) accumulate in the air sacs of the lungs (alveoli).People usually cough and have difficulty breathing.
Diagnosis requires chest x-ray, computed tomography, pulmonary function tests, and often bronchoscopy, biopsy, or both.
Treatment involves corticosteroids, immunosuppressants, or both.
(See also Overview of Idiopathic Interstitial Pneumonias Overview of Idiopathic Interstitial Pneumonias Idiopathic interstitial pneumonias are interstitial lung diseases that have no known cause that have some similarities in symptoms and how they affect the lungs. Some types of these diseases... read more .)
Lymphoid interstitial pneumonia is a form of idiopathic interstitial pneumonia Overview of Idiopathic Interstitial Pneumonias Idiopathic interstitial pneumonias are interstitial lung diseases that have no known cause that have some similarities in symptoms and how they affect the lungs. Some types of these diseases... read more . It can occur in children, usually those infected with the human immunodeficiency virus Human Immunodeficiency Virus (HIV) Infection in Children Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and causes acquired immunodeficiency syndrome (AIDS). Human immunodeficiency... read more (HIV). Lymphoid interstitial pneumonia can also occur in adults, often those with autoimmune disorders such as plasma cell disorders Overview of Plasma Cell Disorders Plasma cell disorders are uncommon. They begin when a single plasma cell multiplies excessively. The resulting group of genetically identical cells (called a clone) produces a large quantity... read more , Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a common autoimmune rheumatic disorder and is characterized by excessive dryness of the eyes, mouth, and other mucous membranes. White blood cells can infiltrate and... read more 
, Hashimoto thyroiditis Hashimoto Thyroiditis Hashimoto thyroiditis is chronic, autoimmune inflammation of the thyroid. Hashimoto thyroiditis results when the body attacks the cells of the thyroid gland—an autoimmune reaction. At first... read more , rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is an inflammatory arthritis in which joints, usually including those of the hands and feet, are inflamed, resulting in swelling, pain, and often destruction of joints.... read more 
, and systemic lupus erythematosus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic autoimmune inflammatory connective tissue disorder that can involve joints, kidneys, skin, mucous membranes, and blood vessel walls. Problems in the... read more 
(lupus). Women and girls are more commonly affected. Average age of affected adults is 54.
Symptoms of Lymphoid Interstitial Pneumonia
Children develop cough and decreased ability to exercise, and they may not grow and gain weight. Adults develop difficulty breathing and cough over months or, in some cases, years. Less common symptoms include weight loss, fever, joint pain, and night sweats.
Diagnosis of Lymphoid Interstitial Pneumonia
Chest computed tomography
Diagnosis requires chest x-ray, computed tomography (CT), and pulmonary function testing Pulmonary Function Testing (PFT) Pulmonary function tests measure the lungs' capacity to hold air, to move air in and out, and to absorb oxygen. Pulmonary function tests are better at detecting the general type and severity... read more 
. Pulmonary function tests usually show a decrease in the amount of air the lungs can hold. Doctors often do bronchoscopy Bronchoscopy Bronchoscopy is a direct visual examination of the voice box (larynx) and airways through a viewing tube (a bronchoscope). A bronchoscope has a camera at the end that allows a doctor to look... read more 
and wash segments of the lung with a salt-water solution and then collect the washings (bronchoalveolar lavage) for testing.
Blood tests may reveal abnormalities in their blood proteins that can help establish the diagnosis. This blood protein test is particularly useful in children and may be adequate to establish the diagnosis. If not, and for all adults, lung biopsy is usually necessary.
Treatment of Lymphoid Interstitial Pneumonia
Corticosteroids or cytotoxic drugs
The prognosis is difficult to predict. The disorder may resolve on its own or after treatment, or it may progress to lung fibrosis or lymphoma Overview of Lymphoma Lymphomas are cancers of lymphocytes, which reside in the lymphatic system and in blood-forming organs. Lymphomas are cancers of a specific type of white blood cells known as lymphocytes. These... read more 
(a cancer). One half to two thirds of people are alive 5 years after diagnosis.
Treatment is with corticosteroids, cytotoxic drugs (such as azathioprine or cyclophosphamide), or both, but the effectiveness of these drugs is unknown.
