Subcutaneous literally means: “under the skin”.
Subcutaneous injections of gammaglobulin were used by Bruton to treat the first patient diagnosed with agammaglobulinemia, in the early 1950’s. Subsequently, intramuscular (IM) injections of gammaglobulin were used in a large study in the United Kingdom and this became the standard route of administration of IgG for patients with antibody deficiencies.
IM “gammaglobulin shots” were also widely used during the 1950’s in patients without PID to prevent outbreaks of infectious diseases such as measles and polio, and were sometimes given to premature babies. The type of gammaglobulin used by Bruton and in the study in the UK is called Immune Serum Globulin (ISG). It is produced as a 16% solution, as compared to most IV preparations which are used at 5 or 10%. The 16% ISG is still used for preventing hepatitis A infection for travelers, and occasionally to prevent infectious disease outbreaks in non-immunized populations.
In the late 1970’s, before intravenous immunoglobulin became available, Dr. Melvin Berger and his colleagues used a small battery-powered pump to give 16% ISG to a patient who would not take her ISG shots because they were quite painful. She also had had bad reactions to plasma transfusions, the only alternative to IM shots available at that time.
The pump gave the ISG slowly- over several hours- and eliminated the pain associated with the deep IM shots. This patient and several others tolerated the ISG quite well using this slow subcutaneous method with the pump. This first young woman who used the pump for ISG soon got married and became pregnant, and took subcutaneous ISG throughout her pregnancy. She used up to 20 cc (which contains 3.2 grams of IgG) every day in the last months. This allowed her to receive over 22 grams of IgG per week. Both the mother and baby had normal IgG levels at the time of birth, meaning that enough IgG had been given to the mother to transfer across the placenta and give the baby a normal level as well.