Identifying recent HIV infections using the avidity index and an automated enzyme immunoassay

We evaluated a procedure for identifying recent HIV infections, using sequential serum samples from 47 HIV-positive persons for whom the seroconversion date could be accurately estimated. Each serum sample was divided into two aliquots: one diluted with phosphate-buffered saline and the other diluted with 1 M guanidine. We assayed the aliquots with the automated AxSYM HIV1/2gO test (Abbott Diagnostics Division), without modifying the manufacturer's protocol. We then calculated the avidity index (AI): the ratio of the sample/cutoff value for the guanidine aliquot to that of the phosphate-buffered saline aliquot. We analyzed 216 serum samples: 34 samples were collected within 6 months of seroconversion (recent seroconversions), and 182 were collected after 6 months. The mean AIs, by time from seroconversion, were 0.68 +/- 0.16 (within 6 months) and 0.98 +/- 0.10 (after 6 months) (P < 0.0001). AI of <0.90 correctly identified 88.2% of recent infections but misclassified as recent infections 13.2% of serum samples collected afterward. The probability of an infection being classified as recent and having AI of > or = 0.90 would be 0.7% in a population with 5% recent infections. AI can identify with a certain degree of accuracy recent HIV infections, and being a quantitative index, it provides different levels of sensitivity and specificity, depending on the selected cutoff value. The standard assay procedure is not modified. This test is simple and inexpensive and could be used for surveillance, decision-making in treatment, and prevention.     

Adoptive transfer of mast cells does not enhance the impaired survival of Kit(W)/Kit(W-v) mice in a model of low dose intraperitoneal infection with bioluminescent Salmonella typhimurium

Mast cells are important effector cells in IgE-associated immune responses, but also can contribute to host defense in certain examples of bacterial infection. We found that genetically mast cell-deficient WBB6F1-Kit(W)/Kit(W-v) mice exhibited more bacterial CFUs per spleen by 6 days after intraperitoneal injection of bioluminescent Salmonella typhimurium, and died more rapidly after infection, than did the congenic WBB6F1-Kit(+/+) wild type mice. Adoptive transfer of bone marrow-derived cultured mast cells of Kit(+/+) origin to the peritoneal cavity of Kit(W)/Kit(W-v) mice resulted in engraftment of mast cells in the peritoneal cavity and mesentery of the recipient mice, and the development of large numbers of mast cells in the spleen. However, such mast cell-engrafted Kit(W)/Kit(W-v) mice appeared sicker after intraperitoneal injection with S. typhimurium than did mast cell-deficient Kit(W)/Kit(W-v) mice, and exhibited numbers of CFUs of bacteria per spleen, and a survival curve, that were not significantly different than those of Kit(W)/Kit(W-v) mice. These results, when taken together with prior studies investigating the roles of mast cells in innate immunity, strongly suggest that whether mast cells can be shown to have a significant role in enhancing survival during bacterial infections may depend critically on the details of the particular experimental systems examined.     

Macrophage-derived chemokine production by activated human T cells in vitro and in vivo: preferential association with the production of type 2 cytokines

Macrophage-derived chemokine (MDC), a potent chemoattractant for chronically activated Th2 lymphocytes, is constitutively expressed by dendritic cells, B cells, macrophages, and thymic medullary epithelial cells, whereas monocytes, NK cells, and T lymphocytes produce MDC only upon appropriate stimulation. In this study, we show in vitro MDC production also by activated T cells, which preferentially associate with the production of Th2 cytokines, IL-4, IL-5, and IL-6, and inversely correlate with the production of the Th1 cytokine, IFN-gamma. Moreover, high levels of MDC were detected in the sera of the great majority of subjects suffering from mycosis fungoides/Sézary syndrome or atopic dermatitis, which are considered as disorders characterized by the predominant expansion and activation of Th2 cells, respectively. By contrast, serum MDC levels in subjects with multiple sclerosis or Crohn's disease, which are characterized by a Th1 predominance, did not differ significantly from those of healthy controls. Finally, MDC expression was detected in the skin biopsy specimens of subjects with atopic dermatitis, where it was expressed by both dendritic cells and T lymphocytes. Taken together, these findings suggest that MDC production by activated T cells may occur both in vitro and in vivo, particularly in association with Th2 cytokines, thus providing an important amplification circuit for Th2-mediated responses.     

