Serodiagnosis of clinical infections caused by Mycoplasma pneumoniae in Poland in 1970-2010

The aim of the study was evaluation of the reliability of serodiagnosis of mycoplasmosis in Poland after replaced of classical assays, as complement fixation test (CFT) and immunoelectroprecipitation test (IEPT), by the ELISA method. The data were obtained from National Public Health Institute in Warsaw (NPHI), which receives quarterly reports of serologically confirmed infection from Sanitary and Epidemiological Stations through the country. Previously, from the 1970 to 1999 the serodiagnosis in Poland was performed only by uniform CFT using the same M. pneumoniae FH antigen prepared at the Mycoplasma Laboratory of NPHI. The first data of M. pneumoniae serological investigation performed by commercial ELISA, mainly Virotech, which gradually replaced the CFT, were obtained in 2000. In the studied period 1970-2010 a total of over 300 thousand patients with respiratory tract infections (85% were children below 18 years old) were tested. During these studies five epidemics of mycoplasmosis were noted in Poland before 2000. However, after introduction of ELISA for serodiagnosis this characteristic distinct difference in epidemic and endemic occurrence of M pneumoniae infections have not been seen. In our opinion it may be caused by changes in the epidemiological pattern of M. pneumoniae infections in Poland as well as, paradoxical, by the decrease of sensitivity and specificity of serological investigation performed by ELISA since 2000. First of all, for the economical reasons 98% of the patients were tested by ELISA only once, secondly, the mycoplasmosis in many laboratories was confirmed only on the basis of the presence of IgG antibodies. The results of our analysis showed also usefulness in the serodiagnosis of mycoplasmosis, mainly during the first 2 weeks of the disease, of IEPT, which detect only specific IgM antibodies to M pneumoniae antigens.     

Evaluation of the usefulness for the latex agglutination test for serodiagnosis of Mycoplasma pneumoniae infections

The usefulness of latex agglutination test prepared in our laboratory for the diagnosis of M. pneumoniae infections was assessed. A total of 628 serum samples obtained from patients with respiratory tract infections were tested by complement fixation test and by latex test, from among them 274 serum samples were additionally tested by ELISA--Ig A/--IgG/--IgM and by immunoelectroprecipitation test. The highest sensitivity and specificity was displayed by the latex test in relation to ELISA when determining mycoplasmal antibodies of IgM class (respectively 82.1% and 89.6%) and to the complement fixation test (81.0% and 89.0%). Positive latex test results in our investigations were associated only with the presence of IgM antibodies and were not dependent on the IgA and IgG antibody classes. The latex agglutination test may be used in routine serodiagnosis of mycoplasmosis under condition that the results obtained in this test will be confirmed by the complement fixation test or ELISA.     

Detection of serum antibodies against Chlamydia pneumoniae by ELISA

Abstract Chlamydia pneumoniae causes pneumonia and other respiratory infections in children, adolescents and adults. We tried to evaluate the diagnostic value of detection of serum antibodies by ELISA for C. pneumoniae infections in Japanese children. Serum IgG, IgA and IgM antibodies to C. pneumoniae were determined by the microimmunofluorescence (MIF) test. Serum IgG and IgA antibodies were also determined by ELISA test kits. Results obtained by ELISA were compared with those obtained by MIF test. IgG antibody to C. pneumoniae was detected in 135 (39.5%) by ELISA and in 125 (36.5%) by MIF out of 342 sera from Japanese infants and children without respiratory infections (aged from 2 months old to 15 years old). IgA antibody to C. pneumoniae was detected in 129 (37.7%) by ELISA and in 117 (34.2%) by MIF out of 342 sera tested. Of 342 specimens 113 were IgG-positive by ELISA and MIF (sensitivity: 90.4%, specificity: 89.9%, r = 0.853). Of 342 sera 28 had IgG antibody titers of 1:256 and none had titers 1:512 or higher by MIF. Of 28 infants and children a total of nine were less than 4 years of age. On the other hand, of 342 specimens 99 were IgA-positive by ELISA and MIF (sensitivity: 84.6%, specificity: 86.7%, r = 0.769). Of 342 sera 16 had IgA antibody titers of 1:256 or higher by MIF. Of 16 infants and children, ten were less than 4 years of age. ELISA had excellent sensitivity and specificity relative to MIF test for detection of IgC and IgA antibodies to C. pneumoniae . It was suggested that C. pneumoniae infection in Japanese infants and children under 4 years of age was not infrequent.     

