Successful Cord Blood Transplantation for Idiopathic CD4⁺ Lymphocytopenia

Abstract

Idiopathic CD4<sup>+</sup> lymphocytopenia (ICL) is the depletion of CD4<sup>+</sup> lymphocytes to <300 cells/mm<sup>3</sup> without human immunodeficiency virus infection or other causes of lymphocytopenia. ICL causes fatal infections; its etiology remains unclear and it lacks consensus regarding therapeutic options. We report the first patient with ICL who had a successful clinical course following a cord blood transplant (CBT). A 45-year-old woman was diagnosed with ICL and underwent partial hepatectomy for an abscess caused by the <i>Mycobacterium avium</i> complex. No specific gene alterations were detected through next generation sequencing-based evaluation. Following a reduced-intensity conditioning (RIC) regimen consisting of fludarabine, busulfan, and 4 Gy total body irradiation, a single-unit CBT was performed. Neutrophils were engrafted on day +14. CD4<sup>+</sup> lymphocyte counts increased to over 300 cells/mm<sup>3</sup> on day +436. After 75 months, she was alive without any sequelae. CBT with an RIC regimen could be a curable treatment option for ICL.

Idiopathic CD4+ T-lymphocytopaenia withFLT1mutation complicated by progressive multifocal leucoencephalopathy and EBV+ polymorphic lymphoproliferative disorder

“…Because of the rarity of ICL, the optimal management of lymphomas in this population is unknown. Reported strategies for pharmacological RI that have shown promise in select cases include IL-219 20 and IL-721 therapy, allogeneic haematopoietic stem cell transplant,22 and, more recently, cord blood transplantation 23. The management of EBV+LPDs in patients with ICL and a history of PML poses a particular challenge, where rituximab and/or chemotherapy could worsen lymphopaenias and lead to JC virus reactivation and worsening PML; in these instances, alternate therapies as detailed above may be favoured.…”