Dissident AIDS Database

Co-factorsStressPsychological stressLymphocytopenia
Mortality, CD4 cell count decline, and depressive symptoms among HIV-seropositive women: longitudinal analysis from the HIV Epidemiology Research Study.
 Ickovics JR, Hamburger ME, Vlahov D, Schoenbaum EE, Schuman P, Boland RJ, Moore J
  "Women with HIV have substantially higher rates of depression than their male counterparts.To determine the association of depressive symptoms with HIV-related mortality and decline in CD4 lymphocyte counts among women with HIV. The HIV Epidemiologic Research Study, a prospective, longitudinal cohort study conducted from April 1993 through January 1995, with follow-up through March 2000. A total of 765 HIV-seropositive women aged 16 to 55 years.HIV-related mortality and CD4 cell count slope decline over a maximum of 7 years, compared among women with limited or no depressive symptoms, intermittent depressive symptoms, or chronic depressive symptoms... women with chronic depressive symptoms were 2 times more likely to die than women with limited or no depressive symptoms. Chronic depressive symptoms were also associated with significantly greater decline in CD4 cell counts..."
  JAMA 2001 Mar 21;285(11):1466-742001
Immunological consequences of acute and chronic stressors: mediating role of interpersonal relationships.
 Kennedy S, Kiecolt-Glaser JK, Glaser R
  "Data are given which document immunosuppressive effects of commonplace, short-term stressors, as well as more prolonged stressors, such as marital disruption and caregiving for a relative with Alzheimer's disease. Immune changes included both quantitative and qualitative changes in immune cells, including changes in herpes virus latency, decreases in the percentages of T-helper lymphocytes and decreases in the numbers and function of natural killer cells. These effects occurred independently of changes in nutrition. Psychological variables, including loneliness, attachment and depression were related to the immune changes. The data are discussed in a framework in which quality interpersonal relationships may serve to attenuate the adverse immunological changes associated with psychological distress, and may have consequences for disease susceptibility and health."
  Br J Med Psychol, 1988, 61(Pt 1):77-851988
Stress and immunity in humans: A meta-analytic review.
 Herbert TB & Cohen S
  "In terms of cell numbers, stress is reliably associated with a ... lower number of circulating B cells, helper cells, cytotoxic cells, and large granular lymphocytes. Stress is also reliably associated with a lower percent of lymphocytes that are T cells, helper T cells, and cytotoxic T-cells."
  Psychosomatic Medicine, 1993, 55;364-3791993
Acute, psychological stressors and short-term immunological changes.
 Kiecolt-Glaser JK, Glaser R
  "The immunological changes observed following short-term stressors are very similar to those that have been described following epinephrine injections: increased percentages of natural killer cells, decreased blastogenesis in response to mitogens (decreased lymphocyte function), and decreased percentages of CD4 cells. Total T cells and monocytes did not change."
  Psychosomatic Medicine, 1992, 54;680-6851992
A bereavement support group intervention is longitudinally associated with salutory effects on the CD4 cell count and number of physician visits.
 Goodkin K, Feaster DJ, Asthana D, et al.
  A group of researchers put the stress-cortisol hypothesis to the test by checking CD4 counts and cortisol levels in people who were randomly assigned either to a bereavement support group intervention or to a wait-list control. The intervention consisted of 10 weekly support group meetings, and blood samples continued to be taken periodically for a total of 6 months. Some of the group members were HIV-positive, and the authors stratified their data according to HIV status. "In HIV-negative intervention subjects, the CD4 cell count increased 112 cells/mm3, while that in HIV-negative control subjects decreased 88 cells/mm3, for a difference of 200 cells/mm3 between treatment and control groups. In treated HIV-positive individuals, the CD4 cell count was stable, within laboratory error over the entire six months. However, that in HIV-positive controls decreased 61 cells/mm3. Both (statistical tests) demonstrated a statistically significant intervention effect on the CD4 cell count." They found that these increases correlated with reduced levels of the stress hormone cortisol.
