S100B and pulmonary hypertension: Studies show that Rhesus macaques demonstrate pulmonary hypertension (PH)-like pulmonary vascular remodeling, when infected with chimeric SHIVnef virions, but not with SIV, indicating a role of HIV-Nef in PH, with certain Nef gene variants showing a higher propensity to develop PH (123, 124).