Development of microscopic polyangiitis-related pulmonary fibrosis in a patient with autoimmune pulmonary alveolar proteinosis

Clinical characteristics of pulmonary alveolar proteinosis

OBJECTIVES

Pulmonary alveolar proteinosis (PAP) is a rare disease with non-specific and various clinical manifestations, often leading to misdiagnosis. This study aims to raise the awareness of this disease via summarizing the clinical characteristics, diagnosis, and therapy of PAP.

METHODS

We retrospectively analyzed clinical data of 25 hospitalized cases of PAP during 2008 and 2019 in the Department of Respiratory and Critical Care Medicine of the Second Xiangya Hospital of Central South University.

RESULTS

Cough with unkown reason and dyspnea were common clinical manifastations of PAP. Five patients had a history of occupational inhalational exposure. Sixteen patients had typical image features including ground-glass opacification of alveolar spaces and thickening of the interlobular and intralobular septa, in typical shapes called crazy-paving and geographic pattern. Fourteen patients underwent pulmonary function tests, revealing a reduction in the diffusing capacity for carbon monoxide. The positive rate of transbronchial biopsy was 95%. Five patients received the whole lung lavage and the symptoms and imaging fcauters significantly relieved after five-years follow-up.

CONCLUSIONS

PAP is characterized by radiographic pattern and pathology. Transbronchial lung biopsy is effective to make diagnosis of PAP. The whole lung lavage remains a efficient therapy.

Natural Autoantibodies in Chronic Pulmonary Diseases

In autoantibody-mediated autoimmune diseases, pathogenic autoantibodies generated by a failure of central or peripheral tolerance, have different effects mediated by a variety of mechanisms. Interestingly, even non-autoimmune chronic diseases have a set of disease-specific natural autoantibodies that are maintained for a long time. Because most of these natural autoantibodies target intracellular proteins or long non-coding RNAs, they are speculated to be non-pathological and have some important as yet unrecognized physiological functions such as debris clearance. Recently, we revealed a set of disease-specific natural autoantibodies of chronic pulmonary diseases with unknown etiology by protein arrays that enable detection of specific autoantibodies against >8000 targets. Surprisingly, some of the targeted antigens of disease-specific autoantibodies were subsequently reported by other laboratories as strongly associated with the disease, suggesting that these antigens reflect the pathology of each disease. Furthermore, some of these autoantibodies that target extracellular antigens might modify the original course of each disease. Here, we review the disease-specific natural autoantibodies of chronic pulmonary diseases, including chronic fibrosing idiopathic interstitial pneumonias, sarcoidosis, and autoimmune pulmonary alveolar proteinosis, and discuss their utility and effects.

Pathological features of explant lungs with fibrosis in autoimmune pulmonary alveolar proteinosis

Association of fibrosis with autoimmune pulmonary alveolar proteinosis (aPAP) is rare. However, prognoses of such cases are poor and the process of the formation of fibrosis is still unknown. In this study, we report a case of aPAP with progressive fibrosis occurring in a 46‐year‐old woman. She had undergone several repetitions of whole lung lavage (WLL) for 7 years and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) inhalation for 3 months; however, the progression of fibrosis was not hindered. Eventually, she was treated with bilateral lung transplantation. The computed tomography (CT) image suggested pulmonary fibrotic changes in her lung similar to usual interstitial pneumonia. However, the pathological analyses of explant lungs revealed that the fibrosis was not similar to ordinary interstitial pneumonias and suggested that the dysfunction of alveolar macrophage in removing the excess surfactant of alveolar spaces played an important role in the fibrogenesis in aPAP.

Pulmonary melanoma and "crazy paving" patterns in chest images: a case report and literature review

Background

In the lung, melanoma is mostly arranged as patterns of multiple nodules, solitary nodules, or miliary invasions. Very rarely, it also displays a “crazy paving” pattern (also described as a “paving stone,” “flagstone,” or “slabstone” pattern), which is rarer still in discrete bilateral nodules. This pattern is considered to be caused by pulmonary alveolar proteinosis, but its association with various diseases is unclear.

Case presentation

A 60-year-old man was diagnosed with pulmonary melanoma. Computed tomography revealed discrete bilateral nodules surrounded by a “paving” pattern. A literature review found more than 40 types of diseases that have presented with “paving” patterns in the lung—predominantly pulmonary alveolar proteinosis, viral pneumonia, exogenous lipoid pneumonia, bacterial pneumonia, pulmonary alveolar microlithiasis, interstitial pneumonia, ARDS, squalene aspiration pneumonia, radiation pneumonitis, drug-induced pneumonitis, pulmonary leptospirosis, pulmonary hemorrhage, and pulmonary nocardiosis.

Conclusions

We describe the first case of pulmonary melanoma in the form of discrete bilateral nodules accompanied with a computed tomography paving pattern. Although pulmonary paving patterns are rare, more than 40 diseases reportedly display them; clinicians should consider melanoma of the lung in differential diagnoses for patients who show such a pattern.

Two cases of autoimmune and secondary pulmonary alveolar proteinosis during immunosuppressive therapy in dermatomyositis with interstitial lung disease

Interstitial lung disease (ILD) with dermatomyositis often requires intensive immunosuppressive therapy. Here, we report two cases of pulmonary alveolar proteinosis (PAP) in dermatomyositis with ILD. One case was secondary PAP, and the other was autoimmune PAP positive for the anti-granulocyte macrophage-colony-stimulating factor antibody. PAP arose during immunosuppressive therapy and symptoms ceased by attenuating immunosuppression. Exacerbation of pulmonary lesions during intensive immunosuppressive therapy may distinguish PAP from worsening ILD and attenuating immunosuppression should be considered.