Israel Medical Association Journal

Background: Fibromyalgia syndrome (FMS) is estimated to affect 2–4% of the general population. While FMS has some known environmental and genetic risk factors, the disorder has no clear etiology. A common coexisting disorder with FMS is small fiber neuropathy (SFN). High levels of serum immunoglobulin M (IgM) binding to trisulfated-heparin-disaccharide (TS-HDS) were recently found to be associated with SFN.

Objectives: To evaluate potential differences in anti-TS-HDS antibody titers in women with FMS compared to healthy controls.

Methods: In this cross-sectional study, we evaluated 51 female participants: 30 with a diagnosis of FMS and 21 healthy controls who had been recruited at the Zabludowicz Center for Autoimmune Diseases, Sheba Medical Center, Israel. All of the participants were older than 18 years of age. Anti-TS-HDS IgM levels were measured in their sera using the enzyme immunoassay technique.

Results: The mean anti-TS-HDS IgM levels were significantly lower in the FMS group, compared with the control group (7.7 ± 5 vs. 13.2 ± 8.6 U/ml, respectively; P = 0.013).

Conclusions: There is a possible association between FMS and anti-TS-HDS IgM. This association might be the missing link for the coexistence of SFN and FMS, but further study should be performed to assess this association and this auto-antibody characteristic.

Background: Heat shock proteins are highly conserved immunodominant antigens found in various species. Humoral immune responses to mycobacterial HSP65[1] and human HSP60 have been established in a number of human autoimmune diseases.

Objective: To assess the prevalence of antibodies to HSP60 kDa and HSP65 kDa in patients with Sjogren's syndrome as compared to normal subjects.

Methods: Thirty-seven patients with SS[2] were compared with normal controls. The antibodies against human HSP60 were measured by the Anti-Human (IgG/IgM) HSP60 ELISA kit. IgGs[3] and IgMs to mycobacterial HSP65 were determined using an enzyme-linked immunosorbent assay with mycobacterial recombinant HSP65 antigens.

Results: The levels of both anti-HSP60 and -HSP65 were lower among patients compared with controls. IgG autoantibodies to HSP60 were significantly different between groups: 162 ± 55.1 ng/ml in controls versus 112.3 ± 30.6 ng/ml in SS patients (P < 0.001). The levels among controls of anti-HSP65 IgM isotype were also significantly higher than among patients: 111.6 ± 33.4 U/ml versus 96.1 ± 8.9 U/ml (P = 0.01).

Conclusions: The results of the present study show that the levels of different isotypes of anti- HSP60 and HSP65 antibodies were lower in patients with SS than in normal subjects. Additional studies on larger patient populations are required to evaluate the prevalence of these autoantibodies in SS patients.