So those are a number of different primary
immunodeficiencies that affect the innate response.
Let’s now look at some of the immunodeficiencies
that affect the adaptive immune response.
Here we can see a common lymphoid progenitor
that is going to develop into T-cells.
So listed here are a number of genes that if they’re
not functioning, the product of those genes is
not produced, and therefore you can’t progress from
this common lymphoid progenitor to a pro-T cell.
So the gamma C-chain which is a component of six interleukin
receptors, the IL-7 receptor α-chain, the IL-2 receptor
α-chain, JAK3, ADA, PNP, can all result in this inability to
produce pro-T cells; a block in the differentiation pathway.
A number of other genes which you can see
listed here, if they’re not functioning, there
will be a block in the progression from pro-T
to pre-T cell development within the thymus.
And eventually in a normal situation,
these pre-T cells will develop into double
positive T-cells and then into single
positive, either CD4 or CD8 T-cells.
And again there are a number of gene defects that you can
see listed here that will result either in a total absence
of both CD4 and CD8 T-cells, or in some cases the CD4
T-cells will be blocked or the CD8 T-cells will be blocked.
What about B-cell maturation?
Well again we have a situation where a common
lymphoid progenitor is going to develop into B-cells.
Mutations in the gene for adenosine
deaminase or purine nucleoside
phosphorylase (PNP) will result in
an inability to produce pro-B cells.
A very large number of mutations will lead in a block
that the pro-B cell cannot reach the pre-B cell stage.