Inflammation involving the inter-alveolar areas of the lungs; often caused by viruses (e.g. CMV), but may also be caused by irradiation and drugs.

inflammation or swelling of the lungs that can occur during chemotherapy; sometimes referred to as interstitial pneumonia; usually responds to steroid treatment

A severe inflammation in the lungs that can occur as a toxic effect of total body irradiation in the conditioning regimen for transplantation. The small airways and intervening spaces between the air sacs get congested and swollen. The exchange of oxygen between inspired air and the blood flowing through the air sac linings can be compromised. Typically, no infection is present although a similar reaction can occur as a result of infection.