Male gender was a protective factor for TDs development, especially for hypothyroidism (p < 0.001); age emerged as a variable associated with both hypothyroidism (p = 0.03) and thyroid cancer (p = 0.03), while CD4+ cell nadir <200 cell/mm3 was associated with symptomatic hyperthyroidism (p = 0.005). This evidence concerns the gene CD4 and hypothyroidism.