Fetal thymus size in pregnant women with Hashimoto disease.

PURPOSE: This study compared fetal thymic-thoracic ratios and fetal thymus transverse diameter measurements in pregnant women with Hashimoto's thyroiditis (HT) and non-immune hypothyroidism. METHODS: The study included a total of 141 pregnant women in three groups: 41 with HT, 50 with non-immune hypothyroidism, and 50 healthy individuals. Fetal thymus transverse diameter and thymic-thoracic ratio were compared between these groups. RESULTS: The mean fetal thymic-thoracic ratio was greater in pregnant women with HT than in the healthy controls (p = 0.031). Mean fetal thymus transverse diameter showed no statistically significant difference between the groups. CONCLUSIONS: Maternal HT was associated with an increased fetal thymic-thoracic ratio. More comprehensive studies are needed on this subject.

Thymus size is associated with breastfeeding and having pets in a sex-specific manner.

AIM: The aim was to examine associations between thymus size and anthropometric measurements, sex, age, breastfeeding status, presence of siblings, household pets, and infections and allergies since birth in 8- to 13-month-old healthy Danish infants. METHODS: Data collected from 256 healthy infants enrolled in the ProbiComp study were used. Thymus size was assessed using sonographic measures, and thymic index (TI) and thymus weight index (TWI) was used as an absolute and a relative volume estimate, respectively. RESULTS: In terms of TI and TWI, boys had approximately 15% and 5% larger thymus than girls (P < .001 and P < .02, respectively). TWI was larger in girls who were still breastfed than girls who were no longer breastfed (ß: 0.16 cm3 /kg; 95% CI: 0.004, 0.29; P = .01), but no difference was observed for boys. Having household pets was associated with a larger TI (P = .02), which seemed to be driven by associations for boys (ß: 1.38 cm3 ; 95% CI: 0.02, 2.74). No other factors associated with thymus size were identified. CONCLUSION: Thymus size was associated with current breastfeeding in girls and with having household pets in boys. Sex-specific associations should be further explored in future studies on factors associated with thymus size.

Influence of maternal HIV infection on fetal thymus size.

Objective To reveal the effect of a maternal human immunodeficiency virus (HIV) infection on the fetal thymus size. Methods The sonographic fetal thymus size was measured retrospectively in 105 pregnancies with maternal HIV infection and in 615 uncomplicated singleton pregnancies. The anteroposterior thymic and the intrathoracic mediastinal diameter were determined in the three-vessel view and their quotient, the thymic-thoracic ratio (TT ratio), was calculated. The study group was subdivided into three groups by the maternal viral load on the date of ultrasound (<50 cop./mL, 50-1000 cop./mL, >1000 cop./mL). Furthermore, an association between prognostic factors of the HIV infection such as the lymphocyte count, CD4/CD8 ratio, HIV medication and the thymus size, was investigated using correlation analyses. Results Fetal thymus size in pregnancies of HIV-positive mothers showed to be noticeably larger than in uncomplicated pregnancies. The mean TT ratio in the HIV-positive group was 0.389 and in the control group 0.345 (P < 0.001). There was no association between any maternal HIV parameter or medication and the size of the thymus gland. Conclusion Maternal HIV infection was associated with an increased fetal thymus size. Further consequences of intrauterine HIV exposure for fetal outcome and the development of the immune system of HIV-exposed uninfected (HEU) infants must be discussed.

Vitamin D deficiency in pregnancy may affect fetal thymus development.

OBJECTIVES: The aim of our study was to evaluate the association of vitamin D deficiency (VDD) during pregnancy with thymus size in full-term fetuses. MATERIAL AND METHODS: In this prospective study, we evaluated mid-pregnancy serum 25-hydroxyvitamin D3 (25(OH)D3) concentrations. The fetal thymus size was measured by ultrasound in the third trimester. Neonatal 25(OH)D3 levels were evaluated by umbilical cord blood sampling. Correlation of maternal and neonatal vitamin D levels and association between thymus size and both, maternal and neonatal vitamin D concentrations were investigated. RESULTS: Serum 25(OH) D3 concentrations were within the normal range in 48 (29.8%) mothers and 10 (13.1%) new-borns. A strong correlation between mid-pregnancy maternal and neonatal 25(OH)D3 concentration (r = 0.8, p < 0.001) was found. A significant linear correlation was observed between both, maternal and neonatal 25(OH)D3 concentrations and thymus perimeter length (r = 0.45, p = 0.04 and r = 0.43, p < 0.01, respectively). Both, maternal and fetal VDDs were associated with decreased thymus perimeter (p = 0.04, p = 0.03). CONCLUSIONS: Vitamin D deficiency during pregnancy may be associated with smaller fetal thymus. Our data suggest that VDD in pregnancy may lead to systemic inflammatory response in the fetus.

Fetal thymic-thoracic ratio in pregnancies with familial Mediterranean fever.

OBJECTIVE: To investigate the thymic-thoracic ratio (TTR) in fetuses of pregnant women with familial Mediterranean fever (FMF). STUDY DESIGN: This prospective case-control study was conducted with 43 pregnant women diagnosed with FMF and 43 gestational age-matched healthy controls. Pregnant women between 28 and 40 weeks who applied for antenatal care were included in the study. Healthy pregnant women whose age and gestational week matched were defined as the control group. RESULTS: TTR was significantly lower in the FMF group compared to the control group. The mean TTR value was 0.34 ±â€¯0.03 in the FMF group and 0.36 ±â€¯0.02 in the control group (p < 0.001). TTR was significantly lower in those with FMF duration of ten years or more than those with FMF of less than ten years (p < 0.001). In addition, pregnant women who had an attack during pregnancy had lower TTR (p < 0.001). TTR was significantly associated with white blood cell count, neutrophil count, monocyte count, platelet count, mean platelet volume, C-reactive protein, red cell distribution width, and platelet­to­lymphocyte ratio. CONCLUSION: Besides the inflammation during the FMF attacks, the ongoing subclinical inflammation between the attacks might affect the fetal thymus size. Since TTR is an easily applicable method, it can be used to evaluate fetal inflammation.

