Purpose: To define the features and course of myelokathexis, a rare congenital neutropenia resulting from impaired release of granulocytes from bone marrow.
Methods: The clinical features, granulocyte function, lymphocyte function, and response to granulocyte colony-stimulating factor (G-CSF) of two patients (mother/son) with myelokathexis were studied. This experience and 14 previous reports lead to a composite description of myelokathexis.
Results: Both patients had chronic neutropenia, recurrent pulmonary infections, bone marrow consistent with myelokathexis, hypogammaglobulinemia, and elevated endogenous G-CSF. Patient 15 had normal granulocyte function, a rise in absolute neutrophil count (ANC) with epinephrine and hydrocortisone, and normal numbers of T- and B-lymphocytes; she also had numerous warts during childhood. Both patients experienced a transient increase in ANC with infection, a significant increase in ANC within 5 hours following a single dose of G-CSF, and fewer infections with daily G-CSF.
Conclusions: Based on 16 cases, myelokathexis occurs more often in females and frequently affects multiple members of a family. The usual number of circulating granulocytes is low although function is normal. Mature marrow granulocytes are mobilized with infection, corticosteroids, epinephrine, G-CSF, and granulocyte-macrophage colony-stimulating factor (GM-CSF). Lymphocyte number is normal but lymphocyte function is abnormal as evidenced by hypogammaglobulinemia and papillomavirus infection.