Tumour necrosis factor-alpha and leukotriene E4 production in wheezy infants.

It is not clear why certain infants wheeze during viral upper respiratory tract infections (URTIs) but it is possible that they have a tendency to mount an exaggerated inflammatory response leading to production of mediators that induce airway narrowing. We studied nasal tumour necrosis factor-alpha (TNF alpha) and urinary leukotriene E4 (LTE4) production during infection and after recovery in 31 wheezy infants (median age 6.2 months). Urinary LTE4 production was not altered during wheezy episodes or URTIs. However, the concentration of TNF alpha in nasal lining fluid (NLF) was significantly increased during acute episodes of wheeze compared to recovery (median [interquartile range] of 293 [42-1753] vs 0 [0-203] pg/ml NLF). TNF alpha was detectable more often and in higher concentration when wheezing was due to respiratory syncytial virus. TNF alpha was also present in 7/30 asymptomatic wheezy infants who had recovered from infection (> 100 pg/ml NLF) and in 4/7 non-wheezy siblings during URTIs (> 200 pg/ml NLF). This suggests that upregulation of TNF alpha production is not the only factor that makes some infants wheeze.

Adrenal function in preterm infants.

The adrenal function of 10 preterm infants of gestational age 27-34 weeks was assessed longitudinally from measurements of excretion rates of steroid metabolites in 24-hour urine samples collected at frequent intervals for up to 80 days after delivery. The changes in steroid excretion with time in preterm infants of gestation over 28 weeks reflect involution of the fetal adrenal zone at a similar rate to term infants. These findings are consistent with the removal at birth of the inhibitory effects of oestrogen on the 3 beta-hydroxysteroid dehydrogenase enzyme. The continued function of the adrenal fetal zone beyond the first month in preterm infants of less than 28 weeks gestation may however be due to persistence of some other fetal regulatory adrenal mechanism.

Microcytosis, iron deficiency, and thalassaemia in preschool children.

To investigate the possible causes of an increased incidence of red cell microcytosis in Asian children, 204 Gujarati Asian children and 88 European children attending community infant welfare clinics underwent initial screening tests for determination of red cell indices. Seventy six Asian (37%) and nine European (12%) children had microcytic red cells (mean corpuscular volume less than 74 fl). Further investigation showed that 16 of the Asian children (21%) with microcytosis had thalassaemia trait (eight were heterozygous for alpha thalassaemia and eight for beta thalassaemia), and 50 (66%) had suspected iron deficiency (confirmed by a response to oral iron in 41 cases): the remaining 'microcytic' children were aged less than 2 years, when mean corpuscular volume between 70 and 74 fl may be normal. Increased values for serum total iron binding capacity were more sensitive in detecting iron deficiency than reduced serum ferritin concentrations. Enthusiastic screening for microcytic anaemia in young children may mean that a substantial minority with thalassaemia genes are given unnecessary iron supplements. The response to a short course of oral iron should therefore be carefully monitored, and the possibility of thalassaemia trait as well as non-compliance with treatment should be reconsidered in all those in whom there is little or no response.

A major role for viruses in acute childhood encephalopathy.

29 children and 3 adults with acute depression of conscious level or acute onset of focal neurological signs were studied prospectively. 3 were found to have a non-infectious cause for their illness. The presence of interferon or specific antibodies in the serum and/or cerebrospinal fluid provided evidence of active virus infection in 25 of the remaining 29 patients. There was laboratory evidence that a virus had invaded the central nervous system in 11 patients. Early investigation gave the highest diagnostic yield. Since several common viruses were identified, it appears that the nature of the illness is due more to the host response than to the nature of the infective agent.

Racial differences in red cell indices.

A high prevalence of iron deficiency was found in apparently healthy Asian immigrant children in Harrow. After excluding children with overtly abnormal red cell indices, Asian and European children had identical haemoglobin values, but Asian children had much lower mean cell volume and mean corpuscular haemoglobin values and higher red blood cell values.

Immunoglobulin levels and function in pre-school children with recurrent respiratory infections.

Thirty pre-school children with recurrent respiratory infections had a higher age adjusted mean serum IgG level than their siblings or a reference group. One index child had persistently low serum IgA, but mean serum IgA and IgM levels for the index children were normal. All of the 23 index children and 17 siblings studied had a four-fold or greater rise in virus neutralizing antibody titre. There was no correlation between serum immunoglobulin levels and frequency of infections. There was, however, a significant inverse correlation between salivary IgA levels when healthy and the number of infections experienced by each child in the study year. Salivary IgA levels rose considerably during acute infections.