[Changes of the immune functions in patients with eating disorders]

In this study we investigated whether calorie restriction or redundant food intake influences the function of regulatory T cells (Tregs), and their main regulators (dendritic cells and macrophages), or the targets of Tregs, CD4+ lymphocytes.

We investigated 11 white adolescents (10 girls and 1 boy) with anorexia nervosa, 12 obese adolescents and 10 healthy controls. With flow cytometry we determined the prevalence of Tregs, myeloid and plasmacytoid dendritic cells. We applied intracellular staining to investigate TNF-alpha and IL-12 production of macrophages, moreover IL-2, IL-4, and IFN-gamma production of CD4+ cells. We also determined calcium flux kinetics upon activation in CD4+ cells.

We did not find any difference between obese, anorectic and control individuals in the prevalence of Tregs, dendritic cells, TNF-alpha and IL-12 positive macrophages, IL-4 and IFN-gamma positive CD4+ lymphocytes. We found that the prevalence of IL-2 positive lymphocytes after activation was lower in anorectic than in control subjects [median (range): 11.50 (7.60-15.30) vs. 13.50 (12.00-22.00), p=0.023], and in obese patients, too [12.50 (8.50-15.50) vs. 13.50 (12.00-22.00), p=0.028]. IFN-gamma/IL-4 ratio in CD4+ cells was higher in obese patients compared with control (p=0.046). The calcium flux characteristics of lymphocytes upon activation differed markedly in anorectic and healthy subjects as maximal calcium levels developed later in anorectic patients [86 (45-232) vs. 215 (59-235) second, p<0.05]. We also tested the association between lymphocyte activation parameters and patients' clinical status, but did not find any association between the variables.

Our results suggest that the antigen presenting cell - regulatory T cell - CD4+ lymphocyte axis might be affected by calorie and nutritional disturbances, further studies are needed to elucidate the underlying processes.