Idiopathic CD4 lymphocytopenia: Pathogenesis, etiologies, clinical presentations and treatment strategies

Idiopathic CD4 lymphocytopenia (ICL) is a rare condition characterized by an unexplained deficit of circulating CD4 T cells leading to increased risk of serious opportunistic infections. The pathogenesis, etiology, clinical presentation, and best treatment options remain unclear.

To describe the clinical presentation, treatment strategies, and outcome of patients with ICL seen in a single referral center.

In a retrospective study, from January 1993 to January 2014, the demographic characteristics, clinical presentation, and treatments of patients diagnosed with ICL were reviewed.

Twenty-four patients (14 female [58%] and 10 male [42%]) were evaluated. The mean age was 45 ± 17.6 years (range 7-76 years). Mean CD4 and CD8 T-cell counts at the time of diagnosis were 119 ± 84/mm³ (range 4-294/mm³) and 219 ± 258/mm³ (range 7-630/mm³), respectively. Seventeen patients (71%) had opportunistic infections, 4 (17%) had malignancies, and 3 (13%) had unexplained demyelinating disease and neurologic problems. Most patients had normal levels of immunoglobulins. Thirteen patients had abnormally low to absent response to phytohemagglutinin, concanavalin A, and antigens (candida and tetanus). Three patients had resolution of warts and 1 had mycobacterial lung infection on interleukin-2 with increases in CD4 count. The 11 patients on trimethoprim and sulfamethoxazole had no further hospital admissions for infections.

The pathogenesis of ICL remains unclear. Although only some patients are healthy, most patients present with opportunistic infections. There is no known standard treatment aside from prophylactic antibiotics.