Cervical screening behavior of women with atypical squamous cells of undetermined significance (ASCUS)

Expectant follow-up based on early repeat Papanicolaou (Pap) smear(s) is the most commonly recommended management of patients with atypical squamous cells of undetermined significance (ASCUS). In a cervical cytology laboratory in northern Italy, a retrospective study of 1,087 ASCUS patients aged 25-64 was conducted. The primary aim was to assess the actual probability of early repeat Pap smear and associated factors. Univariate comparisons were based on the actuarial method. Multivariate associations were evaluated by Cox regression analysis. The cumulative probability of early repeat Pap smear was 0.11 at 6 mo, 0.29 at 12 mo, and 0.41 at 24 mo, with a multivariate association with screening sector (relative hazard, 3.0 for public offices and 2.8 for private offices vs. organized screening) and previous Pap smear history. Laboratory recommendation, patient age, place of birth, place of residence, marital status, and occupation exerted no independent effect. In conclusion, the probability of early repeat Pap smear was poor and independent of demographic and social factors. The frequency of follow-up failures emerged as a major problem with ASCUS management.

Modulation of Moloney leukemia virus long terminal repeat transcriptional activity by the murine CD4 silencer in retroviral vectors

We investigated whether CD4 gene regulatory sequences might be useful for developing transcriptionally targeted Moloney murine leukemia virus (Mo-MLV)-based retroviral vectors for gene expression specifically in CD4(+) cells. We could modulate Mo-MLV long terminal repeat (LTR) activity by inserting a 438-bp-long fragment containing the murine CD4 silencer in the LTR of the vector; both beta-galactosidase and green fluorescent protein reporter gene activities were strongly down-regulated in both murine and human CD8(+) cells, but not in CD4(+) lymphoid cell lines and freshly isolated lymphocytes transduced with this vector, compared with the findings using a control vector carrying wild-type LTRs. Titration experiments on NIH-3T3 cells revealed that inclusion of the CD4 silencer in the LTRs did not reduce the titer of the vectors. These findings indicate that a cellular silencer can be successfully included in retroviral vectors, where it maintains its transcription-regulatory function, thus suggesting a novel approach to transcriptional targeting.

Effects of complement inactivation and IgG depletion on skin reactivity to autologous serum in chronic idiopathic urticaria

BACKGROUND

Intradermal injection of autologous serum elicits a wheal-and-flare response in about 60% of patients with chronic idiopathic urticaria (CIU). This reactivity has been attributed to the presence of IgG autoantibodies directed against IgE or the alpha-chain of the high-affinity IgE receptor (FcepsilonRIalpha) expressed on basophils and mast cells, leading to the hypothesis that at least some forms of CIU could be sustained by an autoimmune process.

OBJECTIVES

The aim of this study was to investigate the relationship between the presence of anti-IgE or anti-FcepsilonRI antibodies and the ability to induce wheal-and-flare responses in CIU sera selected for the capacity to give a positive skin test response.

METHODS

Fifteen patients with CIU and a positive skin test response to autologous serum were injected intradermally with native serum and with serum heated at 56 degrees C for 30 minutes and then adsorbed on Sepharose-protein G to obtain IgG depletion. Serum levels of anti-IgE and anti-FcepsilonRIalpha antibodies were measured by ELISA by using purified IgE and recombinant RIalpha-soluble double-fusion protein RIalpha-human serum albumin-RIalpha, respectively. The histamine-releasing activity of sera was tested by using ELISA with whole human blood from a healthy donor.

RESULTS

All patients had positive cutaneous responses to native serum injection. Anti-FcepsilonRIalpha antibodies were present in 14 of 15 native sera, only two of which were able to induce in vitro basophil degranulation. On the contrary, detectable amounts of anti-IgE antibodies were not found in any serum. IgG depletion by protein G resulted in complete (10/14 samples) or considerable (4/14 samples) removal of anti-FcepsilonRIalpha antibodies. The two sera endowed with functional activity lost their capacity to trigger histamine release from basophils after heating and protein G adsorption. Nonetheless, heat-decomplemented/IgG-depleted sera elicited wheal-and-flare reactions comparable with those observed with untreated sera.

CONCLUSIONS

These results strongly suggest that skin reactivity to autologous serum could be due to as yet unidentified non-Ig reactants present in the sera of patients with CIU.

