The invention relates to a biodegradable microparticle having a diameter between 0.2 and 3.5 micrometer and comprising a pharmaceutically effective amount of at least one small heat-shock protein that induces IL-10 production in macrophages, said small heat-shock protein comprising an amino acid sequence identity of at least 50% to any of the sequences listed as SEQ ID NOs: 1 and 12-26.