Idiopathic CD4+ lymphocytopenia

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. It is widely believed that there is more than one cause.{{cite journal |doi-access=free

Pathophysiology

The loss of CD4+ T cells appears to be through apoptosis.{{cite journal

Diagnosis

The mandatory criteria for diagnosis of idiopathic CD4+ lymphocytopenia include:

• 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. 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.{{cite journal

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.

Treatment

Fludarabine-based hematopoietic stem cell transplantation (HSCT) has shown to be a feasible treatment for ICL.{{Cite journal

Prognosis

In contrast to the CD4+ cell depletion caused by HIV, in general, patients with idiopathic CD4 lymphocytopenia have a good prognosis.{{cite journal

ICL sometimes precedes and may be the first signal of several blood cancers. ICL patients have developed primary effusion lymphoma,{{cite journal |doi-access=free

ICL may indirectly trigger autoimmune diseases. It has been associated with several cases of autoimmune disease Sjögren syndrome.{{cite journal

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.

Epidemiology

ICL is a very rare disease. In 1993, a total of 47 confirmed cases were reported in a survey sponsored by the Centers for Disease Control.

References

References

1. "OMIM Entry - # 615518 - IMMUNODEFICIENCY 13; IMD13".
2. (December 2008). "Idiopathic CD4 lymphocytopenia and opportunistic infection--an update". FEMS Immunol. Med. Microbiol..
3. link. (2011-07-19)
4. UpToDate article on "Techniques and interpretation of measurement of the CD4 cell count in HIV-infected patients", by John G. Bartlett. Accessed 30 Oct 2006.
5. (1993). "Unexplained opportunistic infections and CD4+ T-lymphocytopenia without HIV infection. An investigation of cases in the United States. The Centers for Disease Control Idiopathic CD4+ T-lymphocytopenia Task Force.". N Engl J Med.