Idiopathic CD4+ lymphocytopenia (ICL) is a rare medical syndrome in which the body has too few CD4+ T lymphocytes, which are a kind of white blood cell.[2] ICL is sometimes characterized as "HIV-negative AIDS", though, in fact, its clinical presentation differs somewhat from that seen with HIV/AIDS.[3] People with ICL have a weakened immune system and are susceptible to opportunistic infections, although the rate of infections is lower than in people with AIDS.[4]
| Idiopathic CD4+ lymphocytopenia | |
|---|---|
| Other names | Immunodeficiency 13 |
 | |
| Idiopathic CD4+ lymphocytopenia is inherited via autosomal dominant manner[1] | |
| Specialty | Immunology |
Cause
The cause of ICL, like all idiopathic conditions, is unknown. It does not appear to be caused by a transmissible agent, such as a virus.[5] It is widely believed that there is more than one cause.[6][non-primary source needed]
Pathophysiology
The loss of CD4+ T cells appears to be through apoptosis.[4][7] The accelerated deaths of the T cells is likely driven by crosslinking T cell receptors.[7]
Diagnosis
The mandatory criteria for diagnosis of idiopathic CD4+ lymphocytopenia include:[8]
- Low numbers of CD4+ cells, on two or more measurements over at least six weeks:
- CD4 cell count less than 300 cells per microliter, or
- Less than 20% of T lymphocytes are CD4+
- Laboratory evidence of lack of HIV infection
- Absence of any alternative explanation for the CD4 lymphocytopenia
A one-time finding of low CD4+ cells is usually associated with a recent infection and resolves on its own.[7] Alternative explanations for the low CD4 counts include conditions such as blood cancers (aleukemia), treatment with chemotherapy, immunosuppressive medications, or other medications that suppress or kill T cells, infections, and problems with blood production.[2][9][non-primary source needed]
All criteria must be fulfilled for a diagnosis of ICL. In addition, if these findings are present but combined with other significant findings, such as anemia or thrombocytopenia, then other diagnoses must be considered[citation needed].
Treatment
Fludarabine-based hematopoietic stem cell transplantation (HSCT) has shown to be a feasible treatment for ICL.[10][non-primary source needed]
Prognosis
In contrast to the CD4+ cell depletion caused by HIV, in general, patients with idiopathic CD4 lymphocytopenia have a good prognosis.[6][11][12][13][non-primary source needed] The decline in CD4+ T-cells in patients with ICL is generally slower than that seen in HIV-infected patients.[3] The major risk to people with ICL is unexpected infections, including cryptococcus, atypical mycobacterial and Pneumocystis jiroveci pneumonia (PCP). The condition may also resolve on its own.[14]
ICL sometimes precedes and may be the first signal of several blood cancers. ICL patients have developed primary effusion lymphoma,[15][non-primary source needed][16] primary leptomeningeal lymphoma,[9] diffuse large cell lymphoma,[17][non-primary source needed] MALT lymphoma,[18] and Burkitt's lymphoma,[19] among others.
ICL may indirectly trigger autoimmune diseases. It has been associated with several cases of autoimmune disease Sjögren syndrome.[4][20]
Because all of the reported autoimmune diseases and lymphomas involve B cells, one hypothesis proposes that ICL's narrow T cell repertoire predisposes the immune system to B cell disorders.[4]
Epidemiology
ICL is a very rare disease.[2] In 1993, a total of 47 confirmed cases were reported in a survey sponsored by the Centers for Disease Control.[21]
References
External links
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