Evidence Of A Sub-Clinical Ilymphoproliferative Disease In Patients With 'Idiopathic' Autoimmune Hemolytic Anemia

7074 Background: Idiopathic autoimmune hemolytic anemia (AHA), which accounts for about half of cases, is diagnosed in the absence of a concomitant disease. A lymphoproliferative disease is frequently associated or can follow AHA. The aim of this study was to better define the clinical features of 50 cases defined as idiopathic AHA. Methods: Before starting steroid treatment, the following examinations were performed: immunohematologic study; total body CT scan or a chest XR with abdomen ultrasound; HBV and HCV serology; autoantibody screening (anti-nucleous; anti-cardiolipin; anti-gastric parietal cell; anti-beta 2-glycoprotein-I); peripheral blood (PB) immunophenotype. Results: The median age of the 50 patients was 66 years (range: 20–84), 32 patients were females. The immunohematologic study revealed an anti-erythrocyte auto-antibody in all cases (IgG: 27; IgM:15; IgG + IgM: 7; IgA:1). An idiopathic AHA was confirmed in 26 cases (52%), while in 24 (48%) a concurrent disease was diagnosed (tumor: 4; HCV hepatitis: 2; autoimmune disease: 2). In 16 cases (32 %), all with a normal lymphocyte count, the PB immunophenotype revealed the presence of a small B-lymphocyte clone with a CD5+/CD19+, CD23+ phenotype in 3 cases and a CD5+/CD19+, CD23- or CD5-/CD19+, CD23- phenotype in 13. The median number of clonal B lymphocytes in the PB was 0.5 x 109/L (range: 0.03–1.9 x 109/L). Clonality was confirmed by PCR. The same clonal population was detected in the bone marrow aspirate. No other signs ascribable to a lymphoproliferative disease were detected, except for a patient with an enlarged abdominal lymph node. Conclusions: Our findings indicate that about one third of newly diagnosed patients with otherwise defined “idiopathic” AHA show a underlined sub clinical B-lymphocyte clone which may play a role both in the pathogenesis of the autoimmune disorder and in the subsequent occurrence of a lymphoproliferative disease. The detection of such clones should be considered in the diagnostic work-out of patients with AHA. No significant financial relationships to disclose.