M. Faurschou et al., High prevalence of hyperhomocysteinemia due to marginal deficiency of cobalamin or folate in chronic myeloproliferative disorders, AM J HEMAT, 65(2), 2000, pp. 136-140
Hyperhomocysteinemia is an established risk factor for thrombosis. In patie
nts with myeloproliferative disorders, thrombotic events are common. Our ai
m was to investigate whether the increased burden of proliferating cells pr
esent in these patients implies a risk of homocysteine (HCY) accumulation s
econdary to depletion of folate and/or cobalamin. Fifty patients (PV, 25; E
T, 10; IMF, 15) and 163 healthy volunteers (HV) participated in the study.
The prevalence of hyperhomocysteinemia was 56.0% in PV, 70.0% in ET, 60.0%
in IMF, and 34.9% in HV. The mean P-homocysteine (P-HCY) was 13.88 +/- 4.24
mu mol/L in PV, 12.78 +/- 3.70 in ET, 11.34 +/- 4.22 in IMF, and 9.71 +/-
2.76 in HV. In PV and ET, but not in IMF, the mean P-HCY was significantly
higher than in the HV group (P < 0.001, P = 0.028, and P = 0.163, respectiv
ely). Thirty-three percent of the patients with hyperhomocysteinemia displa
yed metabolic changes compatible with cobalamin deficiency (P-HCY and P-met
hylmalonic acid both elevated), while 67% were folate deficient (P-HCY elev
ated, P-methylmalonic acid normal). Supplementation therapy with the releva
nt vitamin was implemented in 11 vitamin-deficient patients and led to norm
alization of metabolite levels in all cases. No correlation between hyperho
mocysteinemia and thrombosis was found, Our data indicate that patients wit
h PV, ET, and IMF frequently develop hyperhomocysteinemia due to discrete d
epletion of cobalamin or folate. Vitamin therapy leads to normalization of
P-HCY and should be considered, even though hyperhomocysteinemia does not s
eem to be of crucial importance for the thrombotic tendency in the myelopro
liferative disorders. (C) 2000 Wiley-Liss, Inc.