Latin Names & Major Allergens
Since common names vary, the most precise description of a species comes from the Latin name. Latin names come in a speciﬁc format, with the name of the genus, or higher-level group, provided ﬁrst and capitalized, followed by the species name, which is uncapitalized:
Quercus alba = White Oak.
“Quercus” is the general Oak genus, while “alba” refers to the speciﬁc species of Oak.
The Latin name is also the basis for allergenic protein names, such as those for major allergens. A major allergen is an allergen protein that has demonstrated clinical sensitivity in most patients in a population.
While in theory, any molecule can be allergenic. In practice, there are a limited number of molecules that have demonstrated consistent clinical relevance across populations.
The names of these allergenic molecules include the ﬁrst 3 letters of the genus followed by the ﬁrst letter of the species and a chronological number based on the order of discovery. For example, a major allergen of Timothy grass, known as Phleum pratense, is Phl p 5. “Phl p” is simply an abbreviation of the Latin name and “5” is an arbitrary numerical designation. The number chosen does not necessarily reﬂect its allergenic importance.
Generally, there appears to be cross-reactivity between related species of the same genus. For example, Short Ragweed is known as “Ambrosia artemisiifolia” and Giant Ragweed is known as “Ambrosia triﬁda”. These are both members of the genus “Ambrosia” and exhibit cross-reactivity. In this case, the common name makes this intuitive, but it can be confusing. For example, Mugwort is known as “Artemisia vulgaris” and Sagebrush is known as “Artemisia tridentata”. Though they have seemingly unrelated common names, they are both members of the same genus “Artemisia” and are highly cross-reactive.
Beyond a common genus, there can also be signiﬁcant cross-reactivity between seemingly unrelated species of the same family. For example, Birch (genus “Betula”) and Alder (genus “Alnus”), have different Latin names but are highly cross-reactive since they are both members of the higher-level family “Betulaceae”.
In sensitive patients it may be redundant (and possibly excessive) to test and treat with multiple representatives from the same allergenic group since they have overlapping allergenic proteins.
When planning your diagnostic panel, it may be useful to pick the most regionally relevant member of each of the major allergenic families.
In choosing immunotherapy treatments, it may be useful and more efﬁcient to choose only the most clinically signiﬁcant allergen in a group of related allergens based on skin test reactivity. This representative species may provide immunological coverage for related species while minimizing the patient’s exposure to redundant allergens.