  Clin Diagn Lab Immunol, 1998 (may), 5(3); 382-91.1998
Impact of stressful life events, depression, social support, coping, and cortisol on progression to AIDS.
 Leserman J, Petitto JM, Golden RN, Gaynes BN, Gu H, Perkins DO, Silva SG, Folds JD, Evans DL.
  "This study examined prospectively the effects of stressful events, depressive symptoms, social support, coping methods, and cortisol levels on progression of HIV-1 infection. Eighty-two homosexual men with HIV type-1 infection without AIDS or symptoms at baseline were studied every 6 months for up to 7. 5 years. Men were recruited from rural and urban areas in North Carolina, and none was using antiretroviral medications at entry. Disease progression was defined as CD4(+) lymphocyte count <200/microl or the presence of an AIDS indicator condition. Cox regression models with time-dependent covariates were used adjusting for race, baseline CD4(+) count and viral load, and cumulative average antiretroviral medications. Faster progression to AIDS was associated with higher cumulative average stressful life events, coping by means of denial, and higher serum cortisol as well as with lower cumulative average satisfaction with social support. Other background (e.g., age, education) and health habit variables (e.g., tobacco use, risky sexual behavior) did not significantly predict disease progression. The risk of AIDS was approximately doubled for every 1.5-unit decrease in cumulative average support satisfaction and for every cumulative average increase of one severe stressor, one unit of denial, and 5 mg/dl of cortisol."
  Am J Psychiatry 2000 Aug;157(8):1221-82000
CD4 and CD8 counts are associated with interactions of gender and psychosocial stress.
 Scanlan JM, Vitaliano PP, Ochs H, Savage MV, Borson S.
  "This study examined relationships of gender, psychosocial stress/distress (caregiving, hassles, depressed mood), and the relative percentage and absolute cell counts of CD4 and CD8 cells in two samples of older adults (mean age = 69.4)--spouse caregivers of persons with Alzheimer's disease (N = 78) and age- and gender-matched spouses of nondemented controls (N = 72). Counts and percentages of CD4 and CD8 cells and psychosocial variables were assessed twice (Time 1, Time 2) over a 15- to 18-month period. Several covariates were examined in the analyses, including body mass index (BMI), medication use, alcohol use, exercise, and illness history. Caregiver men had fewer CD4 cell counts at Times 1 and 2 than did control men (p < .05)... From Time 1 to Time 2, change analyses showed that increases in hassles scores were associated with decreases in CD4 counts (p < .05), whereas increases in Hamilton Depression Scores were related to increases in both CD8 counts and percentages (p < .05). Caregiver status, hassles, and depressed mood had cross-sectional and/or longitudinal associations with CD4 and CD8 counts, but such relationships occurred primarily in men. Moreover, absolute cell counts were more related to psychosocial factors than were percentages."
  Psychosom Med 1998 Sep-Oct;60(5):644-531998
Repeated restraint stress impairs the antitumor T cell response through its suppressive effect on Th1-type CD4+ T cells.
 Li T, Harada M, Tamada K, Abe K, Nomoto K.
  "Overall, these findings provide evidence that stress significantly impairs the antitumor T cell responses through its suppressive effect on Th1-type CD4+ T cells."
  Anticancer Res 1997 Nov-Dec;17(6D):4259-681997
Effects of job strain on helper-inducer (CD4+CD29+) and suppressor-inducer (CD4+CD45RA+) T cells in Japanese blue-collar workers.
 Kawakami N, Tanigawa T, Araki S, Nakata A, Sakurai S, Yokoyama K, Morita Y.
  "The effects of job strain on helper-inducer (CD4+CD29+) T cells and suppressor-inducer (CD4+CD45RA+) T cells are not clear. The subjects were 65 male blue-collar workers in a chemical plant in Japan. Perceived job stressors were assessed using the Japanese version of Job Content Questionnaire, i.e., job demands, job control, supervisor support and coworker support. Blood samples were taken from these subjects, and number and percentage of total lymphocytes were calculated for total T cells, helper (CD4+) T cells, suppressor/cytotoxic (CD8+) T cells, helper-inducer (CD4+CD29+) T cells and suppressor-inducer (CD4+CD45RA+) T cells using the double-staining fluorescence... It is suggested that higher job strain or lower job control is associated with a decrease in helper-inducer (CD4+CD29+) T cells in Japanese blue-collar workers."
