Characteristics of antibody production to individual cytomegalovirus proteins in children with keratitis and uveitis

The clinical diagnosis of cytomegalovirus (CMV) eye pathology in children needs laboratory confirmation. The disadvantages of determining antibodies to CMV in serum in enzyme-linked immunosorbent assay (ELISA) include the presence of false positive and false negative results.

AIM: To determine the features of the synthesis of antibodies to the proteins of the tegument pp65, pp150, pp28 and the DNA-binding protein pp52 of cytomegalovirus, as well as to compare the diagnostic effectiveness of two laboratory methods of serodiagnostics of CMVI in children with uveitis and keratitis of different genesis: enzyme immunoassay and linear immunolysis.

MATERIAL AND METHODS: A total of 30 children (age 5–16 years) with uveitis (n=14) and keratitis (n=16) were included in the study. The IgM and IgG antibodies to the immediate early (IE) and late antigens of the virus (serological markers of primary, chronic, and reactivation of chronic infection) were determined in the ELISA. The IgG antibodies to individual recombinant CMV antigens containing only immunodominant protein fragments of viral antigens were studied in the line immunoassay (LIA): the main nonstructural IE protein, DNA-binding phosphoprotein p52, and phosphoproteins of the tegument p150, p65, and p28. The results of LIA were evaluated visually.

RESULTS: CMV infection (CMVI) in children with uveitis in ELISA was almost 2 times higher than that with keratitis (10/14%–71% vs. 6/16%–37.5%, p >0.05). Of the four positive results for detection of antibodies to IE antigen in ELISA, one was confirmed in LIA. In general, the discrepancy between the results of the determination of IgG antibodies to IE antigen in ELISA and LIA was noted in 13% of serum samples. LIA showed the increased frequency (p >0.05) and intensity (p <0.05) of antibody formation to viral antigens p65 and p52 in uveitis compared with keratitis, which confirmed the important role of CMVI in the pathogenesis of uveitis.

CONCLUSION: Both methods revealed a higher level of CMVI in children with uveitis than those with keratitis. IgG antibodies to IE-antigen serological markers of the reactivation of chronic CMVI have clinical importance because they serve as the basis for the appointment of antiviral therapy. Discrepancies between the results of ELISA and LIA in the detection of antibodies to IE antigen indicate the expediency of confirming the results of ELISA in LIA.

Thus, laboratory examination of sera in ELISA with subsequent analysis of antibodies to individual recombinant CMV antigens in LIA is an effective, highly sensitive, and highly specific method to verify CMVI and determine its activity. The most informative action is the determination of IgG antibodies to recombinant CMV antigens: IE antigens, p65, and p52.