Platelet-derived growth factor promotes polymorphonuclear leukocyte activation

The platelet-derived growth factor (PDGF) has several well defined important biologic activities. Platelet-derived growth factor is the major mitogen in human serum for cells of mesenchymal origins; it is a potent chemoattractant protein for human monocytes, neutrophils, fibroblasts, and smooth muscle cells; and has been implicated in transformation by simian sarcoma virus and perhaps in transformation by other agents as well. In this article, PDGF has been shown to stimulate activation of human peripheral blood neutrophils defined by loss of membrane associated calcium as reflected by loss of chlortetracycline fluorescence, release of superoxide anion and specific granule enzymes, and enhanced neutrophil adherence and aggregation. These responses occurred in a dose-dependent fashion at concentrations of PDGF between 10 ng/mL (0.4 nmol/L) and 40 ng/mL (1.5 nmol/L) and were comparable to effects obtained with optimal concentrations of fMLP and C5a. Degranulation induced by PDGF was selective for secondary (specific) granules and not primary (azurophil) granules. Platelet-derived growth factor thus is ideally suited for a pivotal role in attracting inflammatory cells locally and initiating neutrophil activation at sites of blood vessel injury. Platelet-derived growth factor or a closely related protein also may play an important role in attracting and activating neutrophils in association with inflammatory tumors.     

Pathology of human intestinal transplantation

BACKGROUND & AIMS: Intestinal transplantation is a developing therapeutic option for patients with irreversible intestinal failure or short bowel syndrome. The aim of this study was to delineate the histopathology of human intestinal allografts and to define the features of intestinal rejection. METHODS: The histological features of 3015 endoscopic biopsy specimens and 23 allograft specimens from 62 intestinal recipients were analyzed retrospectively and correlated with clinical findings. RESULTS: Acute allograft rejection was characterized by a varying combination of crypt injury, mucosal infiltration primarily by mononuclear cells (including blastic lymphocytes), and increased crypt cell apoptosis (more than 2 per 10 crypts). It represented a patchy, often ileal-centered process that could progress to mucosal ulceration; later episodes (more than 100 days posttransplant) tended to show lesser cellular infiltration and greater apoptosis than earlier episodes. Correlation with clinical rejection was good (false-positive rate of 9%; false-negative rate of 26%). Two resected specimens showed obliterative arteriopathy indicative of chronic rejection. In other specimens, preservation injury, cytomegalovirus infection, post-transplant lymphoproliferative disorder, and nonspecific features of active or past mucosal injury could be recognized. CONCLUSIONS: Mucosal biopsy specimens are a useful means of monitoring intestinal allografts. Based on features validated by clinical correlation, acute rejection can be identified reliably and can be differentiated from the other pathological processes affecting the intestinal allograft. (Gastroenterology 1996 Jun;110(6):1820-34)     

Studies on levamisole--induced agranulocytosis

Widespread clinical trials of leavo-tetramisole (levamisole) as an immunopotentiating agent in rheumatoid arthritis, metastatic carcinoma, and immunodeficiency states have been complicated by agranulocytosis (AGC) in 2.5%-13% of patients. Other than a relationship with prolonged high dosage, very little is known regarding the pathogenesis of levamisole-induced AGC. Whereas leukoagglutination was negative, fluorochromatic microgranulocytotoxicity (GCY) tests were positive with serum from 10 of 10 acutely neutropenic patients. The antibody was IgM, reacted with 100% of unrelated granulocytes, but not with T or B lymphocytes. Some sera also reacted with monocytes and the myeloid cell line, K-562. Tests for antigen-antibody complexes or cold autoantibodies were negative. Although clinical evidence strongly suggests a haptene (drug) mechanism, in vitro mixing experiments were also negative. An alternative choice parallels the model of aldomet- induced Coombs'-positive hemolytic anemia. Finally, GCY first became positive 2-3 mo prior to the onset of AGC on two patients, suggesting the possibility of identifying those at risk well before the onset of neutropenia.     

