CD19 negative and dim precursor B-lineage acute lymphoblastic leukemias: real-world challenges in a targeted-immunotherapy era.

Flow cytometric diagnosis and minimal residual disease (MRD) assessment of precursor B-lineage acute lymphoblastic leukemia (B-ALL) are heavily dependent on CD19 based gating strategies. However, this approach is not optimal in the diagnosis and follow-up of CD19 negative or dim B-ALLs. Though CD19 negative B-ALLs are rare, in the current era of CD19 targeted immuno-therapy, CD19 negative B-ALL relapses are frequent.

Selective obliteration of the epidermal calcium gradient leads to enhanced lamellar body secretion.

The epidermal permeability barrier is formed by lipids delivered to the intercellular spaces through the secretion of lamellar bodies. Prior studies have shown that the rate of lamellar body secretion appears to be regulated by the extracellular calcium content of the upper epidermis, which is altered following permeability barrier disruption. To determine directly whether changes in extracellular calcium content in the upper epidermis versus disruption of the barrier regulate lamellar body secretion, we experimentally manipulated the Ca++ content of the upper epidermis by sonophoresis of aqueous solutions containing physiologic Ca++ (and K+) versus ion-free solutions across hairless mouse stratum corneum.