[A new instrument for the evaluation of the medical profession. Use of the OSCE method]

BACKGROUND

Objective structured clinical examination has advantages over traditional oral examination of medical student. However, it is not routinely used in Chile.

AIM

To describe the objective structured clinical examination system and report the results of its first use with Chilean medical students.

MATERIAL AND METHODS

Thirteen interns ware evaluated at the end of their surgical rotation, using the objective structured clinical examination. Thirteen stations were structured for this examination: one for history taking, two for physical examination, four for problem solving and knowledge, one for radiological interpretation, one for instrumental recognition, one for skills and one for text comprehension. There were a total of 88 questions.

RESULTS

All students exceeded 60% of requirements. Mean approval score was 73%. The higher score was 80% and the lower 61%. Ten students had a score over 70%. The method was well accepted by teachers and students.

CONCLUSIONS

This first local experience with the objective structured clinical examination was successful.

CD4 and CD8 T lymphocyte inheritance. Evidence for major autosomal recessive genes

The CD4/CD8 ratio has long been used for the follow-up and monitor of many infectious diseases. Following the demonstration in 1983 that the CD4/CD8 ratio in the mouse is under genetic control, it was subsequently shown to be controlled by a major locus in man. To define the mode of inheritance of the CD4/CD8 ratio, we addressed the absolute number of CD4 and CD8 cells in a large unselected control sample and in members of 70 nuclear families. Pedigrees of nuclear families were analyzed by complex segregation analysis. Data was adjusted prior to this analysis to remove the effects of relevant covariates. The non-genetic-transmission and the multifactorial model could be easily rejected for both CD4 and CD8 cells. Among the different inheritance models, involving both a major gene and a multifactorial (MFT) component, a major autosomal recessive gene with a residual MFT effect controlling the high number of CD4 and a major autosomal recessive gene with a residual MFT effect controlling the high number of CD8 cells were the significantly best-fitting ones. Our findings have some practical implications. Among all, the knowledge of the CD4+ cell number and the proportion between CD4+ and CD8+ T cells could be a useful parameter in predicting human immunodeficiency virus infection outcome.

CD4 and CD8 T lymphocyte inheritance. Evidence for major autosomal recessive genes

The CD4/CD8 ratio has long been used for the follow-up and monitor of many infectious diseases. Following the demonstration in 1983 that the CD4/CD8 ratio in the mouse is under genetic control, it was subsequently shown to be controlled by a major locus in man. To define the mode of inheritance of the CD4/CD8 ratio, we addressed the absolute number of CD4 and CD8 cells in a large unselected control sample and in members of 70 nuclear families. Pedigrees of nuclear families were analyzed by complex segregation analysis. Data was adjusted prior to this analysis to remove the effects of relevant covariates. The non-genetic-transmission and the multifactorial model could be easily rejected for both CD4 and CD8 cells. Among the different inheritance models, involving both a major gene and a multifactorial (MFT) component, a major autosomal recessive gene with a residual MFT effect controlling the high number of CD4 and a major autosomal recessive gene with a residual MFT effect controlling the high number of CD8 cells were the significantly best-fitting ones. Our findings have some practical implications. Among all, the knowledge of the CD4+ cell number and the proportion between CD4+ and CD8+ T cells could be a useful parameter in predicting human immunodeficiency virus infection outcome.

Inhibitory effect of heparin on skin reactivity to autologous serum in chronic idiopathic urticaria

BACKGROUND

Most patients with chronic idiopathic urticaria (CIU) show cutaneous reactivity to intradermal injection of autologous serum. In some cases this reactivity is associated with the presence of autoantibodies directed against IgE or IgE receptors expressed on mast cells, whereas in others no autoimmune mechanisms can be documented.

OBJECTIVES

The aims of this study were to compare the cutaneous reactivity to serum and plasma samples in a series of patients with active CIU and to address the mechanisms of the inhibitory effect exerted by heparin on the cutaneous responsiveness to the histamine-releasing factors (HRFs) present in CIU serum.

METHODS

Fourteen patients with CIU were injected intradermally with autologous serum, plasma (anticoagulated by either heparin or EDTA), or serum samples to which heparin had been added. The effects of heparin injection on cutaneous responsiveness to allergens was tested in 5 atopic patients. Moreover, in a set of experiments sera were also adsorbed with Sepharose-conjugated heparin.

