Can mycotoxin exposure alter immune function without proving mold caused herpesvirus reactivation?

Mycotoxins can affect immune biology, but this does not make a urinary mycotoxin result evidence that indoor mold caused herpesvirus reactivation in this 71-year-old woman.

Immune effects

• Experimental and animal studies show that several mycotoxins can alter macrophage activity and inflammatory cytokine signaling. Effects can vary by toxin, dose, and duration, with inflammatory responses at some exposures and immune suppression at others.
• Human evidence is strongest for biomarker-defined, largely foodborne aflatoxin exposure. Higher aflatoxin B1–albumin adduct levels have been associated with lower CD8+ T-cell perforin expression, lower regulatory/naïve CD4+ T-cell and B-cell proportions in people with HIV, and fewer activated T and B cells.
• These associations support immunomodulatory potential but do not establish clinically meaningful systemic immune dysfunction from ordinary indoor airborne mold exposure.

What urine mycotoxin testing can—and cannot—show

• A urinary mycotoxin result indicates internal exposure, not the source, dose, timing, or clinical consequence of that exposure.
• Dietary exposure is a documented alternative explanation: mycotoxins can be detected in healthy people after consumption of commonly implicated foods, including cereals, corn, nuts, coffee, wine, and dried fruit.
• No FDA-approved urine test diagnoses illness from indoor mold exposure, and no disease-predictive urinary thresholds have been established. Spot urine results may also vary with recent food intake and urine dilution.

Causation and herpesvirus reactivation

• No direct clinical or epidemiologic evidence demonstrates that documented indoor mold or mycotoxin exposure causes EBV, CMV, or other herpesvirus reactivation.
• Immune effects observed in experimental systems are indirect and cannot establish viral reactivation in an individual. Objectively documented reactivation should prompt assessment of more established contributors, including acute illness and immunosuppression.

Bottom line

• Mycotoxins have plausible innate and adaptive immunomodulatory effects, but urine findings cannot attribute exposure to mold or establish that mold triggered herpesvirus reactivation.