INCREASED PREVALENCE OF COLONIC POLYPS AND ALTERED LYMPHOCYTE SUBSET PATTERN IN THE COLONIC LAMINA PROPRIA IN ACROMEGALY

OBJECTIVE The balance of evidence suggests that acromegaly is a risk f actor for colonic neoplasia, We have evaluated the prevalence of colon ic polyps in acromegalics from Southern Italy and characterized the ly mphocyte subsets in the colonic lamina propria in order to analyze dif ferences in the colonic immunological environment. DESIGN All the pati ents and controls were submitted to pancolonoscopy. Ten per-endoscopic biopsies of the intestinal mucosa surrounding polyps were carried out to evaluate lymphocyte subsets. PATIENTS Fifty acromegalics and 318 s ex- and age-matched controls entered this study, Colonic lamina propri a lymphocyte subsets were studied in 34 patients and 34 controls. RESU LTS Colonic polyps were resected in 23 acromegalics (46%) and 42 contr ols (13.2%; P < 0.0001); hyperplastic polyps were found in 24% and 6.3 %, adenomatous polyps in 22 and 6.9%, (P < 0.01), adenocarcinoma in 2 and 1.2% while synchronous polyps occurred in 18% and 2.5% (P < 0.01), respectively, The number of polyps was significantly correlated with age both in acromegalics (r = 0.422, P < 0.005) and in controls (r=0.8 65, P < 0.001). However, polyp prevalence was greater in patients aged below 40 yrs (r.r. = 1.9) and in patients with two or more skin tags (r.r. = 1.2). A significant decrease of CD20, CD19, CD16, gamma/delta, CD4(+)/leu8(-) and increase of CD3 and CD4(+)/leu8(+) was found in th e lamina propria lymphocyte subsets. CONCLUSIONS The results of this s tudy confirm that acromegalics are at increased risk of colonic polyps compared to the healthy population. The increased prevalence of prema lignant polyps, namely the adenomatous type, suggests that acromegalic s should undergo a careful screening and follow-up by pancolonoscopy. An impairment of mucosal immune surveillance seems to exist in acromeg aly although a causal effect in the polyp formation cannot be ruled ou t.