Serum levels of lactoferrin and myeloperoxidase in chronic idiopathic and secondary neutropenia

In 20 patients with chronic neutropenia, serum lactoferrin (S-LF) and serum myeloperoxidase (S-MPO) levels were assessed. By immunofluorescence, granulocyte-bound immunoglobulins were detected in 12 patients, whereas circulating immune complexes were found in the blood of 8 patients by the ¹²⁵-I-Clq-binding test (Clq-BT). In both groups of patients, there was a relative increase of S-LF and a relative or sometimes absolute increase of S-MPO. In the latter group, results of the Clq-BT correlated positively with S-MPO but negatively with neutrophil counts. No correlations between S-LF or S-MPO and the results of the granulocyte immunofluorescence test were found. Our results suggest that S-LF and S-MPO levels may be helpful in the further study of patients with chronic neutropenia, to gain more insight into the pathogenetic mechanisms operative in this disease.