Abstract: | Summary: Increased active rosette formation in patients with gastrointestinal cancer after enzyme treatment of lymphocytes in vitro. B. A. J. Walters, J. C. Rutherford and J. R. Wall, Aust. N.Z. J. Med., 1978, 8, pp. 610–614. Total rosette forming cells (RFC) and active rosette forming cells (ARFC) were estimated in 33 patients presenting with gastrointestinal symptoms suggestive of cancer. When the 33 patients were grouped according to whether they had cancer or not, there was a distinct difference in the percentage of ARFC (P < 0001 Mann-Whitney Test); patients with cancer having much lower values (mean 11 6 ±4–5) than patients without cancer (mean 27 2 ± 3–6). Total RFC were generally lower in the cancer group (mean 54-8 ± 8-3) than the non-cancer group (mean 71-9 ± 4–5) a/though the range was greater. After treatment of the lymphocytes with papain, the percentage of ARFC increased. In the non-cancer group the levels reached a mean of 74-8 ± 1–8, indicating that the T lymphocyte population (mean 71-9 ± 4–5) was converted into cells all having high affinity receptors for sheep red blood cells (SRBC). In the cancer group, after papain treatment of the lymphocytes, the percentage of ARFC increased to levels greater than that obtained for total RFC, suggesting a contribution from the null cell population. Serum taken from these patients was shown to produce a decrease in the percentage ARFC obtained from normal, young individuals. Further, this decrease could be partially reversed by papain digestion indicating that serum from cancer patients may contain a factor that masks T |