Multimodal chronic pain rehabilitation program: its effect on immune function, depression, and health behaviors

Anatomical changes correlated with chronic pain in forensic medicine

This study was performed to determine the relationships between chronic pain and anatomic changes that may occur in the body. Autopsies were performed on fatalities that required death investigation in Linn County, IA, or adjacent and nearby areas. Persons with chronic pain were older than the control population at the time of death. Diabetes, hypertension and depression were more common in persons with chronic pain. Certain causes of death may also have been related to chronic pain. The heart, lungs, liver, spleen and kidneys were significantly heavier in persons with chronic pain; emphysema and pleural and abdominal adhesions were more common in persons with chronic pain. There appear to have been diffuse changes in the body related to chronic pain. These changes may have been mediated by a number of systemic mechanisms that are involved with chronic pain, including cardiovascular activity, the immune system, the neuroendocrine system and others.

Pain, psychological variables, sleep quality, and natural killer cell activity in midlife women with and without fibromyalgia

In women with fibromyalgia (FM), central nervous system (CNS) dysfunction in pain, mood, and sleep processes could be associated with changes in immune system indicators. The primary purpose of this study was to compare pain, psychological variables, subjective and objective sleep quality, lymphocyte phenotypes and activation markers, and natural killer activity (NKA) in midlife women with and without FM. A secondary purpose was to explore relationships among these variables in a step-wise regression. Subjects had pain pressure tender points assessed, completed a psychiatric interview and questionnaires (Beck Depression Inventory, SCL-90, Profile of Mood States, subjective sleep), and underwent polysomnograhic assessment for two consecutive nights. Lymphocyte phenotypes, activation markers, and NKA were assessed from blood drawn the morning after sleep laboratory night 2. Compared to controls, women with FM had lower pain thresholds, more psychological distress, higher depression scores, and reduced subjective and objective sleep quality. They also had fewer NK cells (p <.009) and more NK cells that expressed the IL-2 receptor (p <.04), but these differences were not statistically significant after correction for multiple comparisons. NKA was not statistically significantly lower in the women with FM compared to controls. In a multiple regression of age, tender point threshold, depression, psychological distress, and sleep efficiency, only the effect of group was significant (F = 5.479, p <.03) on NKA. In conclusion, we found little evidence to support the hypothesis that pain, mood, and sleep symptoms are associated with changes in the enumeration of peripheral lymphocytes or function in FM.

The relationship between chronic pain, immune function, depression, and health behaviors

The objectives of this study were 1) to determine the relationships between pain perceptions, immune function, depression and health behaviors and 2) to examine the effects of chronic pain on immune function using depression and health behaviors as covariates. A nonexperimental cross-sectional design was used to compare 24 chronic back pain patients with 33 asymptomatic no-pain healthy subjects. Immune function measures using natural killer (NK) cell activity, percent and numbers of NK cells, and T-cell lymphocyte proliferation with mitogens concanavalin A (ConA) and pytohemagglutinin (PHA) as well as self-report measures for depression and health behaviors were collected on all subjects. Pain perceptions showed positive significant correlations with depression (P = 0.01) and total percent of NK cells (P = 0.04). Depression and health behaviors were negatively correlated (P = 0.01). Positive associations were observed for depression and 2 PHA mitogen levels (P < 0.05). Comparison of group means, controlling for depression and health behaviors, showed that chronic pain patients' immune function, as measured by the combined NK effector to target (E:T) cell ratio levels, was significantly higher than the no-pain comparison group. Pain perceptions may have a deleterious effect on enumerative NK cell measures and depression levels. However, people with chronic pain may not experience attenuation in functional immune parameters.