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.