Category: Etiology

Comment on: Cortisol deficiency may account for elevated apoptotic cell population in patients with chronic fatigue syndrome. [J Intern Med. 1999]

Dear Sir, I would like to thank Dr Baschetti for his very interesting letter. I hope clinicians and CFS patients will be able to benefit from its contents. We agree that chronic fatigue syndrome (CFS) is an illness with uncertain aetiology. Although it is true that no single infectious agent has been identified as a primary cause of CFS, a variety of pathogens, including HTLV-II, EBV, cytomegalovirus, herpes simplex viruses 1 and 2, and human herpes viruses 6, 7 and 8, have been identified in CFS patients [1–7]. In addition to the pathogens previously mentioned, a recent study by our laboratory has identified Mycoplasma fermentans in a statistically significant number of CFS patients over non-CFS control subjects [8]. Further investigation is necessary to determine whether these pathogens are occurring secondarily to some immunological disturbances, as some investigators believe, or whether they are involved as a primary cause of symptoms characteristic of CFS. As mentioned by Dr Baschetti, various measures of immune function have been reported to be altered in CFS subjects, thereby suggesting an association rather than demonstrating a causative link. Abnormalities that have been reported include increased circulating immune complexes, reduced CD4 and CD8 T-lymphocyte subsets, diminished natural killer cell activity, reduction in IgG subclasses, reduced mitogenic response of lymphocytes, altered cytokine production, elevated titres of antibodies to a number of viruses and abnormal production of IFN [9–15]. However, similar immune functional abnormalities have been reported in patients exposed to toxic chemicals without evidence of viral infection or reactivation [16, 17]. Moreover, the symptomatologies described in these patients overlap with CFS patients, thus making the differentiation between the two groups extremely difficult [18–21]. In these articles, the substantial overlap between chemical sensitivity, fibromyalgia and CFA was discussed. It was concluded that the latter two conditions may involve chemical sensitivity and may even be the same disorder. In fact, in a separate study strictly with CFS patients without evidence of viral reactivation but exposed to methyl tertiary-butyl ether (MTBE) and benzene, we showed that programmed cell death and cell cycle were abnormal in both groups [22]. Similarly, in our original article published in this journal, we reported elevated apoptosis and abnormal cell cycle in CFS patients without a history of exposure to toxic chemicals. The interferon-induced protein kinase RNA (PKR) was found to be elevated in these patients as well and was therefore proposed as a possible mechanism of induction of apoptosis and cell cycle abnormalities [23].

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Source: Vojdani A. Single aetiological agent may not be feasible in CFS patients. J Intern Med. 1999 Apr;245(4):410-2. http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2796.1999.00479.x/full