Abstract 34: Increased risks of cancer and autoimmune disease among the first-degree relatives of patients with myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS)
Authors: Moslehi Roxana , Kumar Anil , Dzutsev Amiran 
Published: June 2022

Abstract
Background: Myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) is a disabling multi-system complex disorder with prevalence of 875 per 100,000 (up to 3.4 million people) in the United States. There are no known etiologic or risk factors and no approved treatments for ME/CFS. We conducted a molecular epidemiologic study to test the hypothesis that ME/CFS may be an autoimmune disease (AID) and explore the link between ME/CFS and cancer, specifically hematologic malignancies.
Methods: Our clinic-based study involved carefully selected cases with confirmed diagnosis of ME/CFS (n=59) and healthy controls (n=54) frequency matched to cases on age, gender and ethnicity. During structured interviews, detailed multi-generation pedigrees, epidemiologic and medical questionnaires, and biospecimen were obtained on all subjects. Statistical analysis of pedigree data involved comparison of cases and controls with respect to the prevalence and cumulative incidence of AID and cancer among their first-degree relatives. For unadjusted analysis, risk ratios, 95% confidence intervals (CI), and p-values were calculated. For age-adjusted analyses, cumulative incidence estimates were compared using the log-rank test.
Results: The prevalence of AID was significantly higher among the first-degree relatives of cases compared to those of controls (OR=5.30; 95%CI: 1.83-15.38; p=0.001). The prevalence of AID among mothers was 14% for cases and 1.9% for controls (p=0.03). 11.2% of the first-degree relatives of cases had an AID compared to 3.1% of the relatives of controls (prevalence ratio=3.71; 95% CI: 1.74-7.88; p=0.0007). The cumulative incidence of AID among the first-degree relatives of ME/CFS cases was 9.4% compared to 2.7% for those of the controls (p=0.0025). First-degree relatives of ME/CFS cases had a significantly higher prevalence of any cancer compared to the relatives of unrelated controls (OR=4.06, 95%CI: 1.84-8.96, p=0.0005). Age-adjusted analysis revealed significantly higher (p=0.03) cumulative incidence of any cancer among the first-degree relatives of cases (20%) compared to the relatives of controls (15.4%). The cumulative incidence of hematologic cancers was also significantly higher among the relatives of cases (p&lt;0.05).
Conclusions: We found statistically significant increased risks of AID and cancer among the first-degree relatives of ME/CFS cases. Our findings implicate immune dysregulation as an underlying mechanism, providing etiologic clues and leads for prevention. Given symptomatic similarities between ‘long COVID’ and ME/CFS, it is predicted that there will be a significant increase in incidence of ME/CFS as the result of COVID-19 pandemic. Our findings may enable defining a subset of COVID-19 patients who could be at risk of developing ME/CFS, and who may benefit from treatments used for certain AIDs.
Citation Format: Roxana Moslehi, Anil Kumar, Amiran Dzutsev. Increased risks of cancer and autoimmune disease among the first-degree relatives of patients with myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 34.