  Psychother Psychosom 1997;66(4):192-81997
Adrenocortical and behavioral predictors of immune responses to starting school.
 Boyce WT, Adams S, Tschann JM, Cohen F, Wara D, Gunnar MR.
  "Associations between major psychologic stressors and immune function have been documented in previous research, but few studies have investigated immune changes attending minor, normative stressors. This study examined adrenocortical and behavioral predictors of immune responses to starting kindergarten in 39 five-year-old children, who completed laboratory visits for venipunctures 1 wk before (time 1) and 1 wk after (time 2) school entry... Scores for behavioral difficulty were inversely associated with delta CD4+ and delta CD19+. These data suggest that: 1) school entry is a stressor capable of evoking elevations in cortisol and behavior problems, accompanied by shifts in functional and enumerative measures of immune status; and 2) children with greater adrenocortical reactivity have increases in B cell numbers and less effective B cell-mediated antibody production, whereas children with more behavioral difficulties show declines in all T and B cell subsets."
  Pediatr Res 1995 Dec;38(6):1009-171995
Life stressors and coping style are associated with immune measures in HIV-1 infection--a preliminary report.
 Goodkin K, Fuchs I, Feaster D, Leeka J, Rishel DD.
  "Life stressors and coping style have been associated with alterations in cellular immunity similar to those seen in HIV-1 infection... This pilot study investigated whether life stressors and coping style may account for a portion of this variation. A sample of eleven asymptomatic HIV-1 seropositive homosexual male volunteers responding to a local advertisement was assessed on life stressors, coping style and cellular phenotypic and functional immune measures--T4 "helper" cell/T8 "suppressor" cell ratio, T4 cell count, total lymphocyte count, and natural killer cell cytotoxicity. Significant associations were observed for both major life stressor impact over the previous year and passive coping style use with the total lymphocyte count; higher life stressor impact and passive coping style use were associated with lower total lymphocyte counts. Similarly, a trend in the same direction was found for the relationship of these two measures with the count of T4 cells, which are directly infected and killed by HIV-1... These preliminary findings suggest that life stressors and coping style may also be predictors of the development of AIDS."
  Int J Psychiatry Med 1992;22(2):155-721992
Stress management and immune system reconstitution in symptomatic HIV-infected gay men over time: effects on transitional naive T cells (CD4(+)CD45RA(+)CD29(+)).
 Antoni MH, Cruess DG, Klimas N, Maher K, Cruess S, Kumar M, Lutgendorf S, Ironson G, Schneiderman N, Fletcher MA.
  "Changes in immunologic status were evaluated in 25 HIV-infected men randomly assigned to a 10-week stress management intervention or a wait-list control condition. The authors monitored changes in number of transitional naive T cells (CD4(+)CD45RA(+)CD29(+)) over 6-12 months after the completion of the intervention. Men receiving stress management had higher CD4(+) CD45RA(+)CD29(+) cell counts at follow-up than did the control subjects. This difference was independent of initial number of naive T cells and HIV virus load. Stress management is associated with immunologic reconstitution in HIV-positive gay men."
  Am J Psychiatry 2002 Jan;159(1):143-52002
Effects of prenatal ethanol exposure and stress in adulthood on lymphocyte populations in rats.
 Giberson PK, Weinberg J
  A study in rats compared the effect of three weeks of chronic stress in rats who either had normal pre-natal experiences, or who were exposed to ethanol in utero. Males were especially affected, and ethanol exposed rats had significantly more lowering of CD4 counts when placed in a stressful environment than non-exposed rats. This suggests that chemical insults can increase the susceptibility to stress-induced immunodeficiency, especially if the exposures occur in utero, a finding that is especially significant to childhood AIDS cases as many of them are born to women who are IV drug users.
