Table 1.

The role of IL-37 in allergic diseases. Clinical cases

Pathology	Study design	Detection method	Result	Reference
AtD	55 adult patients with moderate and severe AtD	Evaluation of IL-37b in sera samples using ELISA, evaluation of local expression in skin biopsy material by immunohistochemistry.	Serum IL-37 levels are significantly higher in patients with AtD. IL-37 level positively correlated with the severity of AtD symptoms.	[61]
AR	40 children with AR (among them 10 with BA)	Evaluation of IL-37b in sera samples and nasal lavage using ELISA	The level of IL-37b was decreased in serum and nasal lavage in AR. The level of nasal Th2 cytokine was negatively correlated with local expression of IL-37b. Blood levels of ECP, IgE, and eosinophilia were negatively correlated with the level of serum IL-37b. Intranasal administration of a glucocorticosteroid drug led to the induction of IL-37b and a decrease in AR symptoms	[62]
aBA	21 children with aBA	Evaluation of IL-37 in the supernatants of stimulated PBMCs using ELISA	Production of IL-37 by PBMC-stimulated cells is significantly reduced in children with aBA.	[50]
aBA and nBA	92 children, among them 74 with aBA and 18 with nBA	The expression level of IL-37 in stimulated PBMCs was evaluated by RT-PCR	Patients with nBA have an increased level of IL-37, increased number of neutrophils in the blood, and increased level of pro-inflammatory cytokines IL-1β and IL-17.	[64]
BA	40 children with mild and moderate BA	The expression level of IL-37 in serum and sputum was evaluated using ELISA and RT-PCR	The expression of IL-37 mRNA in sputum and its serum level are significantly decreased in BA patients. Suppressed production of pro-inflammatory cytokines TNFα, IL-1β and IL-6 was observed in sputum cells cultured with rIL- 37 after cell stimulation with LPS. Stimulation of CD4+ T cells of the sputum in the presence of IL-37 decreased the production of IL-17.	[65]
BA	40 children with mild to moderate BA	Incubation of sputum cells in the presence of IL-37	The production of TSLP by sputum epithelial cells was significantly decreased in the presence of IL-37.	[66]
AR	32 adults with AR	Analysis of CD4+ and T cells isolated from PBMCs and cultured with rIL-37	After incubation with IL-37, the production of IL-17 and IL-4 by CD4+ T cells was significantly decreased in patients with AR.	[63]

Note:

AtD – atopic dermatitis;

AR – allergic rhinitis;

ELISA – enzyme-linked immunosorbent assay;

ECP – eosinophil cationic protein;

PBMCs – peripheral blood mononuclear cells;

BA – bronchial asthma;

aBA – allergic bronchial asthma;

nBA – non-allergic bronchial asthma;

RT-PCR – real-time polymerase chain reaction;

rIL-37 – recombinant interleukin-37.