Developing expressed sequence tags (ESTs) from polymorphic transcript-derived fragments (TDFs) in cassava (Manihot esculenta Crantz)

We applied the cDNA-AFLP (amplified fragment length polymorphism) technique to mRNA from the parents of a cassava (Manihot esculenta) genetic mapping population, and obtained more than 500 transcript-derived fragments (TDFs) that were unique in either parent. A subset of 50 TDFs were cloned and sequenced. Sequence alignment of the expressed sequence tags (ESTs) revealed mostly genes of unknown function. Six of the TDFs were mapped on to the cassava genetic map. We also demonstrated by genetic mapping of the TDFs, as RFLP (restriction fragment length polymorphism) markers, that TDFs are more polymorphic than random cDNAs. Generation of ESTs as differentially expressed sequences, in time or between different varieties, is proposed as a way of developing ESTs around specific traits for the candidate locus approach to mapping complex traits.

Antibodies to Borrelia burgdorferi in European populations

We compared the antibodies to B. burgdorferi in three different populations in order to evaluate the diagnostic reliability of Lyme borreliosis serologic analysis. The subjects included 25 patients with Lyme borreliosis (Group 1); 50 patients with diseases of unknown cause, B. burgdorferi ELISA-positive in serum and without B. burgdorferi infection (Group 2); and 1,251 individuals without Lyme borreliosis (Group 3). All samples were tested for B. burgdorferi B31 and B. afzelii antigens using ELISA. The positive results of the ELISA B. burgdorferi B31 assay were confirmed with Western blot for the same strain. In Group 3, 162 (12.9%) patients were ELISA positive for B. burgdorferi B31, while only 6 (0.6%) patients had IgG ELISA antibodies to B afzelii. Bands in WB were detected in 104 (8.4%) of the Group 3 subjects. The bands found to be most reliable for the identification of strain B. burgdorferi B31 by IgG WB were those representing the 93, 39, 34, and 23-kDa proteins. Our results show that serologic diagnosis of Lyme borreliosis is far from clearly established. To date, the only reliable criteria are clinical ones correlated with laboratory evidence.

Comparison of several ELISA tests for detecting the presence of IgG and IgM against herpes simplex viruses

Four enzyme-linked immunosorbent assays designated test 1 (ETI-HSVK-G 1/2); test 2 (ETI-HSVK-M 1/2); test 3 (ETI-HSVK-G 2), and test 4 (BioElisa HSV2 IgG) were studied to evaluate different stages of herpes simplex virus (HSV) infection. Samples (50 sera and 14 cerebrospinal fluid) were included in four groups. Group 1 consisted of samples from patients with primary HSV infections; group 2 comprised samples from patients with recurrent HSV infections; group 3 were samples nonreactive to HSV; and group 4 were samples from patients with infections by other herpes viruses (4a, chickenpox; 4b, herpes zoster; and 4c, infectious mononucleosis by Epstein-Barr virus). The percentages of agreement between tests 1 and 2 were 100 and 72.1%, respectively. The total diagnostic values of tests 1 and 2 were: 100 and 50% sensitivity, respectively; and 100 and 89% specificity, respectively. Few positive results for HSV-2 infection were found, and so, tests 3 and 4 were not evaluated. The results of tests 3 and 4 for a chickenpox patient, and a herpes zoster patient were not in agreement.

Epidemiological study of Streptococcus pneumoniae carriers in healthy primary-school children

To obtain information on the Streptococcus pneumoniae carrier state in Spanish children, 332 healthy 6-year-old children from nine primary schools in northern Spain were screened. Thirty-six percent of the children had positive cultures yielding 128 strains. Seventy-one strains belonged to 14 serogroup/serotypes, the most frequent being 19, 23, 3, 24 and 11. Fifty-seven strains were nontypeable. The identification of strains with equivocal results was confirmed at species level by means of hybridisation with a specific probe, pneumolysin-mediated agglutination and a pathogenicity test in mice. Sixty-four percent of strains showed resistance to penicillin, 22% of these also being resistant to cefotaxime. More than 40% of the strains were resistant to trimethoprim-sulfamethoxazole, tetracycline and erythromycin. Twenty percent of the erythromycin-resistant strains were susceptible to clindamycin. Two strains were resistant to rifampicin and one strain was resistant to ofloxacin. All strains were susceptible to vancomycin. Previous antibiotic administration and having siblings under the age of 2 years correlated with the carriage of pneumococcus. There was no correlation with the carriage of antibiotic-resistant strains, or a record of previous infections, previous hospital admissions or having relatives with chronic respiratory disease.

