Trait mindfulness differentiates the interest in healthy diet from orthorexia nervosa.

BACKGROUND: Obsessive healthy eating and its extreme form orthorexia nervosa are epidemiologically significant problems. Mindfulness, the focused, non-judgmental attention to and awareness of present events, may be an important psychological contributor to (orthorexic) eating habits. METHODS: In this cross-sectional survey-based study, 314 women and 75 men (mean agetotal sample = 27.17 years, SD = 10.64) provided data on mindfulness (Freiburg Mindfulness Inventory, presence and acceptance subscale) and orthorexic eating (Teruel Orthorexia Scale, healthy orthorexia and orthorexia nervosa subscale). RESULTS: In this study, we found a positive relation between mindfulness and healthy orthorexia, the non-pathological interest in eating healthy. By contrast, orthorexia nervosa, the pathological obsession with healthy eating, was negatively associated with mindfulness. Gender differences appeared neglectable. CONCLUSION: Taken together, these results confirm previous research showing that mindfulness encourages eating healthy and may protect against eating-related pathologies. Result also support the notion that orthorexia has two dimensions, healthy and nervosa, which are differently related to psychological factors, herein mindfulness. LEVEL OF EVIDENCE: Level III, cohort study.

Food cue-elicited brain potentials change throughout menstrual cycle: Modulation by eating styles, negative affect, and premenstrual complaints.

BACKGROUND: While there is evidence for increased food intake and craving during the luteal phase, underlying mechanisms are incompletely understood. The present study investigated electrophysiological responses to food pictures as a function of menstrual cycle phase. In addition, the moderating effects of progesterone, eating behaviors (restraint, emotional, orthorexic), negative affect, and premenstrual complaints were explored. METHODS: Using a within-subject design, 35 free-cycling women watched and rated pictures of food (high and low caloric) and control items during the follicular, the ovulatory, and the luteal phase (counterbalanced), while EEG was recorded to examine the late positive potentials (LPP). Salivary gonadal hormones and affect were examined at each occasion. Eating behaviors and premenstrual complaints were assessed once. RESULTS: For parietal regions, average LPPs were comparable between cycle phases but slightly larger LPP amplitudes were elicited by high caloric food pictures as compared to the neutral category. Descriptively, both food categories elicited larger parietal LPPs than neutral pictures during the luteal phase. Analyses of LPPs for central-parietal regions showed no effect of picture category or cycle phase, except higher amplitudes in the right area during the luteal phase. During the luteal phase, progesterone and functional interference from premenstrual symptoms (but not age, BMI, picture ratings, affect, estradiol, or eating behaviors) significantly predicted larger parietal LPPs towards high caloric (but not low caloric) pictures. CONCLUSION: Our findings suggest a heightened food cue reactivity during the luteal phase, which may relate to higher ovarian hormone secretion and more functional impact of premenstrual symptoms. This research contributes to a better understanding of menstrual health and the identification of preventive strategies for premenopausal women.

Attentional bias toward and distractibility by sexual cues: A meta-analytic integration.

From an evolutionary perspective, sexual stimuli are highly salient and are assumed to be processed with high priority. Hence, attentional processing of sexual cues is expected to not only bias attention but to also distract from other cognitive (foreground) tasks. It is, however, unclear to what extent these stimuli capture attention and whether there are differences between men and women. This meta-analysis combined the results of 32 studies employing experiments of attentional bias toward and distraction by sexual stimuli. From these, 13 studies provided data to examine gender differences. Overall, attentional bias and distractibility was lower than anticipated (gz = 0.43, p < .001) and there was support for the assumption of higher attention bias/interference in men (gs = 0.29, p = .031). Importantly, there was evidence for the presence of publication bias. With this in mind, findings are discussed in the context of stimulus features, the impact of provoked sexual arousal and motivational state, and gender-specific and -nonspecific neural processing of sexual stimuli which influence attention toward them.

Neural correlates of gender differences in distractibility by sexual stimuli.