RESULTS

All the patients had positive cutaneous reactions to autologous serum injection. When heparinized plasma was injected, negative reactions were observed in 12 of 14 patients, and a sizable reduction in the wheal-and-flare reactions was recorded in the remaining 2. Compared with results obtained with serum, no substantial change was observed in 6 of 8 patients injected with EDTA-anticoagulated plasma. When heparin was added to serum, abrogation of skin reactivity was seen; nonetheless, no change in the cutaneous response to allergens was associated with locally administered heparin in 5 atopic patients with no history of CIU. Finally, adsorption of CIU sera with solid-phase heparin abrogated the ability to induce cutaneous reactions in 5 of 7 patients, whereas in the remaining 2 a sizable reduction was observed.

CONCLUSIONS

These data indicate that heparin is able to profoundly inhibit the cutaneous response to HRFs present in the sera of patients with CIU. Although the precise level of action of this heparin-mediated effect is unclear from present data, preliminary evidence seems to indicate that heparin could directly interfere with HRFs present in CIU sera.

[An interlaboratory study of the use of PapNet in the quality control of cervico-vaginal cytology]

In this feasibility study of the utilization of the PapNet System (Neuromedical Systems, Suffern, NY) for computer-assisted cervical/vaginal cytology diagnosis, a random sample of 329 negative smears and a series of 68 positive smears reported as such by the Caltagirone laboratory, underwent PapNet review at the Imola laboratory. False-positive (FP) cases (smears originally classified as ASCUS, LGSIL, AGUS, e HGSIL and interpreted as negative on PapNet) and false-negative (FN) cases (reverse discrepancies) were further and conventionally re-evaluated by the staff of the originating laboratory. On PapNet review, there were 16/68 FP cases (23.5%) e 20/329 FN cases (6.1%) with a FP:FN rate ratio of 3.8 (95% confidence interval, 2.2-6.3). At final re-examination of these diagnostic errors, most FP cases (14/16) were confirmed as such whereas the FN cases significantly decreased from 20 to 9, with a final rate of 2.7%. As a consequence, the ratio of the FP rate (14/68) to the FN rate (9/329) rose to 7.5 (4.1-12.6). The study suggests one potential approach to the preliminary utilization of PapNet by those laboratories that are interested in this technology. The results are in accordance with those of the previous PapNet review studies which have generally shown a greater frequency of FP cases compared with FN cases.

An alternatively spliced form of CD79b gene may account for altered B-cell receptor expression in B-chronic lymphocytic leukemia

Several functional anomalies of B-chronic lymphocytic leukemia (B-CLL) cells may be explained by abnormalities of the B-cell receptor (BCR), a multimeric complex formed by the sIg homodimer and the noncovalently bound heterodimer Igalpha/Igbeta (CD79a/CD79b). Because the expression of the extracellular Ig-like domain of CD79b has been reported to be absent in the cells of most CLL cases, we have investigated the molecular mechanisms that may account for this defect. Peripheral blood lymphocytes (PBL) from 50 patients and two cell lines (MEC1, MEC2) obtained from the PBL of one of them were studied. MEC1, MEC2, and 75% of CLL cases did not express detectable levels of the extracellular Ig-like domain of CD79b, which was nevertheless present in greater than 80% CD19(+) cells from normal donors. In healthy subjects the expression of CD79b was equally distributed in CD5(+) and CD5(-) B-cell subsets. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of CD79b RNA from all patients and from MEC1 and MEC2 cell lines consistently yielded two fragments of different size (709 bp and 397 bp). The 709-bp band corresponds to CD79b entire transcript; the 397-bp band corresponds to an alternatively spliced form lacking exon 3 that encodes the extracellular Ig-like domain. Both fragments were also visible in normal PBL. The expression of the 397-bp fragment was increased in normal activated B cells, while no difference was seen between CD5(+) and CD5(-) B cells. To obtain a more accurate estimate of the relative proportions of the two spliced forms, a radioactive PCR was performed in 13 normal and 22 B-CLL samples and the results analyzed using a digital imager. The mean value of the CD79b to the CD79b internally deleted ratio was 0.64 +/- 0.20 SD in normal donors and 0.44 +/- 0.27 SD in B-CLL (P =.01). Direct sequencing of 397-bp RT-PCR products and of genomic DNA corresponding to exon 3 from MEC1, MEC2, their parental cells, and five fresh B-CLL samples did not show any causal mutation. Single-strand conformation polymorphism analysis of exon 3 performed in 18 additional B-CLL cases showed a single abnormal shift corresponding to a TGT --> TGC polymorphic change at amino acid 122. We propose a role for the alternative splicing of CD79b gene in causing the reduced expression of BCR on the surface of B-CLL cells. As normal B cells also present this variant, the mechanism of CD79b posttranscriptional regulation might reflect the activation stage of the normal B cell from which B-CLL derives.