  Alcohol Clin Exp Res;1995 Oct; 19(5):1286-94 (Published erratum appears in Alcohol Clin Exp Res 1996 May;20(3):600)1995
Depression in caregivers of demented patients is associated with altered immunity: impaired proliferative capacity, increased CD8+, and a decline in lymphocytes with surface signal transduction molecules (CD38+) and a cytotoxicity marker (CD56+ CD8+).
 Castle S, Wilkins S, Heck E, Tanzy K, Fahey J.
  "Changes in relevant immune parameters, including function, were found to be associated with depression in elderly caregiver wives of demented patients. We studied the relationship between immune cell phenotype and T cell proliferative capacity of such caregivers to levels of stress and depression over the course of a support group intervention. The data indicate the strongest association between depression (of all stress parameters) and impaired T cell proliferative capacity. Depression was also most strongly (of stress parameters) associated with a shift in T cell populations with an increase in CD8+ T cells, and a reduced percentage of CD38+ cells in both CD8+ and CD4+ T cell populations... This study shows that both chronic stress, and depression in particular, and age have deleterious effects on T cells, and together could significantly contribute to the higher risk of disease and mortality associated with being a caregiver of a demented individual.
  Clin Exp Immunol 1995 Sep;101(3):487-931995
Cognitive-behavioral stress management intervention effects on anxiety, 24-hr urinary norepinephrine output, and T-cytotoxic/suppressor cells over time among symptomatic HIV-infected gay men.
 Antoni MH, Cruess DG, Cruess S, Lutgendorf S, Kumar M, Ironson G, Klimas N, Fletcher MA, Schneiderman N.
  "The present study tested the effects of a multimodal cognitive-behavioral stress management (CBSM) intervention on anxious mood, perceived stress, 24-hr urinary catecholamine levels, and changes in T-lymphocyte subpopulations over time in symptomatic HIV+ gay men. Seventy-three men were randomized to either a group-based CBSM intervention (n = 47) or a wait-list control (WLC) condition (n = 26)... Significantly greater numbers of T-cytotoxic/suppressor (CD3+CD8+) lymphocytes were found 6 to 12 months later in those assigned to CBSM. Moreover, greater decreases in NE output and a greater frequency of relaxation home practice during the 10-week CBSM intervention period predicted higher CD3+CD8+ cell counts at follow-up."
  J Consult Clin Psychol 2000 Feb;68(1):31-452000
Severe stress, depressive symptoms, and changes in lymphocyte subsets in human immunodeficiency virus-infected men. A 2-year follow-up study.
 Leserman J, Petitto JM, Perkins DO, Folds JD, Golden RN, Evans DL.
  "This study examined how severe stress and depressive symptoms were related to changes in immune measures during a 2-year period in a sample of gay men with human immunodeficiency virus (HIV) infection. These analyses follow up our initial cross-sectional observations that severe stress was correlated with lower levels of natural killer (NK) cells and CD8+ T lymphocytes in these men... Sixty-six HIV-infected gay men, who were asymptomatic at baseline, were assessed systematically at 6-month intervals. Severe stress and depressive symptoms were independently related to decreases on immune measures from entry to 2-year follow-up, that is, declines in CD8+ T cells and CD56+ and CD16+ NK cell subsets. Subjects most likely to have decreases on these immune measures were those who scored above the median on both stress and depressive symptoms. Our findings are among the first prospective data showing that stress and depressive symptoms, especially when they occur jointly, are associated with decreased number of NK and CD8+ T lymphocytes in HIV-infected men. Since these immune cells may play a protective role in the progression of HIV infection, our data suggest that stress and depressive symptoms may have clinical implications for the course of this disease."
