Kevin Maher

Chronic fatigue syndrome is associated with diminished intracellular perforin

Chronic fatigue syndrome (CFS) is an illness characterized by unexplained and prolonged fatigue that is often accompanied by abnormalities of immune, endocrine and cognitive functions. Diminished natural killer cell cytotoxicity (NKCC) is a frequently reported finding. However, the molecular basis of this defect of in vitro cytotoxicy has not been described. Perforin is a protein found within intracellular granules of NK and cytotoxic T cells and is a key factor in the lytic processes mediated by these cells. Quantitative fluorescence flow cytometry was used to the intracellular perforin content in CFS subjects and healthy controls. A significant reduction in the NK cell associated perforin levels in samples from CFS patients, compared to healthy controls, was observed. There was also an indication of a reduced perforin level within the cytotoxic T cells of CFS subjects, providing the first evidence, to our knowledge, to suggest a T cell associated cytotoxic deficit in CFS. Because perforin is important in immune surveillance and homeostasis of the immune system, its deficiency may prove to be an important factor in the pathogenesis of CFS and its analysis may prove useful as a biomarker in the study of CFS.

Biomarkers in Chronic Fatigue Syndrome: Evaluation of Natural Killer Cell Function and Dipeptidyl Peptidase IV/CD26

Background Chronic Fatigue Syndrome (CFS) studies from our laboratory and others described decreased natural killer cell cytotoxicity (NKCC) and elevated proportion of lymphocytes expressing the activation marker, dipeptidyl peptidase IV (DPPIV) also known as CD26. However, neither these assays nor other laboratory tests are widely accepted for the diagnosis or prognosis of CFS. This study sought to determine if NKCC or DPPIV/CD26 have diagnostic accuracy for CFS. Methods/Results Subjects included female and male CFS cases and healthy controls. NK cell function was measured with a bioassay, using K562 cells and 51Cr release. Lymphocyte associated DPPIV/CD26 was assayed by qualitative and quantitative flow cytometry. Serum DPPIV/CD26 was measured by ELISA. Analysis by receiver operating characteristic (ROC) curve assessed biomarker potential. Cytotoxic function of NK cells for 176 CFS subjects was significantly lower than in the 230 controls. According to ROC analysis, NKCC was a good predictor of CFS status. There was no significant difference in NK cell counts between cases and controls. Percent CD2+ lymphocytes (T cells and NK cells) positive for DPPIV/C26 was elevated in CFS cases, but there was a decrease in the number of molecules (rMol) of DPPIV/C26 expressed on T cells and NK cells and a decrease in the soluble form of the enzyme in serum. Analyses by ROC curves indicated that all three measurements of DPPIV/CD26 demonstrated potential as biomarkers for CFS. None of the DPPIV/C26 assays were significantly correlated with NKCC. Conclusions By ROC analysis, NKCC and three methods of measuring DPPIV/C26 examined in this study had potential as biomarkers for CFS. Of these, NKCC, %CD2+CD26+ lymphocytes and rMol CD26/CD2+ lymphocyte, required flow cytometry, fresh blood and access to a high complexity laboratory. Soluble DPPIV/C26 in serum is done with a standard ELISA assay, or with other soluble factors in a multiplex type of ELISA. Dipeptidyl peptidase IV on lymphocytes or in serum was not predictive of NKCC suggesting that these should be considered as non-redundant biomarkers. Abnormalities in DPPIV/CD26 and in NK cell function have particular relevance to the possible role of infection in the initiation and/or the persistence of CFS.

HIV, metabolic syndrome X, inflammation, oxidative stress, and coronary heart disease risk: Role of protease inhibitor exposure

Differences on measures of metabolic syndrome X and coronary heart disease (CHD) risk, as well as potential pathophysiological mediators, inflammation, and oxidative stress, were examined as a function of HIV serostatus and highly active antiretroviral therapy (HAART) regimen with and without protease inhibitors (PIs). Data from 164 men and women, aged 18 to 55 yr, were used to compare 82 HIV+ subjects who were free of hepatitis C virus and were on a stable HAART regimen for ≥6 mo, with 82 seronegative subjects matched on age, sex, body mass index, and ethnicity. For the HIV+ subjects, after controlling for diabetes status and HIV disease progression, PI exposure was associated with greater oxidative stress, triglyceridemia, and lipidemia than it was for non-PI-exposed HIV+ subjects, and the risk of a future myocardial infarction was up to 56% greater in PI-exposed than in non-PI-exposed subjects and 129% greater than in controls. Although it is likely that the greatest proportion of CHD risk in the HIV+ subjects may be accounted for by pathological conditions linked to HIV infection in interaction with mediating processes such as inflammation, central obesity, and dyslipidemia, which was greater than in controls, it appears that PI medications may exacerbate oxidative stress and hypertriglyceridemia to enhance this risk.