Frequency of a mutated CCR-5 allele (delta32) among Italian healthy donors and individuals at risk of parenteral HIV infection

The aim of this study was to assess the frequency of a truncated allele of the CCR-5 gene (delta32) in Italy, and address its possible role in parenteral HIV transmission, as well as its influence in HIV-associated disease progression. In 371 unrelated seronegative healthy blood donors the delta32 allele frequency was 0.047; this figure was significantly different from those reported in northern America and northern Europe populations. However, delta32 allele frequency in healthy individuals did not differ significantly from that found in 54 seronegative drug users (0.065), 98 seronegative hemophiliacs (0.051), and 81 seropositive hemophiliacs (0.049). Although in seropositive hemophiliacs the wt/delta32 heterozygous genotype was associated with a trend to a slower decline in CD4+ cell counts, its presence did not seem to influence disease progression, as comparable delta32 allele frequency frequencies were found among progressing (0.042) and nonprogressing (0.111) patients. These data do not seem to support a protective role of the delta32 allele in preventing HIV infection through the parenteral route, or in influencing the natural history of the disease in this particular risk category, although the delta32 heterozygous state was associated with lower plasma viremia levels. On the other hand, the finding of non-syncytium-inducing HIV strains in the majority of delta32 heterozygous seropositive patients suggests that its presence could not be a major factor in driving a switch toward more cytopathic, T-tropic HIV strains through selective pressure in coreceptor usage.

Accuracy comparison between PAPNET diagnoses and conventional diagnoses in an Italian cervical cytology laboratory

In a population-based cervical screening laboratory with a controlled workload, a retrospective PAPNET review of 1,654 Pap smears was performed. The series included a random sample of smears originally and conventionally classified as negative (no. 1,309) and unsatisfactory (no. 43), and 299 consecutive smears originally classified as abnormal. The PAPNET diagnoses and the original diagnoses were compared for accuracy. For smears with discordant classification, a majority diagnosis as obtained on manual review was used as a gold standard. The PAPNET testing showed a greater proportion of negative smears classified as unsatisfactory (3.7% vs. 0.2%; ratio, 16.7; 95% CI 12.4-22.0); a reduced proportion of ASCUS/LGSIL cases correctly identified as positive (i.e., a reduced sensitivity for such lesions) (76.3% vs. 97.9%; ratio, 0.78; 95% CI 0.66-0.91); an equal proportion (96.2%) of AGUS/HGSIL cases correctly identified as positive (i.e., an equal sensitivity for such lesions); and an equal proportion of negative smears correctly identified as such (i.e., an equal specificity). In conclusion, the PAPNET testing did not improve the diagnostic performance of the manual screening.

Differential effect on TCR:CD3 stimulation of a 90-kD glycoprotein (gp90/Mac-2BP), a member of the scavenger receptor cysteine-rich domain protein family

