A novel mechanism for binding of galactose-terminated glycans by the C-type carbohydrate recognition domain in blood dendritic cell antigen 2

Blood dendritic cell antigen 2 (BDCA-2; also designated CLEC4C or CD303) is uniquely expressed on plasmacytoid dendritic cells. Stimulation of BDCA-2 with antibodies leads to an anti-inflammatory response in these cells, but the natural ligands for the receptor are not known. The C-type carbohydrate recognition domain in the extracellular portion of BDCA-2 contains a signature motif typical of C-type animal lectins that bind mannose, glucose, or GlcNAc, yet it has been reported that BDCA-2 binds selectively to galactose-terminated, biantennary N-linked glycans. A combination of glycan array analysis and binding competition studies with monosaccharides and natural and synthetic oligosaccharides have been used to define the binding epitope for BDCA-2 as the trisaccharide Galβ1–3/4GlcNAcβ1–2Man. X-ray crystallography and mutagenesis studies show that mannose is ligated to the conserved Ca2+ in the primary binding site that is characteristic of C-type carbohydrate recognition domains, and the GlcNAc and galactose residues make additional interactions in a wide, shallow groove adjacent to the primary binding site. As predicted from these studies, BDCA-2 binds to IgG, which bears galactose-terminated glycans that are not commonly found attached to other serum glycoproteins. Thus, BDCA-2 has the potential to serve as a previously unrecognized immunoglobulin Fc receptor

Venetoclax ramp-up strategies for chronic lymphocytic leukaemia in the United Kingdom: a real world multicentre retrospective study

This retrospective, observational study evaluated patterns of inpatient versus outpatient tumour lysis syndrome (TLS) monitoring during venetoclax ramp-up in 170 patients with chronic lymphocytic leukaemia. The primary outcome was clinical/biochemical TLS. Two clinical and four biochemical TLS occurred (4.1%). Five of the six events occurred in high-risk patients, four occurred at 20 mg dose and three at the 6-h time-point. Inpatient versus outpatient TLS rates within the high-risk subgroup were 15% and 8%. Risk category was the only predictor of TLS events in multivariate analysis. Outpatient escalation did not associate with clinically meaningful TLS events, suggesting outpatient escalation has manageable associated TLS risks, including in high-risk cohorts. These observations require confirmation in larger studies