[Mechanism of action of nasal glucocorticosteroids in the treatment of allergic rhinitis. Part 2: Practical aspects of application]

Glucocorticoids-All-Rounders Tackling the Versatile Players of the Immune System

Glucocorticoids regulate fundamental processes of the human body and control cellular functions such as cell metabolism, growth, differentiation, and apoptosis. Moreover, endogenous glucocorticoids link the endocrine and immune system and ensure the correct function of inflammatory events during tissue repair, regeneration, and pathogen elimination via genomic and rapid non-genomic pathways. Due to their strong immunosuppressive, anti-inflammatory and anti-allergic effects on immune cells, tissues and organs, glucocorticoids significantly improve the quality of life of many patients suffering from diseases caused by a dysregulated immune system. Despite the multitude and seriousness of glucocorticoid-related adverse events including diabetes mellitus, osteoporosis and infections, these agents remain indispensable, representing the most powerful, and cost-effective drugs in the treatment of a wide range of rheumatic diseases. These include rheumatoid arthritis, vasculitis, and connective tissue diseases, as well as many other pathological conditions of the immune system. Depending on the therapeutically affected cell type, glucocorticoid actions strongly vary among different diseases. While immune responses always represent complex reactions involving different cells and cellular processes, specific immune cell populations with key responsibilities driving the pathological mechanisms can be identified for certain autoimmune diseases. In this review, we will focus on the mechanisms of action of glucocorticoids on various leukocyte populations, exemplarily portraying different autoimmune diseases as heterogeneous targets of glucocorticoid actions: (i) Abnormalities in the innate immune response play a crucial role in the initiation and perpetuation of giant cell arteritis (GCA). (ii) Specific types of CD4+ T helper (Th) lymphocytes, namely Th1 and Th17 cells, represent important players in the establishment and course of rheumatoid arthritis (RA), whereas (iii) B cells have emerged as central players in systemic lupus erythematosus (SLE). (iv) Allergic reactions are mainly triggered by several different cytokines released by activated Th2 lymphocytes. Using these examples, we aim to illustrate the versatile modulating effects of glucocorticoids on the immune system. In contrast, in the treatment of lymphoproliferative disorders the pro-apoptotic action of glucocorticoids prevails, but their mechanisms differ depending on the type of cancer. Therefore, we will also give a brief insight into the current knowledge of the mode of glucocorticoid action in oncological treatment focusing on leukemia.

Clinical value of the high expression of corticosteroid receptor-beta mRNA in the nasal mucosa of steroid-resistant patients with allergic rhinitis

PURPOSE

This study investigated clinical values of corticosteroid (CS) receptor α and β in the nasal mucosa of patients with allergic rhinitis (AR) by determining CS receptor α and β mRNA expression following steroid treatment.

PROCEDURES

Among 120 outpatients, 65 had persistent AR, including 36 being sensitive to steroid treatment (steroid-sensitive group) and 29 being resistant to steroid treatment (steroid-resistant group). In addition, 30 patients with deflection of the nasal septum alone, which was corrected by surgery, were recruited as controls. Fluorescent quantitative reverse transcription-PCR was used to quantify CS receptor α and β mRNA expression in the nasal mucosa of patients.

RESULTS

Results showed that CS receptor β mRNA expression in the nasal mucosa was significantly higher in the steroid-resistant group [(5.62 ± 1.28) × 102 copies/µg] compared with the steroid-sensitive [(4.62 ± 0.48) × 102 copies/µg, t = -6.67, p < 0.01] and control [(5.32 ± 0.55) × 102 copies/µg, t = -8.29, p < 0.01] groups. There were significant differences in the mRNA expression ratio of CS receptor α to β between the steroid-sensitive (658.32 ± 65.16) and steroid-resistant (525.70 ± 68.10) groups (t = 10.16, p < 0.01).

CONCLUSION

A high level of CS receptor β mRNA but a low level of CS receptor α mRNA expression in patients with steroid-resistant AR indicates steroid resistance. CS receptor β plays a role in evaluating the effects of steroid therapy for AR.