Detection of proliferating cell nuclear antigen (PCNA) in peripheral blood mononuclear cells and sera of patients with malignant lymphoma

Proliferating cell nuclear antigen (PCNA) was detected in the peripheral blood mononuclear cells (PBMC) of patients with malignant lymphoma (ML). Twenty-one of 27 patients with ML had PCNA expressing PBMC (5.25 +/- 4.75% cells), which tended to increase in the advanced clinical stage of ML. PCNA in PBMC extracts was detected in 11 of 16 patients (54.5 +/- 41.9 ng/ml). The percentage of PCNA positive cells correlated significantly with the concentration of PCNA in PBMC extracts (P < 0.005). Serum PCNA was detected in 6 of 16 patients (160.1 +/- 141.1 ng/ml), but did not correlate with the number of PCNA-positive cells. In some cases, the concentration of serum PCNA increased after chemotherapy while the percent PCNA-positive cells decreased. Our finding indicate that detection of PCNA in PBMC appears to help monitoring the extent of disease in ML and the serum PCNA level may be used in therapeutic studies of lymphoma patients.