Serum Vitamin‐B₁₂‐Binding Proteins in Kwashiorkor*

Abstract

Summary. In contrast with plasma albumin and transport proteins such as transferrin and ceruloplasmin, vitamin B12‐binding proteins are not decreased in Cape Coloured children with kwashiorkor. Compared with normal coloured adults the mean serum vitamin B12 was increased while the unsaturated vitamin B12 binding capacity (UBBC) was markedly increased mainly due to elevation of the alpha‐1‐globulin vitamin B12 binder (alpha‐binder). In normal coloured children the UBBC was also increased with mean alpha‐binder intermediate between values found in kwashiorkor and normal coloured adults. The mean beta‐globulin‐vitamin B12‐binder (beta‐binder) was decreased in kwashiorkor. The total serum alpha‐1 and beta‐globulins, showed poor quantitative correlation with alpha‐and beta‐vitamin B12‐binders in these patients. Urinary vitamin B12‐levels were similar in kwashiorkor, normal children and adults. In the small series of adult Cape Coloured subjects studied, serum vitamin B12 and UBBC values were higher than in white adults. The alpha‐ and beta‐binders of kwashiorkor and normal children adequately transferred 57 Co‐vitamin B12 to rat liver homogenate while the alpha‐binder of chronic myeloid leukaemia transferred less efficiently.

Serum Transcobalamins in Healthy Nigerian Children

“…This result is in agree ment with what was observed in children of mixed race in South Africa [8], where /i-binder accounted for 48% of the serum UB,2BC. On the other hand, the percen tage of TC II in our children is low com pared with what has been reported on Afri can adults where TC II accounts for about 70% of their scrum UB,2BC [14,16,17].…”

“…Recent evidence has suggested that this binding protein is also synthesized by the mononuclear phago cyte system [2,6], TC II has been shown to be solely responsible for the transport of B,2 to and into the cell [7], Little is known about the distribution of serum transcobalamins in children. The three studies on children previously report ed [8][9][10] showed that the serum unsaturat ed B12-binding capacity (UB12BC) of chil dren under 5 years of age is significantly higher than that of adults. These studies also revealed that the percentage of the binder (TC 1) was very high in children.…”

“…The first study was carried out on children aged 1-5 years while the last two were on cord blood. Unfortunately, the study on children [8] used a method which did not recognize that the «-binder contained two transcobalamins, TC II and TC III.…”

Serum Unsaturated Vitamin B₁₂ Proteins in Adult Patients with Sickle Cell Anaemia (Hb SS)

“…The results in this study reveal that marked changes occur in the pattern of these binding proteins with age among sickle cell patients as it occurs among healthy populations, though the changes are not identical. In healthy populations, both serum TC I and TC III decrease with age with a significant increase in TC II [2][3][4][5][6][7][8][9]. But in sickle cell disease, both serum TC I and TC III increase with age with a significant fall in serum TC II.…”

“…Studies carried out among Africans have shown that serum TC I is gen erally high among children and this level declines with age while TC II increases steadily with age [2][3][4][5]. This steady fall of TC I with age and a gradual rise of TC II had also been observed among the white race [6][7][8][9], In view of the marked changes that occur in the pattern of these binding proteins with age among healthy individuals, this investigation was set up to find out whether identical changes also occur among sickle cell patients with Hb SS.…”