IL-1α is a unique member in the cytokine family in the sense that the structure of its initially synthesized precursor does not contain a signal peptide fragment (same is known for IL-1β and IL-18).

After processing by the removal of N-terminal amino acids by specific proteases, the resulting peptide is called "mature" form.

Calpain, a calcium-activated cysteine protease, associated with the plasma membrane, is primarily responsible for the cleavage of the IL-1α precursor into a mature molecule.

It is found in substantial amounts in normal human epidermis and is distributed in a 1:1 ratio between living epidermal cells and stratum corneum.

[13][14][15] The constitutive production of large amounts of IL-1α precursor by healthy epidermal keratinocytes interfere with the important role of IL-1α in immune responses, assuming skin as a barrier, which prevents the entry of pathogenic microorganisms into the body.

The essential role of IL-1α in maintenance of skin barrier function, especially with increasing age,[16] is an additional explanation of IL-1α constitutive production in epidermis.

IL1A is found on the surface of senescent cells, where it contributes to the production of senescence-associated secretory phenotype (SASP) factors.

This, plus the presence of large depot of IL-1α precursor in keratinocytes, suggests that locally released IL-1α may play an important role and accelerate wound healing.

[29] The treatment with 50 ng/kg IL-1α from day zero of autologous bone marrow or stem cells transfer resulted in an earlier recovery of thrombocytopenia compared with historical controls.