Supplementary Material for: Optical biopsies using probe-based confocal laser endomicroscopy for autoimmune pulmonary alveolar proteinosis

Introduction: Increasing numbers of cases of mild asymptomatic pulmonary alveolar proteinosis (PAP) are being reported with the recent increase in chest computed tomography (CT). Bronchoscopic diagnosis of mild PAP is challenging because of the patchy distribution of lesions, which makes it difficult to obtain sufficient biopsy samples. Additionally, the pathological findings of mild PAP, particularly those that differ from severe PAP, have not been fully elucidated. This study aimed to clarify the pathological findings of mild PAP and the usefulness of optical biopsy using probe-based confocal laser endomicroscopy (pCLE).
Methods: We performed bronchoscopic optical biopsy using pCLE and tissue biopsy in five consecutive patients with PAP (three with mild PAP and two with severe PAP). We compared the pCLE images of mild PAP with those of severe PAP by integrating clinical findings, tissue pathology, and chest computed tomography images.
Results: pCLE images of PAP showed giant cells with strong fluorescence, amorphous substances, and thin alveolar walls. Images of affected lesions in mild PAP were equivalent to those obtained in arbitrary lung lesions in severe cases. All three patients with mild PAP spontaneously improved or remained stable after ≥3 years of follow-up. Serum autoantibodies to granulocyte-macrophage colony-stimulating factor were detected in all five cases.
Conclusion: Optical biopsy using pCLE can yield specific diagnostic findings, even in patients with mild PAP. pCLE images of affected areas in mild and severe PAP showed similar findings, indicating that the dysfunction level of pathogenic alveolar macrophages in affected areas is similar between both disease intensities.

引言：随着近期胸部计算机断层扫描（chest computed tomography, CT）检查的普及，轻度无症状性肺泡蛋白沉积症（pulmonary alveolar proteinosis, PAP）的报告病例数日益增多。由于轻度PAP的病变呈斑片状分布，难以获取足够的活检样本，因此支气管镜下诊断颇具挑战。此外，轻度PAP的病理表现，尤其是与重度PAP存在差异的特征，尚未完全阐明。本研究旨在明确轻度PAP的病理表现，以及基于探针的共聚焦激光内镜检查（probe-based confocal laser endomicroscopy, pCLE）在光学活检中的应用价值。

方法：本研究对5例连续纳入的PAP患者（其中3例为轻度PAP，2例为重度PAP）实施了基于pCLE的支气管镜光学活检及组织活检。通过整合临床资料、组织病理学结果及胸部CT影像，对比轻度与重度PAP患者的pCLE影像特征。

结果：PAP患者的pCLE影像可见强荧光巨细胞、无定形物质及菲薄的肺泡壁。轻度PAP受累病灶的pCLE影像与重度PAP患者任意肺部病灶的影像特征一致。3例轻度PAP患者在随访≥3年后均自行缓解或病情保持稳定。5例患者的血清粒细胞-巨噬细胞集落刺激因子（granulocyte-macrophage colony-stimulating factor）自身抗体均为阳性。

结论：即使对于轻度PAP患者，采用pCLE的光学活检也可获得特异性的诊断依据。轻度与重度PAP患者受累区域的pCLE影像特征相似，提示两种疾病严重程度下，病灶区域的致病性肺泡巨噬细胞功能障碍程度相当。