Prevention of maternal-fetal transmission of cytomegalovirus after primary maternal infection in the first trimester by biweekly hyperimmunoglobulin administration

OBJECTIVE

To examine the efficacy of biweekly hyperimmunoglobulin (HIG) administration to prevent maternal-fetal transmission of cytomegalovirus (CMV) in women with primary first-trimester CMV infection.

METHODS

This was a prospective observational study of women with confirmed primary CMV infection in the first trimester who had the first HIG administration at or before 14 weeks' gestation. All women had biweekly HIG treatment until 20 weeks' gestation at a dose of 200 IU/kg of maternal body weight. Each subject underwent amniocentesis at least 6 weeks after first presentation at about 20 weeks. Primary outcome was maternal-fetal transmission at the time of amniocentesis, and secondary outcome was the frequency of congenital CMV infection at birth. The results were compared with a historic cohort of women with first-trimester CMV infection who did not undergo HIG treatment and who had amniocentesis at about 20 weeks.

RESULTS

Subjects were 40 pregnant women with a primary CMV infection, with a median gestational age at first presentation of 9.6 (range, 5.1-14.3) weeks. On average, HIG administration started at 11.1 weeks and continued until 16.6 weeks. Within this interval, HIG was administered between two and six times in each patient. While CMV immunoglobulin-G (IgG) monitoring showed periodic fluctuations during biweekly HIG administration cycles, high CMV-IgG avidity indices remained stable over the whole treatment period. Maternal-fetal transmission before amniocentesis occurred in only one of the 40 cases (2.5% (95% CI, 0-13.2%)). At delivery, two additional subjects were found to have had late-gestation transmission. Considering all three cases with maternal-fetal transmission, the transmission rate was 7.5% (95% CI, 1.6-20.4%) in our 40 cases. All infected neonates were asymptomatic at birth. The matched historical control group consisted of 108 pregnancies. Thirty-eight transmissions (35.2% (95% CI, 26.2-45.0%)) occurred in the control group, which was significantly higher (P < 0.0001) than the transmission rate in the HIG treatment group.

CONCLUSION

After a primary maternal CMV infection in the first trimester, biweekly HIG administration at a dose of 200 IU/kg prevents maternal-fetal transmission up to 20 weeks' gestation. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Role of pentamer complex-specific and IgG subclass 3 antibodies in HCMV hyperimmunoglobulin and standard intravenous IgG preparations

BACKGROUND

HCMV hyperimmunoglobulin-preparations (HIG) contain high concentrations of HCMV-specific IgG. The reduced maternofetal-HCMV-transmission rate of IgG may be due to HCMV-specific neutralizing antibodies against the HCMV pentameric complex (PC). In contrast to HIG, standard intravenous immunoglobulin (IVIG) may have more neutralization (NT) capacity than HIG due to higher IgG subclass 3 levels (Planitzer et al., 2011).

METHODS

We investigated the HCMV-specific NT-capacity of HIG Cytotect^®, using a recombinant pentameric complex (gHgLUL128-131A) for specific antibody-depletion. We used a modified UL130-peptide (TANQNPSPPWSKLTYSKPH) based on original-sequence of Saccoccio et al. (Vaccine 29(15):2705-2711, 2011) (SWSTLTANQNPSPPWSKLTY) as neutralization target. Both UL130-peptides and the PC were bound via sixfold HisTag and anti-HisTag mAbs to magnetic beads to deplete HCMV-specific IgGs from HIG (Cytotect^®). Modifying this depletion strategy, we analyzed the role of IgG subclass 3 in both HIG and IVIG.

RESULTS

After CMV IgG-normalization of HIG and IVIG, we found a significant trend towards a decrease (16%) of neutralization-capacity for the UL130 TAN-peptide, but not for the original UL130 SWS-peptide. However, highly significant loss of NT-capacity could be only observed by PC depletion (42%). The IgG subclass 3 depletion revealed no significant reduction of NT-capacity in both HIG and IVIG.

CONCLUSION

Via specific antibody depletion, we could demonstrate that pentameric complex-specific antibodies are present in HIG and bind to the recombinant PC resulting in a highly significant reduction of NT-capacity compared to the UL130 TAN-and SWS-peptides. We could not confirm the functional role of IgG subclass 3 neutralizing antibodies in IgG-preparations.

Comparison of cytomegalovirus (CMV)-specific neutralization capacity of hyperimmunoglobulin (HIG) versus standard intravenous immunoglobulin (IVIG) preparations: Impact of CMV IgG normalization

BACKGROUND

Based on a non-randomized study of Nigro et al. (2005) the intravenous administration of hyperimmunoglobulins (HIGs) is applied frequently to women with primary CMV-infection as "off-label use" in Germany.

OBJECTIVES

In order to describe their CMV-specific neutralization-capacity in vitro, we analyzed the HIG preparations Cytotect^®, and Cytogam^® as well as the standard intravenous immunoglobulins (IVIG) Octagam^®, Gamunex^®, Kiovig^®.

STUDY DESIGN

We performed short-term cell-free CMV neutralization assays (CFNT) and long-term cell-adapted neutralization-plaque-reduction assays (PRANT). Human retinal epithelial cells (ARPE-19) were used as target cells. A clinical CMV primary-isolate from amnion fluid propagated in epithelial cells without any initial fibroblast adaption was used. For calibration we previously generated serum-pools (N=100) from two cohorts of mothers at birth: seronegative and latently CMV-infected mothers. Biochemical analysis included total protein, albumin, Ig-class, and IgG-subclasses. Additionally, CMV antibody-reactivity was checked using recombinant immunoblotting.

RESULTS

HIG and IVIG preparations showed differences in levels and patterns of protein, Ig-class and CMV-specific antibody concentrations. All IgG-preparations showed high in vitro NT-capacity and high IgG-avidity. The NT₉₀-values for HIGs and IVIGs and our seropositive reference-pool showed similar NT-capacity at a dilution of (1:100) which corresponded well to 4.1 PEI-Units/ml.

CONCLUSION

All HIG- and IVIG-preparations showed similar NT-capacity following CMV IgG-normalization. Our in vitro results are in strong contrast to former findings suggesting higher functional CMV NT titers in IVIG-preparations compared to HIGs.