Text Box: RENAL INJURY COMPLICATING EPSTEIN-BARR VIRUS INFECTIOUS MONONUCLEOSIS CHILDREN Luo XM, Zhou FY, Wang XX,WU JG Zhejiang People¡¯s Hospital, Hangzhou, China Background: There are only a few reports of renal diseases in the patients with Infectious mononucleosis (IM). The diagnosis of renal injury in previously reported patients was based primarily on abnormalities in urinary sediment and the increase of serum creatinine (Cr) and blood urea nitrogen levels (BUN). This study aimed at evaluating the stage of renal injury in the patients with IM by the sensitive indexes. Methods: 12 boys and 4 girls with mean age of 3.15¡À1.96 years (ranged from 6 months-7 years) were admitted to this prospective study. Clinical diagnosis of IM was confirmed based on fever, lymphadenopathy, splenomegaly, lymphocytosis, atypical lymphocytes in blood smears and the elevated levels of IM antibody against EBV capsid antigen. The day of onset of fever was recognized as day 1 of illness. Microscopic examination of urine sediments was normal in all except two whose urinary analysis showed proteinuria(+) and hematuria(+) respectively. There was a normal serum level of serum Cr and BUN in all cases with IM. All patients were examined both in the acute phase (3-5 days) and in convalescent phase (10-15 days) of the disease. Serum beta-2-microglobulin (s¦Â2-M),Tamm-Horsfall protein (sTHP) and urinary beta-2 microglobulin (u¦Â2-M), Tamm-Horsfall protein (uTHP) and alpha-1-microglobulin (u¦Á1-M) were measured by radioimmunoassays. Nephelometric immunoassay was used for detection of urinary alumin (uA). Results: (1) In acute phase, the levels of s¦Â2-M, u¦Â2-M and u¦Á1-M (3.09¡À 0.78 mg/l, 0.42¡À0.35 mg/l, 14.37¡À5.69 mg/l) markedly increased (p<0.01) in patients as compared with the helthy controls (1.63¡À0.41 mg/l, 0.09¡À 0.05 mg/l, 4.70 2.93 mg/l)and the levels of uTHP (26.91¡À19.15 µg/l) increased as compared with the controls (14.07¡À7.73 µg/l). In convalescent stage, u ¦Â2-M and u ¦Á1-M excretion in patients were significantly higher than that in controls (0.19¡À0.08 mg/l, 9.94¡À3.92 mg/l) (p<0.01). But there were differences between the level in acute and convalescent stage. (2)There was a significant positive correlation between serum level and urinary excretion of ¦Â2-M (r=0.7422, p<0.01) during acute stage and there was no correlation between them during convalescent stage. (3) There were no remarkable difference between the levels of uA and sTHP and that in controls both during acute and convalescent stage. Conclusion: (1)Renal injury appears to be relative common in patient with IM. (2)Interstitial nephritis may be the most common manifestation of renal injury in the patient with IM. (3) The increase of s¦Â2-M in the patient with IM may not reflect the renal injury. 1033