Immunologic abnormalities associated with chronic fatigue syndrome

Complement activation in a model of chronic fatigue syndrome

BACKGROUND

A need exists to identify biological markers in chronic fatigue syndrome (CFS).

OBJECTIVE

To use an exercise and/or allergen challenge to induce the symptoms of CFS and to identify a biological marker that correlates with these symptoms.

METHODS

Patients with CFS (n = 32) and age-matched, normal control patients (n = 29) exercised for 20 minutes on a stationary bike at 70% of their predicted max work load (Watts). Patients from each group with positive skin test results were also challenged with intranasally administered relevant allergens. Symptoms were recorded for 2 weeks before and 1 week after each challenge, using 3 different instruments. Blood samples were taken before, and 0, 1, 6, and 24 hours after challenges. Levels of complement split products, cell-associated cytokines, and eosinophilic cationic protein were measured. Mean preexercise and postexercise symptom scores were evaluated for each group.

RESULTS

Exercise challenge induced significant increases of the complement split product C4a, but not C3a or C5a, at 6 hours after exercise only in the CFS group (P <.01), regardless of allergy status. Mean symptom scores were significantly increased after exercise through the use of a daily diary (P <.03) and a weekly diary (P <.01) for the CFS group only. Mean scores for the Multidimensional Fatigue Inventory categories "reduced activity" and "mental fatigue" were significantly increased in the CFS group only (P <.04 and P <.02, respectively).

CONCLUSIONS

Exercise challenge may be a valuable tool in the development of diagnostic criteria and tests for CFS. Establishment of a role for complement activation products as markers or participants in production of illness require further study.

Predictive immunophenotypes: disease-related profile in chronic fatigue syndrome

BACKGROUND

There is a growing body of evidence supporting the theory that problems with immune function play an important role in chronic fatigue syndrome (CFS).

METHODS

We studied 90 CFS cases and 50 healthy controls from two different areas of upstate New York to determine whether there were differences in the absolute number and pattern of natural killer (NK) and cytotoxic T-cell phenotypes between CFS cases and healthy controls in the two regions. One group was from a small town where a cluster of cases existed; the other was from a large metropolitan area where there was not a known cluster.

RESULTS

The number of CD56+CD3+CD8+ and CD56+CD3+CD8- cells in cases from the two areas were both significantly elevated over that of controls from the metropolitan area (P < 0.03). The number of CD56+CD3-CD8+ and CD56+CD3-CD8- cells was significantly reduced in the two case groups compared to that of controls from the metropolitan area (P = 0.04). However, controls who were from the same town as the cluster cases had numbers of CD56+CD3+CD8+, CD56+CD3+CD8-, and CD56+CD3-CD8- cells that were more like that of cases than controls. Only the number of CD56+CD3-CD8+ cells (an NK cell subset) was significantly different in cases versus controls from the cluster area (P = 0.022).

CONCLUSIONS

These data suggest that differences in controls from cluster and noncluster areas may be responsible for some of the inconsistencies in results from other studies. Furthermore, they suggest the possibility that NK cell function may play an important role in preventing the development of CFS in individuals who live in a community where a cluster of cases have been identified.

Psychosocial characteristics and immunological functions in patients with postinfectious chronic fatigue syndrome and noninfectious chronic fatigue syndrome

Differences between patients with postinfectious chronic fatigue syndrome (CFS, n = 16) and noninfectious CFS (n = 20) were clarified. The noninfectious CFS group had problems in family and developmental history, and had chronic stresses. Members of the postinfectious CFS group were social extroverts while those in the noninfectious CFS group was neurotic and introspective. Natural killer cell activity was suppressed in both groups. These findings suggest that the postinfectious CFS group and the noninfectious CFS group differed in their pathogenesis until the onset of CFS. The latter group should be considered as a variant of psychiatric disorder and treated accordingly.

