REACTIVITY OF AXILLARY LYMPH-NODES DRAINING INVASIVE BREAST CARCINOMAS - IMMUNOHISTOCHEMICAL EVIDENCE OF TUMOR-ASSOCIATED REACTIONS OF B-REGION AND T-REGION

The B and T regions in 495 axillary lymph nodes (TU-LN) draining 104 i nvasive breast carcinomas and 34 non-tumor-draining axillary/cervical lymph nodes (R-LN) were investigated immunohistochernically in frozen sections. The extents of the B regions and T regions were evaluated by staining with TO15 (CD22) and Leu-1 (CD5), respectively. Staining wit h Ki-M4, which specifically recognizes follicular dendritic cells, ena bled determination of the number of lymphatic follicles. The germinal- center index (GCI), the numerical ratio of primary to secondary follic les, was determined to quantify the reactivity of the B regions. The n umber of Ki-67+ proliferating lymphoid cells per 0.5 mm(2) T region (P CT) was assessed as an index of the reactivity of the T regions. (i) I n the TU-LN, the median GCI and PCT (0.1 and 18, respectively) were si gnificantly lower than in the R-LN (0.6 and 26, respectively; both p<0 .01). (ii) Greater TU-LN volumes were found to be associated with pred ominance of the T regions, high GCIs, and high PCTs. (iii) Higher GCIs and PCTs were associated with predominance of the T regions in TU-LN in general, but TU-LN partially destroyed by tumor metastases exhibite d higher GCIs and PCTs when there was predominance of the B regions. T he findings of the study show that LN draining breast carcinomas and r eactive LN with signs of chronic nonspecific lymphadenitis exhibit sig nificant immunohistochemical differences but it remains open to specul ation whether the malignant tumor exerts suppressive effects on the ly mphoreticular tissue or whether its antigenicity is low, particularly when compared with common, mostly infectious stimuli leading to chroni c lymphadenitis.