Attentional interference control is a prominent feature of human cognition. To what extent sexual stimuli attract attention and interfere with cognitive tasks has still little been studied. Our study aimed to identify associations between attentional interference, sexual arousal, trait sexual motivation, and neural activity to sexual distractors while accounting for gender differences. Therefore, the present study examined the neural correlates of attentional interference by arousing sexual distractors using functional magnetic resonance imaging (fMRI). Fifty women and 47 men underwent fMRI while indicating the orientation of two lines (equal or unequal) next to an explicit sexual (as compared to a neutral) picture. Results confirmed prolonged response times when a sexual image was shown. There was neither a difference between genders nor an effect of sexual arousal ratings or trait sexual motivation on distractibility. Neural activity specific to sexual images was found in brain regions implicated in motivation and reward processing. Men as compared to women showed stronger responses in the nucleus caudatus, the anterior cingulate cortex, and the nucleus accumbens. Trait sexual motivation was selectively correlated with nucleus caudatus activity. Taken together, findings support the notion that even when not in the focus, sexual images activate the brains' reward circuitry. Men's higher sensitivity to the rewarding value of sexual cues may be critical for their higher risk of addictive/compulsive sexual behaviors.

Diurnal cortisol and alpha-amylase in the daily lives of older adults with vital exhaustion.

OBJECTIVE: Vital exhaustion (VE) is characterised by unusual fatigue, increased irritability, and a feeling of demoralisation. It has been found a major risk factor for cardiovascular diseases, and one that is independent of subclinical or clinical manifestations of coronary heart disease or lifestyle-related risk factors. Stress-induced alterations in the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system may mediate the link between VE and increased cardiovascular risk. However, no studies have yet assessed both systems simultaneously and in high-risk populations, such as older adults. METHODS: A total of 72 older adults (34 women, mean age 61.7±7.3) who were free of any major physical or mental illnesses filled out the Maastricht Vital Exhaustion Questionnaire (MVEQ) and the Perceived Stress Scale (PSS). To determine cortisol and alpha-amylase, participants collected saliva samples upon awakening, +30min thereafter, and at 11am, 3pm, and 8pm. RESULTS: Participants with higher VE reported lower perceived stress (ß=-0.515, p<0.001). Individuals reporting higher VE also exhibited more diminished cortisol concentrations across the day, although only by trend (ß=-0.218, p=0.092). There was no significant association between VE and diurnal alpha-amylase activity. Moreover, women had lower diurnal cortisol (ß=-0.381, p=0.004) and alpha-amylase (ß=-0.329, p=0.011) when compared to men. CONCLUSIONS: Our findings provide initial evidence for psychosocial stress to be linked to VE in older adults, while evidence for HPA alterations remains tentative. Future research is warranted to determine whether VE related hypocortisolaemia represents a specific stage of the stress adaptation process that may put individuals at risk for incident cardiovascular diseases.

Identification of novel Escherichia coli ribosome-associated proteins using isobaric tags and multidimensional protein identification techniques.

Biogenesis of the large ribosomal subunit requires the coordinate assembly of two rRNAs and 33 ribosomal proteins. In vivo, additional ribosome assembly factors, such as helicases, GTPases, pseudouridine synthetases, and methyltransferases, are also critical for ribosome assembly. To identify novel ribosome-associated proteins, we used a proteomic approach (isotope tagging for relative and absolute quantitation) that allows for semiquantitation of proteins from complex protein mixtures. Ribosomal subunits were separated by sucrose density centrifugation, and the relevant fractions were pooled and analyzed. The utility and reproducibility of the technique were validated via a double duplex labeling method. Next, we examined proteins from 30S, 50S, and translating ribosomes isolated at both 16 degrees C and 37 degrees C. We show that the use of isobaric tags to quantify proteins from these particles is an excellent predictor of the particles with which the proteins associate. Moreover, in addition to bona fide ribosomal proteins, additional proteins that comigrated with different ribosomal particles were detected, including both known ribosomal assembly factors and unknown proteins. The ribosome association of several of these proteins, as well as others predicted to be associated with ribosomes, was verified by immunoblotting. Curiously, deletion mutants for the majority of these ribosome-associated proteins had little effect on cell growth or on the polyribosome profiles.

[Ranking of 20 MHz sonography of malignant melanoma and pigmented lesions in routine diagnosis]. / Stellenwert der 20-MHz-Sonographie des malignen Melanoms und pigmentierter Läsionen in der Routinediagnostik.

