Unexpectedly high prevalence of primary immune deficiency in fibromyalgia: serologic features and clinical correlates

We sought laboratory evidence of primary immune deficiency (PID), a condition known to be associated with recurrent infections and autoimmunity, in fibromyalgia (FM). We correlated laboratory findings with a clinical history of recurrent infections and reduced epidermal nerve fiber density (ENFD).

We prospectively measured serum total and subclass concentrations for IgA, IgG, IgM, IgE, and mannose-binding lectin in 72 adult FM subjects (31 "FM only;" 41 "FM+RA") and compared those results against historical controls. We also administered a novel "Lifetime History of Infections" questionnaire to all FM subjects and 40 apparently healthy, community volunteers matched for age, race, and gender. ENFD values available for 49/72 FM subjects were also correlated with immunoreactant levels.

Of FM subjects, 96% (69/72) had ≥3 and 85% (61/72) had ≥4 of 9 immunoreactants below or within the lowermost quartile of historical normal values. Recurrent sinus infections occurred more often in "FM only" (p=0.06), and "FM+RA" subjects (p=0.02) than controls. "FM+RA" subjects had a significantly greater history of recurrent, severe non-sinus infections (p=0.04). The prevalence of total IgA deficiency was significantly greater in "FM only" than in "FM+RA" subjects (p=0.04). We also found a direct correlation between total IgA (p=0.02), IgA1 (p=0.005), and IgG1 (p=0.04) concentrations and ENFD in "FM only" subjects.

Serologic evidence of PID in FM is common and correlates with a clinical history of recurrent sinus and non-sinus infections, and reduced ENFD. This study suggests that PID may be important to diagnostic and therapeutic considerations in FM.