factor VIII extracts
are now highly purified and considered to be free of viral
hazard, and recombinant factor VIII has been available
since 1994.