Environmental triggers of autoimmunity in anti-synthetase syndrome: the lungs under the spot light.

The prevalence of interstitial lung involvement in anti-synthetase syndrome (anti-SS) may be as high as 70% and is a major contributor to morbidity and mortality. Histidyl-tRNA synthetase (Jo-1) is the most common autoantigenic target among the aminoacyl-tRNA synthetases. We report two well documented anti-SS cases where it was observed significant exposure to a known inhaled offending antigen, development of a lymphocytic interstitial lung disease (ILD) and negative auto-antibodies, interpreted at first as hypersensitivity pneumonitis. Only after 14 and 30 months, respectively, the development of systemic symptoms compatible with anti-SS and anti-Jo-1 was observed. A growing body of evidence suggests that the lungs are the environment in which Jo-1 autoimmunity may be initiated and propagated. The description of the clinical and laboratorial evolution of these patients together with accumulated evidence of biological plausibility support the hypothesis that anti-SS can follow an episode of lung inflammation secondary to inhaled antigen exposure.

[Extrinsic allergic alveolitis. Clinical experience at the Instituto National de Enfermedades Respiratorias (INER)]. / Alveolitis alérgica extrínseca. Experiencia clínica del INER.

Extrinsic allergic alveolitis is an interstitial lung disease caused by exposure to a variety of inhaled antigens. In Mexico, the most frequent form is due to the inhalation of avian antigens, markedly pigeon proteins. Depending on type and time exposure, the disease presents different clinical forms usually characterized by progressive dyspnea, ground glass or reticulonodular images on chest x rays, a restrictive functional pattern, rest hypoxemia worsening with exercise, and increase of T lymphocytes in bronchoalveolar lavage with an inversion in the helper/suppressor ratio. In this paper, we discuss a 15-year experience with this pathological problem in Mexico, emphasizing the differences with this disorder in Caucasian populations. Generally, our patients display a chronic form of the disease, which evolves to fibrosis in about one-half of the patients. In this sense, the diagnostic, prognostic, and therapeutic focusing exhibit different elements, and thus the development of clinical and basic research is strongly required.

[Respiratory function in extrinsic allergic alveolitis caused by pigeons. Clinical, pathological and functional correlation]. / La función respiratoria en la alveolitis alérgica extrínseca por palomas. Correlación clínica, patológica y funcional.

Lung function tests (LFT) were performed in 71 patients with proven extrinsic allergic alveolitis due to pigeons (EAA-P), and they were correlated with lung biopsy (LB) findings. Lung function studies were analyzed to evaluate the clinical course of these patients treated with corticosteroids. Restrictive pulmonary function impairment was found in all cases (vital capacity 38 +/- 4%), residual volume was increased in 9 out of 14 patients (64%) (RV = 0.51 +/- 0.06 L.) and bronchial obstruction was a feature in 11/14 patients (78%) (MMEF = 53 +/- 4%). In all cases a low Pa02 was observed (44 +/- 2 mmHg) and in six an increase in PaC02 was detected. The vital capacity did not correlate with the degree of inflammation or fibrosis observed by LB. A significant negative correlation was found between Pa02 and the degree of inflammation (r = 0.68, p X 0.05) as well as with fibrosis + inflammation degrees (r = -0.63, p less than 0.05). In general, initial LFT and clinical improvement occur simultaneously. Lung function tests support the diagnosis of EAA-P, but are not capable of separating inflammation from lung fibrosis.