B3GAT1

Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase 1 is an is_associated_with::enzyme that in humans is encoded by the B3GAT1 is_associated_with::gene.

In is_associated_with::immunology, the CD57 is_associated_with::antigen (CD stands for is_associated_with::cluster of differentiation) is a is_associated_with::carbohydrate which is also called HNK1 (human natural killer-1) or LEU7. It is expressed as a carbohydrate is_associated_with::epitope that contains a is_associated_with::sulfoglucuronyl residue in several is_associated_with::adhesion molecules of the nervous system.

Immunohistochemistry
In anatomical pathology, CD57 (immunostaining) is similar to CD56 for use in differentiating is_associated_with::neuroendocrine tumors from others. Using is_associated_with::immunohistochemistry, CD57 molecule can be demonstrated in around 10 to 20% of is_associated_with::lymphocytes, as well as in some epithelial, neural, and chromaffin cells. Among is_associated_with::lymphocytes, CD57 positive cells are typically either is_associated_with::T cells or NK cells, and are most commonly found within the germinal centres of is_associated_with::lymph nodes, tonsils, and the spleen.

There is an increase in the number of circulating CD57 positive cells in the blood of patients who have recently undergone organ or tissue transplants, especially of the bone marrow, and in patients with is_associated_with::HIV. Increased CD57+ counts have also been reported in is_associated_with::rheumatoid arthritis and is_associated_with::Felty's syndrome, among other conditions.

Neoplastic CD57 positive cells are seen in conditions as varied as large granular lymphocytic leukaemia, is_associated_with::small-cell carcinoma, thyroid carcinoma, and neural and is_associated_with::carcinoid tumours. Although the antigen is particularly common in carcinoid tumours, it is found in such a wide range of other conditions that it is of less use in distinguishing these tumours from others than more specific markers such as is_associated_with::chromogranin and NSE.