Vitamin B12 transport proteins in patients with HIV-1 infection and AIDS

Haematologica. Mar-Apr 1993;78(2):84-8.

Abstract

Background: Low vitamin B12 levels (B12) are often observed in patients infected with human immunodeficiency virus type 1 (HIV-1). The causes underlying this finding are thought to be intestinal malabsorption and/or abnormalities in the vitamin plasma binding proteins (BP).

Material and methods: Serum levels of B12 and BP were studied in eighty HIV-1-positive patients, 55 of whom met the diagnostic criteria for AIDS. Subjects were divided into various subgroups: non-AIDS HIV-1 positive versus AIDS; low serum B12 levels (DB12, < 150 pmol/L) versus normal serum B12 levels (NB12); and the results obtained were compared both between groups and with respect to a reference population (RF) of normal volunteers.

Results: Low levels of serum B12 were found in 14 patients (17.5%), without differences between the AIDS and non-AIDS subgroups. The levels of holohaptocorrin (holoHP) were lower in the DB12 group than in the NB12 and RF groups (p < 0.01), and no differences were found between the AIDS and non-AIDS groups. The levels of apotranscobalamin (apoTC) were higher in the AIDS group than in the non-AIDs and RF subjects (p < 0.01), but no differences were found between the DB12 and NB12 groups. Likewise, no differences were noted in the levels of holoTC between the DB12 and NB12 groups. A positive correlation between neutrophil counts and free serum haptocorrin levels (apoHP) (rs = 0.36; p = 0.002), and a negative one between the former and the levels of apoTC (rs = -0.3; p = 0.009) were observed. Furthermore, a positive correlation was detected between the erythrocyte sedimentation rate and the levels of apoHP and TC.

Conclusions: Low serum levels of HP in HIV-1 positive patients could lead to the low levels of serum vitamin B12 frequently observed in this patient population, while the high levels of TC could merely represent a non-specific marker of inflammation (acute phase, reactant).

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acquired Immunodeficiency Syndrome / blood*
  • Acquired Immunodeficiency Syndrome / complications
  • Acute-Phase Reaction
  • Adult
  • Apoproteins / blood*
  • Female
  • HIV Infections / blood*
  • HIV-1
  • Humans
  • Incidence
  • Inpatients
  • Leukocyte Count
  • Male
  • Middle Aged
  • Neutropenia / blood
  • Neutropenia / complications
  • Outpatients
  • Transcobalamins / analysis*
  • Transcobalamins / deficiency
  • Vitamin B 12 / blood*
  • Vitamin B 12 Deficiency / blood
  • Vitamin B 12 Deficiency / complications*
  • Vitamin B 12 Deficiency / epidemiology

Substances

  • Apoproteins
  • Transcobalamins
  • Vitamin B 12