Immunological studies on Crohn's disease. IV. Decreased ADCC activity.

Antibody dependent cell-mediated cytotoxicity (ADCC) activity was studied in 16 Japanese patients with Crohn's disease (CD) and 16 healthy controls. ADCC activity was assessed by measuring 51Cr release from antibody coated human B-cell line. Significantly (p less than 0.002) depressed ADCC activity was found in patients with CD, although ADCC activity was not directly related to the disease activity. To determine causative factors related to reductions in ADCC activity, circulating immune complex (CIC) was also assayed by C1q-binding method. CIC levels in patients with CD were similar to those in the control group, thereby suggesting that this impaired ADCC activity was not due to blocking of the FC-receptor on K cells by CIC. However, serum zinc concentrations did correlate to the ADCC activity. Hence, an assumption can be made that a decreased ADCC activity may be caused by malnutrition, mainly zinc deficiency, a phenomena linked to CD. The significance of serum zinc in considerations of immunological abnormalities was given attention.