The cause of<unk> , like all<unk>  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.
Idiopathic CD4+ lymphocytopenia
Persistent polyclonal B-cell lymphocytosis
Monoclonal B-cell lymphocytosis
X-linked lymphoproliferative disease
Thymic hypoplasia
Dermatopathic lymphadenopathy
Adult-onset immunodeficiency syndrome
CD25 deficiency