Arch Hellen Med, 30(6), November-December 2013, 714-729
"PNH-like" erythrocyte populations in patients with autoimmune connective tissue disorders
J.V. Asimakopoulos,1 E. Terpos,2 L. Papageorgiou,1 O. Kampouropoulou,3 D. Christoulas,2
OBJECTIVE To evaluate the presence of CD55 and/or CD59 in the erythrocytes of patients with autoimmune disorders and their possible correlation with the demographic characteristics, clinical features, complete blood count (CBC) and treatment administered.
METHOD CD55 and CD59 expression was evaluated in the erythrocytes of 113 patients with autoimmune connective tissue disorders using the sephacryl-gel microtyping system. Control groups consisting of 121 healthy blood donors of similar age and gender, and 10 patients with paroxysmal nocturnal hemoglobinuria (PNH) were also studied. In all samples with CD55- and/or CD59-negative erythrocytes Ham and sucrose tests were also performed.
RESULTS Of the 113 patients, 104 (92%) demonstrated "PNH-like" erythrocyte populations: 47 (41.6%) with concomitant deficiency of CD55 and CD59, 50 (44.2%) with isolated deficiency of CD55 and 6 (6.2%) with isolated deficiency of CD59. In healthy donors, only 2 (1.6%) had red cells with concomitant CD55/CD59 negativity and 3 (2.4%) with isolated CD55 or CD59 deficiency. All patients with PNH exhibited simultaneous CD55/CD59 deficiency. There was no clinical or laboratory evidence of hemolysis in any patient. Positive Ham and sucrose tests were found only in patients with PNH. No association was found between the presence of "PNH-like" red cell populations and cytopenia or any specific treatment.
CONCLUSIONS This study provides evidence supporting the presence of "PNHlike" erythrocytes in patients with autoimmune connective tissue disorders. It was demonstrated that the presence of "PNH-like" population may affect the hematological profile, in these patients. Further studies will be required to clarify the pathophysiological mechanisms of this phenomenon.
Key words: DAF, MIRL, Paroxysmal nocturnal hemoglobinuria, Rheumatoid arthritis, Systemic lupus erythematosus.