CD4 and pneumocystosis: However, we added in our study a third subgroup of PCP named “putative PCP” to the two existing categories “proven PCP” and “probable PCP” defined by the EORTC/MSGERC classification, in order to include the immunosuppressed patients without CTC who did not have any measure of blood CD4 T cells counts or the subjects who did not have a radiological examination.