PHA-induced cytotoxicity of human lymphocytes against adherent hela cells.

The conditions for a phytohaemagglutinin(PHA)-induced cytotoxicity test of human peripheral blood lymphocytes were investigated. [3H]thymidine prelabelled HeLa cells were used as target cells. Stimulation with 10 microliter PHA/ml during 24 h gave the best measure of lymphocyte cytotoxic capacity. Supernatants of PHA-activated lymphocytes showed no cytotoxicity against adherent HeLa cells. Mitomycin treatment did not influence cytotoxic capacity. Removal of phagocytizing mononuclear cells reduced spontaneous cytotoxicity, but increased PHA-induced cytotoxicity. Adherent cells showed high spontaneous cytotoxicity, with little increase on addition of PHA. The method was evaluated for clinical applicability by testing mononuclear cells from 19 normal subjects and purified lymphocytes from 15 normal subjects. Purified lymphocytes showed a higher PHA-induced cytotoxicity with a smaller variation and greater ratio dependent increase in cytotoxicity than unseparated mononuclear cells. Results with fresh purified lymphocytes were reproducible.

Differentiation between irreversible and reversible rejection in renal transplant patients by monitoring of phytohemagglutinin-induced cytotoxicity.

Phytohemagglutinin (PHA)-induced cytotoxicity against adherent HeLa cells, a reproducible test for primary T cell cytotoxicity, was used in the followup of 34 renal transplant recipients and related to the outcome. During the 1st week, two uncomplicated cases showed a decrease in cytotoxicity of more than 20% and it remained low. One patient with a cytomegalovirus (CMV) infection showed a marked increase in cytotoxicity (37%) and it remained high. In 31 patients with a rejection episode, a change of -20 to +20% was observed. During the 2nd week, all 10 patients who developed an irreversible rejection showed an increase of more than 20% (mean, 29 +/- 8%), in contrast to only 2 of 21 patients with a reversible rejection (mean, -1 +/- 15%, P less than 0.001). There were no differences between these two groups in lymphocyte and T lymphocyte counts, or in prednisone or azathioprine dose or blood urea nitrogen levels. These results indicate that regular assessment of PHA-induced cytotoxicity may be useful in the followup of renal transplant patients.

Phytohemagglutin-induced lymphocyte cytotoxicity in hemodialysis patients with hepatitis B virus infection.

Phytohemagglutinin (PHA)-induced or primary cytotoxicity in vitro which is mediated by T lymphocytes, was studied during hepatitis B virus (HBV) infection in 45 hemodialysis patients, and related to liver cell damage and recovery. HBsAg positive patients with raised transaminases had increased primary cytotoxicity similar to nine otherwise healthy subjects with acute hepatitis B. HBsAg positive patients with normal transaminases showed decreased primary cytotoxicity and recovered patients showed normal values. Increased primary cytotoxicity could not be attributed to an increase in T lymphocytes, as all groups of hemodialysis patients had decreased lymphocyte and T-lymphocyte counts without significant differences between them. In the follow-up study none of the 13 HBsAg positive patients with normal transaminases recovered. However, five of the 18 patients with raised transaminases did recover from hepatitis B, accompanied by a decrease in cytotoxicity. These results show that an increased PHA-induced lymphocyte cytotoxicity corresponds with the occurrence of liver cell damage and subsequent recovery in hemodialysis patients with HBV infection. This suggests that cytotoxic T lymphocytes are involved in liver cell damage and recovery in HBV infection.