TAT and HIV infectious disease: Also, this special issue include review articles on epigenetic alterations in drugs of abuse and HIV infection that affects Vitamin D receptors (Chandel et al.); role of miRNs during HIV infection and effect of drugs of abuse on the expression of miRNAs and its effect on HIV associated neurocognitive disorders (Pilakka-Kanthikeel and Nair); effect of HIV-1 Tat and drugs of abuse during HIV infection and their role in the development of NeuroAIDS (Maubert et al.); and anti-HIV effects of different natural compounds (Kurapati et al.).