PURPOSE: Eleven dermatology clinics from all over Germany took part in our multicenter prospective study with the aim of evaluating 20 MHz sonography in the preoperative diagnosis of malignant melanomas and other pigmented skin tumours. It was to be assessed how effective sonographic measurement of thickness would compare to histology and the clinical palpation of tumour thickness and also the significance of differential diagnosis in sonography of malignant melanomas. METHOD: The prospective multicenter study proceed as follows. To the end of August 1997 264 patients with a primary malignant melanoma and 417 patients with benign skin tumours were examined via 20 MHz sonography. Two different examiners estimated the clinical thickness of the tumour by palpation. The tumour was then excised and examined for postoperative correlation with the histology sections. RESULTS: The final results showed good correlation between the histological and sonographic estimation of tumour thickness (r = 0.97). Estimation of tumour thickness by palpation showed no correlation with the histology (r = 0.59). Most of the benign (44%) and malignant tumours (38.7%) were spindle shaped. There was no significant difference between the benign and malignant tumour groups in relation to the sonographic presented shapes or echo signs. No different diagnosis could be made. CONCLUSION: The technique of high frequency sonography in relation to preoperative diagnosis of malignant melanomas has high priority. In contrast to clinical estimation of tumour thickness, sonography provided a good correlation to histology. The effectiveness of sonography with regard to the valence of the skin tumours is limited and there is no possibility of differentiating between malignant and benign tumours from the morphological face value. Hence, there is a demand for developing a 150 MHz apparatus which will be able to supply evidence regarding the valence of skin tumours.

Neither HMG-14a nor HMG-17 gene function is required for growth of chicken DT40 cells or maintenance of DNaseI-hypersensitive sites.

HMG-14 and HMG-17 form a family of ubiquitous non-histone chromosomal proteins and have been reported to bind preferentially to regions of active chromatin structure. Our previous studies demonstrated that the chicken HMG-17 gene is dispensable for normal growth of the DT40 chicken lymphoid cell line. Here it is shown that the major chicken HMG-14 gene,HMG-14a, is also dispensable and, moreover, that DT40-derived cells lacking both HMG-17 and HMG-14a proteins show no obvious change in phenotype with respect to the parental DT40 cells. Furthermore, no compensatory changes in HMG-14b or histone protein levels were observed in cells lacking both HMG-14a and HMG-17, nor were any alterations detected in such hallmarks of chromatin structure as DNaseI-hypersensitive sites or micrococcal nuclease digestion patterns. It is concluded that the HMG-14a and HMG-17 proteins are not required for normal growth of avian cell linesin vitro, nor for the maintenance of DNaseI-hypersensitive sites in chromatin.

A nucleoside diphosphate kinase A (nm23-H1) serine 120-->glycine substitution in advanced stage neuroblastoma affects enzyme stability and alters protein-protein interaction.

A high level of nucleoside diphosphate kinase A (NDPK A/nm23-H1) in neuroblastoma is associated with advanced stage disease. We have also found a serine 120-->glycine substitution in NDPK A and/or amplification of the nm23-H1 gene in advanced stage neuroblastomas. Serine 120, a highly conserved residue, is located in proximity to histidine 118 which forms a phosphorylated intermediate essential for NDPK activity. The effect of Ser120-->Gly substitution on the biochemical properties of NDPK A was investigated. Phosphate-transferase activity was lower in the recombinant mutant NDPK A and in the immunoprecipitated complex consisting of NDPK A and NDPK B prepared from a neuroblastoma tumor containing the mutation, relative to the wild-type. There was a significant decrease in the enzyme stability toward urea- or temperature-induced denaturation for the recombinant mutant NDPK A and in an immunoprecipitate from a tumor containing the mutation. Recombinant NDPK A containing the Ser120-->Gly mutation exhibited reduced hexameric and increased dimeric oligomerization relative to the wild-type. Moreover a 28 kDa cellular protein was detected, that co-precipitated with the mutant but not wild-type NDPK A. The altered properties of the mutant protein may have relevance to a role for NDPK A in neuroblastoma progression.

Activation of MAP kinase and translocation with HSP27 in bombesin-induced contraction of rectosigmoid smooth muscle.

We have investigated whether mitogen-activated protein (MAP) kinase cascade is essential for sustained contraction of smooth muscle cells of the rabbit rectosigmoid. We have identified MAP kinase as one of the enzymes activated by bombesin, performed immunologic studies blocking the activation of MAP kinase, and conducted confocal localization of MAP kinase in relation to heat-shock protein (HSP27), postulated to be involved in the sustained contraction of smooth muscle. Immunoblotting revealed two forms of MAP kinase (42 and 44 kDa). Activation of MAP kinase by bombesin was rapid, reaching a maximum in 30 s and subsequently declining. [D-Phe6,Leu13,psi(CH2NH),Phe14]BN-(6-14), a potent bombesin antagonist, and protein kinase C (PKC) inhibitors 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, calphostin C, and chelerythrine inhibited the increase in MAP kinase induced by bombesin. Immunofluorescent dual labeling and confocal microscopy indicate that these two proteins are closely distributed in resting cells and that during bombesin-induced contraction MAP kinase translocates accompanied by HSP27. In conclusion, a series of events involving PKC activation, MAP kinase activation, and MAP kinase-HSP27 translocation could be the signaling pathway involved in bombesin-induced sustained contraction.

