Improving methods of assessing natural killer cell cytotoxicity

Abstract

Natural killer (NK) cells are a class of lymphocytes important in immune resistance to viral and other serious diseases. The cytotoxic function, or 'killing activity' of NK cells has become important in studies of the effects of stress and other psychosocial factors on physical health. Unfortunately, research on NK cell function has been plagued by discrepancies in the methods of interpreting NK cytotoxicity data. We briefly review some of the variations in measuring NK cell activity and present a new model for interpreting these results, introducing maximal target cell lysis (A) and the slope of the cytolytic curve (k) as parameters that attempt to make full use of the information and the statistical power in NK cell cytotoxicity data. Examples of these interpretation methods are presented using NK cytotoxicity data from a group of metastatic breast cancer patients. This approach will be useful in applications of NK cell measurement in psychoneuroimmunology research.

Improved body weight and performance status and reduced serum PGE2 levels after nutritional intervention with a specific medical food in newly diagnosed patients with esophageal cancer or adenocarcinoma of the gastro‐esophageal junction

“…NK cell activity was measured at four different E : T ratios, and the Weighted Mean of Specific Lysis was calculated. 26,32 For the ordinal variables performance status (ECOG) and dysphagia score, visits 1 and 3 were compared between the groups using the Mann-Whitney U test adjusted for stratification (group 0-5% WL and group ≥5% WL). All adverse events (AEs) were assessed, and medical history and medication use were checked individually for subjects having AEs.…”

“…When the data were not normally distributed, the Mann– Whitney U test adjusted for stratification (group 0–5% WL and group ≥5% WL) was used, and correlations were made using the Spearman's Rank test. NK cell activity was measured at four different E : T ratios, and the Weighted Mean of Specific Lysis was calculated 26,32. For the ordinal variables performance status (ECOG) and dysphagia score, visits 1 and 3 were compared between the groups using the Mann–Whitney U test adjusted for stratification (group 0-5% WL and group ≥5% WL).…”

Selective Serotonin Reuptake Inhibitor Suppression of HIV Infectivity and Replication

“…Growing evidence suggests that stress and depression may impair key components of cell-mediated immunity (15, 22, 34-36, 52-56), and heighten susceptibility to infectious diseases (57-59) including HIV infection (17-27, 32). Although the specific immune mechanisms by which depression may influence immunity and HIV disease progression and mortality remain to be understood, increasing evidence suggests that killer lymphocytes may play a key role.…”

Objective and Subjective Breast Cancer Risk

“…Therefore, other investigators have used multiple E:T cell ratios to keep important information which might otherwise be missed. The use of multiple E:T cell ratios is believed to be more useful to verify dose-specific responses to a phenomenon under study and to enhance sensitivity to detect fine differences that may emerge only at a certain E:T cell ratio 46,47. We support the use of multiple E:T cell ratios and analyzed the NKCA data accordingly.…”