Velosa Ana Paula Pereira, Brito Lais, de Jesus Queiroz Zelita Aparecida, Carrasco Solange, Tomaz de Miranda Jurandir, Farhat Cecília, Goldenstein-Schainberg Cláudia, Parra Edwin Roger, de Andrade Danieli Castro Oliveira, Silva Pedro Leme, Capelozzi Vera Luiza, Teodoro Walcy Rosolia
Rheumatology Division of the Hospital das Clinicas FMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil.
Department of Pathology of the Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil.
Front Immunol. 2021 Feb 12;11:604602. doi: 10.3389/fimmu.2020.604602. eCollection 2020.
Patients with Systemic sclerosis (SSc) presents immune dysregulation, vasculopathy, and fibrosis of the skin and various internal organs. Pulmonary fibrosis leads to SSc-associated interstitial lung disease (ILD), which is the main cause of morbidity and mortality in SSc. Recently autoimmunity to type V collagen (Col V) has been characterized in idiopathic pulmonary fibrosis and show promise to be related to the development in SSc. Our aim was to evaluate autoimmunity to Col V α1(V) and α2(V) chains and to the antigenic peptides of these Col V chains in early-SSc sera employing lung tissue of SSc-ILD, as antigen source. We found that sera samples from patients with early-SSc were reactive to Col V (41.18%) and presented immunoreactivity for Col5A1(1.049) and Col5A1(1.439) peptides. The IgG isolated from early-SSc patients-anti-Col V positive sera (anti-ColV IgG) was adsorbed with α1(V) chain (anti-ColV IgG/ads-α1(V)) and α2(V) chain (anti-ColV IgG/ads-α2(V)) and biotinylated to evaluate the spectrum of reactivity in SSc-ILD patients lung biopsies by immunofluorescence. The SSc-ILD lung tissue samples immunostained with anti-ColV IgG showed increased green fluorescence in the vascular basement membrane, bronchiolar smooth muscle, and adventitial layer, contrasting with the tenue immunostaining in control lungs. Col V protein expression in these pulmonary compartments immunostained with early-SSc anti-ColV IgG was confirmed by immune colocalization assays with commercial anti-human Col V antibodies. In addition, SSc-ILD lung tissues immunostained with anti-ColV IgG/ads-α1(V) (sample in which Col V α1 chain-specific antibodies were removed) showed decreased green fluorescence compared to anti-ColV IgG and anti-ColV IgG/ads-α2(V). Our data show that autoimmunity to Col V in early-SSc was related to peptides of the α1(V) chain, suggesting that these antibodies could be biomarkers of SSc stages and potential target of immunotherapy with Col V immunogenic peptides.
系统性硬化症（SSc）患者存在免疫失调、血管病变以及皮肤和各种内脏器官的纤维化。肺纤维化导致SSc相关的间质性肺疾病（ILD），这是SSc发病和死亡的主要原因。最近，在特发性肺纤维化中已发现针对V型胶原（Col V）的自身免疫，并且有望与SSc的发展相关。我们的目的是使用SSc-ILD的肺组织作为抗原来源，评估早期SSc血清中针对Col V α1(V)和α2(V)链以及这些Col V链抗原肽的自身免疫。我们发现早期SSc患者的血清样本对Col V有反应（41.18%），并且对Col5A1(1.049)和Col5A1(1.439)肽呈现免疫反应性。从早期SSc患者抗Col V阳性血清（抗ColV IgG）中分离出的IgG用α1(V)链（抗ColV IgG/吸附-α1(V)）和α2(V)链（抗ColV IgG/吸附-α2(V)）进行吸附，然后生物素化，通过免疫荧光评估SSc-ILD患者肺活检中的反应谱。用抗ColV IgG免疫染色的SSc-ILD肺组织样本在血管基底膜、细支气管平滑肌和外膜层显示绿色荧光增加，与对照肺中的微弱免疫染色形成对比。通过与商业抗人Col V抗体的免疫共定位分析证实了这些肺区室中用早期SSc抗ColV IgG免疫染色的Col V蛋白表达。此外，与抗ColV IgG和抗ColV IgG/吸附-α2(V)相比，用抗ColV IgG/吸附-α1(V)（去除了Col V α1链特异性抗体的样本）免疫染色的SSc-ILD肺组织显示绿色荧光减少。我们的数据表明，早期SSc中针对Col V的自身免疫与α1(V)链的肽有关，这表明这些抗体可能是SSc阶段的生物标志物以及Col V免疫原性肽免疫治疗的潜在靶点。
