Igarashi Toru, Itoh Yasuhiko, Shimizu Akira, Igarashi Tsutomu, Yoshizaki Kaoru, Fukunaga Yoshitaka
Department of Pediatrics, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan.
J Nippon Med Sch. 2012;79(4):286-90. doi: 10.1272/jnms.79.286.
Primary Sjögren's syndrome (SS) is a rare autoimmune disease, especially in children. Juvenile primary SS with interstitial nephritis is rare in Japan. We report on a 12-year-old girl in whom salivary gland swelling had recurred from the age of 5 years, SS was diagnosed at the age of 10 years, and interstitial nephritis developed at the age of 12 years. The patient presented with a chief complaint of swelling of both parotid glands. The patient had a history of recurrent parotitis from 5 years of age, with episodes recurring 5 to 6 times a year and resolving within 3 days each time. However, at the age of 11 years, the patient had continuous mild swelling of the parotid glands. Examination on admission showed bilateral nontender parotid gland swelling; mild swelling of the lower extremities, xerostomia, and xerophthalmia but no exanthem. Laboratory findings were as follows: serum protein, 10.1 g/dL; immunoglobulin (Ig) G, 3,828 mg/dL; antinuclear antibodies, 1,280-fold; anti-Ro/SS-A antibody, 512-fold; anti-Ro/SS-B antibody, 4-fold; creatinine, 0.45 mg/dL; blood β2-microglobulin, 2.2 mg/L (slightly elevated); and cystatin C, 0.86 mg/L. Urinalysis showed proteinuria and a β2-microglobulin concentration of 11,265 mg/L. Thus, this patient had low molecular weight proteinuria. Schirmer's test showed decreased tear secretion (5 mm), and fluorescein staining showed marked bilateral superficial punctate keratitis. A lip biopsy showed infiltration by small round cells (mild to moderate), interstitial fibrosis, loss of salivary gland parenchyma, and atrophy, with no obvious epimyoepithelial islands, leading to a diagnosis of SS. Light microscopic examination of the renal biopsy specimens showed expansion of mononuclear cell infiltration in the renal interstitium, inflammatory cell infiltration of interstitial areas with edema and mild fibrosis, and tubulitis and mononuclear cell infiltration that included many lymphocytes and plasma cells. There were no pathological findings of glomerulonephritis. Small arteries showed no obvious abnormalities. Immunofluorescent staining showed slight, nonspecific deposition of IgM, but no deposition of IgG, complement 1q, 3, or 4. On the basis of the renal biopsy showing nonspecific chronic interstitial nephritis, renal tubular atrophy, and interstitial enlargement, tubulointerstitial nephritis associated with SS was diagnosed.
原发性干燥综合征（SS）是一种罕见的自身免疫性疾病，在儿童中尤为少见。在日本，合并间质性肾炎的青少年原发性SS很罕见。我们报告一名12岁女孩，她从5岁起腮腺反复肿胀，10岁时被诊断为SS，12岁时出现间质性肾炎。患者以双侧腮腺肿胀为主诉。患者自5岁起有复发性腮腺炎病史，每年发作5至6次，每次3天内缓解。然而，11岁时，患者腮腺持续轻度肿胀。入院检查显示双侧腮腺无压痛性肿胀；下肢轻度肿胀、口干、眼干，但无皮疹。实验室检查结果如下：血清蛋白10.1g/dL；免疫球蛋白（Ig）G 3828mg/dL；抗核抗体1280倍；抗Ro/SS - A抗体512倍；抗Ro/SS - B抗体4倍；肌酐0.45mg/dL；血β2 -微球蛋白2.2mg/L（轻度升高）；胱抑素C 0.86mg/L。尿液分析显示蛋白尿，β2 -微球蛋白浓度为11265mg/L。因此，该患者有低分子量蛋白尿。施密特试验显示泪液分泌减少（5mm），荧光素染色显示双侧明显的浅层点状角膜炎。唇活检显示小圆细胞浸润（轻度至中度）、间质纤维化、涎腺实质丧失和萎缩，无明显的肌上皮岛，从而诊断为SS。肾活检标本的光镜检查显示肾间质单核细胞浸润扩大，间质区域有炎性细胞浸润伴水肿和轻度纤维化，以及肾小管炎和单核细胞浸润，其中包括许多淋巴细胞和浆细胞。无肾小球肾炎的病理表现。小动脉无明显异常。免疫荧光染色显示IgM有轻微、非特异性沉积，但无IgG、补体1q、3或4的沉积。基于肾活检显示非特异性慢性间质性肾炎、肾小管萎缩和间质增宽，诊断为与SS相关的肾小管间质性肾炎。
