Ccd

CCD stands for the acronym "cross reactive carbohydrate determinant" or cross reactive carbohydrate determinant.

The sugar structures of proteins from insect venoms and plants are very similar. This leads to the fact that antibodies against these cross-reactive carbohydrate determinants (CCD) bind to almost all glycoproteins from plants or insects (toxins). The CCDs themselves do not cause allergic reactions.

However, anti-CCD IgE present in samples provides false-positive IgE results in allergy diagnostics due to their broad cross-reactivity in serum.
Classic CCDs are found in pollen, plant foods, arthropods, molluscs and some pathogenic helminths, but not in humans. The well studied carbohydrate determinants are based on the monosaccharides fucose and xylose.

The importance of CCDs was recognized after anaphylactic reactions occurred after the initial application of the biological agent cetuximab. These patients were presensitized to alpha-galactose. Cetuximab carries alpha-galactose in its murine part, so this connection could be explained.

1. Apostolovic D et al (2015) Red meat allergic patients have a selective IgE response to the α-Gal glycan. Allergy 70:1497- 1500.
2. Chung CH et al.(2008) Cetuximab-induced anaphylaxis and IgE specific for galactose-alpha-1,3-galactose. N Engl J Med 358: 1109-1117.
3. Commins SP et al (2009) Anaphylaxis syndromes related to a new mammalian cross-reactive carbohydrate determinant. J Allergy Clin Immunol 124: 652-657.