OBJECTIVE

To investigate the role of dopamine receptor D₁DR and D₂DR in the production of cytokines interleukin-6 (IL-6) and IL-1β by monocytes and macrophages in patients with relapsing-remitting multiple sclerosis (MS).

MATERIAL AND METHODS

Ten patients with relapsing-remitting MS and 10 healthy subjects were examined. The level of IL-6 and IL-1β production was assessed in culture supernatants obtained from CD14⁺ monocytes or macrophages stimulated with interferon-γ (IFN-γ) and lipopolysaccharide (LPS). To study the role of dopamine receptors in the regulation of CD14⁺ monocytes or macrophages, samples of cells were incubated in the presence of specific D₁DR or D₂DR antagonists, after which IFN-γ/LPS were added to the cultures. Levels of cytokines in culture supernatants were measured by enzyme-linked immunosorbent assay.

RESULTS

The production of IL-6 and IL-1β by CD14⁺ monocytes and macrophages was comparable between the groups. Blockade of D₁DR suppressed cytokine production by CD14⁺ monocytes and macrophages in both groups. In contrast, blockade of D₂DR increased the production of cytokines by CD14⁺ monocytes and did not affect cytokine production by macrophages in both groups.

CONCLUSIONS

Targeting of dopaminergic receptors could be considered as an additional mechanism of immunomodulation in MS with both pro- and anti-inflammatory effects on cells of the innate immune system.