The case definition of chronic fatigue syndrome

The 1994 case definition of chronic fatigue syndrome is widely used not only for diagnosis but also for clinical and laboratory-based observations of this clinical entity. The criteria for the 1994 case definition are based primarily on symptoms and not on physical signs or chemical or immunological tests. This situation has resulted in conflicting clinical and laboratory observations that in all likelihood is due to different populations of patients being studied in different centers. Based on some of the recent publications, there appears to be an emerging picture of this disease entity that we propose could be used to subgroup chronic fatigue syndrome into four different subclasses. These subclasses would consist of chronic fatigue with primarily nervous system disorders such as impaired memory or concentration and headache, chronic fatigue with primarily endocrine system disorders such as unrefreshing sleep and postexertional malaise, chronic fatigue with musculoskeletal system disorders such as muscle pain and joint pain, and chronic fatigue with immune system/infectious disorders such as sore throat and tender lymph nodes. It is suggested that if clinical and laboratory-based studies on chronic fatigue syndrome were conducted on more homogeneous subgroups of patients, the data from one center to the other might not be as conflicting and more insights can be shed on the nature of this clinical condition.

Chronic fatigue syndrome following a toxic exposure

Chronic fatigue syndrome (CFS) is a clinical entity characterized by severe fatigue lasting more than 6 months and other well-defined symptoms. Even though in most CFS cases the etiology is still unknown, sometimes the mode of presentation of the illness implicates the exposure to chemical and/or food toxins as precipitating factors: ciguatera poisoning, sick building syndrome, Gulf War syndrome, exposure to organochlorine pesticides, etc. In the National Reference Center for CFS Study at the Department of Infectious Diseases of 'G. D'Annunzio' University (Chieti) we examined five patients (three females and two males, mean age: 37.5 years) who developed the clinical features of CFS several months after the exposure to environmental toxic factors: ciguatera poisoning in two cases, and exposure to solvents in the other three cases. These patients were compared and contrasted with two sex- and age-matched subgroups of CFS patients without any history of exposure to toxins: the first subgroup consisted of patients with CFS onset following an EBV infection (post-infectious CFS), and the second of patients with a concurrent diagnosis of major depression. All subjects were investigated by clinical examination, neurophysiological and immunologic studies, and neuroendocrine tests. Patients exposed to toxic factors had disturbances of hypothalamic function similar to those in controls and, above all, showed more severe dysfunction of the immune system with an abnormal CD4/CD8 ratio, and in three of such cases with decreased levels of NK cells (CD56+). These findings may help in understanding the pathogenetic mechanisms involved in CFS.

Increased sensitivity to glucocorticoids in peripheral blood mononuclear cells of chronic fatigue syndrome patients, without evidence for altered density or affinity of glucocorticoid receptors

BACKGROUND

In this study we tested the hypothesis that the increased sensitivity to glucocorticoids in chronic fatigue syndrome (CFS)-patients can be attributed to an altered functioning of their glucocorticoid receptors (GR).

METHODS

For this purpose, affinity and distribution of the GR were studied in purified, peripheral blood mononuclear cells (PBMC) of 10 CFS patients and 14 controls along with the responsiveness of these cells to glucocorticoids in vitro.

RESULTS

Affinity (Kd) and number of GR was not different in PBMC of CFS patients when compared with the controls (Kd, 12.9 +/- 8.9 nmol vs 18.8 +/- 16.2 nmol and GR number, 4,839 +/- 2,824/ cell vs 4,906 +/- 1,646/cell). Moreover, RT-PCR revealed no differences in GR messenger RNA expression. Nevertheless, PBMC from CFS patients showed an increased sensitivity to glucocorticoids in vitro. In CFS patients 0.01 micromol dexamethasone suppressed PBMC proliferation by 37%, whereas the controls were only suppressed by 17% (P < 0.01). Addition of phorbol 12-myristate 13-acetate to the cultures rendered the cells resistant to dexamethasone with regard to proliferation and IL-10 and IFN-gamma production, but not to IL-2 and TNF-alpha production in both patients and controls. No difference between patients and controls was observed in this respect

CONCLUSIONS

In conclusion, PBMC of CFS patients display an increased sensitivity to glucocorticoids, which cannot be explained by number or affinity of the GR but should rather be attributed to molecular processes beyond the actual binding of the ligand to the GR.

