Elevated Numbers of Proliferating Mononuclear Cells in the Peripheral Blood of Psoriatic Patients Correlate with Disease Severity

Although psoriasis is characterized by the accumulation of activated proliferating lymphoid cells in the psoriatic skin lesion, it is not known whether these cells are activated and proliferating before entry into the psoriatic plaque. The current study evaluates the number and phenotype of proliferating lymphoid cells in the blood of psoriatic patients. Proliferation of peripheral blood mononuclear cells was evaluated on cytospun preparations of these cells using autoradiographic techniques after pulsing the mononuclear cells with 3 H-methyl thymidine for 2 h. The phenotypes of the labeled peripheral blood mononuclear cells were determined combining autoradiography and immunohistochemistry with monoclonal antibodies directed at CD3, CD4, CD8, CD11c, CD22, and human leukocyte antigen-DR. The data demonstrated elevated numbers of proliferating lymphoid cells in the blood of psoriatic patients compared with normal nonpsoriatic volunteers (p + , CD4 + , CD8 + cells), B cells CD22 + cells), monocytes (CD11c + cells) and human leukocyte antigen-DR + cells were significantly elevated compared with nonpsoriatic skin (p 3 H-methyl thymidine (i.e., proliferating and presumably activated) when assayed in vitro.