This may be a weakness of the study because we are often faced with patients from urban areas, known to be more frequently obese than those from rural areas. Another limitation of this study is the fact that multiple determination of serum leptin was not performed (before/after therapeutic interventions). Obese patients have usually many comorbid-associated conditions and a high risk of viral infectious diseases; therefore we did not include them in our cohort; additionally, we did not include patients with asymptomatic infections before starting the systemic treatment [35-37]. This evidence concerns the gene LEP and viral infectious disease.