Adalimumab Reprograms M1 Macrophages to Attenuate Th1/Th17 Responses in Behçet's Uveitis and Vogt-Koyanagi-Harada Syndrome.

Proinflammatory M1 macrophage polarization was significantly enhanced in patients with Behçet's uveitis and Vogt-Koyanagi-Harada syndrome.

• Ex vivo analyses were performed on monocyte-derived macrophages from patients with active BU (n=43) and VKH (n=35)
• M1 polarization was assessed using flow cytometry
• This finding was observed in both disease conditions, suggesting a shared macrophage-driven inflammatory mechanism

Adalimumab selectively suppressed M1 macrophage polarization and the production of multiple proinflammatory cytokines.

• Adalimumab suppressed production of tumor necrosis factor-alpha, IL-1β, IL-6, and IL-12
• The suppression was selective for M1 polarization
• Cytokine production was assessed using enzyme-linked immunosorbent assay (ELISA)
• Effect was demonstrated in monocyte-derived macrophages from patients with active BU and VKH

Adalimumab-reprogrammed M1 macrophages promoted CD4+ T cell apoptosis and inhibited Th1/Th17 responses.

• The immunomodulatory cascade was evaluated using coculture systems with healthy donor CD4+ T cells
• Adalimumab did not directly affect T cells; rather, its effects on T cells were mediated indirectly through macrophage reprogramming
• Both Th1 and Th17 cell responses were inhibited downstream of macrophage reprogramming

Adalimumab significantly downregulated the expression of metallothionein members in Behçet's uveitis as a disease-specific mechanism.

• Metallothionein members downregulated included MT1H, MT1G, MT1A, MT1F, MT1E, MT1X, and MT2A
• This downregulation was specific to BU and not observed in VKH
• Findings were identified through integrated transcriptomic and proteomic profiling
• Validated by real-time quantitative polymerase chain reaction and western blot

Adalimumab significantly downregulated SLC39A8 expression in Vogt-Koyanagi-Harada syndrome as a disease-specific mechanism.

• SLC39A8 downregulation was specific to VKH and distinct from the metallothionein pathway identified in BU
• Identified through multi-omics (integrated transcriptomic and proteomic) analysis
• Validated by real-time quantitative polymerase chain reaction and western blot
• These disease-specific mechanisms suggest that adalimumab targets different proteins in BU versus VKH

Adalimumab therapy reversed increased frequencies of CD80+ macrophages and Th1/Th17 cells in the spleen and was associated with remission of uveitis in the experimental autoimmune uveitis (EAU) model.

• In vivo experiments were performed using an experimental autoimmune uveitis (EAU) model
• Adalimumab reduced CD80+ macrophage frequencies in the spleen
• Th1 and Th17 cell frequencies in the spleen were also reduced
• These cellular changes were associated with remission of uveitis in the animal model

Adalimumab's immunomodulatory mechanism operates indirectly on T cells via macrophage reprogramming rather than direct T cell targeting.

• Direct effects of adalimumab on T cells were not observed
• CD4+ T cell apoptosis promotion and Th1/Th17 inhibition were downstream consequences of macrophage reprogramming
• This indirect mechanism was demonstrated using coculture systems with healthy donor CD4+ T cells
• The finding has implications for understanding the drug's mechanism of action in uveitis