Down-regulation of the beta-chemokine receptor CCR6 in dendritic cells mediated by TNF-alpha and IL-4

Chemokines are involved in the control of dendritic cell (DC) trafficking, which is critical for the immune response. We have generated DC from human umbilical cord blood CD34+ progenitors cultured with granulocyte-macrophage colony-stimulating factor, tumor necrosis factor alpha (TNF-alpha), and stem cell factor. Using an anti-CCR6 monoclonal antibody, we observed that these cells showed maximum expression of this beta-chemokine receptor when they were immature, as determined by their relatively low expression of several DC maturation markers such as CD1a, CD11c, CD14, CD40, CD80, and CD83. Immature DC responded strongly to macrophage inflammatory protein-3alpha (MIP-3alpha), the CCR6 ligand, in migration and calcium mobilization assays. CCR6 expression decreased in parallel with the DC maturation induced by prolonged TNF-alphaq treatments. Interleukin-4 was also able to decrease CCR6 protein levels. Our findings suggest that the MIP-3alpha/CCR6 interaction plays an important role in the trafficking of immature DC to chemokine production sites such as injured or inflamed peripheral tissues, where DC undergo maturation on contact with antigens.

Regulation of plasma insulin-like growth factor-I levels in brown trout (Salmo trutta)

In this study we report that the use of a heterologous radioimmunoassay (RIA) is valid for the detection of insulin-like growth factor-I (IGF-I) levels in plasma of a variety of fish species. Parallelism between standard curves and plasma dilutions were observed and the standard curve obtained with mammalian IGF-I presented the same characteristics as that obtained with coho salmon recombinant IGF-I. The RIA was biologically validated since total plasma IGF-I values were significantly modified by different experimental conditions. Hyperinsulinemia induced either by arginine or insulin injection was accompanied by increases in IGF-I plasma levels in brown trout (Salmo trutta). In contrast, parallel decreases in insulin and IGF-I circulating levels were observed after 45 days of fasting and 20 days after a single streptozotocin injection. Administration of arginine in fasted fish led to a relative increase in insulin and IGF-I plasma concentrations, while arginine injection in fish previously treated with streptozotocin increased IGF-I levels only. The above data suggest that insulin, together with other factors, may act to increase the levels of IGF-I in plasma.

Congenital anomalies of the upper gastrointestinal tract

A wide spectrum of congenital anomalies may affect the upper gastrointestinal tract, including anomalies of the esophagus (e.g., atresia, fistulas, webs, duplications, vascular rings), stomach (e.g., congenital gastric outlet obstruction, duplications), and duodenum (e.g., atresia, annular pancreas, duplications, malrotation). The evaluation of affected patients can require multiple imaging modalities for diagnosis and surgical planning. Radiography is often diagnostic and specific and can usually provide important clues to help determine the optimal diagnostic procedure. Neonates with complete gastric or upper intestinal obstruction do not usually require further radiologic evaluation after radiography: Barium studies are usually contraindicated, and complementary procedures (e.g., ultrasound [US], computed tomography [CT]) are not usually helpful and may even delay surgery, resulting in death. Nevertheless, US has become important in the evaluation of the pediatric gastrointestinal tract and is being used in an increasing number of applications. CT and magnetic resonance imaging are unsuitable for general screening but provide superb anatomic detail and added diagnostic specificity. They are especially useful in demonstrating esophageal duplications and vascular rings as well as associated abnormalities. However, the decision to perform a given imaging examination should be considered carefully to avoid inconvenience or unnecessary radiation exposure to the patient or delays in surgical correction. Quality control programs should be in place to ensure safe, effective radiologic practice through use of up-to-date equipment and good imaging technique.