We studied the effects of a 90-kD glycoprotein (gp90/Mac-2BP) belonging to the scavenger receptor family, present in normal serum and at increased levels in inflammatory disease and cancer patients, on some T cell function parameters. Whereas the lymphocyte proliferative response to non-specific mitogens such as phytohaemagglutinin (PHA) and concanavalin A (Con A), but not pokeweed mitogen (PWM), was strongly reduced, probably due to the lectin-binding properties of gp90/Mac-2BP, the response to T cell receptor (TCR) agonists such as superantigens and allogeneic cells was potentiated. When lymphocytes were stimulated with different anti-TCR:CD3 MoAbs, both in soluble and solid-phase form, gp90/Mac-2BP was able to down-regulate the proliferative response to anti-CD3 MoAb, whereas the response to anti-TCR alphabeta MoAb was enhanced. A similar differential effect was observed when a MoAb against CD5 (another member of the scavenger receptor superfamily) was added to anti-CD3 or anti-TCR-stimulated cells; anti-CD5 MoAb strongly down-modulated the CD3-mediated response, whereas its presence in culture was associated with potentiation of the response to TCR alphabeta agonists. gp90/Mac-2BP was able per se to up-regulate Ca2+ levels in freshly isolated lymphocytes; moreover, its presence in culture was associated with increased Ca2+ mobilization following stimulation with anti-TCR alphabeta, but not anti-CD3 MoAb. These data indicate that gp90/Mac-2BP could be able to influence some immune responses, possibly through multiple homologous interactions with other members of the scavenger receptor family; moreover, our findings suggest that signalling through the different components of the TCR:CD3 complex may follow distinct activation pathways into the cells.

[The PAPNET system in the rescreening of negative cervical/vaginal smears. A study from the Imola cytology laboratory]

The rescreening of negative cervical/vaginal smears is one of the potential areas of utilization of the systems for computer-assisted cytology diagnosis. In the Imola cytology laboratory, a random sample of 1309 conventionally prepared smears that had been originally reported as negative was rescreened with the PAPNET System (Neuromedical Systems, Inc., Suffern, NY). Smears with a PAPNET diagnosis other than negative were further and independently evaluated by the staff of the laboratory and classified according to the majority report. The PAPNET rescreening confirmed the original negative diagnosis for 1188 smears (907.6/1000) and led to the detection of 46 ASCUS/LGSIL cases (35.1/1000) and 2 AGUS/HGSIL cases (1.5/1000). Seventy-three smears (55.8/1000) were interpreted as unsatisfactory. The majority report confirmed the original negative diagnosis for 42 (91%) of the 46 PAPNET diagnoses of ASCUS/LGSIL and 50 (68%) of the 73 smears interpreted as unsatisfactory. The 2 cases of AGUS/HGSIL diagnosed by PAPNET were confirmed. The detection rate of ASCUS/LGSIL decreased from 35.1/1000 to 3.1/1000 (rate ratio 0.09, 95% confidence interval [95% CI] 0.02-0.22). The rate of unsatisfactory smears decreased from 55.8/1000 to 17.6/1000 (rate ratio 0.31, 95% CI 0.20-0.47). The rate of negative smears increased from 907.6/1000 to 977.9/1000 (rate ratio 1.08, 95% CI 1.02-1.14). In conclusion, the PAPNET rescreening of negative smears brought about a low detection rate of severe cellular changes. Though greater, the detection rate of low grade changes was substantially and significantly reduced by the majority reports. At our laboratory, the PAPNET rescreening does not appear to improve the performance of conventional cytodiagnosis.

[Analysis of the intralaboratory diagnostic variability in the Imola cervical screening program]

