Myeloperoxidase deficient polymorphonuclear leucocytes in leukaemia and allied disorders.

This thesis is a survey of nine previously published articles on MPO deficient PMN. The incidences in leukaemia and allied disorders of the presence of this abnormal subpopulation of mature neutrophils and the relationship to clinical course in AML, susceptibility to infections in AML, FAB classification in AML and MDS, cytogenetically defined aberrations in MDS and morphometrical characteristics were investigated. The aims of the studies were to examine the diagnostic as well as the prognostic value of the parameter, to examine the usefulness of the parameter as an predictive indicator of CR and relapse in AML and to examine the concept that MPO deficient PMN may originate from leukaemic precursors. MPO deficient PMN were found to occur in a minor number (less than 4% of the total number of PMN) in normal humans and the incidences of an abnormal number (greater than 4%) were found to be about 40% in AML (I, II, III, IV, VIII), 60% in CML (I, VII), 30% in MPD other than CML (VII) and 30% in MDS (V). The highest incidences in AML were found in the FAB subtypes possessing the most myeloid differentiation potential i.e. FAB M2 and FAB M4 (IV). In ALL, CLL, HCL, Hodgkin's disease, anaemia not related to leukaemia and leukaemoid reactions the incidences all were 0% (I, unpublished data). The abnormal MPO deficient PMN subpopulation, if present, disappeared when CR was achieved and reappeared when relapse eventually was developed (II, VIII). In both situations serial determinations showed that the change occurred before the usual routine blood examinations predicted CR and relapse; several days and several months prior, respectively (VIII). The probability of obtaining CR was lower in the AML patients with the abnormal subpopulation and the risk of developing relapse higher than in AML patients without the anomaly (II, VIII). These differences were not statistically significant, however. AML patients, showing an increased number of MPO deficient PMN, revealed a statistically significant increased susceptibility to infections (P less than 0.01) during the preremission phase accounting for 18% to 67% of the total number of infections in this period (III). This increase was positively correlated to the extent of the anomaly (P less than 0.002). The spontaneous occurrence of a subpopulation of MPO deficient PMN in MDS went together with a simultaneous progression in cytogenetically determined clonal chromosomal aberrations and were related to progression in FAB subtype as well (VI). Morphometrically MPO deficient PMN were characterized by a decreased total cell size and an increased nucleus size of the projected images (IX).(ABSTRACT TRUNCATED AT 400 WORDS)