Effect of priming polymorphonuclear leukocytes with cytokines (granulocyte-macrophage colony-stimulating factor [GM-CSF] and G-CSF) on the host resistance to Streptococcus pneumoniae in chinchillas infected with influenza A virus

Patients infected with influenza A virus (IAV) are at increased risk for bacterial superinfections, and this occurs in association with depressed polymorphonuclear leukocyte (PMNL) function. Recently, we reported that in vitro exposure of human PMNL to granulocyte-macrophage colony-stimulating factor (GM-CSF) reverses IAV-induced cell dysfunction. The present study used an established animal model of IAV infection to examine whether G-CSF and/or GM-CSF can overcome IAV- induced PMNL dysfunction and thereby prevent secondary infections. Preliminary studies determined a dosing schedule of these cytokines that caused significant priming of chinchilla PMNL. In subsequent studies, animals were inoculated intranasally with IAV (day 1) followed 3 days later by Streptococcus pneumoniae, and administered daily intraperitoneal injections with a cytokine or placebo on days 3 through 9. Animals had blood obtained on multiple occasions for PMNL studies, and were followed-up for evidence of pneumococcal disease. Both cytokines caused significant priming of the PMNL chemiluminescence response and this was associated with reversal of the IAV-induced PMNL dysfunction. However, neither cytokine decreased the incidence of pneumococcal disease.     

Sex hormone binding globulin levels across the adult lifespan in women--the role of body mass index and fasting insulin

SHBG is a major carrier of androgens. In men, SHBG levels increase with age, while in women data are scant. There is evidence that body mass index (BMI) and fasting insulin influence SHBG concentration. Since low SHBG levels are predictors of insulin resistance and diabetes, understanding the relationship of SHBG with age, insulin, and BMI is important to gain insight into the role of SHBG as a cardiovascular risk factor in women. Differences in SHBG across adult life span and their relationship with insulin and BMI were evaluated in a representative cohort of 616 Italian women free of diabetes and not on hormone replacement therapy enrolled in the InCHIANTI Study. The relationship of SHBG with age, BMI, and fasting insulin levels was analyzed using linear regression and by loess smoother. Serum SHBG levels showed a U-shaped trajectory with age, declining from the 2nd to the 6th decade of life and increasing after the 6th decade (p<0.0001). Age-related trends for BMI and fasting insulin mirrored the trend observed for SHBG. After adjusting for fasting insulin, the relationship between log (SHBG) and age square was attenuated (beta coefficient from 0.00044 to 0.00039) and was further reduced after adjustment for BMI (from 0.00039 to 0.00028). SHBG levels show an age-related U-shaped trajectory. These changes mirror the age-related changes in BMI and fasting insulin, suggesting that BMI and insulin negatively influence SHBG concentration.     

Interleukin-10 promoter polymorphisms in rheumatoid arthritis and Felty's syndrome

OBJECTIVE: To examine whether promoter polymorphisms associated with variation in interleukin-10 (IL-10) production are relevant to the development of rheumatoid arthritis (RA) or Felty's syndrome (FS). METHODS: DNA was obtained from 44 FS patients, 117 RA patients and 295 controls. The promoter region between -533 and - 1120 was amplified by polymerase chain reaction, and polymorphisms detected by restriction enzyme digest or sequence-specific oligonucleotide probing. RESULTS: We found no significant difference in allele or haplotype frequencies between the groups. CONCLUSION: There is no association between FS or RA and these recently identified IL-10 promoter polymorphisms. Other genetic or environmental factors could explain the alterations in IL-10 levels seen in these conditions.      

