The potential role of interleukin-37 in infectious diseases.

Interleukin-37 (IL-37) is a newly introduced cytokine to interleukin-1 family. Many studies have demonstrated that IL-37 owns immunosuppressive effects against both innate and acquired immune responses via inhibition of several inflammatory mediators. Thence, IL-37 has anti-inflammatory action in some diseases including cancer, autoimmune diseases, cardiovascular diseases and infectious diseases. Recent investigations have reported the important role of IL-37 in immunity against viral, bacterial and fungal infections as they prevent inappropriate immune activation and suppress the inflammation induced by these infectious agents. Thus, IL-37 could play a crucial role in protecting host tissues from injury during infections by damping excessive inflammatory reactions. However, the precise roles of IL-37 in infectious diseases remain largely unknown. The current review shed light on the pivotal role of IL-37 in infectious diseases such as the human immunodeficiency virus-1 (HIV-1), viral myocarditis, hepatitis C virus (HCV), hepatitis B virus (HBV), tuberculosis, leprosy, pneumococcal pneumonia, listeria infection, aspergillosis, candidiasis and eumycetoma. In conclusion, this review reported that IL-37 has a crucial role in reducing infection-associated inflammation and has a good impact on inflammation-induced pathology. However, tight regulation that achieved balance between effector immune responses that required for pathogen elimination and limited tissue damage that resulted from excessive inflammation should be existed in the potential IL-37 therapy to prevent clinical complications of a disease.

The recurrence of leprosy reactional episodes could be associated with oral chronic infections and expression of serum IL-1, TNF-alpha, IL-6, IFN-gamma and IL-10.

The aim of this study was to determine whether the presence of leprosy reactional episodes could be associated with chronic oral infection. Thirty-eight leprosy patients were selected and divided into 2 groups: group I - 19 leprosy patients with oral infections, and group II - 19 leprosy patients without oral infections. Ten patients without leprosy, but presenting oral infections, were assigned to the control group. Leprosy patients were classified according to Ridley and Jopling classification and reactional episodes of the erythema nodosum type or reversal reaction were identified by clinical and histopathological features associated with serum IL-1, TNF-alpha, IL-6, IFN-gamma and IL-10 levels. These analyses were performed immediately before and 7 days after the oral infection elimination. Patients from group I presenting oral infections reported clinical improvement of the symptoms of reactional episodes after dental treatment. Serum IL-1, TNF-alpha, IL-6, IFN-gamma and IL-10 levels did not differ significantly before and after dental treatment as determined by the Wilcoxon test (p>0.05). Comparison of the 2 groups showed statistically significant differences in IL-1 and IL-6 at baseline and in IL-1, IL-6 and IL-10 on the occasion of both collections 7 days after therapy. Serum IL-6 and IL-10 levels in group I differed significantly at baseline compared to control (Mann-Whitney test; p<0.05). These results suggest that oral infection could be involved as a maintenance factor in the pathogenesis of leprosy reactional episodes.

The recurrence of leprosy reactional episodes could be associated with oral chronic infections and expression of serum IL-1, TNF-á, IL-6, IFN-ã and IL-10

The aim of this study was to determine whether the presence of leprosy reactional episodes could be associated with chronic oral infection. Thirty-eight leprosy patients were selected and divided into 2 groups: group I - 19 leprosy patients with oral infections, and group II - 19 leprosy patients without oral infections. Ten patients without leprosy, but presenting oral infections, were assigned to the control group. Leprosy patients were classified according to Ridley and Jopling classification and reactional episodes of the erythema nodosum type or reversal reaction were identified by clinical and histopathological features associated with serum IL-1, TNF-?, IL-6, IFN-? and IL-10 levels. These analyses were performed immediately before and 7 days after the oral infection elimination. Patients from group I presenting oral infections reported clinical improvement of the symptoms of reactional episodes after dental treatment. Serum IL-1, TNF-?, IL-6, IFN-? and IL-10 levels did not differ significantly before and after dental treatment as determined by the Wilcoxon test (p>0.05). Comparison of the 2 groups showed statistically significant differences in IL-1 and IL-6 at baseline and in IL-1, IL-6 and IL-10 on the occasion of both collections 7 days after therapy. Serum IL-6 and IL-10 levels in group I differed significantly at baseline compared to control (Mann-Whitney test; p<0.05). These results suggest that oral infection could be involved as a maintenance factor in the pathogenesis of leprosy reactional episodes.

