Morphologically defined myeloid cell compartments, lymphocyte subpopulations, and histological findings of bone marrow in patients with nonimmune chronic idiopathic neutropenia of adults

This report describes the morphologically defined myeloid cell compartments , lymphocyte subpopulations, and histological findings of bone marrow in 38 patients with nonimmune chronic idiopathic neutropenia of adults (NI-CINA) and in 14 controls. We found that patients had a striking shift to the lef t of the granulocytic series due to both an increased proportion of prolife rating cells and a reduced proportion of maturating cells compared with con trols (P<0.001 and P<0.001, respectively). Individual proportions of these cells strongly correlated with the number of circulating neutrophils (r= -0 .462, P<0.01 and r=0.495, P<0.01, respectively). However, in the great majo rity of patients (78.9%), no significant changes in marrow cellularity or t he myeloid to erythroid cell ratio could be demonstrated. Patients also had increased proportions of CD19(+)B cells, CD20(+)B cells, and plasma cells with polytypic expression relative to controls (P<0.02, P<0.01, and P<0.001 , respectively). Individual values of plasma cells were inversely correlate d with the number of blood neutrophils (r= -0.414, P<0.01). Dispersed bcl-2 (+)lymphocytic aggregates without germinal centers were seen in about one-t hird of the patients. T cells and natural killer (NK) cells did not show an y significant change. Patients had increased proportions of CD57(+), CD16(), and HLA-DR+ cells and, in a few cases, increased proportions of histiocy tes and eosinophils. CD45RO(+) cells were reduced only in patients with pro nounced neutropenia. Expression of p53 protein has not been detected in any cell population. With the exception of some megaloblastoid features of ery throid lineage seen in two patients and the presence of some micromegacaryo cytes seen in two others, no significant morphological abnormalities were n oted. All of these findings are consistent with our previously reported sug gestion for the possible existence of an underlying low-grade chronic infla mmatory process in NI-CINA patients, which may be involved in the pathogene sis of neutropenia in the affected subjects.