CD4 and viral infectious disease: This is a new option with good results but so far its application has been too limited to allow assessment of its efficacy.[2,12,15] The unsatisfactory results of conventional treatment protocols have prompted a possible association of frequent relapses with an inefficient antiviral immune response.[10] Control and resolution of viral infection require activation of natural cellular mechanisms combined with differentiation of interferon-γ, CD4 (Th1) and CD8 T cells, while a regulatory CD4+FoxP3+T subset prevents the antigen-specific clones from exhaustion, and potentiates formation of memory.