  Arch Gen Psychiatry 1997 Mar;54(3):279-851997
Immune response reduced by intense intellectual stress: changes in lymphocyte proliferation in medical students
 Gloger S, Puente J, Arias P, Fischman P, Caldumbide I, Gonzalez R, Quiroz J, Echavarri O, Ramirez C.
  "There is a relationship between stressful situations and the susceptibility towards certain diseases, probably mediated by immune system modifications.To study T lymphocyte proliferation in medical students during periods of differing academic stress. Blood samples were obtained from 42 medical students during a period of moderate academic stress, immediately before a final examination and after their summer vacations... There is a decrease in lymphocyte proliferation and an increase in cortisol levels during a period of acute academic stress in medical students, suggesting that, the exposure of the healthy subjects to common stressful stimuli, may affect their immunocompetance."
  Rev Med Chil 1997 Jun;125(6):665-701997
Stress and immune responses after surgical treatment for regional breast cancer.
 Andersen BL, Farrar WB, Golden-Kreutz D, Kutz LA, MacCallum R, Courtney ME, Glaser R.
  "Adults who undergo chronic stress, such as the diagnosis and surgical treatment of breast cancer, often experience adjustment difficulties and important biologic effects. This stress can affect the immune system, possibly reducing the ability of individuals with cancer to resist disease progression and metastatic spread. We examined whether stress influences cellular immune responses in patients following breast cancer diagnosis and surgery. We studied 116 patients recently treated surgically for invasive breast cancer. Before beginning their adjuvant therapy, all subjects completed a validated questionnaire assessing the stress of being cancer patients. A 60-mL blood sample taken from each patient was subjected to a panel of natural killer (NK) cell and T-lymphocyte assays. We then developed multiple regression models to test the contribution of psychologic stress in predicting immune function... We found, reproducibly between and within assays, the following: 1) Stress level significantly predicted lower NK cell lysis, 2) stress level significantly predicted diminished response of NK cells to recombinant interferon gamma, and 3) stress level significantly predicted decreased proliferative response of peripheral blood lymphocytes to plant lectins and to a monoclonal antibody directed against the T-cell receptor. The data show that the physiologic effects of stress inhibit cellular immune responses that are relevant to cancer prognosis, including NK cell toxicity and T-cell responses."
  J Natl Cancer Inst 1998 Jan 7;90(1):30-61998
Effects of chronic mild stress on lymphocyte proliferative response. Participation of serum thyroid hormones and corticosterone.
 Silberman DM, Wald M, Genaro AM.
  "There is increasing evidence that stress produces changes in various immune processes. Some of these changes may be due to neurochemical and hormonal alterations including thyroid hormones levels. This work was carried out to study the impact of chronic mild stress (CMS) exposure on proliferative responses and its correlation with serum thyroid hormone levels. In addition, the influence of serum corticosterone levels on these responses was also studied... Taken together, our results suggest an impact of chronic stress on thyroid function that in turn alters T-cell response. These findings may help to elucidate the physiological mechanisms through which stress plays a roll in the etiology of many diseases."
  Int Immunopharmacol 2002 Mar;2(4):487-972002
Stress-associated reductions of cytotoxic T lymphocytes and natural killer cells in asymptomatic HIV infection.
 Evans DL, Leserman J, Perkins DO, Stern RA, Murphy C, Tamul K, Liao D, van der Horst CM, Hall CD, Folds JD, et al
  "Previous research has documented a possible relation of stress and depression to cell-mediated immunity. The authors examined how stressful events and depression may affect key parameters of cellular immunity in subjects with and without HIV infection. Data were collected on 99 asymptomatic HIV-positive and 65 HIV-negative homosexual men as part of an ongoing, longitudinal study. In the HIV-positive men, severe stress was significantly associated with reductions in NK cell populations and a subset of T cells thought to represent cytotoxic T effector cells... The findings suggest that stress is associated with reductions in killer lymphocytes... The data provide evidence that stress may alter cell populations that provide cytotoxic defense against infection in HIV-positive men..."
