Lack of detectable fetal microchimerism in psoriasis vulgaris lesions and in non-affected skin in spite of its presence in peripheral blood CD34-positive and CD34-negative cells

Background Microchimerism is defined as a stable presence of low numbers of cells derived from a different individual due to cell transfer between twins or between mother and fetus during pregnancy. Objective Fetal cells in the organism of the mother (FMc) are postulated to play a role in autoimmune diseases. Psoriasis is a disease which has an autoimmune component, but no study on microchimerism in this disease has been reported. Methods The easiest way to detect microchimerism is to look for male cells in blood or other tissues of a woman who previously delivered a son. Here, we looked for the presence of male cells in mononuclear cell subpopulations from peripheral blood and in skin samples of women with psoriasis and of healthy women. Results We detected FMc in similar proportions of patients and controls in CD4+, CD8+ and CD34+ cells, whereas in CD34- cells they were present in higher fraction of controls, and similar but non-significant difference was observed in CD19+ cells. No microchimeric cells were detected in patients' skin samples, both from affected and non-affected skin, or in skin tissue from healthy control individuals. Conclusion Our result does not prove the involvement of microchimerism in the aetiology of psoriasis.