Hsp27 expression in neuroblastoma: correlation with disease stage.

BACKGROUND: The 27-kd heat shock protein (Hsp27) is differentially expressed in some malignancies, including breast carcinoma, leukemia, and malignant fibrous histiocytoma. In breast carcinoma, a high-level expression of Hsp27 has been associated with shorter disease-free survival in patients with localized disease. PURPOSE: We have observed variable levels of Hsp27 among neuroblastoma tumors. Our aim in this study was to investigate the relationship between Hsp27 expression and stage of the disease and N-myc gene copy number. METHODS: We determined Hsp27 protein levels in 53 neuroblastoma tumors representing different stages of the disease and in 17 neuroblastoma cell lines by quantitative two-dimensional polyacrylamide gel electrophoresis (PAGE). We also performed statistical analysis of Hsp27 levels in relation to stage of the disease and to N-myc gene copy number. RESULTS: Increased Hsp27 expression in neuroblastomas was associated with limited stage disease and inversely correlated with N-myc gene amplification, a feature known to predict poor clinical outcome. An inverse correlation was also observed between N-myc gene amplification and Hsp27 protein levels among the neuroblastoma cell lines analyzed. Immunohistochemical staining of sections of neuroblastomas showed that Hsp27 was most prominently expressed in the cytoplasm of large ganglionic tumor cells present in neuronally differentiated areas of the tumors. Induction of neuronal differentiation in SMS-KCNR neuroblastoma cells using retinoic acid resulted in an increase in Hsp27. CONCLUSION: High level expression of Hsp27 in neuroblastoma is a feature of limited stage, differentiated tumors. IMPLICATION: Hsp27 may play a part in the biology of neuroblastomas with a favorable outcome.

Phorbol 12-myristate 13-acetate-induced phosphorylation of Op18 in Jurkat T cells. Identification of phosphorylation sites by matrix-assisted laser desorption ionization mass spectrometry.

Op18 is a widely expressed, cell cycle-regulated, phosphoprotein involved in signal transduction of a variety of stimuli. In actively proliferating Jurkat T cells which express Op18 at high level, phorbol 12-myristate 13-acetate (PMA) treatment induces a rapid increase in the level of several Op18 phosphorylated forms. To determine phosphorylation sites involved in the PMA effect, the major Op18 phosphorylated forms were resolved in Jurkat T cells, before and after treatment with PMA, using preparative immobilized pH gradient-based two-dimensional polyacrylamide gel electrophoresis. Tryptic fragments of phosphorylated Op18 were analyzed by two-dimensional thin layer peptide mapping and were resolved by reverse-phase high performance liquid chromatography prior to analysis by matrix-assisted laser desorption ionization mass spectrometry. Phosphorylation sites were identified by further treatment of the proteolytic fragments with different enzymes and determination of the mass shifts by matrix-assisted laser desorption ionization mass spectrometry. Two major phosphorylation sites were identified. Low constitutive levels of phosphorylation at Ser25 and Ser38 in Op18a and Op18b was demonstrated. Treatment with PMA resulted in enhanced phosphorylation of Ser25 in Op18a and of both Ser25 and Ser38 in Op18b. Taken together with prior studies of Op18 phosphorylation, the data suggest that Op18 phosphorylation occurs at identical sites in different tissues and organisms.

Maturation stage and proliferation-dependent expression of dUTPase in human T cells.

We have developed a database of lymphoid polypeptides detected by two-dimensional polyacrylamide gel electrophoresis to aid in studies of leukemogenesis and of mutation affecting protein structure. In prior studies, we observed a 19-kDa phosphopolypeptide which was induced with proliferation in mature T cells and constitutively expressed in immature thymocytes. In this report we describe the identification of this polypeptide as the phosphorylated form of dUTPase (EC 3.6.1.23), following cDNA cloning of the gene, based on a partial amino acid sequence of the phosphopolypeptide. Studies of the expression and phosphorylation of dUTPase in human T cells indicate that accumulation and phosphorylation of dUTPase in mature T cells occur in a cell cycle-dependent manner. Interestingly, noncycling immature thymocytes express constitutively high levels of phosphorylated and unphosphorylated dUTPase. These results suggest an important role for dUTPase in immature thymocytes that is independent of proliferation.

