Healthy monozygous twins do not recognize identical T cell epitopes on the myelin basic protein autoantigen

The T cell response against myelin basic protein (MBP) has been extensively studied in humans because of its putative role in the pathophysiology of multiple sclerosis (MS). Higher concordance rates in monozygous twins as well as an increased risk in relatives suggest the role of genetic factors in MS susceptibility. Very little is known about the shaping of T cell repertoire towards self antigens in humans and their contribution to disease susceptibility in autoimmune disorders. Here we report the comparative T cell epitope recognition patterns towards the MBP auto-antigen in healthy identical twins. We have established MBP-specific T cell lines from eight sets of twins and characterized their fine epitope specificity. Intra-pair comparison showed the co-existence of shared as well as distinct epitopes in six of eight pairs and a complete absence of concordant epitope recognition within two other pairs. These findings indicate that important differences in T cell repertoires against a self antigen may be observed between genetically identical healthy individuals, rendering difficult the interpretation of the differences which may be observed between identical twins discordant for an autoimmune disease.     

Twin pregnancy

Twins account for 2–3% of all births. They carry significant risks to both mothers and babies. These risks include preterm delivery, intrauterine growth restriction, and pre-eclampsia. In addition, monochorionic gestations confer an even higher rate of perinatal morbidity and mortality arising from a shared placenta due to placental anastomoses, which may lead to twin-to-twin transfusion syndrome (TTTS) or twin anaemia-polycythaemia sequence (TAPS). It is essential that chorionicity is established in the first trimester in order to initiate the appropriate antenatal management and surveillance. In view of the high risk of both maternal and fetal complications, twin pregnancies are ideally managed in a dedicated clinic according to agreed protocols with both obstetric and midwifery input.     

Outcomes following rescue cerclage in twin pregnancies*

Objective: Our aim was to compare perinatal outcomes in twin pregnancies complicated by premature asymptomatic cervical dilatation treated with rescue cerclage and expectant management.

Methods: A retrospective cohort study was conducted at a single tertiary referral center between 2003 and 2014 and included all women with twins found to have a dilated cervix with intact membranes before 25-week gestation. Pregnancy outcomes were compared between women with rescue cerclage and those managed expectantly. A total of 36 women were eligible for the study, 27 (75.0%) of whom had a rescue cerclage compared to 9 (25.0%) women managed expectantly. Student’s t-test was used to compare continuous variables between the groups and the chi-square and Fisher’s exact tests were used for categorical variables as appropriate. Statistical analysis was performed with the SPSS v21.0 software (IBM Corp; Armonk, NY). Differences were considered significant when the p value was less than .05.

Results: Among the 27 women with a rescue cerclage, the mean gestational age at time of cerclage insertion was 21.5?±?2.6 weeks. The intervention and control groups were similar with respect to the degree of cervical dilatation at presentation (2.6?±?1.3 versus 3.0?±?1.5?cm, p?=?.5). Women in the cerclage group gave birth at a more advanced gestation (28.9?±?6.1 versus 24.2?±?2.6?weeks, respectively, p?=?.03) and were less likely to give birth at <34 and <28?weeks (66.7 versus 100.0%, p?=?.046, and 59.3 versus 100.0%, p?=?.02, respectively). The mean latency from the placement of cerclage to delivery was 7.3?±?5.5 weeks. Similar findings were observed when analysis was limited to women with cervical dilatation of ≤3?cm at presentation.

Conclusions: In asymptomatic women with twin pregnancies and cervical dilatation before 25?weeks of gestation, rescue cerclage can prolong pregnancy and improve perinatal outcomes when compared to expectant management.     

The association between maternal race and adverse outcomes in twin pregnancies with similar healthcare access

Objective: To compare twin pregnancy outcomes between white and nonwhite women with similar access to health care.

Methods: Retrospective cohort study of all twin pregnancies delivered by a single maternal–fetal medicine practice from 2005–2016. All patients had private health insurance and equal access to physician care. Outcomes were compared between white and nonwhite women using logistic regression to adjust for differences at baseline.

Results: Of the 858 women included, 730 (85.1%) were white and 128 (14.9%) were nonwhite. Univariate analysis demonstrated that nonwhite women had higher rates of preterm birth <32 weeks (12.5 versus 6.7%, p?=?.022), cesarean delivery (78.1% versus 61.4% of all women, p?p?p?=?.029) and gestational diabetes (23.2% versus 7.3%, p?Conclusions: Nonwhite women with twin pregnancies have an increased risk of adverse outcomes that cannot be explained by access to care. Although improving access to care is an important goal for health care systems, our data suggest that this alone will not eliminate all disparities in health care outcomes between women of different races.     

Phenotypic discordance in monozygotic twins with 22q11.2 deletion

We report on male monozygotic twins with 22q11.2 deletion and discordant phenotypes. The twins had twin-to-twin transfusion syndrome. Twin 1, the smaller of the pair, had Tetralogy of Fallot, a characteristic facial appearance, swallowing dysfunction, anal atresia, short stature, and mental retardation, whereas twin 2 had a characteristic facial appearance but no other signs of the 22q11 deletion syndrome. Fluorescence in situ hybridization analysis showed a microdeletion on chromosome 22q11.2 in both twins. Zygosity analysis gave a probability of monozygosity greater than 99.999%. These observations indicate that environmental factors or postzygotic events play a role in the phenotypic variability in the twins. Am. J. Med. Genet. 78:319–321, 1998. © 1998 Wiley-Liss, Inc.     

Retardation and twin concordance in infant mental development: A reassessment

A reappraisal is made of Nichols and Broman's conclusion that there is no evidence that genetic influences are important in infant mental development if severely retarded twins are excluded from the sample. The reappraisal touches on certain idiosyncrasies of their sample, the test scores reported, and their definition of severe retardation. Data are presented for a sample of White twins who have been followed longitudinally since birth. For Bayley Mental Scale scores at 9 months of age, the monozygotic within-pair correlation was 0.85 and the dizygotic within-pair correlation was 0.62. With 13 retarded twins excluded, the correlations became 0.81 and 0.64, respectively, with the monozygotic correlation still being significantly larger (p<0.01). The present results indicate that genetic factors play a role in infant mental development.This research was supported in part by research grants from the Grant Foundation and from the National Institutes of Health (MH 23884 and HD 07200).