A novel general and efficient technique for dissociating antigen in circulating immune complexes.

Circulating immune complexes (CICs) are produced during the immune response. It is more clinically important to establish a general and efficient CICs dissociation technique for the detection of antigens for CICs other than the detection of free antigens in the serum. Polyethylene glycol (PEG) two-precipitation separation and glycine-HCl as a buffer system were employed to develop a general and efficient buffer dissociation technique to separate CICs from serum and dissociate antigens from CICs. The measurement value of new PEG two-precipitation separation technique was higher than traditional PEG precipitation separation technique. There were slight differences in the dissociation conditions of HCV Core-IC, HIV P24-IC, Ins-IC and TG-IC as compared to HBsAg-IC. The detection of antigens in HBsAg-IC, HCV Core-IC, HIV P24-IC, Ins-IC and TG-IC with this technique was superior to that with HCl Dissociation, Trypsin Digestion or Immune Complex Transfer technique. PEG two-precipitation dissociation technique may reduce macromolecular protein and the adhesion of free antigens during the co-precipitation, which increases the efficiency of separation and precipitation of CICs. This technique also avoids the damage of reagents to antigens, assuring the repeatability, reliability and validity. Thus, this technique is application in samples negative or positive for free antigens.

Disseminated Nonleukemic Myeloid Sarcoma of the Spleen With Involvement of the Liver in an Infant.

Nonleukemic myeloid sarcoma (MS) is a rare tumor that can occur in several locations without myeloid leukemia. We reported a first case of nonleukemic MS of the spleen involving the liver in a 5-month-old boy presenting with hematochezia, petechial hemorrhage, fever, and hepatosplenomegaly. Bone marrow trephine biopsy and immunophenotypic flow cytometry revealed no evidence of myeloid leukemia. The patient underwent liver biopsy and splenectomy. Clinicopathology and immunohistochemistry suggested a disseminated nonleukemic MS. The patient died of respiratory failure on the seventh postoperative day. Early diagnosis of a disseminated nonleukemic MS may be quite important for patient survival and it should be considered one of the differential diagnoses of hepatosplenomegaly with atypical clinical features.