Autoantibodies to a 68/48 kDa protein in chronic fatigue syndrome and primary fibromyalgia: a possible marker for hypersomnia and cognitive disorders

OBJECTIVE

To identify antinuclear antibodies (ANA) specific for chronic fatigue syndrome (CFS), and in related conditions such as fibromyalgia (FM) or psychiatric disorders.

METHODS

One hundred and fourteen CFS patients and 125 primary and secondary FM patients were selected based on criteria advocated by the Centers for Disease Control and Prevention and by the American College of Rheumatology, respectively. As controls, healthy subjects and patients with either various psychiatric disorders or diffuse connective tissue diseases were included. Autoantibodies were examined by immunoblot utilizing HeLa cell extracts as the antigen.

RESULTS

Autoantibodies to a 68/48 kDa protein were present in 13.2 and 15.6% of patients with CFS and primary FM, respectively. In addition, autoantibodies to a 45 kDa protein were found in 37.1 and 21.6% of the patients with secondary FM and psychiatric disorders, respectively. Meanwhile, these two autoantibodies were not found at all in connective tissue disease patients without FM, nor in healthy subjects (P<0.05). As a group, the anti-68/48 kDa-positive CFS patients presented more frequently with hypersomnia (P<0.005), short-term amnesia (P<0.07) or difficulty in concentration (P<0.05) than those CFS patients without the antibodies.

CONCLUSIONS

The presence of the anti-68/48 kDa protein antibodies in a portion of both CFS and primary FM patients suggests the existence of a common immunological background. These antibodies may find utility as possible markers for a clinicoserological subset of CFS/FM patients with hypersomnia and cognitive complaints.