Evaluation of neutrophil alkaline phosphatase (NAP) activity in untreated myeloproliferative syndromes and in leukaemoid reactions

Abstract

Neutrophil alkaline phosphatase activity was estimated in 194 patients; 59 cases of chronic myeloid leukaemia (CML), 42 cases of polycythaemia vera (PV), 24 cases of primary myelofibrosis, 7 cases of idiopathic thrombocythaemia, 6 cases of leukaemoid reaction, 19 cases of secondary polycythaemia (PS) and 37 cases of the primary myelodysplastic syndrome (MDS). According to NAP activities the groups proved to be separate entities (p < 0.00025). The incidence of decreased NAP score in the CML group was 85% and differed significantly from the other groups as a whole, as well as separately (p< 0.001). The MDS group, the only group besides CML that showed decreased scores, also differed significantly from the others (p < 0.001). The PS group, nearly always showing normal scores, differed significantly from the PV group (p<0.0052). A method evaluating single cell NAP activity proved superior to the score method in discriminating between the different groups. Thus, the incidence of decreased activity in the CML group was 93 % compared with 85% by the score method and the incidences of increased activity in the PV, MP, IT, and LR groups were 79% to 100% compared with 25% to 67% by the score method. The latter difference was statistically significant (p=0.029).

Low neutrophil alkaline phosphatase score is a new aspect of calreticulin-mutated myeloproliferative neoplasms

“…The neutrophil alkaline phosphatase (NAP) score is a useful and reliable biochemical marker that supports the diagnosis of MPN (Bendix-Hansen and Bergmann 1985 ). The chronic phase of chronic myelogenous leukemia (CP-CML) is characterized by a low NAP score that is elevated when the disease enters the accelerated phase (Kaplow 1971 ).…”

Myeloperoxidase‐deficient polymorphonuclear leucocytes (VI): Relation to cytogenetic abnormalities in primary myelodysplastic syndromes

“…8,1985 ABBREVIATIONS PMN = polymorphonuclear leucocytes MPO = myeloperoxidase NAP = neutrophil alkaline phosphatase RA+ = refractory anaemia with ring sideroblasts RA = refractory anaemia RAEB = refractory anaemia with excess of blasts CMML = chronic myelomonocytic leukaemia AML = acute myeloid leukaemia MDS = myelodysplastic syndrome Myeloperoxidase (MP0)-deficient polymorphonuclear leucocytes (PMN) have been demonstrated as a distinct subpopulation in overt leukaemia (1-6) as well as in the primary myelodysplastic syndrome (7). Abnormalities in the neutrophil alkaline phosphatase (NAP) activity too have been reported in the same diseases (4, [6][7][8][9]. Thus the cytochemically abnormal PMN may be involved in the leukaemic process as a subpopulation originating from distinct leukaemic precursors.…”