Maroto C

Improvement in the determination of HIV-1 tropism using the V3 gene sequence and a combination of bioinformatic tools.

Assessment of HIV tropism using bioinformatic tools based on V3 sequences correlates poorly with results provided by phenotypic tropism assays, particularly for recognizing X4 viruses. This may represent an obstacle for the use of CCR5 antagonists. An algorithm combining several bioinformatic tools might improve the correlation with phenotypic tropism results. A total of 200 V3 sequences from HIV‐1 subtype B, available in several databases with known phenotypic tropism results, were used to evaluate the sensitivity and specificity of seven different bioinformatic tools (PSSM, SVM, C4.5 decision tree generator and C4.5, PART, Charge Rule, and Geno2pheno). The best predictive bioinformatic tools were identified, and a model combining several of these was built. Using the 200 reference sequences, SVM and geno2‐pheno showed the highest sensitivity for detecting X4 viruses (98.8% and 93.7%, respectively); however, their specificity was relatively low (62.5% and 86.6%, respectively). For R5 viruses, PSSM and C4.5 gave the same results and outperformed other bioinformatic tools (95.7% sensitivity, 82% specificity). When results from three out of these four tools were concordant, the sensitivity and specificity, taking as reference the results from phenotypic tropism assays, were over 90% in predicting either R5 or X4 viruses (AUC: 0.9701; 95% CI: 0.9358–0.9889). An algorithm combining four distinct bioinformatic tools (SVM, geno2pheno, PSSM and C4.5), improves the genotypic prediction of HIV tropism, and merits further evaluation, as it might prove useful as a screening strategy in clinical practice. J. Med. Virol. 81:763–767, 2009.

Acute meningoencephalitis as the sole manifestation of Q fever

The case of a 25-year old man who presented with meningoencephalitis as the sole clinical manifestation of Q fever is described. Serological studies revealed the presence of IgM and IgG antibodies toCoxiella burnetii. The patient responded favourably to a ten-day course of i.v. ceftriaxone and was discharged without any neurological sequelae.

Reliability of four methods for the diagnosis of acute infection by Epstein-Barr virus.

We studied the reliability of new indirect tests in the diagnosis of acute infection by Epstein‐Barr virus (EBV). Studied for all samples were: method 1, the heterophil antibodies (Abs) (Monolatex, Biokit, Germany); method 2, the IgM Abs to EBV with ELISA tests (antigen pools, Enzygnost, Behringwerke, Germany); method 3, EA (Biotest Diagnostics, Germany); and method 4, the IgG avidity test. The reliability of the four tests for the detection of primary infection by EBV was: sensitivity (method 1:89.1%; method 2: 100%; method 3: 79.7%; method 4: 99%); specificity (method 1: 98%; method 2: 100%; method 3:84%; method 4: 100%); positive predictive value (method 1: 97.6%; method 2: 100%; method 3: 73.6%; method 4: 100% method 4: 100%), and negative predictive value (method 1: 90.7%; method 2: 100%; method 3:84%; method 4: 99%). The IgG avidity test (method 4) is simple and automated in the laboratory and is very useful for ascertaining, from a single sample, the time since infection. It is criteria of recent primoinfection higher levels than 55% of IgG with low avidity for the antigen. The investigation of the Abs to antigen pools (method 2) by ELISA of virus had a high reliability, but the investigation of heterophil Abs by latex (method 1) and the Abs IgM to EA (method 2) were lacking in sensibility regarding their use in the diagnosis of the primoinfection. J. Clin. Lab. Anal. 11:78–81.

