Background
Anemia is a common feature in HIV infection. An increased sensitivity of lymphocytes from HIV patients to lysis by complement has been correlated with a decreased expression of CD55 and CD59 in their surface. The aim of this study was to evaluate CD55/CD59 presence in red cells of HIV patients and explore possible correlations with clinical parameters.
Material and Method
CD55/CD59 expression was evaluated in erythrocytes of 37 patients (30M/7F, median age: 39 years) with HIV infection (25 also having hemophilia), 121 controls, and 8 PNH patients using the sephacryl-gel microtyping system. Ham and sucrose tests were also performed.
Results
Anemia was present in 14/37 (37%) HIV patients. Interestingly, all HIV patients had deficient CD55 and/or CD59 erythrocytes: 8 (21%) for both CD55 andCD59 and 29 (78%) isolated CD55 and/or CD59 negativity. Deficient erythrocytes did not account for more than 10% of the total in the vast majority of patients. In controls, only 2 (1%) had red cells with double CD55/CD59 negativity and 3 (2%) had isolated deficiency. All PNH patients had a simultaneous CD55/CD59 deficiency. Positive Ham and sucrose tests were found only in PNH. There was no correlation between the presence of deficient CD55/CD59 erythrocytes and anemia, hemolysis, antiretroviral therapy, CD4+ counts, viral load, or concomitant hepatitis C infection in HIV patients.
Conclusions
This study provides evidence supporting the presence of erythrocytes with CD55 and/or CD59 deficiency in HIV. Further studies using molecular techniques will be required to clarify the exact role of this deficiency in HIV patients.

Keywords: Hemophilia A - complications, Hemoglobinuria, Paroxysmal - complications, HIV Infections - blood, Gene Expression Regulation, Erythrocytes - metabolism, Complement System Proteins, Phenotype, Hepatitis C - complications, Antigens, CD59 - blood, Antigens, CD55 - blood