  Am J Psychiatry 1995 Apr;152(4):543-501995
High versus low basal cortisol secretion in asymptomatic, medication-free HIV-infected men: differential effects of severe life stress on parameters of immune status.
 Petitto JM, Leserman J, Perkins DO, Stern RA, Silva SG, Gettes D, Zheng B, Folds JD, Golden RN, Evans DL.
  "The authors hypothesized that HIV-infected men with high basal cortisol secretion would exhibit greater stress-related reductions in the ratio of Th1/Th2 cell-derived cytokines and numbers of CD8+ T and NK lymphocytes than low basal cortisol secretors. A semistructured interview was used to assess life stress during the preceding 6 months of 94 HIV-infected men classified as high and low cortisol secretors (n = 47/group). Increased levels of severe life stress were highly correlated with lower numbers of CD8+ T cells, CD16+ and CD56+ NK cells, CD57+ cells, and higher DHEA-S concentrations in the high cortisol group. Conversely, no significant correlations were found in the low cortisol group... These data suggest that severe stress in combination with high glucocorticoid activity may modify select parameters of immune status in HIV-infected men."
  Behav Med 2000 Winter;25(4):143-512000
Effects of a behavioral stress-management program on anxiety, mood, self-esteem, and T-cell count in HIV positive men.
 Taylor DN.
  "This study evaluated the effects of a behavioral stress-management program on anxiety, mood, self-esteem, and T-cell count in a group of HIV-positive men who were asymptomatic except for T-cell counts below 400. The program consisted of 20 biweekly sessions of progressive muscle relaxation and electromyograph biofeedback-assisted relaxation training, meditation, and hypnosis. Ten subjects were randomly assigned to either a treatment group of a no-treatment control group, and the 2 groups were compared on pre- to post-treatment changes in the dependent measures. Analysis showed that, compared with the no-treatment group, the treatment group showed significant improvement on all the dependent measures, which was maintained at a 1-mo. follow-up. Since stress is known to compromise the immune system, these results suggest that stress management to reduce arousal of the nervous system and anxiety would be an appropriate component of a treatment regimen for HIV infection."
  Psychol Rep 1995 Apr;76(2):451-71995
Stress-induced modulation of the primary cellular immune response is mediated by both adrenal-dependent and adrenal independent mechanisms.
 Bonneau RH, Sheridan JF, Feng N, Glaser R
  Stress causes a state of immunodeficiency characterized by a reduction of the number of T-lymphocytes, with special targeting of CD4, helper T cells. There is also a reduced CD4:CD8 ratio, with a relative increase in CD8, suppressor/cytotoxic T cells.
  Journal of Neuroimmunology; 1993; 42; 167-176.1993
Spousal caregivers of dementia victims: Longitudinal changes in immunity and health.
 Kiecolt-Glaser JK, Dura JR, Speicher CE et al.
  Stress causes a state of immunodeficiency characterized by a reduction of the number of T-lymphocytes, with special targeting of CD4, helper T cells. There is also a reduced CD4:CD8 ratio, with a relative increase in CD8, suppressor/cytotoxic T cells. The effects of stress also show a lot of individual variance, which may be due to factors like coping strategies and social support : isolated people have more immune dysfunction than people with high levels of social support.
  Psychosomatic Medicine; 1991; 53;345-362.1991
Coping and immunosuppression: Inescapable but not escapable shock suppresses lymphocyte proliferation.
 Laudenslager M, Ryan SM, Drugan RC, et al.
  Rats who were given some measure of control over the source of stress showed normal lymphocyte responses, while rats who had no control showed impaired responses, even though the amount of external stress producing events (electric shocks) were equal.
  Science, 1983, 221;568-570.1983
Chronic caregiving stress alters peripheral blood immune parameters: the role of age and severity of stress.
 Pariante CM, Carpiniello B, Orru MG, Sitzia R, Piras A, Farci AM, Del Giacco GS, Piludu G, Miller AH
  Stress causes a state of immunodeficiency characterized by a reduction of the number of T-lymphocytes, with special targeting of CD4, helper T cells. There is also a reduced CD4:CD8 ratio, with a relative increase in CD8, suppressor/cytotoxic T cells.