Quantitative Fluorescence Measures for Determination of Intracellular Perforin Content

ABSTRACT We present methodologic details and operating characteristics of a procedure with whole blood for the quantitative assessment of intracellular perforin within distinct lymphocyte subsets. Using this method, we analyzed 20 healthy controls and 2 individuals with an inherited deficiency of perforin. The mean ± standard deviation perforin contents of natural killer (NK) cells and cytotoxic T cells of healthy controls were 3,561 ± 1,157 and 500 ± 779 relative number of molecules (rMol) of antiperforin antibody bound per cell, respectively. The NK cell perforin contents of individuals with heterozygous and homozygous perforin deficiency (familial hemophagocytic lymphohistiocytosis) were 2,260 and 212 rMol of antiperforin antibodies per NK cell. While the homozygous deficiency was found to be associated with negligible antiperforin binding, the heterozygous condition was associated with a level of perforin binding that was below the 15th percentile for healthy individuals. Because 83% of this subjects NK cells were shown to bind to antiperforin antibodies by conventional flow cytometry (relative to the normal range of 81% ± 25%), quantitative cytometry may be more sensitive than conventional cytometric methods in identifying cytolytic defects.

Natural killer cell function in chronic fatigue syndrome

Abstract Chronic fatigue syndrome (CFS) is currently defined by clinical signs and symptoms including debilitating fatigue that is not attributable to other known clinical conditions, by flu-like symptoms (e.g., pharyngitis, adenopathy, low-grade fever, myalgia, arthralgia, headache) and by neuropsychological manifestations (e.g., difficulty concentrating, exercise intolerance, and sleep disturbances). CFS is frequently of sudden onset. Its etiology is unknown. Although immunologic abnormalities are frequently described in the literature of CFS, there is a lack of consensus, and, as of yet, no immunological dysfunctions are part of the existing case definition. This review examines one aspect of the literature, that dealing with natural killer (NK) cell function. A surprising amount of concurrence is found supporting the view that NK cell activity is depressed in CFS patients. Data are presented that suggest a methodology consisting of a whole blood cytotoxicity assay, combined with flow cytometric enumeration of NK cell numbers, would allow interlaboratory comparisons to be made and would be useful in research studies on this perplexing syndrome.

Baseline Cortisol Levels Predict Treatment Outcomes in Chronic Fatigue Syndrome Nonpharmacologic Clinical Trial

ABSTRACTObjective: Understanding how nonpharmacologic interventions differentially affect the subgroups of patients with chronic fatigue syndrome (CFS) might provide insights into the pathophysiology of this illness. In this exploratory study, baseline measures of normal versus abnormal cortisol were compared on a variety of immune markers and other self-report measures. Normal versus abnormal cortisol ratings were used as predictors in a nurse-delivered nonpharmacologic intervention. Methods: Participants diagnosed with CFS were assigned to 6-month nonpharmacologic interventions. Individuals were classified as having abnormal or normal cortisol levels on the basis of scores over the five testing times. Cortisol levels were considered abnormal if they continued to rise, were flat, or were at abnormally low over time. Results: Across interventions, those with abnormal cortisol at the baseline appeared not to improve over time, whereas those with normal baseline cortisol evidenced improvements on a number o...

Depressive Symptoms and Cervical Neoplasia in HIV+ Low-Income Minority Women with Human Papillomavirus Infection

BackgroundPrior work has related elevated life stress to greater risk of cervical neoplasia in women with human immunodeficiency virus (HIV) and human papillomavirus (HPV).PurposeThis study investigated associations between depressive symptoms and cervical neoplasia in HIV+ HPV+ women. Participants were 58 HIV+ HPV+ women.MethodParticipants underwent colposcopy, including HPV screening, Papanicolaou smear, and cervical biopsy to determine study eligibility. Eligible participants completed the Beck Depression Inventory (BDI) and the Center for Epidemiologic Studies-Depression (CES-D) scale.ResultsPresence and severity of clinically significant depressive symptomatology were associated with cervical neoplasia. Hierarchical logistic regression analysis revealed that women with greater depressive symptoms had marginally greater odds of presenting with cervical neoplasia (BDI: OR = 1.16, p = 0.092; CES-D: OR = 1.15, p = 0.067. Women with greater somatic depressive symptoms, specifically, had significantly greater odds of presenting with cervical neoplasia (BDI: OR = 1.86, p = 0.027; CES-D: OR = 1.56, p = 0.017).ConclusionThese findings suggest that screening HIV+ women for somatic depression may help identify those at risk for cervical neoplasia. Future depression research with medical populations should discern somatic depressive symptoms from disease symptoms, as they may have important value in independently predicting health outcomes.