| Abstract: | Eosinophilia is a common clinical presentation in patients with helminthic infections. A study was designed to determine the mechanism(s) for selective or preferential differentiation of precursor cells into mature eosinophils (eos). Thus, experiments were performed to delineate the frequency of colony forming units of eos (CFU-eos) in the peripheral blood of Egyptian patients with active Schistosoma mansoni infection with eosinophilia and normal healthy individuals. The number of CFU-eos among the nonadherent mononuclear cell population was assessed in a double layer soft agar culture with autologous unfractionated mononuclear cells serving as a source of colony stimulating factor(s). Following 14 days of incubation, discrete colonies were distinguished morphologically as eosinophilic, neutrophilic, or mixed. Results indicated a two-fold increase in the total number of colonies per 10(6) cultured nonadherent cells in patients with S. mansoni infection when compared to the number of colonies obtained with adult normal volunteers (57 +/- 10 vs. 24 +/- 4; P less than 0.025). However, the frequency of CFU-eos and CFU-neut was similar in patients and normal individuals (66 +/- 3 vs. 59 +/- 8 percent CFU-eos; 30 +/- 4 vs. 35 +/- 6 percent CFU-neut). These data suggest that: eosinophils may differentiate from progenitor cells at other anatomical sites; there may be an increase in the half life of mature eosinophils in patients; there is no strict correlation between the frequency of progenitor cells and the number of differentiating mature cells of this lineage at least as measured by this in vitro assay; and the in vitro assay may not quantitatively reflect the in vivo differentiating capacity of progenitor cells. |
