It is also possible that CP673451 nmr a salient infection occurred earlier in life, was

cleared, but the infection sequelae are responsible for clinical state. Such infections, in the case of known viruses, can in many cases be detected via serology. Finally, it is possible that chronic fatiguing illness represents a similar clinical OICR-9429 research buy endpoint for multiple different disease etiologies (which may or may not be infectious in nature) and that etiological heterogeneity effectively lessens the probability of detection. Conclusions Our results show a weakly significant difference between affected and unaffected twins in the cross-sectional prevalence of GBV-C viremia. Whether this is etiologically important or due to chance or bias is not clear. However, the possible connection between GBV-C and CFS deserves further study in larger samples. Methods Subjects The protocol was approved in advance by the ethical review board at UNC-CH and the Karolinska Institutet and all subjects provided written informed consent. The parent study is described elsewhere [22–24], and we have previously shown that there were no differences in gene expression in peripheral blood buy AZD2281 in monozygotic twins discordant for chronic fatigue [12]. We screened ~61,000 individual twins from the Swedish

Twin Registry for the symptoms of fatiguing illness. All twins were born in Sweden of Scandinavian ancestry. Of 5,597 monozygotic twin pairs where both were alive and had provided usable responses to CFS screening questions, we identified 140 pairs of twins who met preliminary inclusion criteria: born 1935-1985, classified as a monozygotic twin based on questionnaire responses [25], and discordant for chronic fatiguing illness (i.e., one twin reported substantial fatigue and the other

twin was evidently well). A telephone interview using a standardized script was used to assess eligibility for participation. learn more Twins who remained eligible both attended a half-day clinical assessment by a specially trained physician at the Karolinska Institutet in Stockholm. At this visit, a CFS-focused medical assessment was conducted that included standardized medical history, physical examination, and screening biochemical, hormonal, and hematological studies in accordance with international recommendations [1]. Of 140 monozygotic and preliminarily discordant twin pairs, one or both twins declined participation in 23 pairs, 25 pairs were concordant for CFS-like illness, and inclusion criteria were not met in 35 pairs (e.g., chronic fatigue had resolved or an illness that could explain fatiguing symptoms such as neoplasia had emerged).