Acute eosinophilic pneumonia caused by cigarette smoking

Alterations in smoking habits are associated with acute eosinophilic pneumonia

BACKGROUND

Acute eosinophilic pneumonia (AEP) is characterized by a febrile illness, diffuse pulmonary infiltrates, and pulmonary eosinophilia. The etiology of AEP remains unknown, but several studies have proposed a relationship between cigarette smoking and AEP. However, most studies showing this possibility are single-case reports, and cigarette smoke has not been fully validated as a causative agent of AEP in a large series of patients. The present study was conducted to clarify the etiologic role of cigarette smoking in AEP, with special reference to alterations in smoking habits.

METHODS

We took a detailed history of smoking habits before AEP onset in 33 patients with AEP, and performed a cigarette smoke provocation test.

RESULTS

Of our AEP patients, all but one (97%) were current smokers. Interestingly, 21 of these were new-onset smokers, and 2 had restarted smoking after a 1- to 2-year cessation of smoking. The duration between starting smoking and AEP onset was within 1 month (0.67 +/- 0.53 months). Additionally, six of the remaining smokers had increased the quantity of cigarettes smoked daily, fourfold to fivefold, mostly within the month before AEP onset (0.81 +/- 0.58 months). Only three smokers had not changed their smoking habits before AEP onset. Cigarette smoke provocation tests revealed positive results in all nine patients tested.

CONCLUSION

These data suggest that recent alterations in smoking habits, not only beginning to smoke, but also restarting to smoke and increasing daily smoking doses, are associated with the development of AEP.

Reduced IgG levels found during acute eosinophilic pneumonia, which normalize during recovery from disease

Clinically there are several different types of eosinophilic pneumonia (EP), but other than for tropical pulmonary eosinophilia, the humoral immune response between different types of EP, such as acute eosinophilic pneumonia (AEP), chronic EP, drug-induced EP, allergic bronchopulmonary aspergillosis, and Churg-Strauss syndrome, has not been examined. Immunoglobulin G (IgG) and E (IgE) serum concentrations were analyzed in patients with EP, or bacterial pneumonia, and in age-matched controls. Patients with AEP had lower IgG levels than the age-matched controls. Serum IgG levels in patients with AEP were significantly lower than in patients with other types EP or bacterial pneumonia. IgG2 and IgG4 were also significantly decreased in AEP, compared to age-matched controls. In AEP, the serum IgG levels were significantly decreased during active disease and increased during remission, but the serum IgE levels did not change significantly, indicating a decrease in serum IgG is a common feature of AEP. Low IgG levels were significantly correlated with serum surfactant protein D and absolute eosinophil counts in the bronchoalveolar lavage fluid of patients with AEP. This is the first reported study of immunoglobulin levels in AEP. The pathogenesis of AEP might negatively affect serum IgG levels, but not IgE levels. The present findings might indicate that serum IgG reflects the inflammatory response in AEP.

Acute eosinophilic pneumonia caused by Candida albicans

A 36-year-old man was transferred to the hospital for further evaluation of pulmonary infiltration. A diagnosis of acute eosinophilic pneumonia (AEP) was confirmed by clinical symptoms, bronchoalveolar lavage, and computed tomography findings. Skin tests with fungal antigens were performed by intradermal injection. Both the Arthus (8 h) and delay (24 h)-type skin tests were positive for only Candida albicans. A lymphocyte-stimulating test was also positive for C. albicans. The etiology of the AEP was confirmed by a C. albicans inhalation provocation test. In addition, peripheral blood mononuclear cells obtained from the patient produced Interleukin-5 following C. albicans stimulation. This is the first report of C. albicans as a probable cause of AEP. Evaluation of allergy to C. albicans should be performed in AEP before diagnosing the cause as idiopathic.

Elevated Levels of Antimicrobial Peptides in Bronchoalveolar Lavage Fluid in Patients with Chronic Eosinophilic Pneumonia

BACKGROUND

Chronic eosinophilic pneumonia (CEP) is an idiopathic pulmonary disease. As the lung is in direct communication with the environment, inhaled antigen may activate immune mechanisms in the airway that may participate in the pathogenesis of idiopathic pulmonary diseases. Defensins are antimicrobial peptides that consist of alpha-defensin (HAD) in neutrophils and beta-defensin (HBD) in epithelial cells. Defensins act as innate immunity against pathogens acquired from the environment and as mediators to induce local inflammation.

OBJECTIVES

The aim of the present study was to determine whether immune mechanisms in the airway are induced in CEP patients.

METHODS

We measured BALF defensin levels in patients with CEP, acute EP (AEP) and drug-induced eosinophilic pneumonia (drug-EP). We also measured BALF levels of IL-5, GM-CSF, eotaxin and RANTES. These substances can recruit eosinophils.

RESULTS

BALF HAD levels were higher in patients with CEP than in those with drug-EP and normal controls. HBD-2 was detected in BALF of 10 of 11 CEP patients and in 3 of 5 AEP patients while its level was below detection in drug-EP patients and normal controls. BALF HBD-2 levels correlated with the proportion of lymphocytes in CEP patients.

CONCLUSION

The defensin-linked immune system is activated in CEP but not in drug-EP. This suggests that inhaled antigen(s) may be involved in the pathogenesis of CEP.

Bacterial species diversity in cigarettes linked to an investigation of severe pneumonitis in U.S. Military personnel deployed in operation iraqi freedom

This report presents results from a study on the bacterial diversity of cigarette brands collected from military personnel during the U.S. Army's investigation of a series of cases of acute eosinophilic pneumonitis in military personnel deployed in Operation Iraqi Freedom. Eight species of Bacillus, including five new species, and one new species of Kurthia were isolated from the cigarettes. Some of these species have been identified elsewhere as causes of hypersensitivity pneumonitis and other respiratory syndromes. All of the isolates were facultative anaerobes, and many displayed mucoid growth under anaerobic conditions. In addition, many isolates also displayed the ability to form surface biofilms under liquid culture. Although biofilm formation and mucoid growth were not correlated, the former was found to be much more pronounced under anaerobic conditions as opposed to aerobic ones. The implications of these findings are discussed.