DNA ligase activity was determined in the WBCs from 306 cases of acute lymphoblastic leukemia (ALL) and acute nonlymphocytic leukemia (ANLL). In T-ALL cells this activity was either low or absent. DNA analysis by nucleoid, alkaline elution, and alkaline sucrose centrifugation after cells were embedded in agarose inserts has shown more DNA breaks in T- ALL than in ANLL blasts. Phytohemagglutinin stimulation of T-ALL blasts resulted in the apparent joining of the DNA breaks. Apparent identical results can be obtained by the incubation of DNA with exogenous DNA ligase. The authors suggest that this enzyme is a crucially regulated step of replication and subsequent proliferation in this type of leukemia.
DNA ligase activity was determined in the WBCs from 306 cases of acute lymphoblastic leukemia (ALL) and acute nonlymphocytic leukemia (ANLL). In T-ALL cells this activity was either low or absent. DNA analysis by nucleoid, alkaline elution, and alkaline sucrose centrifugation after cells were embedded in agarose inserts has shown more DNA breaks in T- ALL than in ANLL blasts. Phytohemagglutinin stimulation of T-ALL blasts resulted in the apparent joining of the DNA breaks. Apparent identical results can be obtained by the incubation of DNA with exogenous DNA ligase. The authors suggest that this enzyme is a crucially regulated step of replication and subsequent proliferation in this type of leukemia.
The present study was undertaken to evaluate the immune function of 5 hemodialysis patients with dialysis-related amyloidosis as compared to 6 without, both groups having a dialytic age from 7 to 21 years, and 5 healthy controls. We investigated serum levels of immunoglobulins (IgG, IgA, IgM), made skin tests and measured peripheral lymphocyte subsets using monoclonal antibodies. 1) The absolute numbers of T3, T4 and T8 cells were significantly lower in hemodialysis patients than controls and T3, T4 cells were lower in patients with amyloidosis than in those without: T3 (m +/- SD/microliter), 387 +/- 253 vs 744 +/- 207 (p = 0.03); T4, 262 +/- 115 vs 589 +/- 297 (p = 0.04). 2) Serum levels of IgG and IgM were significantly lower in patients with amyloidosis than in the others: IgG (m +/- SD, g/l), 10.2 +/- 1.4 vs 15.4 +/- 3.2 (p less than 0.001); IgM, 0.65 +/- 0.28 vs 1.65 +/- 0.37 (p less than 0.001). 3) Delayed hypersensitivity studied by skin tests showed less than 3 positive antigens in 4/5 patients with amyloidosis against 1/6 patients without. These data suggest there is a marked defect of T-cell help in uremic patients with dialysis-related amyloidosis.
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