Nucleoli and AgNORs in Hodgkin's disease

To evaluate the morphofunctional characteristics of lymph node cells from patients with Hodgkin's disease by measuring silver stained nucleolar organiser regions (AgNORs).

Nucleoli in Hodgkin's and Reed-Sternberg (HRS) cells, lymphocytes and prolymphocytes were investigated in cytological smears and histological sections of lymph nodes from 32 patients with Hodgkin's disease, and from 34 patients with reactive lymphadenopathy. According to the Rye histological classification of Hodgkin's disease, three cases were the lymphocyte predominant (LP) type, 14 the nodular sclerosing (NS) type, and 15 the mixed cellularity (MC) type. The investigation was done before treatment, by means of a one step silver staining method. In each case, 50 to 100 HRS cells, lymphocytes, and prolymphocytes were evaluated to determine the mean numbers of nucleoli and AgNORs per nucleus. The nonparametric Wilcoxon Mann-Whitney test was used to compare the groups.

The mean numbers of nucleoli and AgNORs were higher in lymphocytes and prolymphocytes compared with those from reactive lymph nodes used as controls. Numbers of nucleoli and AgNORs were higher (not significant) in the NS type of Hodgkin's disease than in the MC type. There was a significant increase in numbers of nucleoli in HRS cells, and their AgNOR counts were increased. The greatest number of nucleoli in HRS cells was found in the NS type. Furthermore, the nucleolar activity of HRS cells was greater in the NS type compared with the MC type (50.2 (SEM 3.9) v 37.7 (2.9) AgNORs per nucleus (p = 0.025)). Comparative analysis of cytological and histological samples showed that the AgNOR score was significantly higher in touch imprints than in tissue sections with tumours of the same histological type.

Assessment of cell activity in Hodgkin's disease patients by silver staining is more convenient and informative in lymph node imprints than in histological sections. The highest expression of interphase ribosomal RNA cistrons found in NS HRS cells is probably explained by their high proliferative activity and elevated production of transforming growth factor 1 which is known to be the most potent cytokine present in the NS subtype of Hodgkin's disease.