The value of the assessment of intralaboratory variability as a method for quality control of cervical screening is an ill-defined one. This model has been advocated and utilized by some Authors and only indirectly addressed by others. In Italy, only occasional studies have been published. The present analysis is part of a series of studies for the evaluation and quality control of the population cervical screening programme in the area of Imola. The agreement between the 5 cytologists was tested over a series of 150 smears selected from the routine material. The data were analyzed with the k statistic and the degree and direction of discrepancies were assessed by the percent distribution of paired diagnoses. The k values for agreement between the 10 possible pairs of cytologists varied between 0.25 and 0.49 (average value, 0.37). The indexes for agreement as based on three classes ('Negative'/ASCUS + LGSIL + HGSIL/'Unsatisfactory') varied from 0.35 to 0.56 (average value, 0.46). The cytologist-specific k values (as based on five classes) ranged from 0.29 to 0.43. For the observer with the lowest specific coefficient (designated as C4), the excess disagreement was restricted to the ASCUS class and the 'Unsatisfactory' notation. In particular, C4 diagnosed more often 'Negative' smears (74% vs. 44-55%) and less frequently ASCUS (11% vs. 22-31%) and 'Unsatisfactory' smears (3% vs. 6-11%). ASCUS was the least reproducible diagnosis (k = 0.22). The evaluation of the degree and direction of the diagnostic discrepancies between the five cytologists showed that the frequency of concordant diagnoses of ASCUS was as low as 39.7%. However, the discrepancies were almost always of one degree and were directed towards the 'Negative' class. Conversely, ASCUS was associated with considerable proportions of the 'Negative' diagnoses (17.3%) and those of LGSIL (31.8%). In the occasions when one observer interpreted a smear as 'Unsatisfactory' the paired diagnoses were almost evenly distributed among 'Unsatisfactory' (49.2%) and 'Negative' (43.0%). In absolute terms, the k coefficients in this study were compatible with moderate agreement. However, they were unfavourably influenced by the modalities for smear selection. The study specimens were selected by all cytologists from the routine material over a short time period and did not include smears interpretable as showing carcinoma. A comprehensive evaluation of the diagnostic performance of C4 showed that the disagreement with other cytologists was restricted to the diagnosis of ASCUS and the 'Unsatisfactory' notation and was accounted for by a lower frequency of such reports coupled with a greater frequency of the 'Negative' diagnoses. A conservative approach to lesions of minor significance is the most likely explanation for that pattern of disagreement. Although characterized by the poorest k value, the ASCUS diagnosis proved to be generally matched with reports of minor cytology changes. This was consistent with the formal definition for ASCUS in the original Bethesda System. The observation that the ASCUS diagnosis is applied to those changes is a prerequisite for a more conservative utilization of such report. In conclusion, the study revealed important correlates of the k coefficients and provided an encouraging picture of the cytologic substrates of the diagnosis of ASCUS.

Lymphoproliferative disease in human peripheral blood mononuclear cell-injected SCID mice. IV. Differential activation of human Th1 and Th2 lymphocytes and influence of the atopic status on lymphoma development

Intraperitoneal transfer of PBMC from EBV+ donors into SCID mice leads to high human Ig levels in mouse serum and B cell lymphoproliferative disease. As these events depend on the activation of coinjected human T cells, we addressed the behavior of the Th1 and Th2 subsets in this model. Production of IFN-gamma, but not of Th2 cytokines such as IL-4, was detected in culture supernatants of PBMC stimulated in vitro with mouse splenocytes. Moreover, anti-CD3 stimulation of the human cells recovered from mice brought about IFN-gamma, but not IL-4, synthesis; on the other hand, PCR and in situ hybridization analysis of ex vivo-recovered cells disclosed the presence of mRNA for both cytokines following in vitro restimulation, thus suggesting posttranscriptional regulation of IL-4 gene expression. When SCID mice were inoculated with PBMC from atopic donors, whose Th1/Th2 profile displays an imbalance toward Th2 cells, tumor development rates were lower, and tumor latency was higher, compared with those in mice injected with PBMC from normal donors. Isotypic analysis of human Ig in mouse serum showed the exclusive presence of IFN-gamma-driven IgG subclasses; in addition, human IgE were low or undetectable in most cases. These findings indicate that following transfer into SCID mice, human Th1 lymphocytes undergo preferential activation, whereas Th2 function is down-regulated. Th1 lymphocytes probably are a major component in promoting EBV+ B cell expansion and tumor development; the individual Th1/Th2 profile could in part account for the as yet unexplained donor variability in tumor generation in this experimental model.

New therapeutic perspectives for demyelinating retrobulbar optic neuritis

In patients with demyelinating retrobulbar optic neuritis (RON), a spontaneous or corticosteroid-induced improvement is generally observed within the first month, but this is clinically insignificant in 5%-7% of patients. We report the case histories of four patients who were considered to be "non-responders" to corticosteroids because their visus remained unchanged or had improved by only 1/10 after one month from intravenous corticoid therapy begun 2-7 days after disease onset, and who were therefore subsequently administered high intravenous doses of immunoglobulin. Three of these patients completely recovered in a period of 3-9 months; the fourth showed only a partial improvement, but this was consolidated after long-term continuation of the same therapy. These cases suggest the possible efficacy of early administration of intravenous immunoglobulin in RON patients who fail to respond to cortisone therapy. As recently demonstrated in animal models, it can be hypothesised that the result is due to immuno-mediated mechanisms of action that reduce autoimmune responses in the short- and medium-term, and in the long-term favour remyelination.

