T lymphocyte subpopulations and pokeweed mitogen(PWM)-induced immunoglobulin (Ig) synthesis of mononuclear cells in vitro were studied in patients with psoriasis as well as in age- and sex-matched normal blood donors. The frequences of T cells with receptors for IgG (T_g) and T cells with receptors for IgM (T_m) were examined. The IgG and IgM synthesis in mononuclear cell suspensions in the presence of different amounts of PWM was determined. The percentage of total T cells (rosetting with neuroaminidase-treated sheep red blood cells), including high and low affinity T lymphocytes showed no difference between the patient group and controls. The patients with psoriasis had a significantly higher mean proportion of T_g cells than the normal donors whereas there was no significant difference in the proportions of T_m cells between these two groups. The PWM-induced Ig synthesis in the mononuclear cell suspension seemed lower in patients with psoriasis than in controls, the difference being statistically significant when the results were expressed as ratios of Ig amounts present in the supernatants of PWM-stimulated and non-stimulated cultures (index of stimulation).

Identification and enumeration of both Ia + dendritic epidermal cells (Ia + DECs) and Thy‐1 + dendritic epidermal cells (Thy‐1 + DECs) from various parts of the body and non‐irradiated and ultraviolet B (UVB) irradiated back skin were examined using epidermal sheets of C3H/He inbred mice of different age groups and indirect immunofluorescent technique. The following results were obtained: [1] There was a significant decline in both Ia + DEC and Thy‐1 + DEC density in the mice in the oldest group (48–50 weeks); [2] The densities of Ia + DECs were significantly higher than those of Thy‐1 + DECs in comparisons of various parts of the body; [3] At 24 h after 60–120 mJ/cm2 UVB irradiation, the Ia + DECs and Thy‐1 + DECs decreased significantly in a dose‐dependent fashion. The Ia + DECs decreased drastically (p<0.01) while the Thy‐1 + DECs decreased mildly (p<0.05). [4] The degree or resistance to UVB differed between Ia + DECs and Thy‐1 + DECs in older mice (40–48 weeks). These findings may imply that the decline of the Ia + DECs and Thy‐1 + DECs reflects alterations in immune response during aging; As do Ia + DECs, Thy‐1 + DECs might also play a role in UVB induced specific unresponsiveness in contact hypersensitivity; each type of Ia + DECs and Thy‐1 + DECs follows a distinct biological kinetic pattern after UVB irradiation.

Lymphocytes were purified from 10 samples of normal peripheral blood. E receptors were detached by heating to +45°C. The sheep red blood cells (SRBC) and 2-aminoethylisothiouronium bromide (AET)-treated SRBC (AET-SRBC) were incubated at +4°C for 2 h, with E receptors. E receptors detached by heating blocked E-rosette formation with SRBC, but not with AET-SRBC. The results suggest that E receptors may exhibit different conformational structures or different molecules which are responsible for E-rosette formation and E-AET-rosette formation, respectively.