Epstein-Barr virus and oral squamous cell carcinoma in patients without HIV infection: viral detection by polymerase chain reaction

In order to test the hypothesis that Epstein-Barr virus (EBV) may be a cofactor for oral squamous cell carcinoma (OSCC) the authors evaluated tumour cells from OSCC of 108 patients without HIV infection, for the presence of EBV DNA by polymerase chain reaction. The sequences of oligonucleotides used in the amplification and hybridization included a set for the DNA polymerase region. The amplification was detected using an ELISA assay with peroxidase. EBV DNA was detected in 17.59% of the tumours. Inhibition studies showed that the ability to detect EBV DNA was not affected by the pathological material, suggesting that the negative PCR results in these samples were not caused by PCR inhibitors in the biopsy. Results revealed that 63.1% of the tumours (12 cases) were DNA positive affecting the lateral margin of the tongue, and were statistically significant (p < 0.001; chi 2). In the pool of tumours with EBV DNA only 26.3% (5 of 19 cases) were well differentiated OSCCs whereas the remaining 73.7% (14 of 19 cases) were moderately and poorly differentiated OSCCs, with a statistical significance of p = 0.08; chi 2. This study suggests a relationship between OSCC and EBV.

Cutting edge: identification of the orphan chemokine receptor GPR-9-6 as CCR9, the receptor for the chemokine TECK

Thymus-expressed chemokine (TECK) has been reported to chemoattract dendritic cells, thymocytes, and activated macrophages. Here, we show that TECK is a specific agonist for a human orphan receptor called GPR-9-6. We have determined the cDNA sequence of human GPR-9-6 and cloned the corresponding murine cDNA. Human and murine GPR-9-6 expression is very high in the thymus and low in lymph nodes and spleen. RT-PCR analysis of murine GPR-9-6 expression on murine FACS-sorted thymocyte subpopulations showed that this gene is expressed in both immature and mature T cells. Additions of human or murine TECK to HEK 293/human GPR-9-6 and HEK 293/murine GPR-9-6 transfectants provoked intracytoplasmic calcium mobilization. Human TECK also induced the in vitro migration of HEK 293/human GPR-9-6 cells. These results confirm that GPR-9-6 is a specific receptor for TECK. According to the established nomenclature system, we propose to rename GPR-9-6 as CC chemokine receptor 9 (CCR9).

Complete duplication of bladder and urethra in the coronal plane in a girl: case report and review of the literature

An unusual case of complete duplication of the bladder and urethra in the coronal plane associated with left ectopic kidney, duplication of the clitoris and a chondrolipomatous malformation in the pelvic region in a girl is reported. The accessory bladder was located posterolateral to the normal bladder and a ureteric opening into the accessory bladder was found. The malformation was initially identified by US and cystography and confirmed by cystoscopy.

[Electrophysiological characteristics of inflammatory demyelinating chronic polyneuropathy]

INTRODUCTION

The electrophysiological studies, specially nerve conduction studies (NCS) constitute one of the basic supports to obtain an early and accurate diagnosis to perform a successful treatment in the chronic inflammatory demyelinating polyneuropathy (CIDP). There is nevertheless, no definite consensus about which would be the most specific and sensitive electric variables in the illness.

OBJECTIVE

To describe the NCS findings in a group of patients with this diagnosis, in order to contribute to its electrophysiological characterization.

PATIENTS AND METHODS

We an analyzed the NCS on 37 patients diagnosed with CIDP. The NCS were done using standard techniques. These studies were assessed according to the reference values of a normative study on 90 healthy persons. We performed somatosensory evoked potentials (SSEP), visual (VEP) and brainstem auditory evoked potentials (BAEP) in 8 patients, and motor potentials (MP) by transcranial magnetic stimulation in 3.

RESULTS

The registered values are presented in media comparison tables (cases/controls). The frequency of abnormalities in latencies (L), amplitudes, conduction velocity (CV) and the presence of partial blocks is analyzed. The affectation of the evoked potentials in some patients, demonstrated subclinical concomitant demyelinization of the central nervous system.

CONCLUSIONS

The most sensitive electrophysiological parameters are the motor CV, the total duration and distal latencies, that gives these variables a confident value in the initial stages of the illness. The relative normality of conduction through the sural nerve, even in the presence of severe abnormalities of the median nerve constitutes a repetitive and specific pattern to this kind of illness.