Descripción de inmunógenos de Chlamydia pneumoniae reconocidos por el suero de sujetos con enfermedad arterial periférica

Fundamento y objetivo: Se estudian, en sujetos con enfermedad arterial periferica, los tipos de anticuerpos frente a Chlamydia pneumoniae y su relacion con la presencia de la bacteria. Pacientes y metodo: Se ha realizado un estudio en 68 casos y 50 controles en los que se investigaron en suero las inmunoglobulinas (Ig) G y A frente a C. pneumoniae mediante Western-blot (comercial y no comercial), enzimoinmunoanalisis y microinmunofluorescencia (MIF), asi como el ADN de la bacteria en biopsia de tejido vascular mediante reaccion en cadena de la polimerasa. Resultados: Mediante Western-blot comercial se encontro, en los casos, una presencia significativa de IgG anti-39 kDa y anti-54 kDa, que se relacionaron con los resultados obtenidos mediante MIF y con la presencia de ADN de C. pneumoniae; asi como de IgA antilipopolisacarido, anti-92 kDa y anti-Hsp60 kDa, que se relacionaron con la presencia de ADN. Mediante Western-blot no comercial destaco la presencia significativa, en los casos, de las bandas de 128,8 y 9,2 kDa para la IgG, que se asocio con la existencia de ADN; tambien se detectaron en los casos bandas de IgG de 70,8, 58,9, 47,9, 47,5, 18,4, 12,1, 10,6, 8,1 y 7,6 kDa; asimismo se detecto ADN cuando se observaron las bandas de 54,6 y 1,1 kDa de IgG, y las bandas de 79,4, 50,1 y 18,4 kDa de IgA. Conclusiones: En los sujetos con enfermedad arterial periferica se encontro una respuesta serologica, mediante Western-blot, mas importante frente a determinadas proteinas de la bacteria. Esto podria reflejar una fase inicial con presencia de ADN e IgG especifica. Posteriormente, aun en ausencia de la bacteria, podria existir una enfermedad inmunomediada con presencia de IgA e IgG.

A study of IgM antibodies in diagnosis of acute infection by Toxoplasma gondii in Spain

Abstract A study of two ELISA methods (Eti-toxok-M, Sorin; Vidas Toxo IgM, bioMerieux) and one agglutination (Toxo Isaga, bioMerieux) was carried for the detection of specific IgM antibodies to Toxoplasma gondii in Southern Spain in different population groups. For diagnosis of acute toxoplasmosis ELISA methods showed 100% sensitivity, 99.4% specificity, 12% predictive value positive and 100% predictive value negative. Toxo Isaga showed 100% sensitivity, 99.5% specificity, 15% predictive value positive and 100% predictive value negative.

Relación entre la enfermedad arterial periférica oclusiva y la infección por Chlamydophila pneumoniae

Fundamento y objetivo: Estudiar la relacion entre la enfermedad arterial periferica oclusiva y la infeccion por Chlamydophila pneumoniae a traves del estudio de muestras clinicas de 95 enfermos (casos) y 100 controles. Pacientes y metodo: Se investigaron mediante enzimoinmunoanalisis las inmunoglobulinas (Ig) G y A frente al lipopolisacarido (LPS) y antigenos especificos de C. pneumoniae presentes en cuerpos elementales (CE) purificados; mediante microinmunofluorescencia la IgG anti-CE; mediante reaccion en cadena de la polimerasa semianidada, el ADN de C. pneumoniae en biopsias arteriales y leucocitos de sangre periferica; mediante enzimoinmunoanalisis el LPS, y la recuperacion de la bacteria en celulas Hep-2 desde biopsias arteriales. Resultados: Los valores obtenidos para la IgG anti-LPS en los grupos de casos y controles fueron del 21 y el 14%, respectivamente, sin diferencias significativas; tampoco la hubo para la IgA (el 22 y el 21%, respectivamente). Si se encontraron diferencias para la IgG anti-CE entre los casos (el 74 y el 72%, para el enzimoinmunoanalisis y la microinmunofluorescencia, respectivamente) y los controles (el 31 y el 34%). No hubo diferencias para la IgA anti-CE. El ADN de la bacteria se detecto en el 67% de las placas de ateroma (casos) y en el 12% de las arterias pudendas (controles) (p = 0,0001). No se detectaron ADN y LPS de C. pneumoniae en los leucocitos y biopsias arteriales, respectivamente. No se pudo recuperar la bacteria mediante cultivo en el grupo de casos. Conclusiones: Nuestros resultados asocian de manera significativa la enfermedad arterial periferica oclusiva con la infeccion por C. pneumoniae a traves de la presencia de la IgG anti-CE en suero y el ADN de la bacteria en biopsia arterial.

