Mucosal-Associated Invariant T (MAIT) cells are highly activated in duodenal tissue of humans with Vibrio cholerae O1 infection: A preliminary report.

Mucosal-associated invariant T (MAIT) cells are unconventional T lymphocytes with a semi-conserved TCRα, activated by the presentation of vitamin B metabolites by the MHC-I related protein, MR1, and with diverse innate and adaptive effector functions. The role of MAIT cells in acute intestinal infections, especially at the mucosal level, is not well known. Here, we analyzed the presence and phenotype of MAIT cells in duodenal biopsies and paired peripheral blood samples, in patients during and after culture-confirmed Vibrio cholerae O1 infection. Immunohistochemical staining of duodenal biopsies from cholera patients (n = 5, median age 32 years, range 26-44, 1 female) identified MAIT cells in the lamina propria of the crypts, but not the villi. By flow cytometry (n = 10, median age 31 years, range 23-36, 1 female), we showed that duodenal MAIT cells are more activated than peripheral MAIT cells (p < 0.01 across time points), although there were no significant differences between duodenal MAIT cells at day 2 and day 30. We found fecal markers of intestinal permeability and inflammation to be correlated with the loss of duodenal (but not peripheral) MAIT cells, and single-cell sequencing revealed differing T cell receptor usage between the duodenal and peripheral blood MAIT cells. In this preliminary report limited by a small sample size, we show that MAIT cells are present in the lamina propria of the duodenum during V. cholerae infection, and more activated than those in the blood. Future work into the trafficking and tissue-resident function of MAIT cells is warranted.

Effects of exclusive breastfeeding intervention on child growth and body composition: the MINIMat trial, Bangladesh.

AIM: Exclusive breastfeeding (EBF) for 6 months is recommended for optimal infant health, but the evidence for longer-term impacts is weak. We examined whether randomization to receive EBF counselling (BFC) in rural Bangladeshi women had an impact on childhood growth trajectories and body composition. METHODS: In the Maternal and Infant Nutrition Interventions in Matlab trial, 4436 pregnant women were randomized to six equally sized, food and micronutrient groups. Of these, 3214 were randomized during the last trimester of pregnancy to receive either BFC or the usual/standard health message (UHM). Their infants were extensively followed up, with anthropometric measurements between 0 and 54 months and assessment of body composition at 54 months. RESULTS: The mean duration of EBF in the BFC group was 111 days compared to 76 days in the UHM group (mean difference: 35.0 days, 95% CI 30.6-39.5, p < 0.001). There was no difference in growth trajectories between the BFC and UHM groups and no difference in body composition at 54 months. Children exposed to prenatal multiple micronutrients (vs 60 mg iron and folate) combined with BFC (vs UHM), however, had slower linear growth (mean difference -0.17 SD score, p < 0.01). CONCLUSION: Exclusive breastfeeding counselling resulted in neither differential growth trajectories in infancy and childhood, nor body composition differences at 54 months. The combination of prenatal multiple micronutrient supplementation (MMS) and BFC was unfavourable for linear growth during 0-54 months, which raises questions about possible negative effects of MMS.

Young children non-immunized against measles: characteristics and programmatic implications.

AIM: To examine the presenting characteristics, including nutritional status, of young children without measles immunization and to suggest appropriate public health measures to improve immunization status. METHODS: In this retrospective case-control analysis, we studied 4075 children aged 12-23 mo of either sex, who attended ICDDR,B's Dhaka hospital during 1994-2003. Cases included children who reported to this facility without receiving measles vaccine, and the control children were those who received the vaccine. RESULTS: 3181 of 4075 (78%) children, including 1227 (39%) girls and 1954 (61%) boys, received measles immunization. The proportion of vaccinated children increased from 74% in 1997 to 82% in 2001. Some non-specific effects of measles immunization were observed. Fifty-one per cent of the children without measles immunization were stunted, 76% were underweight, and 48% were wasted. The non-immunized children were twice as likely to be stunted, underweight, and wasted than the immunized children; they were more often dehydrated (some or severe dehydration) (28% vs 22%, p<0.001), required longer duration (>72 h) of hospitalization (15% vs 10%, p<0.001), did not receive vitamin A capsule in the previous 6 mo (56% vs 36%, p<0.001), and had more frequent abnormal lung auscultation indicative of acute lower respiratory tract infections (8% vs 5%, p<0.001). Female children, illiterate mother, lack of vitamin A supplementation, and history of measles were significantly associated with non-immunization against measles after controlling for co-variables. Results were similar when different nutritional indicators (underweight, stunting, or wasting) were added separately to logistic regression models. CONCLUSION: Intervention strategies to enhance immunization coverage in infants should target illiterate mothers and their children, particularly the females and malnourished ones, provide them with measles immunization and vitamin A capsule, and encourage their periodic follow-up visits as part of a preventive nutritional programme.