Glial heterotopy of the nose ("nasal glioma"). Description of a case]

A six months female infant was admitted in our hospital for congenital dysmorphism of face: a subcutaneous nodule in left nose region was present. An x-ray study showed relevant scoliosis of the nasal septum. On surgery a white firm nodule was incompletely excised; a post-operatory CT-scan excluded any communication of neoplasia with brain. No bone lacunae were seen. Clinically there was neither rhinorrhea nor meningitis. The baby was discharged on 7th day. Grossly the mass presented white surface, firm consistency with small hemorrhages on cut surface. Microscopically the nodule, encircled by a fibrous pseudo-capsule, was mostly composed of gemistocytic astrocytes, occasionally binucleated, interspersed within fibrillary neuroglial tissue. Strands of fibrous tissue, in continuity with the pseudo-capsule, separated the glial tissue. No neuronal cells were seen. Necrosis, mitotic figures and vascular proliferations were absent. GFAP immunohistochemical stain confirmed the glial nature of the cells. Our diagnosis was one of "heterotopic glial tissue of nose" (nasal glioma). The absence of connection between the nodule and endocranial contents (CSF-filled spaces, leptomeningeal or dural tissue), excluded the diagnosis of encephalocele. In our case, the tissue was only of embryonic neuroectodermal derivation: on this basis the diagnosis of teratoma, which is classically composed of two or three embryonic layers could be excluded. The pathogenesis of nasal glioma is briefly discussed by authors.     

The S1 glycoprotein but not the N or M proteins of avian infectious bronchitis virus induces protection in vaccinated chickens

Summary The S1, N and M proteins, obtained from the nephropathogenic N1/62 strain of infectious bronchitis virus (IBV) by immunoaffinity purification with monoclonal antibodies, were used for immunization of chickens. For all three antigens multiple immunizations were necessary for induction of an antibody response. Protection of chickens vaccinated with the S1 glycoprotein against virulent challenge was demonstrated by the complete absence of virus in tracheas and kidneys of vaccinated chickens. Following four immunizations with the S1 glycoprotein 71% and 86% of chickens were protected at the level of tracheas and kidneys, respectively. Three immunizations with the S1 glycoprotein protected 70% and 10% of chickens at the level of kidney and trachea, respectively. Neither the N nor the M antigen induced protection to a virulent challenge with the nephropathogenic N1/62 strain of IBV after four immunizations. Virus neutralizing, haemagglutination inhibiting and ELISA antibodies were detected in chickens immunized with the S1 glycoprotein and inactivated N1/62 virus, however there was no correlation between the presence of any of these antibodies and protection.     

Matrix metalloproteinase-2, -9, and tissue inhibitor of metalloproteinase-1 in patients with hypertension.

There are conflicting data in the literature regarding the expression pattern of the vascular matrix metalloproteinase (MMP) system and their inhibitors (TIMPs) in human hypertension. The authors hypothesized that MMP-2, MMP-9, and TIMP-1 would be abnormal in hypertension, reflecting alterations in extracellular matrix (ECM) turnover. The authors measured plasma levels and activities of MMP-2, MMP-9, and TIMP-1 in 44 hypertensive patients and 44 controls. MMP-2 levels and activity were significantly higher in hypertensive group (p < .0001). Significant increase was also observed for MMP-9 level and activity (p < .0001) and for TIMP-1 (p < .0001) in hypertensive patients. Plasma levels and activities of MMP-2, MMP-9, and TIMP-1 are increased in hypertensive patients, which may reflect abnormal ECM metabolism.     

