So how does one treat a patient
with primary immunodeficiency?
Well it rather depends on the exact
nature of the immunodeficiency.
But early intervention with antibiotics
and antifungals is very important.
Long term low dose prophylactic antimicrobials
can be used to prevent re-infection.
Cytokine therapy with granulocyte-colony
stimulating factor will enable one to boost
neutrophil numbers in patients with
neutropenia, with low levels of neutrophils
you can stimulate the bone marrow to produce
more neutrophils using G-CSF and gamma
interferon to stimulate phagocytes in
patients with chronic granulomatous disease.
IL-2 can be used to stimulate lymphocytes in
patients with common variable immunodeficiency.
Intravenous or subcutaneous pooled
human immunoglobulins can be utilized.
Intramuscular bovine ADA (adenosine deaminase)
conjugated to polyethylene glycol to increase
its half life can be used in patients who
have SCID due to mutations in the ADA gene.
And bone marrow, cord blood or adult peripheral blood
hematopoietic stem cell transplantation can be used.
And then finally gene therapy, and this is very much I think
the future of treatment of primary immunodeficiencies.
There is a gene defect, let’s get in there and actually
replace the defective gene with a normal functioning gene.
And although it’s relatively early days in this type of
therapy, there have been quite a number of successful trials.
And this is now becoming a more routine
procedure in a number of places worldwide.
The ultimate therapy for primary immunodeficiency is to replace
the defective gene with a normal functioning copy of the gene.
Viral vectors are used to insert the functional gene
into patient’s CD34+ hematopoietic stem cells.
This has been used to treat patients with SCID,
using a normal copy of the ADA gene or the γC gene.
It’s also been used in Wiskott-Aldrich syndrome, to replace the
defective gene encoding the Wiskott-Aldrich syndrome protein.
And replacement of defective gp91phox in chronic
granulomatous disease has also been employed.