Clinicopathologic characteristics and prognosis of Sjögren's syndrome complicated with renal invo-lvement

Abstract

Objective To analyze the clinical manifestations, immunological characteristics, patho-logical changes and prognosis in primary Sjogren's syndrome complicated with renal involvement. Methods Three hundred and eighty-seven patients with pSS were enrolled in this retrospective study. Among these patients, 198 patients were complicated with renal involvement and 189 patients without renal involvement. The data of the two groups were analyzed for clinical manifestations, blood tests, urine tests and immunological characteristics by independent sample t test, χ2 test, Fisher exact probability and Logistic regression model respectively. Seventy-two patients in the group with renal involvement had kidney biopsies. Results The average of these 387 patients (female/male 345/42 cases) were (55.3 ± 13.2) years old. The average age of 198 patients with renal involvement (female/male 168/30 cases) was (55.3±13.2) years old. The serum RF and IgG of the group with renal volvement was significantly higher than the patients without renal involvement. In the 198 patients with renal involvement, 102 patients(51.5%) developed type Ⅰ renal tubular acidosis (RTA Ⅰ). Among these RTA Ⅰ patients, 54 patients presented hypokalemia; 12 patients developed hypokalemic plegia , 30 patients with urolithiasis, 6 patients with osteoporosis; 69 patients presented with overt renal glomerulus impairment, 36 cases had nephrotic syndrome (NS), and 33 cases had chronic glomerulonephritis; In 81 patients with renal failure, including 27 were stage 1 CKD, 18 were stage 2 CKD, 9 were stage 3 CKD, 15 were stage 4 CKD, 12 were stage 5 CKD. Among these patients with renal biopsie, light microscopy showed chronic interstitial nephritis(IN, 69/72), mesangial proliferative glomerulonephritis (36/72), hyperplastic and sclerosing glomerulonephritis (9/72), partly sclerosing glomerulonephritis (9/72) and membranous nephropathy (6/72). Immunofluorescent examination revealed: IgG deposition in 21 patients (29.1%), IgA in 21(29.1%), IgM in 33 (45.8%), C3 in 12(16.6%), C4 in 18(25%) and C1q in 15(20.8%). Sixty-six cases with renal biopsies were followed for (8-30)months, except the patient died of cerebral bemorrhage, all the other patients survived, and renal functions were steady or improved. Conclusion ① The pSS patients with renal involvement mainly shows interstitial nephritis. However, the occurrence of glomerulonephritis is not rare. ② Rheumatoid factor (RF) or IgG is significantly associated with renal involvement in patients with pSS. ③ When renal involvement is presents, renal biopsies is a necessary for patients with pSS. Key words: Sjogren's syndrome; Renal involvement; Clinical features; Pathology