The leucocyte count was significantly higher in the immunocompromised control group compared to the group of proven PJP cases (p = 0.0214, Table 3); the CD4+ Th-lymphocyte count was significantly higher in the healthy control group compared to proven PJP cases (p = 0.0006, Table 3) as well as the total T-lymphocyte count (p = 0.0092, Table 3). Here, CD4 is linked to pneumocystosis.