Purpose of review: Although 6 years have elapsed since the initial report describing the presence of microchimeric cells in affected tissues from patients with systemic sclerosis, a mechanism by which these cells might contribute to the pathogenesis of the disease is still unknown. This article reviews the published literature related to the possible role of microchimeric cells in the pathogenesis of systemic sclerosis.
Recent findings: Numerous studies have reported the identification or quantification of microchimeric cells in the peripheral blood or tissues from systemic sclerosis patients; however, only one study to date has investigated their function. Recent investigations have demonstrated microchimeric cells in the clinically uninvolved tissues from patients with systemic sclerosis, suggesting that these cells are present in early disease. However, after the identification of microchimeric cells in blood and tissues of patients with systemic sclerosis, these cells have been found in organs affected by nonautoimmune conditions. These cells are also commonly detected in the peripheral blood of healthy people.
Summary: These observations have raised questions about whether microchimeric cells are responsible for the pathologic events in systemic sclerosis or are merely remnants of a pregnancy remote in time, and it has been suggested that they might also have beneficial effects for the host.