INTEGRIN EXPRESSION IN THYROID-CELLS FROM NORMAL GLANDS AND NODULAR GOITERS

To assess the expression of the very late antigens family of the integ rin superfamily in normal and diseased thyroid glands, tissue specimen s were digested to a single cell suspension and analyzed by flow cytom etry with antibodies against the common beta1 chain and the six a chai ns known to be associated to beta1. In multinodular goiters, two cell populations were recognized. The thyroglobulin containing follicular c ell population, represented the majority of cells; a minor population was composed of leukocytes. In normal glands, more than 97% of follicu lar cells expressed the beta1 chain, associated with high levels of al pha3 and very low levels of alpha1, alpha5, and alpha6. The remaining cells (<3%) expressed the beta1 chain with a 10-fold higher intensity, associated with relatively high levels of alpha1, alpha5, and alpha6, in addition to a3. This small subset was much more represented in mul tinodular goiters, where it ranged from 10-60% of the total follicular cell population. Immunofluorescence on tissue sections showed that ve ry late antigens were mostly located on the basal cell membrane and th at in multinodular goiters cells expressing the alpha1, alpha5, and al pha6 chains occurred in clusters.