Expression of myelomonocytic antigens on chronic lymphocytic leukemia B cells correlates with their ability to produce interleukin 1

We analyzed the expression of myelomonocytic-associated antigens on lymphocytes from B cell chronic lymphocytic leukemia (B-CLL) patients. Blood mononuclear cells were depleted of monocytes by one-step Percoll density gradient centrifugation and tested for antigen expression by fluorescent microscopy and flow cytometry. The reactivity of patient lymphocytes was as follows: 26 of 31 were positive for CD14 (Myr), 22 of 31 for a monocyte Fc receptor (MFC-1), 22 of 31 for CD11b (C3bi receptor), eight of 31 for CD15 (Leu-M1), five of 18 for CD13 (My 7), seven of 18 for My 9, and five of 30 for Mo 2. The B lymphocytes of B- CLL patients were also tested for the ability to produce interleukin 1 (IL-1) after depletion of monocytes and T lymphocytes. In 13 of 17 cases, B lymphocytes of patients produced IL-1 as detected in a mouse thymocyte proliferation assay and, in selected cases, a radioimmunoassay specific for IL-1 beta. The 13 cases that produced IL- 1 were also positive for the expression of one or more myelomonocytic- associated antigens, whereas the four cases that did not produce IL-1 lacked expression of these antigens. In conclusion, the malignant B cells of B-CLL patients frequently express a variety of antigens generally considered specific for myelomonocytic cells, and expression of these antigens is associated with the ability to produce IL-1.     

Determinants of postoperative abscess occurrence and percutaneous drainage in children with perforated appendicitis

Purpose

Postoperative abscesses after perforated appendicitis have no clear risk factors or indications for percutaneous drainage. Our study addressed these two issues.

Methods

A logistic regression model was used to delineate risk factors for postoperative abscess in children with perforated appendicitis treated during a recent 5-year period. Drainage of abscess was compared to antibiotic treatment.

Results

Postoperative abscess occurred in 42 (14.8 %) of 284 patients. Higher WBC count, presence of bowel obstruction at presentation, diffuse peritonitis with a dominant abscess at surgery, and one specific surgeon were significantly associated with postoperative abscess, while fever or pain requiring narcotics at the time of abscess diagnosis was significantly associated with drainage. Compared to non-drainage, those drained had longer hospital stay including readmissions (15.9 ± 5.3 vs. 12.2 ± 4.6 days, p < 0.005) and less readmissions (9.5 vs. 33.3 %, p = 0.06). Over the 5-year period, there was no increased trend in abscess occurrence (p = 0.56), but there was an increased trend in the use of percutaneous drainage (p = 0.02).

Conclusions

The risk of a postoperative abscess can be predicted by specific clinical characteristics, surgical findings, and treatment-related factors. Percutaneous drainage was associated with longer hospital stays, but less readmissions.     

Efficient surface expression of platelet GPIIb-IIIa requires both subunits

Platelet membrane GPIIb-IIIa is a member of the integrin family of heterodimeric adhesion receptors. Processing and export of certain leukocyte and melanoma integrins is disrupted in cells lacking one subunit. We found that surface expression of GPIIb-IIIa, measured by fluorescent activated cell sorting or by surface labeling, required cotransfection of both subunits. In contrast, surface expression was not detected when the subunits were transfected individually. Immunoprecipitation of metabolically labeled transfected cells confirmed the presence of comparable levels of intracellular protein in all cases. When both subunits were transfected, post-translational cleavage of Pro-GPIIb to yield GPIIb heavy chain was also seen, while transfection with GPIIb alone resulted in coprecipitation of Pro-GPIIb with a second band that may be an endogenous beta subunit. Pro-GPIIb in these transfectants was not processed to yield GPIIb heavy chain. When transfected into COS cells alone, transiently expressed GPIIIa remained intracellular and did not appear to complex with any endogenous proteins. Thus, surface expression of processed GPIIb-IIIa depends on the presence of both subunits; the coordinate reduction of both subunits observed in some cases of Glanzmann's thrombasthenia may result from mutation affecting only one.