Interactions between the hypothalamic-pituitary-adrenal axis and allergic inflammation

Area of Science:

• Immunology
• Endocrinology
• Allergy Research

Background:

• Glucocorticoids are vital for managing allergic conditions like asthma and dermatitis.
• Endogenous cortisol, an adrenal hormone, exhibits a diurnal rhythm and influences allergic inflammation.
• Low cortisol levels may correlate with increased asthma risk.

Purpose of the Study:

• To explore the regulatory role of endogenous cortisol in allergic disease.
• To investigate the impact of cortisol's diurnal rhythm on allergic inflammatory responses.
• To understand the complex interaction between cortisol production and allergic inflammation.

Main Methods:

• Review of existing evidence on glucocorticoid therapy and endogenous cortisol.
• Analysis of studies correlating plasma cortisol levels with lung function and inflammatory cell counts.
• Examination of treatment and challenge studies examining the timing of steroid administration and antigen exposure.

Main Results:

• Lung function and inflammatory cell counts correlate with plasma cortisol levels.
• Evening administration of steroids may be more effective due to lower endogenous cortisol.
• Antigen challenges are less likely to trigger late-phase responses when cortisol levels are high.

Conclusions:

• Endogenous cortisol plays a significant role in regulating allergic inflammation.
• The diurnal rhythm of cortisol influences the efficacy of glucocorticoid therapy.
• A complex feedback loop exists between inflammation and cortisol production, with potential for glucocorticoid resistance.