慢性骨髄増殖性疾患のビタミンB₁₂および結合蛋白

抄録

Serum vitamin B₁₂ and transcobalamin (TC) were studied in 62 cases with chronic myeloproliferative disorders (CMPD). A newly-established radioimmunoassay for serum R-protein was used in addition to conventional analyses because TC changes in CMPD are mainly attributable to R-protein increase.
Quantitatively, marked, moderate and mild increases of R-protein were noted in chronic myelocytic leukemia (CML), polycythemia vera (PV) and essential thrombocythemia (ET), respectively. R-protein was also increased in all cases of primary myelofibrosis, chronic neutrophilic leukemia, undifferentiated CMPD and Ph¹ negative CML; there have been few detailed reports concerning vitamin B₁₂ and TC in these disorders.
Because TC elevation in CMPD principally results from R-protein increase, analyses by gel filtration and immunological analyses were not helpful for differential diagnosis among CMPD. On DEAE, increased TC was separated into three types as follows: TC I in CML (both Ph¹ positive and negative), PV-binder or TCIII in PV and TC III in the remainder.
These characteristic TC elevations were also detected in CML cases with myeloid blastic crisis and in PV cases with a normal red cell mass because of venesection or iron deficiency. On the other hand, TC were normal both quantitatively and qualitatively in three out of eleven cases with untreated ET, while constant increases of R-protein were seen in all cases of CMPD except for ET. From these results, it is possible that cases different from true CMPD are included among ET diagnosed by the present criteria.
As mentioned above, the examination of TC in CMPD is useful for differential diagnosis among the various cases of CMPD and from diseases other than CMPD and may play an important role especially in atypical cases difficult to diagnose.