Post-natal decline of fetal haemoglobin in homozygous sickle cell disease: relationship to parental Hb F levels

The decline of fetal haemoglobin (Hb F) from birth to 6 years has been compared in a cohort of 266 Jamaican children with homozygous sickle cell (SS) disease and in 243 matched controls with a normal haemoglobin (AA) genotype. Hb F levels were significantly higher in the SS cases from 1 month onwards but, unlike the normal controls, no sex differences was apparent. The Hb F levels in SS disease were significantly correlated with parental Hb F levels, suggesting that genetic factors regulating adult Hb F levels are active at earlier stages in development. Furthermore, some of these genetic determinants of Hb F production may be linked to the á-like globin gene complex and be in linkage disequilibrium with the áý allele (Summary)

Serum immunoglobulin levels in children with homozygous sickle cell disease

Serum immunoglobulin levels (IgA, IgG, and IgM) have been assayed in a representative sample of children (aged 1-7 years) with homozygous sickle cell disease and in age/sex-matched control children with a normal haemoglobin genotype, followed from birth in a prospective cohort study. In SS disease, significant elevation of IgA occurred from the age of two years and of IgG from the age of six years. IgM levels were not significantly different in the two genotypes. The mechanisms contributing to these changes in immunoglobulins are currently unclear as is their clinical significance.(AU)

Splenific opacification in homozygous sickle cell disease

A prospective radiological and haemotological study of 182 patients with homozygous sickle cell anaemia has been undertaken to assess the prevalence and pattern of splenic opacification and relate this to the blood indices. Opacification was observed in 31 percent of patients. In 55 percent of these, the pattern was punctuate, whereas in 32 percent it was amorphous. A curvilinear appearance was seen in the remainder. In the amorphous group, a high percentage (72 percent), the spleen was severely contracted. The pattern of opacification and degree of contraction was related to age. The haemotological indices indicate a lower haemolytic rate in patients with splenic opacifications indicating a milder disease process with a greater persistence of the splenic capillary bed (AU)

The development of haematological changes in homozygous sickle cell disease: a cohort study from birth to 6 years

A cohort study of sickle cell disease from birth has allowed observations on the disease without the symptomatic selection inherent in previous series. The development of haematological indices from birth to 6 years in male and female infants with homozygous sickle cell (SS) disease is presented and compared with values in age and sex matched controls with a normal haemoglobin (AA) genotype previously presented elsewhere. In SS disease total haemoglobin levels fell rapidly from birth to a plateau at 3-6 months before falling again to 15 months after which no age related change occured. Mean cell haemoglobin concentration fell from birth to lowest values at 15-18 months before increasing to reach the level present at birth by the age of 5 years. Red cell counts fell rapidly after birth to a plateau at 2 months, increased slightly to 2 months and then fell steadily throughout the remaining period of study. The mean cell voloume and mean cell haemoglobin also fell rapidly after birth reaching the lowest values by 6 months and then increased progressively. Female patients showed significantly higher haemoglobin levels from 15 months to 4« years. Compared to AA controls, SS patients manifested significantly lower levels of haemoglobin from 2 weeks, and red cell counts from 1 month, and significantly higher levels of MCHA from 4 months to 3 years, MCV from 8 months to 5 years, and serum iron levels from 1 to 4 years. Children with SS disease were partially protected from iron deficiency in early childhood, perhaps by increased intestinal absorption of iron, and the associated increase in intracellular haemoglobin concentration might be disadvantageous during this high risk period (Summary)

Fetal haemoglobin and clinical severity of homozygous sickle cell disease in early childhood

The relationship of the clinical features of homozygous sickle cell disease in the first two years of life to the level of fetal hemoglobin at 6 months was investigated. Mean HgbF levels were significantly lower in children manifesting early palpable splenomegaly, dactylitis, acute splenic sequestration, and in those who died. The risks of dactylitis and ASS were significantly greater in patients with lower HgbF levels. Since early splenomegaly itself may increase the risks of ASS, infection, and death, the relationship of HgbF to these features was further analyzed within the early splenomegaly group.The results suggest that a low HgbF may have a direct effect on the etiology of ASS, but any effect on infection or death is probably mediated via its relationship with the appearance of a palpable spleen. A protective effect of a high HgbF on the risk of dactylitis was demonstrated coincident with the accepted theory of its pathogenesis. Early HgbF determinations may be of value in identifying patients at high risk of serious complications during infancy (AU)

Haematological indices in normal negro children: a Jamaican cohort from birth to five years

Haematological indices, including total haemoglobin, mean cell haemoglobin concentration, red cell count, mean cell volume, mean cell haemoglobin, reticulocytes, and serum iron values, in a cohort of 243 randomly selected Negro children with normal haemoglobin genotype, followed from birth to 5 years, are reported. Total haemoglobin fell rapidly from high levels at birth to a plateau at 2-6 months, a secondary fall occurred after 6 months and a gradual increase after 18 months. The red cell count also fell rapidly, but increased after 2 months to a plateau and then slowly declined from age 1-5. Mean cell volume and mean cell haemoglobin fell continously from birth to the lowest values at 15 months and then progressively increased to the age of 5 years. Serum iron levels were low at one year of age (mean 9.7 mumol/1) increasing slowly by age 4 and sharply by age 5. Mean cell haemoglobin concentration fell gradually to 1-1 1/2 years and then increased progressively to age 5. Values for Hb, MCHC, MCV, and MCH were consistently and often significantly lower in males before the age of 2 years, compatible with greater depletion of iron stores. Serum iron values were generally lower in males but there was no sex difference at one year when highly significant differences in Hb, MCHC, MCV, and MCH occurred. The cause of sex differences in early haematological development is currently unclear (AU)

Early splenomegaly in homozygous sickle-cell disease: an indicator of susceptibility to infection

135 children with homozygous sickle-cell (SS) disease diagnosed at birth have been followed for 1-5 years. Severe bacterial infections were confined to those in whom the spleen was first palpable at or before 1 year of age and were commonest in those in whom the spleen was first palpable at or before age 6 months. Regular follow-up of children with SS disease diagnosed at birth will identify children particularly at risk of severe infections. (Summary)