Relationship Of 24h-urinary Free Light Chains And 24h-urinary Proteins And The Etiopathogenisis In Nephrotic Syndrome Patients

Background:To identify the etiopathogenisis of nephrotic syndrome(NS),the urinary and haemic free light chains(FLCs) of the patients usually have to be examined.According to the results,we observed that 24h-urinary flee light chains exceed 1000mg in some patients with NS,but they without M protein nor signs of multiple myeloma.Here,the relationships among 24h-urinary FLCs and 24h-urinary proteins and the etiopathogenisis were analysed in patients with NS and the clinical significance of urinary FLCs in NS were detected.Objective:To analyze the relationship of 24h-urinary FLCs and 24h-urinary proteins and the etiopathogenisis in NS patients and detect the clinical significance of urinary FLCs in NS.Methods:Urine specimens of 80 patients with NS hospitalized in the second accociated hospital of medical college,Zhejiang University from Jan.2006 to Nov.2008 were collected.The levels of 24h-urinary FLCs and 24h-urinary proteins were examined. And levels of urinary microalbumin,IgG,transferrin,α1-microglobulin and NAG of patients with primary nephrotic syndrome(PNS) were detected at the same time.The age,genda,etiopathogenisis,renal function and the pathologic characteristics of renal biopsy of all 80 patients were also carefully recorded.On one hand,according to the 24h-urinary levels of FLCs,these 80 patients were devided into 2 groups:Group FLCs1(FLCs＞1000mg) and Group FLCs2 (FLCs≤1000mg).Then the relationship both group in 24h-urinary FLCs and 24h-urinary proteins was analyzed by t-test.Furthermore,dependability and hierarchical analysis were also done between 24h-urinary FLCs and 24h-urinary proteins.The patients with PNS were again devided into 2 groups according to 24h-urinary levels of FLCs:Group FLCsA(FLCs＞1000mg) and Group FLCsB(FLCs≤1000mg). The urinary levles of microalbumin,IgG,transferrin,α1-microglobulin and NAG were analyzed respectively by t-test in the two groups.Results:1.Clinical data:no statistical difference of age and genda existed among different groups of these patients.2.Etiopathogenisis:Among these 80 patients,in the Group FLCs1,10 were PNS, and 12 were secondary NS:6 SLE,3 DM,1 scleroderma,1 monoclonal gammopathy of undetermined significance(MGUS) and 1 hypertension.While in the Group FLCs2,51 were PNS(87.9%),7 were secondary NS(12.1%):1 SLE,1 hypertensive disease,2 DM,1 HBV-related nephrosis,1 anaphylactoid purpura and 1 polycystic kidney.It is thus suggested that patients with secondary NS may be more than that with PNS in group FLCs2,while majority ones were suffered from PNS when FLCs1. 3.The relationship of 24h-urinary FLCs and 24h-urinary proteins:Level of 24h urinary proteins in Group FLCs1 was significantly higher than that in Group FLCs2(p＜0.01)[(10600.42±5213.94)mg vs(6761.14±3148.20)mg].The pearson correlation index was 0.33343(P=0.0025),which indicated 24h-urinary FLCs and 24h-urinary proteins were positive correlated although without linear dependability.Moreover,according to the result of hierarchical analysis,the 24h-urinary level of FLCs was above 1000mg as soon as the level of 24h-urinary proteins exceeded 7000mg(p＜0.005).4.Among the PNS patients,the levels of the urinary macro-proteins in Group FLCsA were:4747±905.17mg/g.crof urinary microalbumin,781.5±532.18mg/g.cr of urinary IgG,537.5±205.99mg/g.cr of urinary transferrin,125.75±82.67 mg/g.cr of urinaryα1-microglobulin and 65.75±32.07mg/g.cr of urinary NAG:FLCsB were: 4161.28±1717.47 mg/g.cr of urinary microalbumin,296.77±211.72 mg/g.cr of urinary IgG,520.64±182.71 mg/g.cr of urinary transferrin,97.22±59.87 mg/g.cr of urinaryα1-microglobulin and 48.02±29.61mg/g.cr of urinary NAG According to the result of t-test,compared with Group FLCsB,the level of urinary IgG of Group FLCsA was significantly higher(p＜0.05).Furthermore,it is indicated by renal biopsy that more cases were with urine protein cast,tubulointerstitial epithelial denaturation and interstitial inflammatory cells infiltration in the FLCsA group.Conclusion:When the level of 24h-urinary FLCs significantly increased,the level of 24h-urinary proteins remarkably increased as well,although there was no leaner dependablity between both.And in our clinical practice,secondary NS should be considered much more if the level of 24h-urinary FLCs strikingly raised.The level of 24h-urinary FLCs could be used to evaluate the reabsorption function and damage of renale tubule.