Evaluation of the usefulness of the ELISA method for determining the level of enterovirus antibodies in serum and cerebrospinal fluid

The usefulness of the methods was compared: complement fixation test (CFT), neutralization test (NT) and ELISA IgG and IgM against enteroviruses for the evaluation of specific immune reaction in sera and cerebrospinal fluid (CSF) samples of patients with confirmed enterovirus infections. The criteria were established for the assessment of ELISA results in rapid diagnosis of enterovirus neuroinfections. The criteria accepted by the producer lowered the sensitivity of the method and the possibility of recognition of local synthesis of antibodies in the CNS. The use of serum negative in CFT and negative CSF as reference for the determination made possible using of that kit for rapid diagnosis of neuroinfections. The modified ELISA IgG test makes possible determination of antibodies in CSF and serum, and accepting the generally recognized criteria for local production of antibodies in the CNS the ELISA test makes possible rapid diagnosis of neuroinfections which is not possible by other methods.     

Humoral response to selected antigens of Yersinia enterocolitica and Yersinia pseudotuberculosis in the course of yersiniosis in humans. I. Occurrence of antibodies to enterobacterial common antigen (ECA)

The antibodies against the Enterobacterial Common Antigen (ECA) were detected using the ELISA in 293 serum samples collected from 185 persons suspected for yersiniosis, as well as 115 serum samples from healthy individuals (blood donors). The presence of IgA antibody in diagnostically significant titres for ECA were detected by ELISA in 3.5%, IgG in 13.0%, and IgM in 5.2% of blood donors. Statistical analysis showed that the frequency of detecting antibodies for ECA among the patients with yersiniosis was significantly higher (p < 0.05) in relation to the blood donors. Most frequently the elevated antibody levels were detected among patients with reactive arthritis (IgA 29.2%, IgG 35.4%, IgM 16.7%) while the most infrequent among patients with abdominal pain in acute phase of yersiniosis (IgA 14.9%, IgG 25.3%, IgM 19.5%). The level of antibodies for ECA, together with age increased reaching its peak, on the average, among individuals aged 41 - 60 years. In majority of the individuals studied antibodies of the IgG class reached the level much higher in relation to those of the IgA and IgM classes. The obtained results showed that the detection of antibodies to ECA may be useful in serodiagnosis of Yersinia infections.     

儿童呼吸道肺炎支原体感染的实验室诊断

目的同时用目前常用的几种诊断肺炎支原体（MP）感染的实验方法检测MP,相互比较,得出适于常规诊断MP感染的方法或组合。方法搜集我院于2006年10月至2007年5月间以呼吸道感染入院儿童病例75例,采集其咽拭子和双份血清标本,以多种方法检测有无MP感染：培养法、EIA法测抗原、PCR法测MP-DNA,ELISA法测MP特异性IgG、IgA型抗体以及捕获法ELISA测MP特异性IgM型抗体。结果上述75例儿童中,共计有12例感染MP。以此为基础,上述各方法的敏感度分别是：培养法（25％）、EIA法测抗原（8．3％）、PCR法测MP-DNA（75．0％）、ELISA法测MP特异性IgA型抗体（单份血清为0,双份血清为33．3％）、捕获法ELISA测MP特异性IgM型抗体（单份血清为66．7％,双份血清为100％）。特异度分别是：100％、96．8％、93．7％（93．7％）、98．4％（98．4％）。PCR法和捕获法ELISA测MP特异性IgM型抗体结合后敏感度和特异度分别达到100％和95．2％。结论PCR法测MP-DNA和捕获法ELISA测MP特异性IgM型抗体的组合可高效地诊断MP感染,因而可作为临床诊断MP感染的一个常规组合。     

Development and validation of ELISA for detection of antibodies to Legionella pneumophila serogroup 1, 3 and 6 in human sera

