Temporal patterns of immunoblot-reactive antibodies to cytomegalovirus in transplant recipients

Pattern and persistence of the epitope-specific IgM response against human cytomegalovirus in renal transplant patients

The humoral immune response against human cytomegalovirus (HCMV) was evaluated in immunocompromised patients by Western blotting (WB) based on recombinant viral envelope (gB and gH) and tegument (pp150 and pp65) proteins. Three groups of patients were investigated: (a) 74 renal transplant recipients; (b) 24 hemodialysis patients, both groups without clinical evidence of viral infections; and (c) 19 renal transplant patients with manifest HCMV infections. The results obtained suggest that (i) the WB is considerably more sensitive, recognizing the HCMV-specific IgM response rather than the enzyme-linked immunosorbent assays. An IgM response was detected in one-third of all clinically asymptomatic renal patients. (ii) The virus-specific IgM response is primarily directed against the pp150 epitope. (iii) In patients with clinically manifest HCMV disease, additional IgM reactivities are most frequently directed against the glycoprotein B epitope. (iv) The severity of HCMV infections correlates with the extent of the IgM antibody response, i.e. with the number of specific epitopes involved. (v) After transplantation, IgM reactivity and its epitope-specific pattern persist for years.

Assessment of cytomegalovirus infections using neopterin and a new immunoblot

Human cytomegalovirus (HCMV) infections are a major cause of morbidity and mortality in immunocompromised patients despite advances in diagnostic tests and antiviral therapies. The underlying study investigates the diagnostic value of the immune marker neopterin and a recently developed HCMV-specific western blot to detect HCMV infections and to differentiate them into either syndromes or diseases. The mean period of observation was 1428 days. Thirteen HCMV diseases and nine syndromes were diagnosed retrospectively. The first appearance of clinical signs or symptoms was always associated with a marked increase of serum and urine neopterin. The HCMV-specific IgM response followed in the mean 9 days later. Median values and the course of the neopterin levels were significantly higher during the HCMV diseases. In addition, the strength of the humoral immune response was related to the severity of the HCMV infection. Patients with HCMV diseases developed antibodies against a higher number of epitopes. The anti-HCMV IgM response persisted in more than 80% of the patients for longer than 3 years. In conclusion, combining the HCMV-specific western blot and neopterin permit detection of the immune response against HCMV, reflect the severity of the infection and might guide the anti-viral therapy.

Evaluation of a novel immunoglobulin A capture enzyme immunoassay for diagnosis of cytomegalovirus infection in renal and heart transplant recipients

In a retrospective cohort study of 68 organ transplant patients, the usefulness of a new commercial immunoglobulin A (IgA) antibody capture enzyme immunoassay (EIA) specific to human cytomegalovirus (CMV) for the early diagnosis of CMV disease was investigated. The results were compared with those obtained with the CMV pp65 antigen assay in peripheral blood leukocytes, an IgM immunoblot assay, and six other commercial EIAs. In 21 of 28 patients with CMV disease, the pp65 antigen assay and the immunoblot assay identified patients before the onset of disease more frequently than any other serological test method (17 and 13 patients, respectively; p = 0.0029). In patients at risk for primary CMV infection, the pp65 antigen assay was the only method that identified all patients prior to the onset of CMV disease (p = 0.008). For the other patients who were at risk for CMV infection, the pp65 antigen assay and the immunoblot assay detected infection before CMV disease more frequently than any other test system (p = 0.026). With respect to CMV disease, both immunoblotting and the pp65 antigen assay showed excellent sensitivity (100% and 89%, respectively). However, the specificity of the immunoblot was poor (41%), while the specificity of the pp65 antigen assay was reasonably good (68%). The IgA capture EIA showed moderate sensitivity (61%) and reasonable specificity (76%). In conclusion, the pp65 antigen assay, which detects pp65 antigen in leukocytes, is the method of choice for diagnosis of either primary or recurrent CMV infection. The specificity of the pp65 antigen assay was improved by additional testing for specific IgA and IgM antibodies (95% vs. 68%). The IgA assay is of limited value in renal and heart transplant patients, since it detected IgA antibodies only sporadically, and even then, too late for a timely therapy.

IgM antibody detection of ppUL80A and ppUL32 by immunoblotting: an early parameter for recurrent cytomegalovirus infection in renal transplant recipients

The value of IgM detection for the early diagnosis of an active cytomegalovirus (CMV) infection in renal transplant recipients was evaluated prospectively. Sequential serum samples obtained from 22 allograft recipients with active CMV infection were tested for the presence of CMV-specific immunoglobulin M antibodies (IgM) by an enzyme-linked immunosorbent assay (ELISA) and a microparticle enzyme immunoassay (MEIA) and were compared with the Western-immunoblotting technique (IB). The time course of CMV IgM antibody detection was evaluated in relation to the shell vial assay (SVA), CMV disease, and immunosuppressive regimen. By IB, IgM antibodies against the capsid protein ppUL80a and the basic matrix phosphoprotein ppUL32 were detected in all 22 recipients with active CMV infection. Using the MEIA and the ELISA, the presence of CMV IgM antibodies was detected in 17 (77%) and ten (46%) of these 22 recipients, respectively. The SVA was the earliest parameter for detection of primary CMV infection in seven of nine (78%) recipients, in contrast to two of 13 (15%) patients with recurrent CMV infection (P < .05). The detection of IgM antibodies by IB was the earliest parameter for detection of recurrent CMV infection in seven out of 13 (54%) recipients in contrast to one out of nine (11%) patients with primary CMV infection (P < .05). During a primary CMV infection, the development of an abundant IgM antibody response was associated with recovery from CMV disease and the end of the viremic phase.

Antigenemia, immunoblotting, and enzyme immunoassay for early diagnosis of cytomegalovirus infection in renal transplant patients

Timely and rapid diagnosis of cytomegalovirus (CMV) infection is important for the management of transplant patients. We compared three serological assays, IgM immunoblot and IgG/IgM enzyme immunoassay (EIA), as well as the detection of CMV antigens in polymorphonuclear blood leukocytes (antigenemia), for their value in the early diagnosis of CMV infection. Thirty-one patients were monitored longitudinally for 3 months after renal transplantation. Laboratory documented CMV infection occurred in 20 patients. All of these cases showed a positive IgM immunoblot result that was confirmed by at least one of the other test assays (IgG EIA 19/20, antigenemia assay 13/20, and IgM EIA 12/20). All of the ten patients whose clinical picture was compatible with symptomatic CMV disease were positive for CMV infection according to IgM immunoblot and IgG EIA, nine were positive according to the antigenemia assay, and seven were positive according to IgM EIA. With reference to the temporal pattern, the antigenemia assay indicated CMV infection significantly earlier than the serological tests (P < or = 0.05). In symptomatic patients CMV antigen-positive leukocytes were, on the average, detected on the day of onset of symptoms, whereas detection by IgM immunoblot, IgG EIA, and IgM EIA followed 8, 13, and 14 days later, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)