Maternally acquired IgG immunity in neonates born to renal transplanted women

Parenthood with kidney failure: Answering questions patients ask about pregnancy

Achieving parenthood can be an important priority for women and men with kidney failure. In recent decades, the paradigm has shifted toward greater support of parenthood, with advances in our understanding of risks related to pregnancy and improvements in obstetrical and perinatal care. This review, codesigned by people with personal experience of kidney disease, provides guidance for nephrologists on how to answer the questions most asked by patients when planning for parenthood. We focus on important issues that arise in preconception counseling for women receiving dialysis and postkidney transplant. We summarize recent studies reflecting pregnancy outcomes in the modern era of nephrology, obstetrical, and perinatal care in developed countries. We present visual aids to help clinicians and women navigate pregnancy planning and risk assessment. Key principles of pregnancy management are outlined. Finally, we explore outcomes of fatherhood in males with kidney failure.

Measles Antibody Levels in Young Infants

BACKGROUND

Infants are often assumed to be immune to measles through maternal antibodies transferred during pregnancy and, in many countries, receive their first measles-containing vaccine at 12 to 15 months. Immunity may wane before this time in measles-eliminated settings, placing infants at risk for measles and complications. We investigated humoral immunity to measles in infants <12 months of age in Ontario, Canada.

METHODS

We selected sera collected at a tertiary pediatric hospital from infants <12 months who were born at ≥37 weeks' gestational age. We excluded infants with conditions that affect antibody levels. We selected ≤25 sera from 8 predetermined age bands and tested them for measles-neutralizing antibody using the plaque-reduction neutralization test. We calculated the proportion immune at each age band, and predictors of infant susceptibility were assessed by using multivariable logistic regression and Poisson regression.

RESULTS

Of 196 infant sera, 56% (110 of 196) were from boys, and 35% (69 of 196) were from infants with underlying medical conditions. In the first month, 20% (5 of 25) of infants had antibodies below the protective threshold, which increased to 92% (22 of 24) by 3 months. By 6 months, all infants had titers below the protective threshold. In a multivariable analysis, infant age was the strongest predictor of susceptibility (odds ratio = 2.13 for each additional month increase; 95% confidence interval: 1.52-2.97).

CONCLUSIONS

Most infants were susceptible to measles by 3 months of age in this elimination setting. Our findings inform important policy discussions relating to the timing of the first dose of measles-containing vaccine and infant postexposure prophylaxis recommendations.

Waning of measles maternal antibody in infants in measles elimination settings - A systematic literature review

INTRODUCTION

Most infants are born with immunity to measles through maternal antibodies transferred in pregnancy, which decay over time. However, in measles elimination settings, where measles does not circulate endemically and most immunity is from immunization rather than infection, maternal antibody levels are lower. This results in infant immunity that wanes earlier, and a wider susceptibility gap between maternal antibody decay and infant immunization than in non-eliminated settings. We aimed to systematically quantify the extent and duration of protection from measles in infants in settings that have sustained measles elimination.

METHODS

We conducted a systematic review of studies of measles maternal antibody waning in infants in measles elimination settings. We searched MEDLINE, Embase, CINAHL, Scopus, BIOSIS Previews, and Global Health databases for relevant studies. Studies were included if they were set in countries that had eliminated measles for ≥3 years, and if the study cohort included healthy, full-term, unvaccinated infants ≤12 months, born to healthy mothers, and reported a relevant measure of measles maternal antibody in infants. We assessed study quality using the MetaQAT tool.

RESULTS

We identified 4692 unique citations, eight of which met inclusion criteria. One study reported anti-measles antibody in cord blood, six reported antibody in infant sera, and one reported both. Two studies reported that 80 and 100% of infants were protected from measles at birth. One study reported no protection amongst 3-7 month old infants, and another reported limited protection in infants >4 months. The remaining studies reported the proportion of infants with detected antibody, but not the proportion immune.

CONCLUSION

Although limited, these data suggest that in settings that have sustained measles elimination, some infants are susceptible to measles well before the age of routine measles immunization. Setting-specific seroprevalence and vaccine effectiveness studies are required to evaluate this in different jurisdictions.

Growth of children born to renal transplanted women

Neonates born to transplanted mothers are exposed to immunosuppressive drugs during gestation and have a higher risk of being born prematurely and small for gestational age than the general population. We have prospectively followed up 27 children born to renal transplanted mothers from a single center and 31 healthy children born at term with adequate weight for gestational age. Comparisons of weight and length measurements were made at birth, 1 month (±0.9), 3 months (±1.0), 6 months (±1.0), 9 months (±1.5), and 12 months (±1.49) of age. There were a high rate of prematurity (51.9%) and neonates small for gestational age (40.7%) in the transplant group. At birth, in the transplant group, 28% of neonates had subnormal z-scores for weight and 40%, low z-scores for length. However, at 6 months of age, no significant differences were noticed in mean weight-for-age z-scores between groups (weight -0.43 vs -0.03; length -0.53 vs -0.08). At 12 months of age, comparable mean length-for-age z-scores were observed in both groups (weight 0.01 vs 0.27; length -0.07 vs 0.26).

CONCLUSION

Despite high rates of premature births and neonates small for gestational age in the transplant group, there was a good recovery of growth during the first year.. What is Known: • Children born to renal transplanted mothers are exposed to immunosuppressive drugs during gestation [4]. • They have high risk of premature birth and fetal growth restriction, immune alterations at birth, and risk of hospitalization for infection in the first months of life [5]. What is New: • Despite high rates of premature birth and neonates small for gestational age, these infants had good growth recovery by 1 year of age.

Response to immunization in children born to renal transplant recipients using immunosuppressive drugs during gestation

The use of immunosuppressive drugs can impair vaccination responses. When used during pregnancy, they may interfere with the development of the fetus's immune system. However, little is known regarding their influence on infant's response to vaccinations. Twenty-seven children born to renal transplant mothers (Tx) taking immunosuppressive drugs and 31 healthy children had the humoral immune response and reactogenicity to tetanus, Haemophilus influenzae type b (Hib) and 7 pneumococcal serotypes evaluated. The evolution of BCG vaccine scar was also registered. Antibodies were measured by ELISA. Lymphocyte immunophenotyping was performed on cord blood and at 7-8 months of age. Among Tx neonates, 82.4% had low B lymphocyte numbers at birth, and 29.4% had also low numbers of other lymphocyte subpopulations. Nevertheless, all children developed protective antibodies with similar antibody concentrations to the control group. Vaccine reactogenicity was similar in both groups and BCG healing was uneventful.