Although PCP rates have dropped in the combination antiretroviral therapy (cART) era from 29.9 (1994-1997) to 3.9 (2003-2007) per 1000 person-years in a US cohort [2], PCP mortality still carries a relative mortality hazard of 2.8, even after adjusting for cART, demographics, CD4 cell count and viral load [2]. Here, CD4 is linked to pneumocystosis.