Evaluation of recomWell Treponema, a novel recombinant antigen-based enzyme-linked immunosorbent assay for the diagnosis of syphilis.

OBJECTIVE: To evaluate the diagnostic performance of an enzyme immunosorbent assay (recomWell Treponema) for the diagnosis of syphilis. The novel recombinant antigens Tpn47, TpN17 and TpN15 were utilized. METHODS: A total of 782 human serum specimens, belonging to four different categories (blood donors, n = 200; routine laboratory screening for syphilis, n = 400; syphilis patients, n = 122; potential cross-reactors, n = 60), were evaluated to compare the sensitivity and specificity of the recomWell Treponema kit with a standard whole Treponema pallidum cell lysate antigen-based ELISA (Syphilis Screening) and with micro-haemagglutination (MHA-TP). RESULTS: The overall specificity and sensitivity of the recomWell Treponema IgG was 98.9% and 98.3%, respectively. The specificity and sensitivity of Syphilis Screening ELISA was 98.7% and 98.3%, respectively. The agreement between recomWell Treponema and Syphilis Screening was 100%, 97.8%, 95.9% and 95% among the blood donor specimens, screening samples, syphilis specimens and the potential cross-reactors, respectively. Values of concordance varying from 96.7% to 98.3% were found in the different groups of sera between recomWell Treponema and MHA-TP. In addition, recomWell Treponema demonstrated a good diagnostic performance when used to detect the IgM to T. pallidum. No false-positive sera were identified and, in 17/19 samples from primary infection, an IgM immune response was found. CONCLUSIONS: recomWell Treponema was shown to be a highly specific and sensitive method in all stages of syphilis screening and it can be considered as alternative to other ELISA tests based on native antigen preparations.

Western immunoblotting with five Treponema pallidum recombinant antigens for serologic diagnosis of syphilis.

Five immunodominant Treponema pallidum recombinant polypeptides (rTpN47, rTmpA, rTpN37, rTpN17, and rTpN15) were blotted onto strips, and 450 sera (200 from blood donors, 200 from syphilis patients, and 50 potentially cross-reactive) were tested to evaluate the diagnostic performance of recombinant Western blotting (recWB) in comparison with in-house whole-cell lysate antigen-based immunoblotting (wclWB) and T. pallidum hemagglutination (MHA-TP) for the laboratory diagnosis of syphilis. None of the serum specimens from blood donors or from potential cross-reactors gave a positive result when evaluated by recWB, wclWB, or MHA-TP. The evaluation of the immunoglobulin G immune response by recWB in sera from patients with different stages of syphilis showed that rTmpA was the most frequently identified antigen (95%), whereas only 41% of the specimens were reactive to rTpN37. The remaining recombinant polypeptides were recognized as follows: rTpN47, 92.5%; rTpN17, 89.5%; and rTpN15, 67.5%. The agreement between recWB and MHA-TP was 95.0% (100% with sera from patients with latent and late disease), and the concordance between wclWB and MHA-TP was 92.0%. The overall concordance between recWB and wclWB was 97.5% (100% with sera from patients with secondary and late syphilis and 94.6 and 98.6% with sera from patients with primary and latent syphilis, respectively). The overall sensitivity of recWB was 98.8% and the specificity was 97.1% with MHA-TP as the reference method. These values for sensitivity and specificity were slightly superior to those calculated for wclWB (sensitivity, 97.1%, and specificity, 96.1%). With wclWB as the standard test, the sensitivity and specificity of recWB were 98.9 and 99.3%, respectively. These findings suggest that the five recombinant polypeptides used in this study could be used as substitutes for the whole-cell lysate T. pallidum antigens and that this newly developed recWB test is a good, easy-to-use confirmatory method for the detection of syphilis antibodies in serum.

Treponema pallidum surface immunofluorescence assay for serologic diagnosis of syphilis.

A surface immunofluorescence assay (SIFA) using live spirochetes was analyzed and compared with Western blot (WB), fluorescent treponemal antibody absorption (FTA-ABS), microhemagglutination (MHA-TP), and Treponema pallidum immobilization (TPI) assays for detecting serum antibodies to T. pallidum in patients with syphilis, in disease controls, and in healthy subjects. SIFA and WB were 99% sensitive (99 of 100 positive specimens) and specific (140 of 140 negative specimens); FTA-ABS showed a sensitivity and a specificity of 90 and 89% (90 of 100 positive and 125 of 140 negative specimens), respectively. MHA-TP showed a sensitivity of 84% (84 of 100 positive specimens) and a specificity of 98.5% (138 of 140 negative specimens). Finally, TPI had a sensitivity of 52% (52 of 100 positive specimens) and a specificity of 100% (140 of 140 negative specimens). The T. pallidum SIFA was therefore highly specific, showing no equivocal reactivities with control sera, and sensitive. The results suggest the possible use of SIFA as a confirmatory test in the serologic diagnosis of syphilis.