Toward a model of social course in chronic illness: the example of chronic fatigue syndrome

Retrospective, narrative accounts of illness experience in chronic fatigue syndrome provide the empirical basis for a preliminary conceptual model of social course in chronic illness. Qualities of distress interact with culturally specific expectations for social life and personal conduct to trigger microsocial processes of marginalization: role constriction, delegitimation, impoverishment, and social isolation. Marginalizing processes are opposed by acts of resistance initiated by ill individuals and directed toward integration in social worlds. Social distance from the perceived centers of CFS sufferers' interpersonal worlds expands and contracts with the changing predominance of marginalizing and resisting influences over time. Social course thus consists of successive, bi-directional movements along a 'continuum of marginality' by persons living lives with chronic illness.

RNAs in the sera of Persian Gulf War veterans have segments homologous to chromosome 22q11.2

Reverse transcriptase PCR (RT-PCR) was used for polyribonucleotide assays with sera from deployed Persian Gulf War veterans with the Gulf War Syndrome and a cohort of nonmilitary controls. Sera from veterans contained polyribonucleotides (amplicons) that were obtained by RT-PCR and that ranged in size from 200 to ca. 2,000 bp. Sera from controls did not contain amplicons larger than 450 bp. DNA sequences were derived from two amplicons unique to veterans. These amplicons, which were 414 and 759 nucleotides, were unrelated to each other or to any sequence in gene bank databases. The amplicons contained short segments that were homologous to regions of chromosome 22q11.2, an antigen-responsive hot spot for genetic rearrangements. Many of these short amplicon segments occurred near, between, or in chromosome 22q11.2 Alu sequences. These results suggest that genetic alterations in the 22q11.2 region, possibly induced by exposures to environmental genotoxins during the Persian Gulf War, may have played a role in the pathogenesis of the Gulf War Syndrome. However, the data did not exclude the possibility that other chromosomes also may have been involved. Nonetheless, the detection of polyribonucleotides such as those reported here may have application to the laboratory diagnosis of chronic diseases that have a multifactorial etiology.

Decreased nitric oxide-mediated natural killer cell activation in chronic fatigue syndrome

BACKGROUND

L-Arginine (L-Arg), one of the essential amino acids, has been reported to have an immunomodulatory effect. The precise mechanism of the L-Arg-induced natural killer (NK) cell activation remains unresolved,and the effect of L-Arg on NK cells in chronic fatigue syndrome (CFS) patients has not been estimated.

METHODS

NK cell function was evaluated in 20 subjects with CFS and compared with that in 21 healthy individuals.

RESULTS

In healthy control subjects, NK activity was significantly increased after treatment with L-Arg, an NK function enhancer, for 24 h, whereas the same treatment failed to enhance NK activity in the CFS patients. We thus focused on L-Arg metabolism, which involves nitric oxide (NO) production through NO synthase (NOS). The expression of inducible NO synthase (iNOS) transcripts in peripheral blood mononuclear cells was not significantly different between healthy control subjects and CFS patients. The L-Arg-mediated NK cell activation was abolished by addition of NG-monomethyl-L-arginine, an inhibitor for iNOS. Furthermore, incubation with S-nitroso-N-acetyl-penicillamine, an NO donor, stimulated NK activity in healthy control subjects but not in CFS patients.

CONCLUSION

These results demonstrate that the L-Arg-induced activation of NK activity is mediated by NO and that a possible dysfunction exists in the NO-mediated NK cell activation in CFS patients.

Reproductive correlates of chronic fatigue syndrome

A case-control study was conducted to determine whether menstrual and gynecologic abnormalities precede the onset of chronic fatigue syndrome (CFS) in women with this disorder to a greater extent than that observed among healthy controls. We identified 150 women who met the 1988 Centers for Disease Control criteria for CFS from the Brigham and Women's Hospital Cooperative CFS Research Center. A comparison group of 149 women being seen for nongynecologic conditions were selected from the waiting area of the Brigham and Women's Hospital Internal Medicine outpatient department. Women with and without CFS completed self-administered questionnaires on menstrual, reproductive, and medical history. Women with CFS reported increased gynecologic complications and a lower incidence of premenstrual symptomatology. After adjustment for age, a somewhat greater number of cases compared with controls self-reported irregular cycles, periods of amenorrhea, and sporadic bleeding between menstrual periods. Factors suggestive of abnormal ovarian function--such as a history of polycystic ovarian syndrome, hirsutism, and ovarian cysts--were reported more often in CFS cases compared with controls. Frequent anovulatory cycles due to ovarian hyperandrogenism (PCOS) or hyperprolactinemia may increase risk for CFS through loss of the potential immunomodulatory effects of progesterone in the presence of continued estrogen production. We hypothesize that frequent anovulatory cycles due to PCOS and/or hyperprolactinemia may explain the increased reporting of gynecologic complications and the lower reported premenstrual symptomatology observed in women with CFS.

