Anti-C1q antibodies in lupus nephritis children with glomerular microthrombosis.

Abstract

Glomerular microthrombosis (GMT) was a common vascular lesion in patients with lupus nephritis (LN). The objective of this study was to investigate the relationship between serum anti-beta2-glycoprotein I antibodies (a-β2GP1) and anti-complement 1q antibodies (a-C1q) antibodies and to investigate the possible mechanism of GMT in children with LN. The subjects were 191 children with LN diagnosed by renal biopsy in our hospital from January 2017 to January 2020. The patients were divided into GMT group and non-GMT group. The clinical manifestations, laboratory tests, renal pathology, prognosis of the two groups and the relationship between a-β2GP1 and a-C1q antibodies were observed. In 191 children with LN, 52 cases (27.23%) presented with GMT. The value of C3, haemoglobin (Hb), estimate glomerular filtration rate (eGFR) and anticardiolipin antibody (ACA) in GMT group were lower than that of non-GMT group (p < .05, p < .01). The value of serum creatinine (Scr), 24 h proteinuria (PRO), urine red blood cells (RBC), N-acetyl-β-d-glucosidase (NAG) and retinol-binding protein (RBP), a-C1q, a-β2GP1, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and renal histopathological activity index (AI) score in GMT group were higher than that of non-GMT group (p < .05, p < .01). The positive proportions of serum a-C1q and a-β2GP1 in GMT group were higher than those in non-GMT group (p < .05). According to Spearman correlation analysis, a-C1q was positively correlated with AI score, SLEDAI, a-β2GP1, GMT, LN-III and LN-IV. Hb, eGFR and a-C1q Ab were associated with the formation of GMT in children with LN. The complete proteinuria remission and renal survival in GMT group were significantly lower than those in non-GMT group (p < .05, p < .01). LN children with GMT had more severe clinical manifestations and renal pathologic damages, and poor outcome. Serum a-C1q level was positively correlated with a-β2GP1, and a-β2GP1 may be involved in the formation of GMT in children with LN, which might involve in the activation of complement classical pathway.