CD25 deficiency or interleukin 2 receptor alpha deficiency is an immunodeficiency disorder associated with mutations in the
interleukin 2 receptor alpha (CD25) (IL2RA) gene. The mutations cause
expression of a defective α chain or complete absence thereof, an essential part of high-affinity
interleukin-2 (IL-2) receptors. The result is a syndrome described as
IPEX-like
or a
SCID.
In one patient, deficiency of CD25 on
CD4+ lymphocytes
In molecular biology, CD4 (cluster of differentiation 4) is a glycoprotein that serves as a co-receptor for the T-cell receptor (TCR). CD4 is found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic ce ...
caused significantly impaired sensitivity to IL-2. This was demonstrated by a lack of measurable response in anti-inflammatory
interleukin-10
Interleukin 10 (IL-10), also known as human cytokine synthesis inhibitory factor (CSIF), is an anti- inflammatory cytokine. In humans, interleukin 10 is encoded by the ''IL10'' gene. IL-10 signals through a receptor complex consisting of two IL-10 ...
(IL-10) secretion to low-dose IL-2 incubation. Greatly reduced IL-10 secretion compared to healthy humans results in a syndrome comparable to IPEX syndrome, a type of autoimmunity which is caused by
FoxP3 transcription factor dysfunction. In addition to IPEX-like symptoms, CD25 deficiency increases susceptibility to viral infections
and possibly fungal and bacterial infections.
As IL-2 is an important inducer of
lymphocyte
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic ad ...
proliferation, the absence of highly sensitive IL-2 receptors may also significantly hinder activation and
clonal expansion of
CD8+ and CD4+ lymphocytes and
NK cells.
One case also reported the absence of
CD1
CD1 (cluster of differentiation 1) is a family of glycoproteins expressed on the surface of various human antigen-presenting cells. They are related to the class I MHC molecules, and are involved in the presentation of lipid antigens to T ...
, a
MHC-like glycoprotein involved in the presentation of
lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...
antigens
In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. ...
to T cells, in a CD25 deficient patient. Furthermore, chronic upregulation of anti-
apoptotic Bcl-2 in
thymocytes
A Thymocyte is an immune cell present in the thymus, before it undergoes transformation into a T cell. Thymocytes are produced as stem cells in the bone marrow and reach the thymus via the blood. Thymopoiesis describes the process which turns thymo ...
was also described possibly allowing autoreactive T cells to escape deletion.
References
External links
{{Immune disorders
Noninfectious immunodeficiency-related cutaneous conditions