Human macrophage development: a morphometric study

The development of macrophages from the blood monocytes of ten normal subjects has been studied at intervals over a six day period. Suspension cultures were used to obtain randomly orientated cells and morphometric measurements were made on electron micrographs. In order to meet the requirements for normality of distribution and homoscedasticity, data were logarithmically transformed. A two-way analysis of variance was then carried out, taking subjects and time intervals as fixed effects, and using a least significant difference procedure to detect variations between culture time intervals. The whole cell and cytoplasmic volumes showed 3-4 fold increases during culture. The cell surface area more than doubled; this was partly attributable to the larger cell volume and partly to increased surface irregularity. The mitochondrial volume also showed a similar significant increase, attributable to an increase in both number and size of mitochondrial profiles, the cytoplasmic volume fraction remaining approximately constant. Although there was a statistically significant increase in nuclear surface area, the nuclear changes were relatively small. The results and the application of appropriate statistical methods have thus provided basic morphometric data for human macrophage development in culture. The experimental system should permit further investigation of factors governing impaired macrophage development in malignant disease.