Mononuclear cells in subcutaneous haemorrhage with special consideration of myeloid precursor cells

Various hematogenous markers were used to differentiate and quantify the ty pes of mononuclear cells present in subcutaneous haemorrhages. Fifty sample s of subcutaneous bleeding with a survival time of a few minutes to more th an 48 hours were studied. The various cell types were detected using the fo llowing stains: Naphthol AS-D chloracetate esterase for myeloid cells, incl uding mast cells; (alpha (1)-antichymotrypsin for monocytes/macrophages; UC HL1 for T-lymphocytes; and L26 for B lymphocytes. The percentage of monocyt es/macrophages was found to increase in dependence on survival time, wherea s T-lymphocytes declined. Within minutes of injury neutrophilic granulocyte s had emigrated into the surrounding tissue and mast cell degranulation had occurred within the haemorrhagic zone. Esterase-positive mononuclear cells , namely metamyelocytes, were detected within minutes after injury and were still present after survival times exceeding 48 hours; however, no depende nce on survival time or cause of death was found. Although the increasing n umber of monocytes/macrophages and T-lymphocytes was expected, the sometime s high percentage of myeloid precursor cells within the wound were surprisi ng. Possible explanations for this phenomenon are discussed.