The causes of persistent immune activation are poorly understood, and may include low levels of ongoing HIV replication, microbial translocation, co-infections with non-HIV pathogens, loss of immunoregulatory cells, persistent elevation of type I and II IFN, and dysregulated cytokine/chemokine production (Appay and Sauce 2008; Boasso and Shearer 2008; d’Ettorre et al. 2011; Sandler and Douek 2012). The gene discussed is IFNA1; the disease is coinfection.