P2RX4 and sensory peripheral neuropathy: The authors suggested that polymorphisms in the P2RX4 gene and association with HIV-associated sensory neuropathy may be due to the role of P2X4 in pain (139) and the fact that some patients presenting specific P2RX4 alleles had increased TNF-α concentrations in their PBMC (140), which contributes to the onset of disease.