| Stroke or central nervous system event lasting >24 h |
| ACS with recurrent hospitalizations or previous exchange transfusion |
| Recurrent VOC (≥2/y for several years) or recurrent priapism |
| Impaired neuropsychological function and abnormal brain MRI |
| Stage I or II sickle lung disease |
| Sickle nephropathy (moderate or severe proteinuria or GFR 30% to 50% of predicted) |
| Bilateral proliferative retinopathy and major visual impairment in at least 1 eye |
| Osteonecrosis of multiple joints |
| Red cell alloimmunization (≥2 antibodies) during long-term transfusion therapy |
| Stroke or central nervous system event lasting >24 h |
| ACS with recurrent hospitalizations or previous exchange transfusion |
| Recurrent VOC (≥2/y for several years) or recurrent priapism |
| Impaired neuropsychological function and abnormal brain MRI |
| Stage I or II sickle lung disease |
| Sickle nephropathy (moderate or severe proteinuria or GFR 30% to 50% of predicted) |
| Bilateral proliferative retinopathy and major visual impairment in at least 1 eye |
| Osteonecrosis of multiple joints |
| Red cell alloimmunization (≥2 antibodies) during long-term transfusion therapy |