 Lymphocytes will be stimulated in 24-well plates in RPMI-1640 at 10 fetal calf serum in the presence of phorbol 12-myristate 13 acetate, 25 ngmL; ionomycin; 1 μmol; and Brefeldin A, 10 μgmL Sigma-Aldrich; St, Louis, MO. Cytospins will be made using cytocentrifugation of 150 μL of the stimulated suspension and store at - 80C. Approximately 175,000 cells will be cytospun on each slide of which are sufficient lymphocytes to stain. The double immunocytochemical method for the determination and measurement of CD8IFN-, CD8IFN- or CD4IFN-, CD4IFN- will be performed in two steps. At step one, use the primary anti-CD8 or anti-CD4, respectively mouse anti-human monoclonal antibody with secondary rabbit anti-mouse IgG-FITC antibody. At step two, after permeabilization, a primary anti-IFN- or IL-4 mouse anti-human monoclonal antibody Caltag; Burlingame, CA with secondary rabbit anti-mouse IgG-PE. A permeabilization kit of will be used according to the instructions of the manufacturer Dako. For the estimation of each ratio, 500 T cells we count 10 cytospins stained if necessary because this number is sufficient to obtain a mean value per subject that remain constant after further increasing the number of cells counted. 