Elevated proliferating cell nuclear antigen levels in immature thymocytes. Dissociation from cell cycle progression.

Entry into and progression through the cell cycle is associated with a tightly regulated program of gene expression in mature T cells. One such gene product, proliferating cell nuclear Ag (PCNA), is the auxiliary protein of DNA polymerase delta, and is induced during late G1 and early S phase after stimulation of resting (G0) cells. Blockade of PCNA production has been found to inhibit cell division suggesting that PCNA plays an important role in cell proliferation. The extent to which PCNA and other proliferation-related gene products are similarly regulated in thymocytes has been largely undetermined. Here, we report that immature double positive (CD4+CD8+) thymocytes express high levels of PCNA protein and mRNA relative to mature single positive (CD4+CD8- or CD4-CD8+) thymocytes or peripheral blood T cells. Elevation of PCNA expression among double positive thymocytes is not the result of increased numbers of cycling cells in this subpopulation, being specifically observed in double positive thymocytes with normal diploid DNA content and resting (G0) levels of RNA. Unlike mature thymocytes and T cells, mitogenic stimulation did not induce an increase in PCNA expression in double positive thymocytes. These data indicate that immature thymocytes express high levels of PCNA in the absence of cell cycle progression, thus providing evidence for differential regulation of proliferation related pathways during lymphoid development. Altered expression patterns of these genes in immature vs mature thymocytes may contribute to the process of thymic selection.

Data base analysis of protein expression patterns during T-cell ontogeny and activation.

We have developed a data base of lymphoid proteins detectable by two-dimensional polyacrylamide gel electrophoresis. The data base contains two-dimensional patterns and derived information pertaining to polypeptide constituents of unstimulated and stimulated mature T cells and immature thymocytes, single-cell-derived T- and B-cell clones, leukemia cells, and lymphoid cell lines. Using this data base, we have compared the protein constituents of mature T cells and immature thymocytes before and after mitotic stimulation. A subset of polypeptides that are induced in mature T cells following mitotic stimulation were found to be constitutively expressed in immature thymocytes. Other polypeptides exhibited differences in their expression between mature and immature thymocytes in a manner unrelated to proliferation. The identity of several constitutively expressed or mitotically induced proteins in lymphoid cells was established by microsequencing. These initial findings point to significant differences in the molecular pathways leading to proliferation between mature and immature T cells. The construction of this database should facilitate further studies of lymphoid differentiation and function.

Differential expression of Op18 phosphoprotein during human thymocyte maturation.

Op18 (also termed prosolin/stathmin) is a highly conserved 18-kD cytosolic phosphoprotein expressed in low levels in mature resting G0 lymphocytes, but induced in late G1 and S phases after entry into the cell cycle. In addition to its induction in normal proliferating lymphocytes, Op18 has been found to occur at high levels in acute leukemias and in neuroendocrine tissue. The presence and rapid phosphorylation of Op18 after stimulation of proliferating cells correlates with subsequent functional responses of the cells, and, therefore, Op18 has been suggested to play a key role in signal transduction. The pattern of expression of Op18 during lymphoid development is of interest in view of its high levels of expression in acute leukemias, representing cells arrested at an immature stage, thus raising the possibility that Op18 may be regulated differently in mature and immature lymphoid cells. We report here that immature human thymocytes bearing the cortical double positive phenotype (CD4+CD8+) constitutively express high levels of Op18 protein. In contrast, in mature single positive thymocytes (CD3+CD4+ or CD3+CD8+), Op18 protein is expressed at a lower level, comparable to that seen in peripheral blood T cells. Cell cycle analysis demonstrated that most of the cells in the double positive thymocyte population expressing high levels of Op18 were noncycling and arrested in G0. Furthermore, there was no correlation between Op18 levels and the proportion of cycling cells in double positive thymocyte populations isolated from different thymuses. Interestingly, although Op18 protein levels did not increase any further after mitogenic stimulation of double positive thymocytes, an increase in Op18 phosphorylation was observed, thus coupling of Op18 phosphorylation to cell activation remained intact. Our results show that during lymphoid maturation Op18 expression is uncoupled from cell proliferation. These data also suggest that the ordered expression of proliferation-associated genes seen in mature T cells may be disrupted during T cell maturation.

