Immunohematologic tolerance of chronic transfusion exchanges with erythrocytapheresis in sickle cell disease.

BACKGROUND: Sickle cell disease (SCD) has become a major public health issue. Hydroxyurea and red blood cell (RBC) transfusion are the cornerstone treatments. Erythrocytapheresis (ECP) is an automated method for transfusion exchange. Given that ECP requires more blood than conventional transfusion, there is concern about alloimmunization and hemolytic transfusion reactions. We evaluate the incidence of hemolytic transfusion reactions and alloimmunization rates in patients receiving conventional blood transfusions and in patients participating in long-term blood exchange programs with ECP. STUDY DESIGN AND METHODS: All hemolytic transfusion reactions and alloimmunizations in SCD patients were recorded over the period 2006 to 2011. Conventional transfusions and ECP were compared. RESULTS: The cohort consisted of 188 SCD patients. The median (±SD) age was 23 (±14) years. The ECP and conventional transfusion groups comprised 49 and 139 patients, respectively. The prevalence of alloimmunization was 33% in the ECP group and 22% in the conventional transfusion group (p = 0.1797). The alloimmunization/RBC unit (RBCU) ratio was lower in the ECP group than in the conventional transfusion group (1.6 and 11.6 per 1000, respectively; p < 0.0001). Although patients in the ECP group received more than 10 times more RBCUs than patients in the conventional transfusion group (206 vs. 19 RBCUs per patient, respectively; p < 0.0001), none of the four recorded hemolytic transfusion reactions (n = 4) occurred. CONCLUSION: Regarding alloimmunization, ECP exhibits a good immunohematologic safety profile relative to conventional transfusion in a large SCD mainly adult cohort.

Immunologic and clinical responses to highly active antiretroviral therapy over 50 years of age. Results from the French Hospital Database on HIV.

OBJECTIVE: To study immunologic and clinical responses to HAART in patients over 50 years old. DESIGN AND METHODS: A prospective cohort study which included 68 hospitals in France. A total of 3015 antiretroviral-naive patients, 401 of whom were aged 50 years or over, were enrolled following initiation of HAART. The influence of age on the mean CD4 cell count increase on HAART was studied by using a two-slope mixed model. Progression, defined by the occurrence of a new AIDS-defining event (ADE) or death, was studied by Cox multivariate analyses. RESULTS: Among patients with baseline HIV RNA above 5 log copies/ml, CD4 mean increase during the first 6 months on HAART was +42.9 x 10(6) cells/l per month in patients under 50 years and +36.9 x 10(6) cells/l per month in patients over 50 years (P < 0.0001); subsequently, the respective monthly changes were +17.9 and +15.6 x 10(6) cells/l per month (P < 0.0001). Similar trends were observed in patients with baseline HIV RNA below 5 log copies/ml, and also after stratification for the baseline CD4 cell count. After a median follow-up of 31.5 months, 263 patients had a new ADE and 44 patients died. After adjustment for baseline characteristics, older patients had a significantly higher risk of clinical progression (hazard ratio (HR) = 1.52 [95% confidence interval (CI), 1.15-2.00]) and were more likely to achieve a viral load below 500 copies/ml [HR = 1.23, (95% CI, 1.11-1.38)]. CONCLUSION: Patients over 50 years of age have an immunologic response to HAART. However, their CD4 cell reconstitution is significantly slower than in younger patients, despite a better virologic response. This impaired immunologic response may explain their higher risk of clinical progression.