Clinical reliability of IgG, IgA, and IgM antibodies in detecting Epstein-Barr virus at different stages of infection with a commercial nonrecombinant polyantigenic ELISA

We studied the diagnostic reliability of a modification of the Enzygnost EBV test (Behringwerke, Germany) for the detection of IgG, IgA, and IgM antibodies (Abs) in the diagnosis of Epstein-Barr virus (EBV) disease. One hundred and twenty-three serum samples were studied: 14 asymptomatic subjects without EBV infection, 48 patients with primary infection, 46 subjects with past EBV infection (11 patients with other acute infections), 8 patients without EBV infection but with other viral infection, and 7 patients with probable acute clonal stimulation of B lymphocytes caused by different microorganisms. Enzygnost EBV is based on an ELISA test with a pool of viral antigens. In our series the reliability of IgM for the diagnosis of recent primary EBV infection was: sensitivity 100%, specificity 95%, positive predictive value 90.5%, and negative predictive value 100%. The IgG detection with Enzygnost was: sensitivity 98%, specificity 100%, positive predictive value 100%, and negative predictive value 91.7%. Only two subjects had positive IgA. The Enzygnost test is an efficient method for the diagnosis of EBV infection although a few IgM false positives can occur.

Insulin, insulin-like growth factor-I (IGF-I) and glucagon: the evolution of their receptors

Insulin and glucagon, two of the most studied pancreatic hormones bind to specific membrane receptors to exert their biological actions. Insulin-like growth factors IGF-I and IGF-II are structurally related to insulin, although they are expressed ubiquitously. The biological functions of the IGFs are mediated by different transmembrane receptors, which includes the insulin, IGF-I and IGF-II receptors. The interaction of insulin, insulin related peptides and glucagon with the corresponding receptors has been studied extensively in mammals and continues to be so. At the same time, research on ectothermic animals has made enormous progress in the recent years. This paper summarizes current knowledge on insulin, IGF-I and glucagon receptors, from a comparative point of view with special attention to non-mammalian vertebrates. The review covers adult and mostly typical target tissues, and with very few exceptions, developmental aspects are not considered. Binding characteristics, tissue distribution and structure of insulin and IGF-I receptors will be considered first, because both ligands and receptors are structurally related and have overlapping functions. These sections will be followed by similar distribution of information on glucagon receptors. Readers interested in either structure or functions of insulin, IGFs and glucagon in nonmammalian vertebrates are referred to other reviews (Mommsen TP, Plisetskaya EM. Insulin in fishes and agnathans: history, structure and metabolic regulation. Rev Aquat Sci 1991;4:225-259; Mommsen TP, Plisetskaya EM. Metabolic and endocrine functions of glucagon-like peptides: evolutionary and biochemical perspectives. Fish Physiol Biochem 1993;11:429-438; Duguay SJ, Mommsen TP. Molecular aspects of pancreatic peptides. In: Sherwood NM, Hew CL, editors, Fish Physiology. vol 13. 1994:225-271; Plisetskaya EM, Mommsen TP. Glucagon and glucagon-like peptides in fishes. Int Rev Citol 1996;168:187-257.).

A new biotyping method for Streptococcus mutans with the API ZYM system

OBJECTIVE: To test a new system for the biotyping of Streptococcus mutans, based on the measurement of enzyme activity, and to investigate the relationship between biotype and in vitro susceptibility to seven clinically useful antibiotics. METHODS: In total, 160 oral isolates of S. mutans were classified into different biotypes with the APIZYM test for enzyme activity, excluding results that were positive or negative in >80% of the strains. The susceptibility of all 160 strains to amoxycillin, cefazolin, erythromycin, clindamycin, vancomycin, teicoplanin and imipenem was tested by dilution in a solid medium. Statistical analysis of susceptibility (mean minimum inhibitory concentrations (MICs)) was based on chi-squared tests. RESULTS: Eight different biotypes (1-8) were identified on the basis of three kinds of enzyme activity: valine aryl amidase, acid phosphatase and alpha-galactosidase. Biotype 5 was found to be the most common. The mean MIC values showed strains belonging to biotype 4 to be the most susceptible to amoxycillin, cefazolin and erythromycin, whereas biotype 1 was the least susceptible to teicoplanin. CONCLUSIONS: The proposed biotyping method, which is relatively fast and simple to perform, provided reproducible results, and may contribute to clinically effective treatment of S. mutans infections.

