Rituximab is an effective agent in the treatment of PTLD without the morbidity characteristic of chemotherapy. Chemotherapy should be reserved only for those refractory to Rituximab therapy.

A study was undertaken to examine the role of bacterial adherence in the development of infection at the site of an implant. The amount of in vitro adherence of Staphylococcus epidermidis was greatest for stainless steel, followed by polymethylmethacrylate and commercially pure titanium, and was least for polymethylmethacrylate with gentamicin. These materials then were preincubated with S. epidermidis and implanted. The number of organisms that were isolated and the rate of infection followed the same pattern as that in the in vitro studies. Materials that were not preincubated with bacteria also were implanted and bacteria were injected into the site. The number of organisms isolated from the site and the rate of infection were lower than those for the preincubated materials, but the trend was the same as in both the in vitro and the in vivo studies. The rates of infection and colonization correlated with the propensity for the organisms to adhere to a given material. Materials colonized with S. epidermidis at the time of implantation caused a high rate of infection. The ability of organisms to adhere to a material in vitro is correlated with their propensity to cause biomaterial-based infection.

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The Sysmex R-3000 (TOA Medical Electronics, Kobe, Japan) evaluates maturation of reticulocytes by quantitating the fraction of reticulocytes within low-, middle-, and high-fluorescence intensity regions. We defined the immature reticulocyte fraction (IRF) as the sum of the fraction of high-fluorescence intensity regions plus the fraction of middle-fluorescence intensity regions. Then, we studied the clinical significance of IRF in the evaluation of anemia by comparing the IRF with the absolute reticulocyte count (ARC) and with the reticulocyte production index (RPI) and by r e v i e w i n g p e r t i n e n t clinical information about the patients. In the study, 132 specimens from 102 patients undergoing evaluation of anemia were analyzed. By using simple regression analysis, our results showed that the IRF has a weak but significantly positive correlation with ARC and with RPI, indicating that IRF is an additional useful parameter to evaluate the erythropoietic activity in anemia. Interpretation by integrating IRF and reticulocyte enumeration (ARC and RPI) provided useful information for further subclassification of anemia. Increased IRF Besides the actual reticulocyte count, assessment of reticulocyte maturation is important for evaluating the degree of effective erythropoiesis, for understanding the pathophysiologic changes of anemia, and for the differential diagnosis of anemia. (IRF >0.23) and increased ARC generally indicated an adequate erythroid response to anemia. All but three specimens with an IRF less than 0.23 showed an RPI of 2 or less. These specimens were from patients with underlying diseases known to lead to decreased erythropoietic activity, predominantly chronic renal insufficiency. Specimens with a s u b n o r m a l or normal ARC (with a corresponding RPI <2) but with an IRF of more than 0.23 were from patients with various underlying conditions, i n c l u d i n g acute infection, iron deficiency anemia, h u m a n immunodeficiency virus infection, sickle disease with crisis, pregnancy, and myelodysplastic syndrome. enumeration.

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Irreversible graft failure is more prevalent with polyoma virus infection. Enhanced immunosuppressants with mycophenolate mofetil with tacrolimus may play a role in the development of this infection. An increase in CD20 and a decrease in cytotoxic T cells in allografts is characteristic of polyoma virus infection.

The present study was designed to evaluate the lineage differentiation (particularly monocytic differentiation) of immature myeloid cells in granulocytic sarcoma (GS) by immunohistochemistry and correlate the results with lineage differentiation of blasts in the bone marrow and to determine the degree of maturation of the infiltrating myeloid cells in GS by immunohistochemistry using CD34 and HLA-DR. Immunohistochemical stains were performed on paraffin-embedded tissue from 17 GS lesions with lineage-associated markers: myeloperoxidase, CD68 (KP1), CD68 (PG-Ml), glycophorin A, factor VIII, and CD56; and with markers for blasts and immature myeloid cells: CD34 and HLA-DR. Our results show that positive staining with PG-M1, but not KP1, suggests monocytic differentiation of myeloid cells in GS and correlates with the monocytic differentiation of blasts in the bone marrow. Expression of CD56 is frequent in GS, especially when the marrow blasts have monocytic differentiation, and should not be interpreted as a primary natural-killer cell process. The immature myeloid cells in GS are frequently HLA-DR positive. However, CD34 positivity of the immature myeloid cells is relatively uncommon, except in cases with underlying myelodysplastic syndrome or chronic myelogenous leukemia.

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