Abstract
Chronic lymphocytic leukaemia (CLL), even when severe, is not directly associated with opportunistic infections. Opportunistic infections that occur with CLL are almost exclusively related to immunosuppression caused by chemotherapeutic drugs used to treat CLL. We report a case of Pneumocystis jirovecii (PJ) pneumonia that occurred in a patient with untreated CLL with pulmonary involvement. We suspect that PJ pneumonia resulted from an inadequate immune response in the lung parenchyma resulting from excessive local accumulation of CLL cells.