Commensal Fungi are Involved in Antigen-Specific Antibody Production in the Elderly

Aims: Fungi are an important health hazard as commensal antigens. To demonstrate sensitization to fungi in the elderly and the influence of prohibition of oral intake under intravenous hyperalimentation (IVH) management with administration of antibiotics, we measured commensal fungus-specific antibodies.

Methodology: Thirty one college students (21.7±1.0 years): Young adult group, 28 elderly subjects over 75 years from the outpatient department (84.3±4.5 years): Outpatient group, and 21 elderly subjects over 75 years who were inpatients and required IVH (87.6±6.0 years): Inpatient group were enrolled. Plasma β-D-glucan and serum total immunoglobulin (Ig) E, antigen-specific IgE for house dust (HD), Cladosporium, Alternaria, Trichophyton, and Candida and Candida-specific IgG were measured.

Results: Total IgE level was significantly decreased in the outpatient group compared to the young adult group (p＜0.01), and was increased in the inpatient group compared to the outpatient group (p＜0.05). HD-specific IgE was elevated in the young group compared to the two elderly groups (p＜0.01, respectively). There was no tendency for detection of Cladosporium-or Alternaria-specific IgE in the three groups. Tricophyton-specific IgE level was significantly elevated in the inpatient group compared to the young adult group (p＜0.01). Candida-specific IgE level was significantly elevated in the inpatient group compared to the outpatient group (p＜0.05). Candida-specific IgG was significantly elevated in the inpatient group compared to the other two groups (p＜0.001, respectively).

Conclusion: It is suggested that commensal fungi, such as Trichophyton and Candida, are more markedly associated with antigen-specific immunoglobulin production in an immunocompromised condition in the elderly.