Similarity of spontaneous germinal and in vitro somatic cell mutation rates in humans: implications for carcinogenesis and for the role of exogenous factors in "spontaneous" germinal mutagenesis.

The rate of spontaneous mutation resulting in electrophoretic variants per cell generation in a human lymphoblastoid cell line, on the basis of experiments described in this paper, is found to be 7.2 x 10(-8) per locus. A review of similar data on electrophoretic variants resulting from spontaneous mutation in the human germ line leads to an estimate of 3.3 x 10(-8) per locus per cell generation. It is argued that the similarity of these two estimates, despite an average cell generation time of 18.5 hr for the cultured somatic cells but about 26 days in the germ line, suggests that spontaneous mutation involving nucleotide substitutions is much more dependent on cell generation than on time. This finding permits the inference that environmental (exogenous) variables make a relatively small contribution to the rate of this type of human germinal spontaneous mutation. While in vitro somatic-cell mutation rates, such as derived in this study, provide a basis for modeling the contribution of nucleotide substitutions in multihit/clonal theories of carcinogenesis, it is also argued that the complex of events involved in carcinogenesis, including chromosomal rearrangements and mitotic recombination, could have very different individual probabilities. Estimates for the rates of these other types of mutation are needed to provide a better understanding of the manner in which multiple mutations accumulate in malignant cells.

Activation of resting peripheral blood lymphocytes through the T cell receptor induces rapid phosphorylation of Op18.

Op18 is a highly conserved major cytosolic phosphoprotein that has been implicated in signal transduction in a wide variety of cell types. Freshly isolated peripheral blood lymphocytes (PBL) constitutively express low levels of mostly unphosphorylated Op18. After mitogenic stimulation of PBL, Op18 synthesis is induced at a time when cells are entering S-phase. In this study, we have examined the phosphorylation of Op18 in freshly isolated PBL after activation of the T cell receptor by OKT3. Quantitative analysis of Op18 phosphorylation was undertaken by metabolic labeling with 32Pi and PhosphorImager analysis of two-dimensional gels. After 10 or 15 min of activation by OKT3, one of the three major phosphorylated forms of Op18, designated Op18c, increased approximately 10-fold, which represented a most pronounced change among a large number of phosphoproteins analyzed. In time course experiments, increased Op18 phosphorylation to yield Op18c was observed as early as 2 min. Continued OKT3-induced activation for 20 to 72 h resulted in a further increase in phosphorylated Op18 forms, which paralleled new Op18 synthesis and occurred at a time when cells were entering S-phase, as determined by [3H]-thymidine incorporation. Inhibitors of lymphoid proliferation, cyclosporin A and RPM, had no effect on early (less than 15 min) phosphorylation. Addition of calphostin C, a specific inhibitor of protein kinase C, 1 min prior to stimulation of resting T cells with OKT3 completely inhibited further phosphorylation of Op18. Incubation of PBL with calphostin C for 75 min decreased constitutive levels of phosphorylated Op18. In contrast, inhibition of cyclic nucleotide-dependent protein kinases with HA1004 had no effect on Op18 phosphorylation. Activation of cAMP-dependent protein kinase with Forskolin or 8Br-cAMP did not increase Op18 phosphorylation. Our results suggest that Op18 phosphorylation is mediated by protein kinase C activation as an early event in T cell activation through the T cell receptor.

Phenotypic and functional similarities between 5-azacytidine-treated T cells and a T cell subset in patients with active systemic lupus erythematosus.

OBJECTIVE: Antigen-specific CD4+ T cells treated with DNA methylation inhibitors become autoreactive, suggesting a novel mechanism for autoimmunity. To test whether this mechanism might be involved in systemic lupus erythematosus (SLE), phenotypic markers for the autoreactive cells were sought. METHODS: Cloned normal T cells were treated with the DNA methylation inhibitor 5-azacytidine (5-azaC) and studied for altered gene expression. T cells from patients with active SLE were then studied for a similar change in gene expression, and cells expressing the marker were tested for autoreactivity. RESULTS: 5-azaC-treated normal T cells had increased CD11a (leukocyte function-associated antigen 1 alpha) expression relative to other membrane molecules. A T cell subset with similar CD11a expression was found in patients with active SLE. This subset contained cells that spontaneously lysed autologous macrophages, with a specificity similar to that of 5-azaC-treated cells.