Glutathione peroxidase (GPX) activity in seminal plasma of healthy and infertile males

Human spermatozoa are more dependent on glutathione peroxidase/glutathione reductase (GPX/GR) system, via reduced glutathione (GSH), to inactivate reactive oxygen metabolites (ROMs) such as hydrogen peroxide and organic hydroperoxides. To demonstrate whether there is a substantial difference in GPX activity between normal and pathological seminal plasma, we decided to evaluate the activity of this enzyme in healthy subjects and infertile males with normal hormonal patterns. Our results demonstrate that in healthy subjects the seminal plasma contains a GPX activity that is about 10 times greater than the GPX activity detected in the seminal plasma of infertile males. By using specific antibodies against plasmatic GPX (GPX3), we also demonstrate that enzymatic activity, detected in the seminal plasma of both healthy and infertile males is GPX3. Therefore, the evaluation of GPX activity in human seminal plasma could be a new useful marker of gonadal function in men.     

Differentiation of natural killer (NK) cells from human primitive marrow progenitors in a stroma-based long-term culture system: identification of a CD34+7+ NK progenitor

We have recently described a marrow stroma-dependent long-term culture system that supports differentiation of CD34+ human marrow primitive progenitors into natural killer (NK) cells. We postulate that CD7 expression may be an early event in commitment of hematopoietic progenitors to the NK lineage. Here we compare the characteristics of CD34+7- and CD34+7+ marrow cells cultivated in the stroma-based NK culture system. These CD34+ populations were further compared with a marrow derived, more committed, CD34-7+ progenitor to emphasize the continuum of NK development and to highlight differences between progenitors in our assays. No progenitor proliferated when plated in media without stroma, underscoring the importance of stroma in NK differentiation. Plating progenitor populations in interleukin-2 containing media directly on preestablished, allogeneic, irradiated marrow stroma for 5 weeks resulted in CD56+CD3- NK cells; however, characteristics of the cultured populations differed. Fold expansion and cloning efficiency of the CD34+7+ population, determined by a functional limiting dilution assay was significantly higher than of the CD34+7- or CD34+7+ populations. This suggests that the CD34+7+ population is highly enriched for an NK progenitor and a possible intermediate in NK lineage differentiation. Further dividing the CD34+7+ population by the relative fluorescence of CD7 into CD34+7+dim and CD34+7+bright populations showed that the CD34+7+bright population exhibited a significantly higher cloning frequency than parallel experiments with CD34+7+dim cells (11.8% +/- 2.4% v 2.4% +/- 0.7%, n = 6; P = .005). Plating of the more primitive CD34+7- population in a transwell system (which separates progenitors from stroma by a microporous membrane) prevents differentiation into NK cells. In contrast, plating of CD34+7+ progenitors in transwells resulted in generation of NK cells. These data suggest that primitive, but not more mature NK progenitors may require direct contact with stroma for the initial differentiation steps. Finally, differentiation of the NK progenitors in this stroma-dependent model results in expression of CD2 not present on any of the starting populations. This observation suggests that marrow stroma can stimulate CD2 expression on NK progenitors in a previously undescribed fashion that may be analogous to the thymic effect on CD2 expression in immature T lymphocytes. These observations identify early steps in the commitment of primitive marrow CD34+ hematopoietic progenitors to a lymphoid lineage and underscore the importance of coexpression of CD7 with CD34 as an early lymphoid commitment characteristic and direct progenitor-stroma interactions in this process.     

Repeated transient hypergonadotropic amenorrhea during pharmacologic induction of multiple follicular development with exogenous gonadotropins

Human gonadotropins are widely used for induction of ovulation in the treatment of anovulatory infertility and for induction of multiple follicular development (MFD) in in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT), and artificial insemination with husband's semen (AIH) programs. Reported is a patient with normal menstrual cycles, who had two episodes of gonadal unresponsiveness to human gonadotropin therapy, followed by transient hypergonadotropic amenorrhea ("resistant ovary" syndrome), during induction of MFD in conjunction with AIH as treatment for unexplained infertility. The first episode occurred during the sixth cycle of a first series of MFD induction with daily intramuscular injections of exogenous gonadotropins. The second episode occurred during the second cycle of a second series of MFD induction with intravenous pulsatile administration of FSH. On both occasions, normalization of endogenous gonadotropin levels and reappearance of ovulatory cycles occurred spontaneously, after two and three months, respectively. A similar mechanism could occur in the failures of MFD induction observed in IVF programs.