Purpose of review: Idiopathic CD4+ lymphocytopenia (ICL) is defined by the reduction of the main lymphocyte subtype in peripheral blood and CD4+ T cells below 300/μl in the absence of any secondary known causes of lymphopenia, including viral causes. The present review aims to state the latest available data on clinical, pathological and therapeutic aspects related to ICL, published from 1990 to 2014. The last observed clinical presentation and complications of ICL patients are described. The latest findings and possible mechanisms involved in the development of ICL features are included in the present review; however, pathogenesis of ICL has remained mainly obscured. Finally, recent therapeutic efforts considered in ICL patients are discussed.
Recent findings: In spite of the serious complications ICL has on the patients’ quality of life, data on clinical, etiopathological and therapeutic behavior for ICL are very limited. On one side, an abnormal blood cell count may be the sole presentation; however, occurrence of disseminated malignant tumors is not uncommon in patients. Recent findings highlight the role of cytokines, especially interleukin-2, on features such as phenotype severity and responsiveness of the condition to therapy. In addition, some studies have suggested that a defect in hematopoietic stem cells may be involved in disease progression, an idea that is supported by the success of bone marrow transplantation in acquiring persistent remissions in ICL patients.
Summary: ICL is a hematologic condition of increasing importance due to its diverse clinical and pathological spectrum. Molecular studies have shown the presence of mutations involved in lymphocyte development as potential factors that may contribute to ICL occurrence. ICL patients could present either with common infections or really serious malignant conditions. The role of cytokines, especially interleukin-2, has emerged as one of the main possible mechanisms involved in clinical and pathological behavior of ICL. Today, the main therapeutic approaches are controlling life-threatening infections and underlying disorders along with efforts to cure ICL through rising CD4+ cell counts using cytokine interventions and transplantation.
aDivision of Human Genetics, Immunology Research Center, Avicenna Research Institute
bDepartment of pathology, Faculty of medicine, Zabol University of medical sciences
cMedical Genetics Research Center, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran
Correspondence to Mohammad Reza Abbaszadegan, MT(ASCP), PhD, Adjunct Professor, George Mason University Head, Medical Genetics Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad 9196773117, Iran. Tel/. fax: +98 513 7112343; e-mail: firstname.lastname@example.org