IgG western blot as a confirmatory test in early syphilis.

Sensitivity and specificity of IgG detection by Western blotting performed with a lysate of Treponema pallidum whole cells were compared with those of the most common assays used in the laboratory diagnosis of syphilis, i.e. fluorescent treponemal antibody absorption test (FTA-ABS) and treponemal haemagglutination assay (TPHA). Thirty-five serum samples obtained from twenty-one patients with a clinical diagnosis of early syphilis, based on the presence of typical chancre or skin or mucous membrane lesions, were studied. In addition, thirty blood samples from donors, ten sera positive for Borrelia burgdorferi and five positive for Leptospira interrogans were tested as controls. The clinical diagnosis was the reference method used to compare the performance of the serological tests. Western blotting performed with a sensitivity and specificity of 100%, whereas the corresponding sensitivity and specificity for FTA-ABS were 88.5% and 98%, respectively. The performance of TPHA showed a sensitivity of 86% and a specificity of 100%.

Evaluation of immunoassays for the detection and typing of PCR amplified human papillomavirus DNA.

AIMS: To evaluate different hybridisation techniques to detect and type human papillomavirus (HPV) DNAs amplified by consensus primer polymerase chain reaction (PCR) in biopsy and cytological specimens. METHODS: A hybrid capture-immunoassay in microtitre wells was performed to detect HPV sequences amplified by PCR and typed by specific oligoprobes. Consensus primers were used to amplify a sequence within the L1 open reading frame, and direct digoxigenin labelling of amplified products was performed during the amplification reaction. The amplified product was separately hybridised with six biotinylated type specific probes (HPV6, 11, 16, 18, 31, and 33); hybrids were then captured into streptavidin coated microtitre wells and detected by a spectrophotometer as an ELISA using antidigoxigenin Fab fragment labelled with peroxidase and a colorimetric substrate. The results were compared with the dot-blot immunoassay used to detect and type PCR amplified HPV DNA sequences. Consensus primers were used to generate the same unlabelled PCR product; digoxigenin labelled type specific probes for HPV6, 11, 16, 18, 31, and 33 were used and hybrids visualised by colorimetric immunoenzymatic reaction. Thirty nine biopsy specimens and 31 cytological samples were tested by the PCR-ELISA and by standard PCR followed by dot-blot hybridisation. RESULTS: The PCR-ELISA proved to be more sensitive than standard PCR with dot-blot hybridisation typing. All samples positive for HPV-DNA in standard PCR with dot-blot hybridisation method were confirmed positive by the PCR-ELISA assay; however, seven samples were positive only by PCR-ELISA. CONCLUSIONS: The PCR-ELISA assay, which can be performed in one day, is easily standardised and therefore seems to be a practical, sensitive, and reliable diagnostic tool for the detection and typing of HPV genomes in biopsy and in cytological specimens in the routine diagnostic laboratory.

Detection of Chlamydia trachomatis by a ligase chain reaction amplification method.

BACKGROUND AND OBJECTIVES: The ligase chain reaction is an in vitro DNA amplification technique that exponentially amplifies selected DNA sequences. GOAL: To evaluate a ligase chain reaction assay for the detection of Chlamydia trachomatis cryptic plasmid DNA (LCx Chlamydia) in patients routinely attending a sexually transmitted disease center in Italy. STUDY DESIGN: Urethral or cervical swabs were obtained from 501 consecutive patients (334 men and 167 women). The samples were assayed in parallel with LCx Chlamydia and conventional tissue culture; discordant results were further assayed by direct immunofluorescence and a ligase chain reaction with alternate primers. RESULTS: After resolution of discordant results, the LCx method showed a sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 99.3%, 96.7%, and 100% in men; 100%, 100%, 100%, and 100% in women; and 100%, 99.5%, 97.1%, and 100% overall, respectively. By comparison, the sensitivity of tissue culture was 81.4% in men, 50% in women, and 77.6% overall. CONCLUSIONS: The automated LCx method is sensitive, fast, and accurate and represents a useful diagnostic tool for C. trachomatis infection, even in low and medium prevalence populations.

Vulvitis plasmacellularis: two new cases.

Vulvitis chronica plasmacellularis or Zoon's vulvitis is a rare benign circumscribed inflammation of the vulvar mucosa. It is found in women ranging in age from 26 to 70 years. Shiny, macular erythematous lesions, which are irregular in shape and sharply marginated are usually observed. The histologic findings show chronic subepithelial dense inflammation composed largely of plasma cells. We here report two cases of vulvitis plasmacellularis with typical clinical manifestations, courses and histopathologic findings.

