Therapeutic hotline. Abatacept: our experience of use in two patients with refractory psoriasis and psoriatic arthritis.

The B7 family of molecules on antigen presenting cells (APCs) regulate T cell activation. They deliver stimulatory signals through CD28 and inhibitory signals through CD152, or cytotoxic T lymphocyte-associated antigen-4 (CTLA-4). CTLA4Ig (abatacept) is a soluble chimeric protein consisting of the extracellular domain of human CD152 linked to the modified Fc portion of human IgG1.

Increased apoptosis in cystinotic fibroblasts and renal proximal tubule epithelial cells results from cysteinylation of protein kinase Cdelta.

Cystinosis is a rare genetic disease characterized by defective lysosomal cystine transport and increased lysosomal cystine. How lysosomal cystine causes the lethal nephropathic phenotype is unknown. It was shown recently that cultured fibroblasts and renal proximal tubule epithelial cells whose lysosomes are cystine-loaded display a two-fold or greater increase in apoptosis after both intrinsic and extrinsic stimuli.