A sustained response to low dose interferon‐α in a case of refractory pure red cell aplasia

Abstract

Acquired pure red cell aplasia (PRCA) may be the result of a cellular or humoral autoimmune process. One proposed mechanism is the destruction of erythroid progenitors by self-reactive, cytotoxic T cells or natural killer (NK) cells. These cells normally express MHC class I receptors (KIR) which inhibit cytotoxicity when the target cell expresses the HLA class I antigen(s) they bind. Therefore, loss of these antigens on maturing erythroid progenitors may render them susceptible to destruction by the pathogenic cells. Interferon-alpha (INF-alpha) increases HLA class I expression on hematopoietic precursor cells. Therefore, we initiated a trial of INF-alpha in a patient with refractory PRCA. Following treatment, he developed transfusion independence, and a sustained normal hematocrit. Analysis of bone marrow erythroid cells revealed an increase in expression of HLA class I molecules. INF-alpha should be used in a controlled trial in patients with PRCA to determine its activity and mechanism of action.

Large Granular Lymphocyte Leukemia

“…T cells or NK cells normally express KIRs, which inhibit cytotoxicity when the target cell expresses the specific HLA class I antigen(s). Loss of these antigens on maturing erythroid progenitors makes them susceptible to destruction by the LGL leukemia cells [52,53]. Thrombocytopenia (<150 × 10 9 /l) presents in about 20% of patients [1].…”

Anti-erythropoietin antibody–mediated pure red cell aplasia in a living donor liver transplant recipient treated for hepatitis C virus

“…Retrospective data from European centers have documented varying levels of clinical recovery in patients with PRCA treated with combinations of corticosteroids, cyclophosphamide, intravenous immunoglobulin, cyclosporin, rituximab, or mycophenolate mofetil 23. As an interesting contrast to our case, IFN has been used successfully in the treatment of idiopathic pure red cell aplasia 24…”

Difficulties of lymphoid neoplasia diagnosis in patients with rheumatoid arthritis

“…killer immunoglobulin-like receptor), которые ингибируют цитотоксичность, если клетки-мишени экспрессируют специфические антигены HLA I класса. Потеря этих антигенов на созревающих эритроидных предшественниках делает их восприимчивыми к уничтожению клетками LGL лейкемии [28,29].…”