Pre-Transplant Total Lymphocyte Count Determines Anti-Thymocyte Globulin Exposure, Modifying Graft-versus-Host Disease Incidence and Post-Transplant Thymic Restoration: A Single-Center Retrospective Study.

The use of anti-thymocyte globulin (ATG) as part of conditioning to prevent graft-versus-host disease (GVHD) may severely impair immune reconstitution (IR). We analyzed relationships between ATG exposure, the recipient lymphocyte count, IR, and transplant outcome. We retrospectively reviewed patients aged ≤ 18 years who underwent allogeneic HSCT between April 2005 and April 2020. The outcomes of interest included the incidence of GVHD, overall survival (OS), and IR. IR was analyzed through thymic magnetic resonance imaging (MRI) and by quantifying T CD4+ and recent thymic emigrants (RTEs). The ATG-exposed group was split into a low ATG/lymphocyte ratio subgroup (ratio < 0.01) and a high ATG/lymphocyte ratio subgroup (ratio > 0.01). The low ratio subgroup had a higher incidence of GVHD (29 [59%] vs. 7 [16.6%]) but a better IR in both laboratory and MRI imaging assessments (p < 0.0001). The median thymic volume in the low ratio subgroup was significantly higher (14.7 cm3 vs. 4.5 cm3, p < 0.001). This was associated with a better OS and lower transplant-related mortality (TRM) (80.4% vs. 58.0%, p = 0.031) and (13.1% vs. 33.0%, p = 0.035). An individualized approach to ATG dosing allows for the obtainment of rapid thymic reconstitution and the best transplant-related outcomes.

Is thymus size at birth associated with respiratory distress syndrome in preterm infants?

AIM: Thymus size in neonates depend on many factors. We aimed to assess the thymus size radiographically in preterm neonates and its relationship with respiratory distress syndrome (RDS) and other complications of prematurity. METHODS: Thymus size was assessed by cardiothymic: thoracic ratio (CT/T), measuring the width of the cardiothymic shadow at the level of carina and dividing it by the width of the thorax at the costophrenic angles, from the first chest radiograph in patients less than 34 weeks gestational age. RESULTS: Neonates born between 30-34 weeks of gestation with RDS had smaller CT/T than non RDS group (0.34±0.1 vs 0.36±0.05, p = 0.045). Birth weight has positive correlation with CT/T (r = 0.166, p = 0.03). CONCLUSION: Thymus involution in the perinatal period is a complex process and the response is variable in different clinical situations. Activated hypothalamic-pituitary-adrenal (HPA) axis may be responsible for thymic involution in preterm infants between 30-34 weeks of gestation with RDS.

Assessment of thymus size in healthy term neonates using sonography - A study from tertiary care hospital of Central India.

OBJECTIVE: A cross-sectional study was done to assess the size of thymus in term healthy infants using sonography and to assess its variation in size, shape, location, echogenicity and echotexture for both male and female reference population. MATERIAL AND METHODS: A total of 250 term healthy neonates of either sex were subjected to thymic sonography. The shape, size in maximal anteroposterior, longitudinal, and transverse dimensions of both right and left lobes of thymus was evaluated. Their echotexture and echogenicity were determined and standards for reference population were calculated. The results were statistically evaluated. RESULTS: According to the shape; the thymus was quadrilateral in 156 neonates (62%), round in 37 (15%), bilobate in 32 (13%), and crescent shaped in 25 (10%) in transverse scan. According to the echo texture, the thymus echogenicity was homogeneous and almost similar or slightly less to that of the liver and spleen in most cases 200 [80%] and was coarse in 50 (20%). In all subjects, the echogenicity of the thymus was less than that of the thyroid gland. Variations in location of the thymus were found in 70 (28%) neonates. The range of mean AP diameter was 0.39-2.36 cm (mean 1.43 ± 0.3), that of transverse 1.4 - 4.3 cm (mean 2.16 ± 0.54) and that of thymic index 1.2-5.1 cm2 (mean 2.98 ± 0.64). CONCLUSIONS: A normative range was calculated for standard population, which can be used as a reference for comparing thymus size for both normal and diseased neonates for various immunological diseases.

Fetal tyhmus size as a predictor of histological chorioamnionitis in preterm premature rupture of membranes.

OBJECTIVE: To predict histological chorioamnionitis (CA) in the cases of preterm premature rupture of membranes by using fetal thymus transverse and anteroposterior diameters and areal measurements. METHODS: Fifty healthy and 50 patients diagnosed with preterm premature rupture of membranes (PPROM) between 24 and 37 weeks of gestation were included in the study. Fetal thymus measurements were done and repeated on a weekly basis until delivery, Furthermore white blood cell, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were measured every other day until delivery, too. Following delivery, all patients' placentas were sent to pathology. RESULTS: Histological CA was detected in 48% of the PPROM patients. There were no patients in either group with clinical CA. Thymus transverse diameter had 91% sensitivity, 81% specificity, 82% PPV, and 91% NPV in predicting histological CA in PPROM patients. No linear relationship was found between thymus anteroposterior diameter measurements and gestational age. Thymus area measurements have sensitivity of 75%, specificity of 81%, PPV of 78%, NPV of78% in determining CA in patients with PPROM. CONCLUSION: Both thymus transverse diameter and area measurement are more significant than sedimentation and CRP values in predicting histological CA. Fetal thymus measurements can be used in early diagnosis of infections among high risk patients.