Reliability of low-avidity IgG and of IgA in the diagnosis of primary infection by rubella virus with adaptation of a commercial test

The detection of IgA and low-avidity IgG and antibodies in serum is a potentially useful marker of recent infection by a microorganism. We studied the reliability of IgG avidity and presence of IgA for the diagnosis of recent acute infection by rubella virus. Low-avidity IgG (Avy-EIA test) was determined with a modified commercial test using 8 molar urea (indirect ELISA, DiaSorin, Italy) and IgA was determined with a homemade indirect ELISA test. Twenty-five patients with recent primary infection by rubella virus (group I) and 50 healthy subjects (group II) were studied. In group I low-avidity IgG varied between 100 and 0% (67.3+/-21.8%); IgA was present in 24 patients (96%). In group II low-avidity IgG varied from 50.4 to 0% (19.8+/-16.9%). IgA was present in 2 subjects (4%). The sensitivity of the Avi-EIA and the IgA test was 92 and 96%, respectively; specificity was 100 and 96%, respectively. We conclude that both low-avidity IgG and IgA tests are helpful and reliable for the diagnosis of recent primary infection.

[Radioimmunoscintigraphy of colorectal cancer using the anti-CEA monoclonal antibody BW 431/26. Final results]

The anti-carcinoembryonic antigen (CEA) antibody, BW 431/26 (Scintimun CEA, Behringwerke, Marburg, Germany ) labeled with technetium pertechnectate (99mTc), is an intact immunoglobulin G1, monoclonal antibody that has been used to image colorectal cancer. Planar and SPECT images of chest, abdomen and pelvis were performed at 10 minutes, 4-6 and 18-24 hours after the intravenous antibody injection. 44 patients were studied and the pathological antibody concentration localization by radioimmunoimaging (RI) were correlated with surgical, clinical and other imaging modality findings to validate the RI. The RI was positive in 29 patients and negative in the other 15 patients. The CEA and CA 19.9 were elevated in the serum of some patients with primary tumors or recurrence. The HAMA were determined in all the patients before and after the RI.

Molecular cloning, functional characterization and mRNA expression analysis of the murine chemokine receptor CCR6 and its specific ligand MIP-3alpha

We have cloned the murine CCR6 receptor and its ligand, the beta-chemokine mMIP-3alpha. Calcium mobilization assays performed with mCCR6 transfectants showed significant responses upon addition of mMIP-3alpha. Murine MIP-3alpha RNA is expressed in thymus, small intestine and colon, whereas mCCR6 RNA is expressed in spleen and lymph nodes. RT-PCR analysis of FACS-sorted lymphoid and antigen presenting cell subsets showed mCCR6 expression mainly in B cells, CD8- splenic dendritic cells and CD4+ T cells. The cloning and functional characterization of the mCCR6 and mMIP-3alpha will allow the study of the role of these proteins in mouse models of inflammation and immunity.

Influence of high-carbohydrate enriched diets on plasma insulin levels and insulin and IGF-I receptors in trout

Insulin and insulin growth factor-I (IGF-I) binding to skeletal muscle semipurified receptors were assessed in rainbow trout (Oncorhynchus mykiss) fed with different enriched carbohydrate diets. The animals were fed for 2 months, either in spring, summer or autumn with a control diet (C, commercial diet containing 21% raw carbohydrates) or with two diets supplied with highly digestible carbohydrates (E1, 22% expanded wheat; and E2, 37% expanded wheat). Insulin and IGF-I receptors were semipurified by affinity chromatography (WGA-agarose). Fish fed with a carbohydrate enriched diet did not show lower growth rates than those fed with the control diet. Independently of the season, rainbow trout fed E1 and E2 presented higher insulin and glucose plasma levels as well as higher tissue glycogen reserves than fish fed C. An increase in the number of insulin receptors during the diet adaptation was observed especially in fish fed with E2. No differences in the affinity of receptors were observed. IGF-I specific binding in skeletal muscle was higher than that of insulin in all groups and in all seasons. Furthermore, IGF-I receptors showed the same tendency as insulin receptors, with increases in their number in experimentally fed fish, especially those fed with E2. Insulin and IGF-I receptors TKA increased only slightly, as a consequence of E1 and E2 diet adaptation. In conclusion, rainbow trout can be fed high-carbohydrate levels and show good rates of growth. This adaptation determines increases in circulating glucose and insulin, and muscle insulin receptors, which indicate an adaptation of the fish to higher levels of glucose supply. The response of IGF-I receptors also suggests a possible role in the regulation of metabolism.

