Circulating soluble CD5 in atopic dermatitis.

The CD5/Leu-1 is involved in the activation of the T-cell helper function through T/B-cell collaboration by CD5/CD72 interaction. T-cell function is known to be dysregulated in atopic dermatitis. However, to date, the role of CD5 has not been investigated in atopic dermatitis, nor has the presence of circulating soluble CD5 been reported in atopic dermatitis. Five patients with atopic dermatitis who showed typical symptoms, 5 acute febrile patients and 5 normal subjects were tested. Peripheral blood mononuclear cells and plasma were separated. The T- and B-cells were separated using immunomagnetic beads. Reverse transcription polymerase chain reaction was performed using CD5 specific primers. Immunoblotting with the mouse antiCD5 monoclonal antibody was done. Circulating soluble CD5 was present only in 4 out of 5 atopic patients. However, it was not detected in acute febrile patients nor in normal subjects. CD5 mRNA expression was detected in all atopic patients and acute febrile patients. CD5 mRNA expression in T- and B-cells was tested in patients with atopic dermatitis and was detected only in the T-cells. In this study, circulating soluble CD5 was detected in atopic patients and soluble CD5 was suspected to participate in the pathogenesis of atopic dermatitis. CD5 mRNA expression was detected only in T-cells, which suggests that circulating soluble CD5 might be produced from T-cells.