Contribution of immunoenzymatic technics to the assay of anti-native DNA antibodies in the biological diagnosis of lupus erythematosus disseminatus

Anti native DNA antibodies (anti nDNA Ab), which are a highly specific feature of systemic lupus erythematosus (SLE) were measured by 3 methods: an enzyme linked immunosorbent assay (ELISA), an indirect immunofluorescence test on Crithidia luciliae (IFCL) and the Farr assay (reference test). 114 sera from patients with SLE or another connective tissue disease or without autoimmune rheumatic disease were tested. This study showed that ELISA seemed to be a more sensitive and specific test than IFCL (classical test). ELISA was also as sensitive as the Farr assay. ELISA should replace IFCL for the diagnosis and the follow up of patients with SLE. In other connective tissue diseases, ELISA might give more positive results. Thus these had to be confirmed, especially in the case of low antibodies levels, by using another method (e.g., the Farr assay).     

Comprehensive comparison of the VERSANT HIV-1 RNA 3.0 (bDNA) and COBAS AMPLICOR HIV-1 MONITOR 1.5 assays on 1,000 clinical specimens.

BACKGROUND: Plasma human immunodeficiency virus type 1 (HIV-1) RNA level is an important parameter for patient management, yet viral load assays from different manufacturers are not standardized. OBJECTIVES AND STUDY DESIGN: In this study, we evaluated the concordance between test results obtained for 1,000 plasma specimens collected from HIV-1-infected individuals measured with the VERSANT HIV-1 RNA 3.0 assay (bDNA) and the COBAS AMPLICOR HIV-1 MONITOR 1.5 test (PCR). We compared viral load values obtained by each of these assays throughout their dynamic ranges, with particular focus on samples with low viral load (i.e. 50-250 copies/mL), and calculated the estimated distribution of distinct plasma viral load levels for the entire study population modeled from the data observed in the study. RESULTS: We found that these two assays show excellent agreement, with a correlation (R(2)) of 0.957 and a slope of 1.004. The mean difference in viral load values between the two assays was less than 0.10-log(10) throughout the dynamic range and 98.2% of all samples had bDNA and PCR results within 0.5-log(10) of each other, a difference that is within the range considered to be a minimal change in plasma viremia. Moreover, the two assays show very similar results across all assay ranges tested. The estimated prevalence of samples with results <50 copies/mL, 50-250 copies/mL, and 250-500,000 copies/mL were 41.6%, 7.7%, and 49.7%, respectively, by the bDNA assay, and 42.4%, 6.9%, and 50.7%, respectively, by the PCR assay. CONCLUSION: Based on our findings from 1,000 clinical specimens, we do not see the need to re-establish a baseline value or apply a conversion factor when switching from one assay to the other. Since the majority of our patient population likely is infected with subtype B virus, it is unclear if our findings will apply to other patient populations with a greater incidence of infection with non-B subtypes.     

Antigen-induced, IgE-mediated degranulation of cloned immature mast cells derived from normal mice

Cloned, immature mast cells derived from normal mice were passively sensitized with mouse monoclonal IgE antibodies with specificity for DNP, and then stimulated to degranulate with DNP35-HSA. Cells were fixed for transmission electron microscopy or recovered for quantitation of histamine release at various intervals up to 30 minutes after antigen challenge. The cloned mast cells rapidly extruded the contents of their immature granules (dense progranular material and membrane-bound vesicles) to the exterior via multiple openings in the plasma membrane. Degranulation was associated with striking activation of the cell surface, characterized initially by elongation of surface processes, as well as by close approximation of strands of rough endoplasmic reticulum to the cell surface and by the development of coated pits. At later times after stimulation, degranulated mast cells had released nearly all of their granules and exhibited angular surfaces lacking elongated processes. These findings demonstrate for the first time that cloned, immature mast cells, like their mature counterparts, can undergo classic morphologic release reactions involving exocytosis of granules.