Haftan Eckholdt

Immunity in adolescents with major depression.

OBJECTIVE The association between major depression (MD) and altered immunity appears to be age-related, with differing immune changes found in prepubertal children, young adults, and older adults. There is limited information concerning immunity in adolescents with MD. METHOD Thirty-six otherwise healthy medication-free adolescents (aged 14-20; 23 female) from a community sample, meeting Diagnostic Interview Schedule for Children DSM-III-R criteria for unipolar MD, were compared with 36 nondepressed adolescents matched by gender, age, and racial background. A battery of quantitative and functional immune measures was obtained. RESULTS MD adolescents had increased (p < .05) circulating lymphocytes and lymphocyte subsets; however, altered distribution of lymphocyte subsets was found only for activated T (HLA-DR+) cells (p < .004) and, possibly, natural killer (NK) (CD56+) cells (p < .06), each showing lower percentages in the MD adolescents. Concanavalin A (but not phytohemagglutinin or pokeweed mitogen) mitogen response was lower in the MD adolescents (p < .02). NK cell activity was elevated at higher effector-target ratios (p < .001), an effect not associated with the number of circulating CD56+ (NK) cells. CONCLUSIONS Depressed adolescents showed changes in immune measures that have been found to be altered in other MD groups, although the pattern of effects differs.

Analysis of Partial Variance (APV) as a Statistical Approach to Control Day to Day Variation in Immune Assays

The considerable day to day variability in some immunologic assays can obscure relationships among measures of interest and thereby complicate interpretation of findings when effect sizes are modest. Analysis of partial variance (APV) is a technique that utilizes data obtained from controls run in the laboratory on the day of each assay to control for day to day variance statistically. The application of this technique to permit detection of otherwise obscured effects for both larger and smaller samples is exemplified utilizing data from two studies in which subjects were assessed on multiple different dates. These included a study of the association of depression with in vitro immune measures in 296 adolescents and a longitudinal study of 20 spouses of patients admitted to a cardiac intensive care unit studied together with 20 matched controls. APV was most useful in analyses of mitogen-induced lymphocyte proliferation assays, which had considerable day to day variability. In general, multivariate studies with functional immune measures may benefit most from application of this technique.