The Frequency of HLA Class II Antigens in Chronic Fatigue Syndrome

Abstract Chronic fatigue syndrome is a condition characterized by unexplained, persistent fatigue in conjunction with other generalized symptoms. However, the patients as a group are more likely to have objective abnormalities of the immune system than control subjects. We measured the frequency of certain HLA antigens in a representative group of 35 patients. We restricted our analysis to class II molecules as these appear to be more specific predictors of susceptibility to immunologically-based disorders. The frequency of the HLA-DQ1 antigen was increased in patients compared to general population Caucasian controls. This association between chronic fatigue syndrome and the HLA-DQ1 antigen translates into a relative risk of 3.2. This association has not been reported previously in chronic fatigue syndrome. Differences in the ethnic sub-grouping of patients in this study and in previous studies also could have contributed to the difference between our findings and those of previous investigators. Conversely, this study did not find HLA associations that have been reported by previous studies. The sample size of this study could have led to type II statistical errors and a failure to recognize certain HLA associations as significant.