Significance Of Detecting Serum Complement C3 And C4 In Patients With Multiple Myeloma

Object:Multiple myeloma which is characterized by abnormal monoclonal plasma cell infiltration in the bone marrowis a malignant bone marrow heterogeneous disease.Myeloma bone diseaseseriously affects the life quality and survival of patients.The imbalance of proliferation and differentiation of osteoblasts and osteoclasts has been considered to be a major cause of myeloma bone disease.As an important part of the immune system,serum complement is involved in regulating almost every step of the immune response.The serum complements C3 and C4,important proteins in the complement system,have been shown to affect the activity of osteoblasts and osteoclasts and the development and maintain homeostasis in bone.Our study aimed to determine the bone mineral density by dual X-ray absorptiometry and the expression levels of serum complement C3 and C4 by scatter nephelometry in patients with multiple myeloma,explore the significance of detection in multiple myeloma,and analyze its correlation with myeloma bone disease.This study is to find new biomarkers of myeloma bone disease.Methods:We selected the newly diagnosed multiple myeloma patients(69 cases)admitted to the Department of Hematology,Chaohu Hospital of Anhui Medical University from July2014 to July 2018 as the experimental group(MM group).At the same time,30 health volunteers from physical examination center in the same hospitalwere selected as the control group.The serum complement C3 and C4 levels in both MM group and control groupwere determined by scatter nephelometry,and quantitatively analyzed.The bone density of L1-4 vertebral body,bilateral femoral neck and bilateral hip joints were measured by dual energy bone density meter(DXA).We analyze the differences between the two groups and explore the relationship between serum complement C3,C4 and the severity of bone disease,also the correlation with bone density.Results:(1)The bone mineral density in MM patients is lower than that in healthy controls(P<0.01);(2)The bone mineral density in MM patients with advanced stage of ISS clinical stage were significantly lower than those in stable stage(P<0.01);(3)According to whole body X-ray examination,MBD is divided into A grade,B grade and C grade: grade A is no osteoporosis and osteolytic lesion;grade B is 1-3 anatomical osteolytic lesions;grade C is osteolytic lesion or pathological fracture of more than 3anatomical sites.Among different MBD grades,the bone mineral density in grade C were significantly lower than those in grade A and B(P<0.01);(4)The levels of serum complement C3 and C4 in the MM group were significantly enhanced compared with the control group(P<0.01);(5)The levels of serum complement C3 and C4 in patients with advanced stage of ISS clinical stage were significantly higher than those in stable stage(P<0.01);(6)Among different MBD grades,the levels of complement C3 and C4 in grade C were significantly higher than those in grade A and B(P<0.01);(7)The levels of serum complement C3 and C4 in MM patients were negatively correlated with bone mineral density in L1-4 vertebral body,bilateral femoral necks and hip joints.And the correlation coefficients were(r =-0.938,r =-0.659,r =-0.745,r =-0.748,r =-0.596)and(r =-0.908,r =-0.623,r =-0.710,r =-0.714,r =-0.595).Conclusions:The levels of complement C3 and C4 in MM are closely related to the severity of bone disease and bone density in MM patients.The lower bone density,the higher expression levels of serum complement C3 and C4 indicates that complement C3 and C4 may play an important role in the development of MBD.The level of serum C3 and C4 may bea sensitive biomarker of MBD.