The aim of this study was to determine whether separate measurement of immunoglobulin (Ig) M and G antibodies to Legionella (L.) pneumophila serogroups (sg) 1, 3 and 6 as single antigens can facilitate an early diagnosis of Legionnaires' disease. The developed ELISA was evaluated and compared with an in-house indirect Legionella immunofluorescence antibody test (IFAT) measuring Total Ig. A total of 193 sera from 128 patients with confirmed L. pneumophila infections were used to assess the sensitivity of the developed ELISA. The sensitivity was assessed in different time-periods after onset of symptoms. It was found that the sensitivity of the test increased during the first month of infection, IgM being the most sensitive; ranging from 13% in the first week after onset of symptoms, 45% in the second week to 84% in the third week; in the fourth (and beyond) week a drop to 67% was observed. The IFAT detecting L. pneumophila sg 1-6 had a sensitivity of 11%, 27%, 80% and 59%, respectively, during these time-periods. The test with the lowest sensitivity was the IgG ELISA (0%, 21%, 36% and 52%), but by combining the IgG results with the IgM results, the overall sensitivity of the assay was improved (13%, 48%, 88% and 70%).This study confirms that detection of IgG and IgM antibodies by ELISA is an important diagnostic tool especially during the initial phase of the disease, when supported by other tests like the urinary antigen test, PCR or culture.Furthermore, we showed that the ELISA is suitable for the detection of significant changes in antibody levels in paired serum samples. It was found that the sensitivity was higher for the ELISA assays than for the IFAT. Both the in-house IgM ELISA and the IFAT had a low false positive rate, while a 14% false positive rate was found for the IgG ELISA among serum samples from patients with other infections.     

Specificity of the microimmunofluorescence assay for the serodiagnosis of Chlamydia pneumoniae infections.

Chlamydia pneumoniae infections are mostly confirmed using an indirect microimmunofluorescence test for which potential cross-reactions between antigens from different chlamydial species are not well documented. Using this assay, 928 sera (507 subjects) submitted for Chlamydia pneumoniae serology were tested for specific IgM and IgG to this bacteria using the TW-183 antigen. IgM and IgG reactivities to Chlamydia trachomatis serotypes C, D, E, and L2 and Chlamydia psittaci strain 6BC antigens were also tested. A sample was interpreted as positive only when evenly fluorescent elementary bodies were observed. Twenty-five subjects (4.9%) showed serological evidence of recent Chlamydia pneumoniae infection (IgM positive and (or) IgG seroconversion); 11 of them also showed serological evidence of recent infection with at least one other chlamydial species. Specificity was 50 and 63% for IgM and IgG detection, respectively. These results suggest that mixed or temporally related infections might occur, or, more likely, that some Chlamydia pneumoniae IgM or IgG reactivities might be due to heterotypic antibodies.     

Serum immunoglobulin in Mycoplasma pneumoniae infection

The dynamics and nature of serum antibodies in experimental and natural M. pneumoniae infection have been studied. The synthesis of specific IgM, IgA and IgG has been found to occur in the course of infection. During repeated M. pneumoniae infection in guinea pigs, as well as in cases of acute and chronic mycoplasmal pneumonia in humans (at the acute period of the disease), the prevalence of the synthesis of specific IgM is observed. At the acute period of the disease a rise in the quantitative levels of IgM and IgG occurs in patients. High titers of specific IgM (1:32 and greater) determined at the acute period of the disease can serve as the diagnostic criterion of the mycoplasmal etiology of pneumonia.     

Multicenter evaluation of the novel enzyme immunoassay based on P1-enriched protein for the detection of Mycoplasma pneumoniae infection

