John G. Howe

Defective Control of Latent Epstein-Barr Virus Infection in Systemic Lupus Erythematosus

EBV infection is more common in patients with systemic lupus erythematosus (SLE) than in control subjects, suggesting that this virus plays an etiologic role in disease and/or that patients with lupus have impaired EBV-specific immune responses. In the current report we assessed immune responsiveness to EBV in patients with SLE and healthy controls, determining virus-specific T cell responses and EBV viral loads using whole blood recall assays, HLA-A2 tetramers, and real-time quantitative PCR. Patients with SLE had an ∼40-fold increase in EBV viral loads compared with controls, a finding not explained by disease activity or immunosuppressive medications. The frequency of EBV-specific CD69+ CD4+ T cells producing IFN-γ was higher in patients with SLE than in controls. By contrast, the frequency of EBV-specific CD69+ CD8+ T cells producing IFN-γ in patients with SLE appeared lower than that in healthy controls, although this difference was not statistically significant. These findings suggest a role for CD4+ T cells in controlling, and a possible defect in CD8+ T cells in regulating, increased viral loads in lupus. These ideas were supported by correlations between viral loads and EBV-specific T cell responses in lupus patients. EBV viral loads were inversely correlated with the frequency of EBV-specific CD69+ CD4+ T cells producing IFN-γ and were positively correlated with the frequencies of CD69+ CD8+ T cells producing IFN-γ and with EBV-specific, HLA-A2 tetramer-positive CD8+ T cells. These results demonstrate that patients with SLE have defective control of latent EBV infection that probably stems from altered T cell responses against EBV.

Reduced incidence of Epstein-Barr virus-associated posttransplant lymphoproliferative disorder using preemptive antiviral therapy.

BACKGROUND Posttransplant lymphoproliferative disorder (PTLD) has been observed with increasing frequency consequent to the availability of more effective and potent immunosuppression. Prior work suggested that a peripheral blood monitoring strategy detecting peripheral B lymphoproliferation was effective in the early diagnosis of PTLD among 7 of 179 (3.9%) consecutive transplant recipients. Each of those seven patients received at least one course of antithymocyte globulin, Minnesota antilymphocyte globulin, or OKT3 before developing PTLD. METHODS To determine whether antiviral prophylaxis might reduce the incidence of PTLD, a subsequent group of 198 consecutive recipients received either ganciclovir or acyclovir during antilymphocyte antibody administration. When the donor or recipient were cytomegalovirus-seropositive, ganciclovir was given; acyclovir was used when both were cytomegalovirus-seronegative. Baseline and protocol posttransplant cell surface profiles were obtained using immunofluorescence and flow cytometry to detect T cells, lymphocyte activation markers, and the CD19 B cell antigen. RESULTS Demographic factors, including the incidence of recipients more than 50 years of age, non-Caucasians, previous transplantation, and diabetes mellitus, were similar in both groups. Additionally, the number of patients receiving antilymphocyte preparations was similar. However, only one patient (0.5%) from the latter group who received preemptive antiviral therapy developed PTLD. Although elevations in CD19+ B cells preceded clinical PTLD among each of the seven earlier patients, evidence of peripheral B cell proliferation was not demonstrated for the sole patient from the latter group, which suggests a possible effect of antiviral therapy. CONCLUSIONS Prophylactic antiviral therapy may reduce the sensitivity of peripheral monitoring for B lymphoproliferation, but the dramatic reduction in PTLD incidence strongly supports its use among transplant recipients at risk.

Educating medical students in laboratory medicine: a proposed curriculum.

As the 100th anniversary of the Flexner report nears, medical student education is being reviewed at many levels. One area of concern, expressed in recent reports from some national health care organizations, is the adequacy of training in the discipline of laboratory medicine (also termed clinical pathology). The Academy of Clinical Laboratory Physicians and Scientists appointed an ad hoc committee to review this topic and to develop a suggested curriculum, which was subsequently forwarded to the entire membership for review. The proposed medical student laboratory medicine curriculum defines goals and objectives for training, provides guidelines for instructional methods, and gives examples of how outcomes can be assessed. This curriculum is presented as a potentially helpful outline for use by medical school faculty and curriculum committees.