The cancer registry in the monitoring of cervical screening practice: the neglected value of the Pap smear in patients diagnosed with CIN3 on biopsy

Patients diagnosed with CIN3 on biopsy without a Pap smear are an inevitable correlate of the extensive utilization of colposcopy as a basic screening test. In a series of 248 CIN3 cases diagnosed on biopsy and notified to the Romagna Cancer Registry between 1986 and 1993, we evaluated the independent association between the Pap smear result and (1) the final histology diagnosis, (2) the first choice treatment, and (3) the appropriateness of hysterectomy. The patients were grouped into the following categories: (1) no smear, ie colposcopy only (n = 40 or 16%), (2) CIN1, CIN2, LGSIL, and minor changes, (3) CIN3 and HGSIL, and (4) carcinoma. In multiple logistic regression analysis, patients without a Pap smear were used as a reference category. Patients with smears reported as CIN1-2/LGSIL or less as well as CIN3/HGSIL had a significantly lower probability of invasive squamous carcinoma (odds ratio = 0.26 for both categories) compared with those not undergoing cytology. The Pap smear result was not a determinant of the first choice treatment. Hysterectomy had a greater probability of being unnecessary if performed in patients with smears reported as showing CIN3/HGSIL (odds ratio = 5.05) or less. In conclusion, this registry-based study demonstrated that the Pap smear had an independent but neglected value in the assessment of cases reported as CIN3 on colposcopy-guided biopsy.

Pseudotyping of Moloney leukemia virus-based retroviral vectors with simian immunodeficiency virus envelope leads to targeted infection of human CD4+ lymphoid cells

In view of our recent findings that a truncated form of the envelope (Env) glycoprotein of human immunodeficiency virus type 1 (HIV-1) was efficiently incorporated into MoMLV particles, we studied the generation of Moloney murine leukemia virus (MoMLV)/simian immunodeficiency virus (SIV) pseudotypes. Unlike HIV-1, both the wild-type SIV Env and a truncated form, which lacks most of the cytoplasmic domain of the transmembrane glycoprotein, were incorporated into MoMLV particles and generated infectious retroviral vectors which could transduce CD4+ sMAGI macaque cells. The infection depended on target cell CD4 expression, and was neutralized by both soluble CD4 and sera from SIV-infected macaques. We also observed pseudotype-mediated gene transfer of a green fluorescent protein marker into the CD4+ CEMX174 and C8166 lymphoid cell lines. More importantly, primary human lymphocytes were also successfully transduced ex vivo by MoMLV/SIV pseudotypes, albeit at lower efficiency, and gene transfer was specifically restricted to the CD4+ subset. These findings demonstrate that MoMLV/SIV pseudotypes can be used to transduce cells which are susceptible to SIV infection, and thus might be advantageously employed in animal models for direct in vivo delivery of gene therapy-based approaches.

DNA immunization of mice against SIVmac239 Gag and Env using Rev-independent expression plasmids

Simian immunodeficiency virus (SIV) structural gene expression, including gag and env, strictly depends on the interaction of the viral posttranscriptional regulator Rev with its target RNA, the Rev-responsive element (RRE). A small RNA element, termed the constitutive transport element (CTE), located in the 3' portion of simian retrovirus 1 (SRV-1) mRNA, can efficiently substitute for the human immunodeficiency virus (HIV) Rev-RRE interaction, and thus render HIV expression and replication Rev independent. We tested the ability of the SRV-1 CTE to drive the expression of SIVmac239 env and gag from subgenomic constructs designed for possible use in vaccine trials. In vitro expression studies showed that when the SRV-1 sequence is coupled to the SIV gag and env mRNAs, it functions in an orientation-dependent fashion, and leads to strong expression of SIV Gag and Env in human and monkey cell lines; levels of CTE-mediated protein expression were similar to those obtained with a functional Rev-RRE system. On the other hand, in murine fibroblast-like cells, SIV Gag and Env were expressed from constructs at relatively high levels even in the absence of Rev-RRE; nevertheless, their expression was increased by the presence of the SRV-1 CTE. As reported previously for HIV, the murine cell lines appeared to be defective for Rev-RRE activity, and required overexpression of Rev to induce a Rev response. Intramuscular injection of the gag-CTE and env-CTE constructs in BALB/c mice resulted in the expression of the corresponding mRNAs, and the production of anti-Gag and anti-Env antibodies, thus suggesting that these vectors might be used for genetic immunization approaches.

