An Observational Case-Control Study of the Anti-Inflammatory Effects of Bromelain on Peripheral Blood Mononuclear Cells from Patients with Systemic Lupus Erythematosus.

Background: Bromelain is a proteolytic enzyme that has been investigated as an adjuvant for treating autoimmune disorders. However, data regarding the role of bromelain in systemic lupus erythematosus is limited. In the present study, we examined the effect of bromelain on the mononuclear cells of SLE patients, precisely its anti-inflammatory properties. Materials and Methods: Peripheral blood mononuclear cells (PBMCs) from SLE patients and healthy controls were stimulated with bromelain (10μg/ml), lipopolysaccharide (10μg/ml), or without any stimulant and cultured for 12 hours. The supernatants were harvested and quantified for IL-1β, TNF-α, IL-6, and IL-17A levels. The mean cytokine levels were compared among different groups using ANOVA and Tukey's post hoc test. Results: Our study revealed that PBMCs of SLE patients (n=41) had significantly higher levels of IL-6 (P=0.0003) and IL-1β (P<0.0001) compared to healthy controls (n=36). When stimulated with lipopolysaccharide, PBMCs of SLE patients showed even higher cytokine levels than healthy controls (IL-6:P<0.0001, TNF-α:P=0.01; IL-1β:P<0.0001). However, the most significant finding was that PBMCs stimulated with bromelain exhibited reduced levels of IL-1β (P<0.0001) and TNF-α (P<0.0001) compared to unstimulated cells of SLE patients. Moreover, cells subjected to lipopolysaccharide and bromelain stimulation displayed lower levels of all cytokines than those stimulated with lipopolysaccharide alone (IL-6:P=0.005, TNF-α:P<0.0001, IL-1β:P<0.0001, IL-17A:P=0.02). Conclusions: The present study highlights the anti-inflammatory role of bromelain in SLE patients by reducing the production of pro-inflammatory cytokine levels in vitro cultured PBMCs derived from SLE patients. Bromelain may be an efficacious adjuvant in managing inflammation in SLE; however, further studies are required.