Dermal IgG deposits and increase of mast cells in patients with fibromyalgia--relevant findings or epiphenomena?

Skin biopsies from 25 patients with fibromyalgia, 5 healthy controls, 8 patients with rheumatoid arthritis, and 9 patients with local chronic pain after whiplash injury, were examined for the occurrence of IgG deposits and collagen types, using direct and indirect immunofluorescence, and for dermal connective tissue mast cells, using semithin Epon sections. Fibromyalgia skin biopsies had significantly higher values of IgG deposits in the dermis and vessel walls and showed a higher reactivity for collagen III. They also had a higher mean number of mast cells. There was a correlation between the percentage of damaged/degranulated mast cells and the individual IgG immunofluorescence scores. These findings support the hypothesis of neurogenic inflammation involvement in fibromyalgia.