Impact of anorexia nervosa on activation characteristics of lymphocytes Introduction
  Anikó Páli1, Peter Švec2 , Ferenc Túry3, András Treszl4 , Bea Pászthy1
1. 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
2. 2nd Department of Pediatrics, Comenius University School of Medicine, Bratislava, Slovakia
3. Institute of Behavioural Sciences, Semmelweis University, Budapest, Hungary
4. Research Group of Pediatrics and Nephrology, Hungarian Academy of Sciences, Budapest, Hungary

Anorexia nervosa (AN) is an extreme form of dietary calorie restriction. In this study we aimed to gather data about the cell activation in AN patients. As a surrogate marker for the characterization of cellular activation we analyzed the calcium-flux patterns and membrane potential kinetics during ex vivo stimulation of CD4+ lymphocytes and demonstrated striking differences between AN patients and controls. We also measured activated leukocytes’ interleukin-2 cytokine production as another measure of lymphocyte activation process.

Methods: 11 Caucasian adolescents (10 girls and 1 boy) with AN were investigated. According to previous evaluation, none of them suffered in hypo- or hyperthyreosis and hypercortisolemia. Peripheral blood mononuclear cells were isolated and lymphocytes were then activated with anti-CD3/anti-CD28 coated beads or phythohemagglutinin for the determination of IL-2 production and calcium-flux kinetics.

Results: We found that the prevalence of IL-2 positive lymphocytes after activation was higher in AN than in control subjects (median [range]: 11.50 [7.60 - 15.30] vs. 13.50 [12.00 - 22.00], p< 0.05 ). The calcium-flux characteristics of lymphocytes upon activation differed markedly in AN and healthy subjects as maximal calcium levels developed later in AN samples (86 [45-232] vs. 215 [59-235] second, p<0.05). We also tested the association between lymphocyte activation parameters and patients’ clinical status.

Discussion: Our findings are the first data about calcium handling of lymphocytes in AN. As membrane potential is the primary determinant of transmembrane electrolyte fluxes, we tested the association of calcium flux with membrane potential. In this study we demonstrated that lymphocytes behave differently after unspecific activation of cell membrane receptors in AN patients and healthy controls.

keywords: anorexia nervosa, calcium uptake, cell excitability, interleukin-2, lymphocyte, membrane potential