Superoxide anion production and expression of cytochrome b 558 by neutrophils are impaired in some patients with myelodysplastic syndrome.
Superoxide anion (O2-) production and expression of cytochrome b 558 by neutrophils were determined in 20 patients with myelodysplastic syndrome (MDS). The reduction of O2- production was noted in eight of the 20 patients and an increase was noted in four patients when neutrophils were stimulated by n-formyl-methionyl-leucyl-phenylalanine (FMLP), while a low level of O2- production was found in 11 and an increase in six MDS patients when they were stimulated by phorbol myristate acetate (PMA). Among them, seven patients showed a decrease and four an increase in O2- production on stimulation with either FMLP or PMA. Expression of cytochrome b 558 was found to be at low levels in patients who had neutrophils showing decreased O2- production when stimulated with FMLP, indicating that decreased expression of cytochrome b 558 might contribute to the impairment of O2- production in some MDS patients. In this study, no significant differences in O2- production were noted among subtypes of MDS; however, the patients who had received prednisolone showed lower levels of O2- production than those who had not received prednisolone. Patients manifesting episodes of infection had reduced levels of O2- production compared with those without infection. Furthermore, the fact that one patient who exhibited a marked reduction in neutrophil counts together with reduced O2- production died of fatal infection, suggests that the determination of O2- production, in combination with hematological features, may be of some help in predicting severe infection.
Itoh
Y
Y
First Department of Internal Medicine, Tokyo Medical College, Japan.
Kuratsuji
T
T
Aizawa
S
S
Sai
M
M
Ohyashiki
K
K
Toyama
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003573:Cytochrome b Group / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000097:blood*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D019255:NADPH Oxidases; D009504:Neutrophils / Q000201:enzymology*; D013481:Superoxides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D003573:Cytochrome b Group; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; C036888:cytochrome b558; D019255:NADPH Oxidases; D013755:Tetradecanoylphorbol Acetate