Endocarditis Caused by Culture-Negative Organisms Visible by Brown and Brenn Staining: Utility of PCR and DNA Sequencing for Diagnosis

ABSTRACT Two cases of culture-negative endocarditis with cocci seen in valve vegetations are presented. The organisms were identified by molecular analysis using broad-range PCR primers complementary to the 16S rRNA gene, sequencing, and database search using BLAST software. The results and utility of this method are discussed.

Real-time quantitative RT-PCR identifies distinct c-RET, RET/PTC1 and RET/PTC3 expression patterns in papillary thyroid carcinoma

RET/PTC1 and RET/PTC3 are the markers for papillary thyroid carcinoma. Their reported prevalence varies broadly. Nonrearranged c-RET has also been detected in a variable proportion of papillary carcinomas. The published data suggest that a wide range in expression levels may contribute to the different frequency of c-RET and, particularly, of RET/PTC detection. However, quantitative expression analysis has never been systematically carried out. We have analyzed by real-time RT-PCR 25 papillary carcinoma and 12 normal thyroid samples for RET/PTC1, RET/PTC3 and for RET exons 10–11 and 12–13, which are adjacent to the rearrangement site. The variability in mRNA levels was marked and four carcinoma groups were identified: one lacking RET/PTC rearrangement with balanced RET exon levels similar to those of the normal samples (7/25 cases, 28%), the second (6/25 cases, 24%) with balanced RET expression and very low levels of RET/PTC1, the third with unbalanced RET exons 10–11 and 12–13 expression, high RET/PTC1 levels but no RET/PTC3 (7/25 cases, 28%), and the fourth with unbalanced RET expression, high RET/PTC1 levels and low levels of RET/PTC3 (5/25 cases, 20%). Papillary carcinomas with high RET/PTC1 expression showed an association trend for large tumor size (P=0.063). Our results indicate that the variability in c-RET and RET/PTC mRNA levels contributes to the apparent inconsistencies in their reported detection rates and should be taken into account not only for diagnostic purposes but also to better understand the role of c-RET activation in thyroid tumorigenesis.

Comparison of assay systems for warfarin-related CYP2C9 and VKORC1 genotyping

BACKGROUND A variety of commercial genotyping assays is available to detect variants in the CYP2C9 and VKORC1 genes. The assay results are used in genotype-based warfarin dosing algorithms. We compared the performance of four such assay systems: Verigene, eSensor, Invader, and Luminex. METHODS Result concordance and no call rates were determined on patient specimens tested on all four instruments. Turnaround times (TAT), hands-on time (HOT), pipetting steps and cost were obtained for runs of 1, 8 and 24 samples. RESULTS The four assays were 100% concordant for the common CYP2C9 and VKORC1 alleles (n=100). Verigene had the shortest TAT and HOT for 1 and 8 samples. Verigene had the fewest pipetting steps for all sample sizes, while Invader had the most. Luminex had the longest TAT and highest cost for all sample run sizes. Verigene had the lowest cost for 1 and 8 samples and Invader the lowest for 24 samples. The no call rates for Verigene, Luminex, eSensor, and Invader were 10%, 4%, 1% and 0%, respectively. CONCLUSIONS All assays gave comparable results for common variants. Each system offered unique advantages and disadvantages, whose relative importance depends on the needs of the adopting clinical laboratory.

Epstein-Barr virus suspension cell assay using in situ hybridization and flow cytometry

We have developed a procedure for quantitative assay of Epstein-Barr virus (EBV)-infected cells in suspension in either latent or replicative phase using in situ hybridization and flow cytometry. The cells were hybridized with EBV-specific digoxigenin or biotin-labeled oligonucleotide probes, followed by binding to fluorescein-conjugated anti-digoxigenin or phycoerythrin-conjugated streptavidin, respectively. The cells hybridizing to the specific probes were quantitated by flow cytometry. A strong shift in fluorescence intensity (20-fold) was observed when the EBV-positive culture cells were hybridized with a specific EBER1 antisense probe. The sensitivity of the assay was at least one positive cell out of 9,000 beyond the normal control mean +/- 2 S.D. We performed two-color in situ hybridization/flow cytometry using probes to an EBV replication phase-specific mRNA and EBER1 on B95-8 cells in which a small portion (2-4%) of cells induce spontaneously into the replicative phase. In addition, we have developed a method for simultaneous analysis of the cell surface phenotype and EBV nucleic acid content in individual cells.