Rapid identification of viable retrovirus-transduced cells using the green fluorescent protein as a marker

Various methods for determining the expression of the beta-galactosidase (beta-gal) gene after retroviral transduction were compared as a means to assess retroviral titre. To allow better comparison, different retroviral vectors were constructed carrying two mutants of the green fluorescent protein and assessed as sensitive markers of retroviral gene transfer. It could be demonstrated that GFP is generally superior to beta-gal in terms of sensitivity, speed and non-invasiveness of assay, allowing easy direct FACS sorting of populations of transduced cells. This opens the possibility of enrichment by sorting of ex vivo transduced cells in gene therapy protocols.

Live attenuated simian immunodeficiency virus prevents super-infection by cloned SIVmac251 in cynomolgus monkeys

The ability of a live attenuated simian immunodeficiency virus (SIV) to protect against challenge with cloned SIVmac251/BK28 was evaluated in four cynomolgus macaques. The intravenous infection of the C8 variant of the SIVmac251/32H virus, carrying an in-frame 12 bp deletion in the nef gene, did not affect the CD4+ and CD8+ cell counts, and a persistent infection associated with an extremely low virus burden in peripheral blood mononuclear cells (PBMCs) was established. After 40 weeks, these monkeys were challenged intravenously with a 50 MID50 dose of SIVmac251/BK28 virus grown on macaque cells. Four naive monkeys were infected as controls. Monkeys were monitored for 62 weeks following challenge. Attempts to rescue virus from either PBMCs or bone marrow from the C8-vaccinated monkeys were unsuccessful, but in two cases virus was re-isolated from lymph node cells. The presence of the SIV provirus with the C8 variant genotype maintaining its original nef deletion was shown by differential PCR in PBMCs, lymph nodes and bone marrow. Furthermore, in contrast to the control monkeys, the vaccinated monkeys showed normal levels for CD4+ and CD8+ cells, minimal lymphoid hyperplasia and no clinical signs of infection. Our results confirm that vaccination with live attenuated virus can confer protection. This appears to be dependent on the ability of the C8 variant to establish a persistent but attenuated infection which is necessary for inducing an immune response, as suggested by the persistence of a strong immune B cell memory and by the over-expression of interleukin (IL)-2, interferon-gamma and IL-15 mRNAs in PBMCs of C8-vaccinated monkeys but not in those of control monkeys.

TCR expression and clonality analysis in peripheral blood and lymph nodes of HIV-infected patients

We compared the T cell receptor (TCR) V beta gene family repertoire in peripheral blood mononuclear cells (PBMC) and lymph node (LN) cells from 7 human immunodeficiency virus (HIV)-infected patients and 3 seronegative healthy controls. Virtually all the V beta family specificities were represented in patient PBMC and LN cells, and mean values for each specificity were comparable to figures in seronegative controls. In 4 patients, however, some V beta gene segment transcripts were overrepresented in the LN compartment, compared to the peripheral blood counterpart. To ascertain whether this phenomenon was due to polyclonal or oligoclonal expansion of T cells bearing the relevant V beta gene product, we sequenced the entire CDR3 region of a panel of 238 PCR clones corresponding to the V beta transcripts expanded in LN; as control, the same regions were cloned and sequenced in patient's PBMC, and in PBMC and LN cells from seronegative individuals. This analysis disclosed preferential usage of J beta 2 genes in PBMC and LN cells from both seropositive patients and controls, regardless of the V beta gene segment considered, thus indicating that this skewness in the V beta-J beta repertoire could be a consistent feature of at least a part of the V beta repertoire in different lymphoid compartments, regardless of the pathologic conditions. In addition, in LN from HIV seropositive patients we found the presence of recurrent TCR rearrangements, accounting for 8-23% of the generated clones, in each of the 4 V beta specificities analyzed; recurrent sequences were not found in PBMC from patients nor in PBMC and LN cells from seronegative controls. These findings suggest that antigen-driven oligoclonal T cell expansions may occur in vivo in lymphoid organs of HIV seropositive patients.