Patients with non-immune chronic idiopathic neutropenia syndrome have increased splenic volume on ultrasonography

Clinically detectable splenomegaly is rarely seen in patients with non-immu ne chronic idiopathic neutropenia syndrome (NI-CINS). Using ultrasound, we estimated splenic volume in 52 NI-CINS patients and 14 age- and sex-matched normal controls by determining the 'corrected splenic index' (CSI) from th e product of length, width and thickness of the organ expressed in cm(3)/m( 2) body surface area. We found that CSI was significantly higher in the gro up of patients compared to controls (202.8 +/- 82.0 vs. 133.8 +/- 28.1 cm(3 )/m(2), P=0.003), and that individual CSI values was inversely correlated w ith the number of circulating neutrophils (r=-0.5097, P<0.0001). About 48.1 % of the patients had CSI above 190 cm(3)/m(2) body surface, representing t he upper 95% confidence limit of values found in the controls. Patients als o had increased serum concentrations of pro-inflammatory cytokines and chem okines mainly produced by activated macrophages (IL-1,<beta> TNF-alpha, RAN TES and IL-8), as well as increased serum levels of soluble cell adhesion m olecules derived from activated endothelium (sE-Selectin, sICAM and sVCAM). We hypothesize that the increased splenic volume in NI-CINS patients may b e due to the accumulation of activated macrophages inside the spleen, possi bly as the result of an unrecognized low-grade chronic inflammatory process . The nature of such an inflammation is unknown. A study was designed to se arch for viral or bacterial genomic material in patients' bone marrow strom al macrophages in which the unknown causal agent might be located.