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

Abstract

Clinically detectable splenomegaly is rarely seen in patients with non-immune 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 the product of length, width and thickness of the organ expressed in cm3/m2 body surface area. We found that CSI was significantly higher in the group of patients compared to controls (202.8 +/- 82.0 vs. 133.8 +/- 28.1 cm3/m2, P=0.003), and that individual CSI values was inversely correlated with the number of circulating neutrophils (r=-0.5097, P < 0.0001). About 48.1% of the patients had CSI above 190 cm3/m2 body surface, representing the upper 95% confidence limit of values found in the controls. Patients also had increased serum concentrations of pro-inflammatory cytokines and chemokines mainly produced by activated macrophages (IL-1beta, TNF-alpha, RANTES and IL-8), as well as increased serum levels of soluble cell adhesion molecules derived from activated endothelium (sE-Selectin, sICAM and sVCAM). We hypothesize that the increased splenic volume in NI-CINS patients may be due to the accumulation of activated macrophages inside the spleen, possibly as the result of an unrecognized low-grade chronic inflammatory process. The nature of such an inflammation is unknown. A study was designed to search for viral or bacterial genomic material in patients' bone marrow stromal macrophages in which the unknown causal agent might be located.