Natural killer cells and natural killer cell activity in chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is associated with insidious and persistent immunologic abnormalities that have proved difficult to reproduce. The heterogeneity of CFS, the variable quality of immunologic assays and their performance, along with an almost complete absence of longitudinal studies of cellular immune abnormalities in CFS may explain this difficulty. However, in a significant proportion of cases, low levels of natural killer (NK) cell activity have been reported. This article will explore the mechanisms responsible for low NK cell activity, discuss the relation between levels of NK cell activity and health/disease, describe new findings on NK cell-brain interactions, and put forth a specific hypothesis for the role of NK cells in the pathogenesis of CFS.

Chronic fatigue syndrome: an immunological perspective

OBJECTIVE

The aim of this study is to review research examining an immunological basis for chronic fatigue syndrome (CFS) and to discuss how a disturbance in immunity could produce central nervous system (CNS)-mediated symptoms.

METHOD

Data relevant to the hypothesis that abnormal cytokine release plays a role in the pathogenesis of CFS are reviewed as well as recent evidence relating to potential mechanisms by which immune products may enter the brain and produce a disturbance in CNS processes.

RESULTS

Examinations of cytokine levels in patients with CFS have produced inconclusive results. Recent evidence suggests that abnormal release of cytokines within the CNS may cause neural dysfunction by a variety of complex mechanisms.

CONCLUSION

Neuropsychiatric symptoms in patients with CFS may be more closely related to disordered cytokine production by glial cells within the CNS than to circulating cytokines. This possibility is discussed in the context of unresolved issues in the pathogenesis of CFS.

Dysfunction of natural killer activity in a family with chronic fatigue syndrome

A family was identified with 5 of 6 siblings and 3 other immediate family members who had developed chronic fatigue syndrome (CFS) as adults. All 8 met criteria for the CFS case definition as recommended by the Centers for Disease Control and Prevention. Sixty-eight blood samples were obtained over a period of 2 years from 20 family members (8 affected, 12 unaffected) and 8 normal controls. All blood samples were tested for NK activity in 4-h 51Cr-release assays and for the number of circulating CD3-CD56(+) and CD3-CD16(+) by flow cytometry. NK activity of the affected immediate family members (cases, n = 8) was significantly lower (P = 0.006, two-sided) than that of the concurrently tested normal controls. The results for unaffected family members were intermediate between these two groups, and the pairwise comparison of unaffected family members to either cases or controls showed no statistically significant difference (P = 0.29, two-sided). No differences were seen between the groups in the absolute number of CD3-CD56(+) or CD3-CD16(+) lymphocytes in the peripheral blood. Familial CFS was associated with persistently low NK activity, which was documented in 6/8 cases and in 4/12 unaffected family members. In the family with 5 of 6 siblings who had documented CFS, 2 of their offspring had pediatric malignancies. Low NK activity in this family may be a result of a genetically determined immunologic abnormality predisposing to CFS and cancer.

Chronic fatigue syndrome: an update

Among the many patients who seek medical care for the complaint of fatigue, a small number suffer from chronic fatigue syndrome (CFS). CFS is a poorly understood condition characterized by debilitating fatigue and associated symptoms lasting at least six months. Studies indicate that the illness is not simply a manifestation of an underlying psychiatric disorder, but rather is an illness characterized by activation of the immune system, various abnormalities of several hypothalamic-pituitary axes, and reactivation of certain infectious agents.

Consequences of live poliovirus vaccine administration in chronic fatigue syndrome

The effect of live oral polio virus vaccination on chronic fatigue syndrome (CFS) patients was examined in a double-blind study. CFS patients were allocated randomly to placebo (N = 7) or vaccine (N = 7) conditions. All controls subjects received the vaccine (9). Vaccine administration was not associated with clinical exacerbation of CFS. However, objective responses to the vaccine revealed differences between patients and controls: increased poliovirus isolation, earlier peak proliferative responses, lower T-cell subsets on certain days post vaccination and a trend for reduced gamma-interferon in the CFS-vaccine group. Polio vaccination was not found to be clinically contraindicated in CFS patients, however, there was evidence of altered immune reactivity and virus clearance.

