This pneumonia is characteristically an opportunistic infection, occurring in people whose immune system has been profoundly impaired by cancer or by powerful immunosuppressive drugs. William L. Heyward and James W. Curran
Progression of conditions associated with human papillomavirus, such as cutaneous warts, is common in patients receiving long-term immunosuppressive therapy after transplantation. Nektarios I. Lountzis et al.