Elevation of Candida IgG antibodies in patients with medically unexplained symptoms

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".

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.

This was a case-controlled study.

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.

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.

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.