# Immunomodulatory Effects of Multi‐Strain Probiotic Capsules for Psoriatic Arthritis: A Pilot Double‐Blind Randomized Controlled Trial

## TL;DR

A 12-week trial found that a multi-strain probiotic reduced inflammation and boosted anti-inflammatory responses in people with psoriatic arthritis.

## Contribution

This study is the first to demonstrate the immunomodulatory effects of a multi-strain probiotic in psoriatic arthritis patients.

## Key findings

- Probiotic use significantly reduced CD4+ IFN-γ T cells and B cells in PsA patients.
- The probiotic group showed increased levels of anti-inflammatory cytokines like IL-10 and TGF-β.
- Probiotics decreased pro-inflammatory IFN-γ while enhancing regulatory cytokines.

## Abstract

Psoriatic arthritis (PsA) is characterized by joint inflammation and is frequently associated with psoriasis. Gut dysbiosis has been implicated in PsA pathogenesis, raising interest in probiotics as potential immunomodulatory agents. In a pilot, double‐blind, randomized, placebo‐controlled trial, 14 adults aged 18–60 years with mild‐to‐moderate psoriatic arthritis (PsA; Disease Activity in Psoriatic Arthritis [DAPSA] < 28) were randomized to receive either probiotic capsules or placebo daily for 12 weeks. The probiotic group received a multi‐strain cocktail with a total concentration of 1 × 109 CFU (including
Lactobacillus rhamnosus, Lactobacillus plantarum, Lactobacillus casei, Lactobacillus helveticus, Lactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus bulgaricus, Lactobacillus gasseri, Bifidobacterium lactis, Bifidobacterium longum, and Streptococcus thermophilus
). The placebo group received lactose‐based inert capsules for the same period. Immune cell populations (CD4+ IFN‐γ T cells, B cells, Th2 cells) and cytokine levels (IFN‐γ, IL‐10, TGF‐β, IL‐4) were assessed. Compared with the placebo, probiotic supplementation resulted in a significant reduction in CD4+ IFN‐γ T cells (6% ± 0.82 vs. 3.6% ± 0.8; p < 0.001), B cells (14.6% ± 1.05 vs. 8.9% ± 1.7; p < 0.0001), and IFN‐γ concentrations (37.5 ± 2.4 pg/mL vs. 29.3 ± 2.6 pg/mL, p = 0.016). In addition, a significant increase was observed in IL‐10 (9.4 ± 2.8 pg/mL vs. 99.89 ± 28.1 pg/mL, p = 0.0032), TGF‐β (18.1 ± 2.7 pg/mL vs. 30.48 ± 7.7 pg/mL, p = 0.0073), and IL‐4 (17.6 ± 6.7 pg/mL vs. 58.3 ± 29.2 pg/mL, p = 0.0117). Changes in Th2 cell levels were not statistically significant (p = 0.54). A multi‐strain probiotic demonstrated promising immunomodulatory effects in PsA by reducing pro‐inflammatory markers and enhancing regulatory cytokines that can be used as a complementary or alternative treatment for PsA patients.

Trial Registration: IRCT20221213056802N1

Psoriatic arthritis (PsA) is a systemic autoimmune disease linked to joint inflammation and skin psoriasis. Gut dysbiosis may contribute to PsA, making probiotic supplementation a potential therapy. In our pilot study, PsA patients received a probiotic cocktail or placebo for 12 weeks. The probiotic group showed reduced inflammatory markers and increased anti‐inflammatory cytokines, suggesting probiotics may offer a complementary natural approach to managing PsA.