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Reversal in fatigued athletes of a defect in interferon γ secretion after administration of Lactobacillus acidophilus
  1. R L Clancy1,
  2. M Gleeson2,
  3. A Cox2,
  4. R Callister1,
  5. M Dorrington2,
  6. C D’Este1,
  7. G Pang1,
  8. D Pyne3,
  9. P Fricker3,
  10. A Henriksson4
  1. 1Department of Immunology and Microbiology, University of Newcastle, Newcastle, NSW, Australia
  2. 2Hunter Area Pathology Service, John Hunter Hospital, New Lambton, NSW, Australia
  3. 3Australian Institute of Sport, Belconnen, ACT, Australia
  4. 4University of New South Wales, Sydney, NSW, Australia
  1. Correspondence to:
 Professor Clancy
 Department of Immunology and Microbiology, University of Newcastle, NSW 2300, Australia; robert.clancy{at}


Background: Fatigue and impaired performance in athletes is well recognised and has been loosely linked to “overtraining”. Reduced concentration of IgA in the saliva and increased shedding of Epstein Barr virus (EBV) have been associated with intense training in elite athletes.

Objective: To determine whether athletes presenting with fatigue and impaired performance had an immune defect relevant to defective containment of EBV infection, and whether a probiotic preparation (Lactobacillus acidophilus) shown to enhance mucosal immunity in animal models could reverse any detected abnormality.

Results: The fatigued athletes had clinical characteristics consistent with re-activation of EBV infection and significantly (p  =  0.02) less secretion of interferon (IFN) γ from blood CD4 positive T cells. After one month of daily capsules containing 2 × 1010 colony forming units of L acidophilus, secretion of IFNγ from T cells had increased significantly (p  =  0.01) to levels found in healthy control athletes. A significant (p  =  0.03) increase in salivary IFNγ concentrations in healthy control athletes after the one month course of L acidophilus demonstrated in man the capacity for this probiotic to enhance the mucosal IFNγ concentration.

Conclusion: This is the first evidence of a T cell defect in fatigued athletes, and of its reversal following probiotic therapy.

  • EBV, Epstein Barr virus
  • IFN, interferon
  • IL, interleukin
  • PCR, polymerase chain reaction
  • fatigue
  • overtraining
  • Epstein Barr virus re-activation
  • interferon γ deficiency
  • Lactobacillus acidophilus

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  • The study was funded in part by DSM Food Specialties Australia, who provided the Lactobacillus acidophilus (LAFTI®-10).

  • Competing interests: RC is a consultant for DSM (but received no payment for this study). AH is an employee of DSM. AC was funded by DSM. None of the other investigators had links with DSM or related companies.

  • Ethics: The study was approved by the human research ethics committee of the University of Newcastle, NSW, Australia, and the Hunter Area Research Ethics Committee, John Hunter Hospital, Newcastle, NSW, Australia, and all subjects gave informed and signed consent.