1. Department of Infectious Diseases, King's College London, London, United Kingdom.
2. Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
3. Instituto de Nutrição Josué de Castro, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
4. Metabolic Unit, Department of Clinical Chemistry, VU Medical Center, Amsterdam, the Netherlands.