Assessment of the "Amplicor" PCR test in the diagnosis of Chlamydia trachomatis infection.

We compared a commercially available PCR assay (Amplicor, Roche, Switzerland) and tissue culture isolation for the detection of C. trachomatis in urethral and/or endocervical swabs. Of the 200 patients studied (130 men and 70 women) PCR and tissue culture gave concordant results in 199 cases; in one case PCR was positive and culture negative. The Amplicor PCR assay proved fast and sensitive and suitable for routine use in most clinical microbiology laboratories.

Surface immunofluorescence assay for diagnosis of Lyme disease.

A surface immunofluorescence assay (SIFA) was analyzed and compared with a conventional indirect immunofluorescence assay (IFA) and whole-cell enzyme-linked immunosorbent assay (ELISA) for detecting immunoglobulin G (IgG) antibodies to Borrelia burgdorferi in sera from patients with Lyme disease. Fifty-five patients with syphilis and 33 patients with rheumatoid arthritis were used as disease controls. The sensitivity of the SIFA was low during the acute phase of Lyme disease (sera from seven of nine patients presenting with erythema chronicum migrans were negative during the first 2 months of illness); later, seroconversion was observed in all patients at various times during convalescence. Sera from five patients with complicated Lyme disease were strongly positive. SIFA was found to be highly specific, since sera from all patients with secondary or latent syphilis and patients with rheumatoid arthritis did not react in the test. Strong cross-reactivity occurred when these sera were tested in conventional IFA and ELISA; sera from 38 (69%) patients with syphilis were positive by IFA and sera from 51 (93%) patients were positive by ELISA, whereas 7 (21%) and 12 (36%) of the serum samples from patients with rheumatoid arthritis were positive by IFA and ELISA, respectively. Immunoblot analysis of SIFA-positive sera showed that the 31- and 34-kDa outer surface proteins (proteins A and B, respectively) of B. burgdorferi were the major reactive antigens involved in the test. The results support a role for SIFA in the investigation of complicated Lyme disease as well as in the differentiation of Lyme disease from other diseases associated with B. burgdorferi cross-reactive antibodies.

[Tungiasis. A clinical case]. / Tungiasi. Un caso clinico.

Tungiasis is a cutaneous infestation by the female sand flea, Tunga penetrans. Because of the increase in international travel, the disease is reported in Europe, in spite of it being formerly restricted to the equatorial zones. This report describes a case of tungiasis and discusses clinical features, diagnosis and treatment.

Inhibition of herpes simplex virus type 1 (HSV-1) plaque enlargement by neutralizing sera.

The inhibitory activity of neutralizing sera on Herpes simplex virus type 1 (HSV-1) plaque enlargement (PE) is easily detected using the S variant of low passage clinical isolates (Mannini-Palenzona et al., 1985b; Costanzo et al., 1986). The same sera show little or no activity on PE of the product of the S variant rapid in vitro conversion, the L variant, and laboratory strains HSV-1 (F) and (MP). No significant difference was found in the inhibitory activity of sera from healthy individuals with no history of recurrence and patients with recurrences.

[Thymopentin in the treatment of recurrent condylomata acuminata]. / La timopentina nel trattamento dei condilomi acuminati recidivanti.

Twelve patients who had been suffering from genital and/or perianal recurrent condyloma acuminatum for a minimum of 5 to a maximum of 24 months, in spite of treatment, were studied from the immunological viewpoint and treated with 50 mg s.c. Thymopentin three times a week for 4 or 6 weeks. Six of the patients were cured at the end of treatment, five after 5 months, and one was not cured. Analysis of the clinico-laboratory data shows a significant agreement between the course of clinical signs and the immunological picture. The various cure stages are probably attributable to the basic immune arrangement which was more impaired in the 5 patients who were cured more slowly and in the non-cured case. In the latter too, however, Thymopentin permitted correcting the balance of the relationship between the various lymphocyte subpopulations.

Ketoconazole treatment of chronic mucocutaneous candidiasis.

The authors report the results of treatment with ketoconazole in 8 patients with chronic mucocutaneous candidiasis (CMC). The drug, administered in the dose of 200 mg once a day orally for a period of time varying from 2 to 12 months, led to improvement in or elimination of clinical symptoms in all patients. One patient had a relapse on suspension of treatment, but this regressed rapidly on resumption of ketoconazole. In 7 cases there were no side-effects. In one case there was an increase in serum liver enzymes which disappeared spontaneously 7 days after suspension of treatment. These results appear encouraging in view of the difficulty of treating this disease, which is often resistant to conventional antifungal therapy.