Pediatric AIDS-Associated Lymphocytic Interstitial Pneumonia and Pulmonary Arterio-Occlusive Disease: Role of VCAM-1/VLA-4 Adhesion Pathway and Human Herpesviruses

Because the mechanisms of lymphocyte accumulation in the lungs of children with AIDS-associated lymphocytic interstitial pneumonia (LIP) are unknown, we studied the relative contributions of known adhesion pathways in mediating lymphocyte adherence to endothelium and the potential role of human herpesviruses in the expansion of these lesions. LIP was characterized by lymphoid hyperplasia of the bronchus-associated lymphoid tissue (BALT) and infiltration of the pulmonary interstitium with CD8(+) T lymphocytes. In some individuals there was expansion of the alveolar septae with dense aggregates of B lymphocytes, many containing the Epstein-Barr viral (EBV) genome. Patients with concurrent EBV infection also demonstrated large-vessel arteriopathy characterized by thickening of the intimae with collagen and smooth muscle. Venular endothelium from the lung of children with LIP, but not uninflamed lung from other children with AIDS or lung from children with nonspecific pneumonitis, expressed high levels of vascular cell adhesion molecule-1 (VCAM-1) protein. In turn, inflammatory cells expressing very late activation antigen-4 (VLA-4), the leukocyte ligand for VCAM-1, were the predominant perivascular infiltrate associated with vessels expressing VCAM-1. Expression of other endothelial adhesion molecules, including intracellular adhesion molecule-1 and E-selectin, was not uniformly associated with LIP. Using a tissue adhesion assay combined with immunohistochemistry for VCAM-1, we show that CD8(+) T cell clones that express VLA-4 bind preferentially to pulmonary vessels in sites of LIP: vessels that expressed high levels of VCAM-1. When tissues and cells were pretreated with antibodies to VCAM-1 or VLA-4, respectively, adhesion was inhibited by >/=80%. Thus, infiltration of alveolar septae with CD8(+) T cells was highly correlative with VCAM-1/VLA-4 adhesive interactions, and focal expansion of B cells was coincidental to co-infection with EBV.

Flow Cytometric DNA Ploidy Analysis of Peripheral Blood From Patients With Sézary Syndrome Detection of Aneuploid Neoplastic T Cells in the Blood Is Associated With Large Cell Transformation in Tissue

We reviewed and screened 219 cutaneous T-cell lymphoma (CTCL) cases for Sezary syndrome (SS); 63 met the criteria for SS. Of these, 17 (27%) demonstrated circulating aneuploid cells and 46 (73%) showed only euploid cells in blood samples. Of 17 aneuploid cases, DNA ploidy study was essential for initial blood-based diagnosis of SS in 4 (24%) and important in monitoring minimal residual disease after treatment in 9 (53%) in which neoplastic T cells showed otherwise unremarkable or nonspecific flow cytometric immunophenotypic findings. Tissue biopsy slides (predominantly skin and lymph node) at the time of DNA ploidy studies were available for 47 of 63 cases. Of 14 cases with circulating aneuploid cells, 11 (79%) showed large cell transformation (LCT; 6 [43%]) or markedly increased large cells (ILC; 5 [36%]) in tissue, whereas only 10 (30%) of 33 euploid cases showed LCT (4 [12%]) or ILC (6 [18%]) (P < .01). There was no significant difference in blood tumor burden, immunophenotype, or proliferation index between euploid and aneuploid groups or histologic high- and low-grade groups. DNA ploidy study by flow cytometry is important for blood-based diagnosis of SS and detection of minimal residual disease in aneuploid SS after treatment. Detection of aneuploid neoplastic T cells in peripheral blood samples of patients with CTCL is associated with LCT in skin, lymph node, or other tissues.

Identification of Bordetella pertussis in a Critically Ill Human Immunodeficiency Virus-Infected Patient by Direct Genotypical Analysis of Gram-Stained Material and Discrimination from B. holmesii by Using a Unique recA Gene Restriction Enzyme Site

ABSTRACT Bordetella pertussis was diagnosed in a human immunodeficiency virus-infected patient by a newly developed method in which bacterial DNA is amplified directly from sputum Gram-stained slides. The validation of the method is described along with an additional new PCR-based assay that can distinguish between B. pertussis and Bordetella holmesii.