Elevation of bioactive transforming growth factor-beta in serum from patients with chronic fatigue syndrome

The level of bioactive transforming growth factor-beta (TGF-beta) was measured in serum from patients with chronic fatigue syndrome (CFS), healthy control subjects, and patients with major depression, systemic lupus erythematosis (SLE), and multiple sclerosis (MS) of both the relapsing/remitting (R/R) and the chronic progressive (CP) types. Patients with CFS had significantly higher levels of bioactive TGF-beta levels compared to the healthy control major depression, SLE, R/R MS, and CP MS groups (P < 0.01). Additionally, no significant differences were found between the healthy control subjects and any of the disease comparison groups. The current finding that TGF-beta is significantly elevated among patients with CFS supports the findings of two previous studies examining smaller numbers of CFS patients. In conclusion, TGF-beta levels were significantly higher in CFS patients compared to patients with various diseases known to be associated with immunologic abnormalities and/or pathologic fatigue. These findings raise interesting questions about the possible role of TGF-beta in the pathogenesis of CFS.

Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) has emerged as a public health concern over the past decade. A working case definition was created in 1988 and revised in 1994, and this has been used to establish prevalence estimates using physician-based surveillance and an a random digit dial telephone survey. Although CFS has some characteristics of an infectious disease, so far no infectious agent has been associated with the illness. Studies of immune function in CFS patients failed to detect differences between cases and healthy controls. However, when cases were subgrouped according to whether they had a sudden or gradual onset, differences in immunologic markers were detected between cases and their matched controls.

Double-blind randomized controlled trial to assess the efficacy of intravenous gammaglobulin for the management of chronic fatigue syndrome in adolescents

A double blind randomized controlled trial was conducted in 71 adolescents aged 11-18 years. Inclusion in the trial required fulfilment of the diagnostic criteria, (Fukuda et al., 1994). Three infusions of 1 gm/kg (max 1 litre of 6 gm/100 ml in 10% w/v maltose solution) were given one month apart. The dummy solution was a 10% w/v maltose solution with 1% albumin of equivalent volume for weight. Efficacy was assessed by difference in a mean functional score including school attendance, school work, social activity and physical activity, between baseline, three months and six months after the final infusion. There was a significant mean functional improvement at the six month follow-up of 70 adolescents with Chronic Fatigue Syndrome of average duration 18 months. There was also a significant improvement for both groups from the beginning of the trial to the six month post infusion follow-up. Adverse effects were common with both solutions but not predictive of response. Neither solution could be identified by recipients.

Frequency of deviant immunological test values in chronic fatigue syndrome patients

Of 11 immunological tests done on chronic fatigue syndrome patients and on fatigued controls, 3 tests (protein A binding, Raji cell, or C3 or C4 [deviant values in either complement component were counted as positive]) with deviant results discriminated best among the groups. Other tests, including immunoglobulin G subclasses, complement component CH50, interleukin-2, and anticardiolipin antibodies, did not discriminate well among the groups.

Chronic fatigue syndrome. 1: Etiology and pathogenesis

Chronic fatigue syndrome (CFS) is a disorder of unknown etiology characterized by debilitating fatigue and other somatic and neuropsychiatric symptoms. A range of heterogeneous clinical and laboratory findings have been reported in patients with CFS. Various theories have been proposed to explain the underlying pathophysiologic processes but none has been proved. Research findings of immunologic dysfunction and neuroendocrine changes suggest the possible dysregulation of interactions between the nervous system and the immune system. Without a clear understanding of its etiopathogenesis, CFS has no definitive treatment. Management approaches have been necessarily speculative, and they have evolved separately in a number of medical and nonmedical disciplines. The results of several controlled treatment studies have been inconclusive. An accurate case definition identifying homogeneous subtypes of CFS is needed. The integration of medical and psychologic treatment modalities and the use of both biologic and psychologic markers to evaluate treatment response will enhance future treatment strategies.