Soluble CD4, soluble CD8, soluble CD25, lymphopoieitic recovery, and endogenous cytokines after high-dose chemotherapy and blood stem cell transplantation

Mononuclear cell preparations from peripheral blood after mobilization with hematopoietic growth factors have been shown to induce accelerated neutrophil and platelet recovery as compared with that induced by autologous bone marrow transplantation after myeloablative chemotherapy. Because these mononuclear cell products contain many immunocompetent cells other than hematopoietic progenitors, these accessory cells might contribute to the rapid immunohematopoietic reconstitution. We have monitored the concentrations of soluble CD4 (sCD4), sCD8, and sCD25; the recovery of the lymphocyte subsets and of natural killer (NK) cells; and the endogenous levels of granulocyte colony-stimulating factor (G-CSF), interleukin-3 (IL-3), IL-6, and granulocyte-macrophage-CSF (GM-CSF) in 12 patients who underwent high- dose chemotherapy supported by blood stem cells that were obtained by mobilization with chemotherapy and GM-CSF. The concentrations of both G- CSF and IL-6 peaked at 7 days after reinfusion of stem cells, and this transient elevation preceded the increase in the white blood cell count by approximately 5 to 7 days. The levels of sCD4 and sCD8 increased to a maximum on day 21, and the time to peak levels coincided with the maximum increase in white blood cell count, absolute neutrophil count, or lymphocytes. The levels of sCD25 were found to be elevated from day 7 to day 21. Statistically, the increases in sCD4, sCD8, sCD25, G-CSF, and IL-6 were highly significant, whereas there were no significant changes in IL-3 and GM-CSF. A rapid recovery of the NK activity was found in all 8 of the patients who could be monitored for this assay. Therefore, our study suggests that recovery of CD4+ cells, CD8+ cells, and NK activity coincided with that of neutrophils, which is preceded by a marked, but transient, elevation of IL-6 and G-CSF.     

Disease-free survival after autologous bone marrow transplantation in patients with acute myelogenous leukemia

Autologous bone marrow transplantation (ABMT) makes it possible to escalate the dose of cytotoxic treatment to a lethal range. Disease- free survival (DFS) following myeloablative therapy and ABMT has been shown to be superior to conventional treatment in high risk patients with acute myelogenous leukemia (AML). It was the purpose of the present study to compare hematopoietic reconstitution, actuarial DFS, and relapse rate of patients transplanted in first complete remission (CR) of AML with those in second or subsequent CR, and to evaluate transplant related mortality. Fifty-two patients with AML, 22 in first CR (low risk) and 30 in second or subsequent CR (high risk), underwent total body irradiation (12.1 to 16.7 Gy) and cyclophosphamide (CY) treatment (200 mg/kg) followed by ABMT. The autograft was incubated with the active CY derivative Mafosfamide (ASTA Werke, Bielefeld, Federal Republic of Germany) to reduce the number of possibly contaminating clonogenic tumor cells. All patients showed three lineage engraftments with platelet recovery observed as being the slowest. The transplant related death rate was low at 5.8%. There was no significant difference in the kinetics of polymorphonuclear (PMN) cell or platelet reconstitution between the low and high risk patient subgroups. The estimated probability of DFS (relapse) after ABMT in first CR was 61% (36%) compared with 34% (65%) in second or subsequent CR, the longest follow-up being 55 months and 57 months, respectively (median follow-up 31 months and 19 months, respectively). ABMT offers a stable long-term DFS when performed in first CR with no relapses occurring in over a year after transplantation. Six later relapses, however, were seen after ABMT in second or subsequent CR, although DFS was not statistically different from that of first remission patients (P = .72).     

Presumptive diagnosis and treatment of pulmonary tuberculosis based on radiographic findings

We analyzed the outcome of therapy for 139 patients who were treated for a presumptive diagnosis of pulmonary tuberculosis based on radiographic abnormalities. Patients who had acid-fast bacilli seen on sputum smears and patients who had received adequate therapy for tuberculosis in the past were excluded from the analysis. Accuracy of the diagnosis was determined by comparison of clinical and radiographic findings after 3 months of isoniazid, rifampin, and ethambutol, as well as the results of sputum cultures. Of 139 patients started on therapy presumptively, 66 (48%) were determined to have current tuberculosis (16 had positive cultures, 43 because of improvement in their chest films, and 7 because of clinical improvement). Adverse reactions requiring change of therapy occurred in six of 72 (8.3%) patients determined to have inactive tuberculosis. One patient had both tuberculosis and carcinoma found at bronchoscopy after 3 months of therapy. For purposes of comparison, chest radiographs of 59 patients documented by culture to have current tuberculosis were reviewed. Of these, 45 (70%) were improved at 3 months. Presumptive therapy is of benefit in that it stops progression of the disease at an early stage and decreases the potential for spread of tuberculous infection. In addition, such therapy coupled with systematic reevaluation of patients substantiates the diagnosis or indicates that further evaluation is needed. These benefits must be weighed against the adverse reactions and costs of overtreating patients with inactive disease. Determining the appropriateness of presumptive therapy must be based on local factors including prevalence of tuberculosis and available resources.     