[Clinical evaluation of a new non-radiometric automatic system for the rapid diagnosis of tuberculosis]

BACKGROUND

Tuberculosis (TB) is again a public health problem un many countries and is considered a re-emerging disease. The fastest possible diagnosis in our patients is essential for TB control programs. ESP is a non-radioactive, totally automated, continuously monitored system designed to detect mycobacteria.

METHODS

Clinical evaluation of this new system for the rapid diagnosis of tuberculosis. During 1997 a total of 1,022 clinical sputum specimens were investigated. Specimens were processed in triplicate for ESP, BACTEC 460 TB and Löwenstein-Jensen systems. The validity, isolates of Mycobacterium tuberculosis and time required for detecting M. tuberculosis by the three systems were determined.

RESULTS

The sensitivity, specificity, positive predictive and negative predictive values of the new systems were 98%, 99.8%, 98% and 99.8%, respectively. No significant differences were found between the recovery rates by the three systems. The mean time for detection was 10 days (range: 7-13 days) for specimens with positive bacilloscopy and 14 days (range: 10-28 days) for specimens with negative bacilloscopy. The difference was statistically significant between ESP and Löwenstein-Jensen, but not between ESP and BACTEC.

CONCLUSIONS

The new system proved to have an excellent sensitivity and specificity, which along with its total automation renders it a system of great clinical interest for the rapid diagnosis of TB and an alternative method for radiometric systems.

[Angina caused by subclavian-coronary steal in patients revascularized with internal mammary artery]

After coronary bypass surgery in the left internal mammary artery, occlusive atherosclerosis in the proximal subclavian artery can produce reverse flow in the mammary artery and myocardial ischemia (coronary-subclavian steal syndrome). This is a rare cause of recurrent myocardial ischemia. We present two patients with postoperative complete obstruction in the proximal subclavian artery and inverse flow in the mammary artery producing severe ischemia in the left anterior descending artery territory. Both patients were treated with subclavian-subclavian bypass, which in one patient was ineffective in producing an adequate anterograde flow in the left internal mammary artery. We review clinical management, diagnostic methods and therapeutic options used in the coronary-subclavian steal syndrome.

Insulin-family peptide-receptor interaction at the early stage of vertebrate evolution

This is an overview of our studies on insulin and insulin-like growth factor-I (IGF-I) interactions with their own and each other's receptors in the lamprey (Lampetra fluviatilis L.), an extant representative of the ancient vertebrate group of Agnathans as compared to mammal (rat). Lamprey insulin receptor shows species specificity, namely, it binds its own insulin with higher affinity than mammalian hormone. Nevertheless, and unlike mammalian insulin receptor, lamprey receptor discriminates relatively poorly between insulin and IGF-I. Autophosphorylation patterns are identical for both receptors. In contrast, IGF-I receptors in lamprey tissues are very similar to mammalian IGF-I receptors confirming known evolutionary conservatism of IGF receptor system. Presumed common evolutionary origin of insulin and IGF-I receptors and poor ability of lamprey insulin receptor to discriminate between two ligands, implies that lamprey insulin receptor is closer to putative ancestral protein that IGF-I receptor. Contrary to the common belief, ambient temperatures for lampreys (4-15 degrees C) put no constraints on either downregulation of receptors or the endocytosis of hormone-receptor complexes.

A recombinant protein-based enzyme immunoassay for IgM antibody to human cytomegalovirus

The reliability of an enzyme-linked immunosorbent assay (ELISA) which used recombinant antigen to detect human cytomegalovirus IgM was studied. Serum samples from each of 283 children aged 5 +/- 2 years were studied. In all samples the anti-IgM antibodies were investigated with the ELISA techniques Enzygnost (Behring) and ETI-Cito (Sorin) which were both based on whole viral particles, and OPUS (Behring) based on recombinant antigen. Of the samples, 254 (89.4%) were negative with all three tests. The 29 remaining samples were positive with one or two of the three techniques. The diagnostic efficacy of Enzygnost, ETI-Cito and OPUS, respectively, was for sensitivity of 50%, 66.7% and 50%, and for specificity of 100%, 95.6% and 96%, respectively. The results with each of the three ELISAs did not differ widely and their diagnostic efficacy was similar. The method based on recombinant antigen was not found to be more effective than tests based on whole viral particles.