Impact of maternal engrafted cytomegalovirus-specific CD8+ T cells in a patient with severe combined immunodeficiency

Pregnancy-induced transfer of pathogen-specific T cells from mother to fetus in mice

Neonatal health is determined by the transfer of maternal antibodies from the mother to the fetus. Besides antibodies, maternal cells cross the placental barrier and seed into fetal organs. Contrary to maternal antibodies, maternal microchimeric cells (MMc) show a high longevity, as they can persist in the offspring until adulthood. Recent evidence highlights that MMc leukocytes promote neonatal immunity against early-life infections in mice and humans. As shown in mice, this promotion of immunity was attributable to an improved fetal immune development. Besides this indirect effect, MMc may be pathogen-specific and thus, directly clear pathogen threats in the offspring postnatally. By using ovalbumin recombinant Listeria monocytogenes (LmOVA), we here provide evidence that OVA-specific T cells are transferred from the mother to the fetus, which is associated with increased activation of T cells and a milder course of postnatal infection in the offspring. Our data highlight that maternally-derived passive immunity of the neonate is not limited to antibodies, as MMc have the potential to transfer immune memory between generations.

Genetic diagnosis of inborn errors of immunity using clinical exome sequencing

Inborn errors of immunity (IEI) include a variety of heterogeneous genetic disorders in which defects in the immune system lead to an increased susceptibility to infections and other complications. Accurate, prompt diagnosis of IEI is crucial for treatment plan and prognostication. In this study, clinical utility of clinical exome sequencing (CES) for diagnosis of IEI was evaluated. For 37 Korean patients with suspected symptoms, signs, or laboratory abnormalities associated with IEI, CES that covers 4,894 genes including genes related to IEI was performed. Their clinical diagnosis, clinical characteristics, family history of infection, and laboratory results, as well as detected variants, were reviewed. With CES, genetic diagnosis of IEI was made in 15 out of 37 patients (40.5%). Seventeen pathogenic variants were detected from IEI-related genes, BTK, UNC13D, STAT3, IL2RG, IL10RA, NRAS, SH2D1A, GATA2, TET2, PRF1, and UBA1, of which four variants were previously unreported. Among them, somatic causative variants were identified from GATA2, TET2, and UBA1. In addition, we identified two patients incidentally diagnosed IEI by CES, which was performed to diagnose other diseases of patients with unrecognized IEI. Taken together, these results demonstrate the utility of CES for the diagnosis of IEI, which contributes to accurate diagnosis and proper treatments.

Peripheral Plasmodium falciparum Infection in Early Pregnancy Is Associated With Increased Maternal Microchimerism in the Offspring

BACKGROUND

Placental malaria has been associated with increased cord blood maternal microchimerism (MMc), which in turn may affect susceptibility to malaria in the offspring. We sought to determine the impact of maternal peripheral Plasmodium falciparum parasitemia during pregnancy on MMc and to determine whether maternal cells expand during primary parasitemia in the offspring.

METHODS

We conducted a nested cohort study of maternal-infant pairs from a prior pregnancy malaria chemoprevention study. Maternal microchimerism was measured by quantitative polymerase chain reaction targeting a maternal-specific marker in genomic DNA from cord blood, first P falciparum parasitemia, and preparasitemia. Logistic and negative binomial regression were used to assess the impact of maternal peripheral parasitemia, symptomatic malaria, and placental malaria on cord blood MMc. Generalized estimating equations were used to assess predictors of MMc during infancy.

RESULTS

Early maternal parasitemia was associated with increased detection of cord blood MMc (adjusted odds ratio = 3.91, P = .03), whereas late parasitemia, symptomatic malaria, and placental malaria were not. The first parasitemia episode in the infant was not associated with increased MMc relative to preparasitemia.

CONCLUSIONS

Maternal parasitemia early in pregnancy may increase the amount of MMc acquired by the fetus. Future work should investigate the impact of this MMc on immune responses in the offspring.