Anal intraepithelial neoplasia and squamous cell carcinoma in HIV‐infected adults

Anal cancer is one of the most common non‐AIDS‐defining malignancies in the era of combination antiretroviral therapy. Its precursor lesion, anal intraepithelial neoplasia (AIN), is highly prevalent in HIV‐infected populations. More than 90% of anal squamous cell cancers are attributable to human papillomavirus (HPV). While the biology of HPV‐related intraepithelial neoplasia is consistent across lower anogenital sites, the natural history of AIN is not well established and cannot be assumed to be identical to that of cervical intraepithelial neoplasia. Screening strategies to prevent anal cancer should be developed based on robust natural history data in HIV‐infected and uninfected populations. Likewise, treatments need to be tested in randomized clinical trials, and reserved for those at significant risk of progression to cancer. This review covers the epidemiology, pathogenesis and immunology of HPV infection, AIN and anal cancer, and summarizes the current diagnosis, screening and treatment strategies in HIV‐infected adults.     

High molecular weight kininogen: localization in the unstimulated and activated platelet and activation by a platelet calpain(s)

High mol wt kininogen (HMWK), the major cofactor-substrate of the contact phase of coagulation, is contained within and secreted by platelets. Studies have been performed to localize platelet HMWK in both the unstimulated and activated platelet and to ascertain the effect of platelet enzymes on HMWK itself. On platelet subcellular fractionation, platelet HMWK was localized to alpha-granules, and platelets from a patient with a deficiency of these granules (gray platelet syndrome) had 28% normal platelet HMWK. Platelet HMWK, in addition to being secreted from the platelet, was also localized to the surface of the platelet when activated. Using a competitive enzyme- linked immunosorbent assay for HMWK as an indirect antibody consumption assay, the external membrane of thrombin-activated platelets as well as the releasate from these stimulated platelets had 17 ng HMWK antigen/10(8) platelets available, whereas unstimulated platelets and their supernatant had only 4.9 and 4.2 ng HMWK/10(8) platelets present, respectively. The anti-HMWK antibody consumption by activated normal platelets was specific for membrane-expressed platelet HMWK, since activated platelets from a patient with total kininogen deficiency did not adsorb the anti-HMWK antibody. Enzymes in the cytosolic fraction of platelets cleaved 125I-HMWK (mol wt 120,000) into a mol wt 100,000 polypeptide as well as smaller products at mol wt 74,000, mol wt 62,000, mol wt 47,000, and a few components below mol wt 45,000. No cleavage products were observed when DFP and leupeptin were present. The cleavage of HMWK was specifically prevented by inhibitors of calcium-activated cysteine proteases (leupeptin, N-ethylmaleimide, iodoacetamide, and EDTA) but not by inhibitors of serine proteases (DFP, benzamidine, soybean trypsin inhibitor, or aprotinin). Platelet cytosol increased the coagulant activity of exogenous purified HMWK with maximum HMWK coagulant activity (35-fold) occurring within ten minutes of exposure to platelet cytosol. Treatment of platelet cytosol with leupeptin prevented the increase in the coagulant activity of exogenous HMWK. These studies indicate that activated platelets express platelet HMWK on their external membrane and platelet enzymes can cleave and increase the coagulant activity of exogenous HMWK.     

The effect of the Fanconi anemia polypeptide, FAC, upon p53 induction and G2 checkpoint regulation

Fanconi anemia (FA) is an autosomal recessive disease marked by developmental defects, bone marrow failure, and cancer susceptibility. FA cells are hypersensitive to DNA cross-linking and alkylating agents and accumulate in the G2 phase of the cell cycle in response to these agents. FA cells also display genomic instability, suggesting a possible defect in the p53 pathway. To test the effect of heterologous expression of FAC cDNA on drug-induced cytotoxicity, G2 accumulation, and p53 induction in FA cells, we compared two isogenic FA cell lines: HSC536N (mock), a FA type C cell line sensitive to mitomycin C (MMC), and the same cell line transfected (corrected) with wild-type FAC cDNA (HSC536N [+FAC]). HSC536N (+FAC) cells showed a 30-fold increase in resistance to MMC concentration. Similarly, increases in resistance were observed following exposure to cisplatin, carboplatin, and cyclophosphamide. In addition, HSC536N (+FAC) cells showed a twofold lower G2 accumulation following MMC treatment. To analyze the possible interaction of FAC with the p53 pathway, we analyzed p53 induction in mock and corrected cell lines following exposure to MMC. HSC536N (mock) cells induced p53 at lower MMC concentrations than HSC536N (corrected). Caffeine, a known G2 checkpoint inhibitor, not only inhibited G2 accumulation seen in both cell lines but also caused the resistant HSC536N (+FAC) to become as sensitive to MMC as HSC536N (mock) cell line. We conclude that the FAC protein has a specific cytoprotective effect and may function as a cell cycle regulator of the G2 phase of the cell cycle.