Is there any relationship between eosinophilia myalgia syndrome (EMS) and fibromyalgia syndrome (FMS)? An analysis of clinical and immunological data.

The eosinophilia-myalgia syndrome (EMS) caused by intake of contaminated L-tryptophan resembles in its clinical presentation the fibromyalgia syndrome (FMS). We, therefore, analysed clinical and immunological parameters in 16 patients with chronic EMS and 100 patients with FMS in order to see whether there may be a relationship between both disorders. From 12 FMS patients and 12 controls also peripheral blood mononuclear cells (PBMC) were obtained. Myalgia and arthralgia was observed in chronic EMS in the same incidence as in patients with FMS (81%). Also antibodies to serotonin, gangliosides and phospholipids were present in both groups. In vitro stimulation of PBMC with different L-tryptophan preparations revealed in six of the 12 FMS patients but only two of the control individuals a production of type 2 cytokines (IL-5, IL-10). We, therefore, conclude that EMS may have developed in patients suffering primarily from FMS as an allergic reaction towards a more immunogenic L-tryptophan preparation.