Uses for Recombinant Protein Drugs - Biotechnology and Your Health: Pharmaceutical Applications - page 67

blood was the only source for the replacement clotting factors. The
first version was fresh frozen plasma from donated blood. Plasma is
the fluid part of blood that has not clotted, which would use up the
clotting proteins. Fresh frozen plasma has to be kept cold to remain
active and useful, and the low concentration of proteins in the
plasma meant that a large volume—a quart or so—had to be
injected slowly into the patient's vein. Storage and treatment at
home were impractical.
In the 1960s and 1970s, concentrated clotting factors were
developed, and storage and treatment at home became possible—
a welcome advance because it meant fewer trips to hospital emer-
gency rooms for people with hemophilia. However, in the early
1980s, it became clear that commercial sources for the concentrated
factors were infecting hemophiliacs with HIV because some of the
blood used to prepare the concentrates had been donated by people
unknowingly infected with HIV. Back then, the virus had not yet
been identified and there was no way to detect it. Because of the
danger of using commercial concentrates, hemophiliacs were once
again forced to make frequent visits to the emergency room.
Something had to be done to protect hemophiliacs from serious
bleeding problems without infecting them with a deadly virus.
Better methods for preparing clotting factors from blood and
the development of recombinant clotting factors provided the
solutions. Methods of detecting, inactivating, and removing viruses
were improved, and none of the hemophilia replacement products—
conventional or recombinant—has transmitted either HIV or
hepatitis since 1987. As an alternative, recombinant clotting factors
8 and 9, produced in animal cells, were approved in 1992 and 1997,
without the risk associated with human blood products.
WORKING WITH BLOOD CELLS
Our blood cells do many different types of work: They carry oxygen,
fight infections, and help repair leaks in blood vessels. The cells also