Complex sentence: Idiopathic CD4 + lymphocytopenia (ICL) is a very rare medical syndrome in which the body has too few CD4 + T lymphocytes, which are a kind of white blood cell.
Split into simpler sentences: Idiopathic CD4 + lymphocytopenia (ICL) is a very rare medical syndrome. In this condition, the body has too few CD4 + T lymphocytes, which are a kind of white blood cell.