Measures to reduce red cell use in patients with sickle cell disease requiring red cell exchange during a blood shortage.

The COVID-19 pandemic has created major disruptions in health care delivery, including a severe blood shortage. The inventory of Rh and K antigen-negative red cell units recommended for patients with hemoglobinopathies became alarmingly low and continues to be strained. Because patients with sickle cell disease requiring chronic red cell exchange (RCE) incur a large demand for red cell units, we hypothesized that implementation of 2 measures could reduce blood use.

Red cell transfusion and alloimmunization in sickle cell disease.

Red cell transfusion remains a critical component of care for acute and chronic complications of sickle cell disease. Randomized clinical trials demonstrated the benefits of transfusion therapy for prevention of primary and secondary strokes and postoperative acute chest syndrome. Transfusion for splenic sequestration, acute chest syndrome, and acute stroke are guided by expert consensus recommendations.

Semaphorin 4A is dynamically regulated during thymocyte development in mice.

Semaphorins are important regulators of peripheral T and B-cell mediated immune responses in mice and humans. Modulatory roles of semaphorins in T cell development are also being characterized. We carefully analyzed the gene expression and protein levels of semaphorins 4A, 4D, and 7A at various developmental stages of T cell maturation in the thymus of C57BL/6 mice.