GB virus C in patients with liver disease of unknown etiology.

To assess the prevalence of GBV‐C in patients suffering unknown liver disease we have investigated the GBV‐C‐RNA in serum of 54 patients: 10 with acute and 32 with chronic non‐A‐E hepatitis (16 active and 16 persistent), 10 with hepatocellular carcinoma, 2 diagnosed with hepatic fulminant failure, and 91 healthy blood donors (control). PCR with primers from NS3 helicase region was performed and the product was identified by a double strand DNA enzyme immunoassay. GBV appears to infect 40 and 31% of acute or chronic non‐A‐E hepatitis respectively. Also the GBV genome was found in 1 in 10 samples of hepatocarcinoma, in 2 cases of fulminant hepatitis, and in 1 in 91 of the control group. In spite of these results the role of GBV in the etiology of liver diseases has to be analyzed in more comprehensive studies. J. Clin. Lab. Anal. 14:70–72, 2000.

Seroepidemiology of human herpesvirus 6 infection in normal children and adults in Spain

Summary We have studied the prevalence of anti-human herpesvirus 6 (HHV-6) antibodies in different population groups from Spain. Serum samples from 271 children between 0 and 15 years old, 512 intravenous drug addicts (IVDA) (262 seropositive for human immunodeficiency virus (HIV)) and 254 healthy individuals (100 pregnant women). The indirect immunofluorescence technique was used for antibody investigation from initial dilutions of 1 : 40. Seroprevalence studies showed antibody presence in 37.6%. The highest positivity was found in the group of children (49.4%, PcO.OOl), followed by the pregnant women (39%), the IVDAs (34%) and healthy subjects (28%). When the IVDA group was split into HIV positive and HIV negative, no significant difference was found between them (P= 0.45). Antibody titres oscillated between 1 : 40 and 1 : 2560, with the greatest frequency at 1 : 40 in both male and female patients. A statistically significant difference (P ~0.05) was only found between sexes in the control group.

Evaluation of two reverse transcription polymerase reaction assays (GEN ETI-K HGV RNA and LCx GBV-C assay) for the detection of GB virus C/hepatitis G virus RNA in clinical samples.

Our study evaluates the analytical performance of two amplification methods in the detection of GB Virus C/Hepatitis G Virus, GEN ETI‐K HGV RNA (GEN) and the LCx® GBV‐C Assay (LCx). GB Virus C RNA was detected by at least one test in 58/315 samples (18.41%). Fifty‐five samples (17.46%) were positive by the GEN method and 51 samples (16.19%) by the LCx method. The same rate of detection was found for 71 haemodialysis patients and 18 non‐A non‐E hepatitis. Method based differences in prevalence were observed for patient samples from the general population, 8/106 (7.55%) positive by GEN vs 7/106 (6.60%) by LCx; and HIV infected patients, 26/98 (26.53%) vs 23/98 (23.46%). For chronic type C hepatitis 10/22 (45.5%) were positive by both methods, with two samples discordant. Overall, discordance was observed for ten samples, with seven positive only by the GEN ETI‐K HGV RNA, and three positive only by the LCx GBV‐C Assay. An additional evalua‐tion of serial samples, from chronic type C hepatitis patients under interferon treatment, revealed three samples which were positive only by the GEN method. Results were 100% concordant for patients under haemodialysis and for non‐A non‐E hepatitis, 95.9% in the HIV positive group, 90.9% in the chronic type C hepatitis group, and 97.1% in the general population group. Overall, a 97.2% of con‐cordance was found between methods. Both tests have a similar diagnostic performance, though in our opinion, LCx GBV‐C Assay better suits the requirements of a clinical microbiology diagnostic laboratory.