Distinct Patterns of IL-Lα and IL-Lβ Organ Distribution-A Possible Basis for Organ Mechanisms of Innate Immunity

The findings presented in this work show that IL-1α and IL-1β display differential and even inverse patterns of organ expression, demonstrated most clearly at old age and beyond the realm of immunology. Based on these IL- 1α /IL- 1β specific patterns of organ expression and considering the distinct physiological function of various organs, IL-1 á may be highlighted more as a potent anti-infectious/toxic agent, which can initiate and potentiate prolonged inflammatory responses, apparently mainly based on activation of cellular immunity. In contrast, it possibly appears that IL-1α may be involved in more restricted inflammatory responses, than conceived before. Other homeostatic functions of both IL-1 molecules can also be envisioned, including for example control of the cell cycle and apoptosis. In this context, diverse and even opposing biological effects of IL-la/IL-lb may be anticipated. The “net” activity of IL-1 in a certain organ may depend on the type of expressed IL-1 and IL-lreceptors, as well as on the locally operant cytokine network. The in vivo interactions between the two IL-1 forms may be of crucial importance to organ homeostasis, especially under the stressful conditions, characterizing old age. Further studies are needed to clarify the full perspective of IL-la and IL-lb roles in organ homeostasis, the understanding and manipulation of which may hopefully lead to development of beneficial therapeutic interventions.