  Psychother Psychosom; 1997; 66(4):199-207.1997
Effects of acute and chronic social stress on blood cellular immunity in rats.
 Stefanski V, Engler H
  It is important to note that short-term stress can have very different effects from long-term stress : this study compared the effects of two hours of social stress in rats with the effects of 48 hours of stress. After two hours, there were decreases in the number of T-cells, but an increase in the CD4/CD8 ratio. After 48 hours of the same social stress, however, the CD4/CD8 ratio had lowered to the normal range, while T-cell numbers remained reduced
  Physiol Behav; 1998 Jul; 64(5):733-411998
Psychosocial factors and immunity in nonhuman primates: A review.
 Coe CL
  Coe reviewed the research that examined the effect of psychosocial factors on the immune systems of non-human primates. Many studies showed that when young, captive monkeys were separated from friends or from their mothers, their T-cells showed markedly impaired function. Researchers also tried to assess why some monkeys were more affected than others, and found that many subtle variables such as the timing of the separation, the age of the monkeys, and the way the separation was created, could all have a significant effect. Thus measuring the effects of social support is a complex task, as is measuring psychological stress. The influence of subtle factors related to the social environment and to the person's internal coping mechanisms may have significant mediating effects.
  Psychosomatic Medicine 1993, 55; 298-308.1993
Behavioral, endocrine and immunological correlates of immigration by an aggressive male into a natural primate group.
 Alberts SC, Sapolsky RM, Altmann J
  A group of researchers measured total lymphocyte counts and cortisol levels in a group of baboons that were invaded by a highly aggressive young male baboon, whom they named Hobbs. Hobbs was particularly threatening to females in the group, and was apparently attempting to use fear, physical intimidation, and abuse to increase his chances of successful mating. Cortisol levels in the group nearly doubled after Hobbs joined the group, with a slightly greater increase among females. T-lymphocytes plummeted in the group, from a pre-Hobbs level of 67 per 10,000 red blood cells to a level of about 39, a drop of 42%. When looking at only the levels in baboons who were victims of Hobbs' aggression, the levels fell even more steeply, to only 29 per 10,000 RBC's, a drop of 55%.
  Hormones and Behavior 1992, 26; 167-178.1992
Urinary cortisol levels, cellular immuno-competency, and loneliness in psychiatric inpatients.
 Kiecolt-Glaser JK, Ricker D, George J
  The effects of stress also show a lot of individual variance, which may be due to factors like coping strategies and social support : isolated people have more immune dysfunction than people with high levels of social support.
  Psychosomatic Medicine; 1984; 46(1): 15-23.1984
Psychoneuroimmunology and HIV-1.
 Antoni MH, Schneiderman N, Fletcher MA, Goldstein DA, Ironson G, Laperriere A.
  Animals subjected to uncontrollable stressors, for instance, have been noted to display... immune system decrements such as thymic involution, decreased NK cell cytotoxicity, suppressed lymphocyte proliferation, and decreased helper/suppressor cell ratios... In research using naturally occuring uncontrollable stressors in human subjects... (there were) decreases in total T-lymphocyte number, total macrophage number, and total number of CD4 cells... Other recent work has noted that a high stress level, increased depressive symptoms, dissatisfaction with social support, and limited use of coping strategies predicted decreased CD4 cell number and increased CD8 cell number... Several different types of stressors led to these immune system changes, including loneliness, lack of social support, and bereavement, all three of which have a high prevalence in people diagnosed with AIDS... Indeed, we have observed discrete and significant psychological and immunological changes among asymptomatic gay men across the anticipatory period preceeding HIV-1 antibody testing and during the impact period following news of diagnosis. Furthermore, we have noted significant benefits of behavioral interventions on psychological and immunological functioning among asymptomatic, HIV-1 seropositive and seronegative gay men.
  J Consult Clin Psychol. 1990 Feb;58(1):38-491990