O objetivo deste estudo foi determinar se os episódios reacionais da hanseníase podem estar associados a infecções orais crônicas. Trinta e oito pacientes com hanseníase foram selecionados e divididos em dois grupos: grupo I & 19 pacientes com hanseníase apresentando infecções orais, e grupo II & 19 pacientes com hanseníase sem infecções orais. Os pacientes foram classificados, quanto à forma clínica da doença, de acordo com Ridley and Jopling, e os episódios reacionais, tipo eritema nodoso e reação reversa, foram identificados pelas características clínicas, histopatológicas associadas à quantificação no soro de IL-1, TNF-?, IL-6, IFN-? e IL-10. Estas analises foram realizadas imediatamente antes e 7 dias após a resolução dos focos de infecção. Pacientes do grupo I aprentando infecções orais relataram melhora clínica dos sintomas dos episódios reacionais após o tratamento odontológico. Os níveis séricos de IL-1, TNF-?, IL-6, IFN-? e IL-10 não diferiram significantemente antes e após o tratamento odontológico, como determinado pelo teste Wilcoxon (p>0,05). As comparações entre os grupos mostrou diferenças estatisticamente significantes nos níveis de IL-1 e IL-6 na coleta inicial e nos níveis de IL-1, IL-6 e IL-10 nas duas coletas 7 dias após o tratamento (teste Mann-Whitney; p<0,05). Estes resultados sugerem que infecções orais estão envolvidas na patogênese dos episódios reacionais da hanseníase, como fatores mantenedores.

Impaired maturation and function of dendritic cells by mycobacteria through IL-1beta.

Dendritic cells (DC) are pivotal for initiation and regulation of innate and adaptive immune responses evoked by vaccination and natural infection. After infection, mycobacterial pathogens first encounter monocytes, which produce pro-inflammatory cytokines, including IL-1beta, TNF-alpha and IL-6. The role of these cytokines in DC maturation remains incompletely understood. Here, we show that maturation of DC from monocytes was impaired by pretreatment of monocytes with low doses of IL-1beta. Under these conditions, Mycobacterium leprae-infected DC failed to stimulate antigen-specific T cell responses. Expression of CD86 and CD83 and production of IL-12 in response to lipopolysaccharide and peptidoglycan were diminished. In contrast, these DC functions were not impaired by pretreatment with TNF-alpha, IL-6 or IL-10. When monocytes were infected with M. bovis Bacillus Calmette-Guérin, and subsequently differentiated to DC, the activity of these DC was suppressed as well. Thus, IL-1beta acts at early stages of differentiation of DC and impairs biological functions of DC at later stages. Therefore, production of IL-1beta by mycobacteria-infected antigen-presenting cells counteracts effective stimulation of innate and adaptive immune responses.

Spontaneous apoptosis in peripheral blood mononuclear cells of leprosy patients: role of cytokines.

Peripheral blood mononuclear cells from leprosy patients underwent spontaneous apoptosis upon culture for 24 h. The apoptosis was inhibited by anti-TNFalpha antibodies and to a certain extent by anti-IL-1alpha and IL-6, thus showing that T(H)2-type cytokines (mainly TNFalpha) are responsible for inducing apoptosis. This cytokine-mediated apoptosis could be inhibited by ionomycin and zinc, thereby suggesting that these metal ions can be used to decrease the levels of these inflammatory cytokines in various diseases.