Elevation of Candida IgG antibodies in patients with medically unexplained symptoms.

Background: The hypothesis that an immunologic reaction to Candida yeasts, present in the gastrointestinal tract, causes a diffuse collection of multisystem symptoms is not generally accepted within conventional medicine. A questionnaire, the Fungus Related Disease Questionnaire (FRDQ-7), was previously developed and used to identify patients for a randomized, placebo-controlled trial of the nonabsorbed antifungal drug nystatin. Nystatin was superior to placebo in relieving these symptoms. This provides some support for the hypotheses that underpin the "Candida syndrome".

Aim: The aim of this study was to identify a population with a high (>9) FRDQ-7 score and symptom-free controls and, subsequently, to explore the relationship between FRDQ-7 scores and Candida immunoglobulin (Ig)A, IgG, and IgM levels.

Design: This was a case-controlled study.

Methods: Santelmann has suggested that the FRDQ-7 describes people with Candida syndrome if the FRDQ-7 score is >9; 35 patients with medically unexplained symptoms, between ages 18 and 64, were selected for the study if they scored > 9 on the FRDQ-7 questionnaire. Serum Candida IgA, IgG, and IgM measurements were undertaken both for this group and a group of 45 healthy age- and gender-matched controls, and the Ig concentrations were compared.

Results: Candida IgG concentration was significantly higher in the noncontrol group than in the control group (p < 0.001). No significant difference was found for Candida IgA or IgM concentrations.

Conclusions: Further studies are required to identify whether there is a causal link for the elevation of serum IgG found in this subgroup of patients with increased FRDQ-7 scores, or whether these two observations are parallel manifestations of a common underlying disorder.