The aim of the study was to evaluate new Mycoplasma pneumoniae IgG, IgA and IgM EIA methods based on the enrichment of P1-protein (ThermoLabsystems, Helsinki, Finland) (L) for the detection of acute infection. This evaluation was performed in two independent routine clinical microbiology laboratories. The first laboratory used samples preselected by IgG and IgM Platelia enzyme immunoassay (P) and the second used samples preseleced by Serion ELISA Classic M. pneumoniae IgG, IgM (V). The L method was also compared to the FDA approved method of ImmunoWell M. pneumoniae IgG and IgM (G). When the agreement of two methods was applied as a serologic criteria for an acute infection, the following ratios of acute to nonacute infection were calculated 32/86 (totally 118) in the first and 20/72 (totally 92) in the second laboratory. In the first laboratory, the corresponding ratios by methods were 35/83 (sensitivity 100%, specificity 96.5%), 31/87 (sensitivity 97%, specificity 100%), and 55/63 (sensitivity 100%, specificity 79%) for the L, P and G methods, respectively. In the second laboratory, the ratios were 21/71 (sensitivity 100%, specificity 99%), 16/76 (sensitivity 83%, specificity 100%), and 53/39 (sensitivity 100, specificity 69%) for the L, V and G methods, respectively. Taking into account that the tested sample material was preselected by the P and V methods, which may have introduced some bias in their favor, the newly developed L method utilizing P1-enriched protein was found reliable for serodiagnosis of acute M. pneumoniae infection. The method G was the least specific in detection of acute infection.     

Reliability of the cut-off value in the routine serodiagnosis of pertussis performed by the commercial ELISA assays

In clinical practise, serodiagnosis of pertussis is mostly based on single-sample serology using a single cut-off. The reliability of the cut-off value has the crucial influence for the sensitivity and specificity of the used tests. In this context we compared the value of cut-off used in two commercial ELISA kits (NovaLisa Bordetella pertussis-NovaTec and ELISA Bordetella pertussis ELISA-Virotech) with cut-off settled by calculation the IgA and IgG results from the 60 healthy Polish children and 100 blood donors (arithmetic mean plus 2 or 3 standard deviations). Our study indicates that IgA cutoff used in NovaTec ELISA, in contrary to Virotech ELISA, correspond better to the level x+3SD calculated in children sera and x+2SD calculated in adult blood donors sera. The value of IgG cut-off used in Virotech ELISA was lower about 20% and 30% from the cut-off settled by us respectively on the level ofx+2SD and x+3SD in all tested sera. The most inadequate value had the IgG cut-offused in NovaTec ELISA, which was over three times lower than mean cut-off value settled by calculation results from the sera obtained from healthy children and blood donors. This low cut-off value established by the NovaTec was the reason that 23.3% of healthy children and 55.0% of blood donors have the IgG antibodies on the diagnostic significant level. Our data suggest that commercial ELISAs need further improvement and standardization.     

Cross-reactive antibodies to mycoplasmas found in human sera by the enzyme-linked immunosorbent assay (ELISA)

Antibodies against Mycoplasma pneumoniae in patients' sera with M. pneumoniae infection were measured by the complement fixation (CF) test and enzyme-linked immunosorbent assay (ELISA). Many patients' sera cross-reacted with heterologous mycoplasmal ELISA antigens such as M. hominis, M. hyorhinis, M. orale, M. pulmonis and M. salivarium. The sera with high CF (CF greater than or equal to 40) titers gave significantly higher ELISA values to M. hyorhinis (P less than 0.001) and M. pulmonis (P less than 0.001), which are not parasitic for humans, than those with low CF (CF less than 20) titer. Human normal immunoglobulin G (human normal IgG) containing 98% or more IgG, prepared from pooled plasma of at least 500 normal human donors, showed ELISA reactions with all mycoplasmal strains used. The nonspecific adsorption of human normal IgG on the surface of plate wells and on medium components which might contaminate mycoplasmal ELISA antigens could be disregarded. These results suggest that cross-reactive antibodies to mycoplasmas exist in human sera, and they affect the results of ELISA for serodiagnosis of M. pneumoniae infection.     

Diagnostic significance of influenza subtype-specific IgG, IgA, and IgM antibodies

Up to now, the complement fixation test (CFT) has been the basis for the serological diagnosis of influenza virus infection in routine laboratories. Generally, low CF titers (1:20 or 1:40) are difficult to interpret. This means that the differentiation between recent and remote influenza infections is not possible by CFTs on single sera. Nonetheless this is generally possible by the subtype- and immunoglobulin class-specific immunofluorescence test (IFT) reported in this paper. Sera from 76 patients with confirmed influenza infection were tested and we obtained the following results: only 27.6% contained antibodies of all immunoglobulin classes, 51% contained IgG and IgA antibodies (without IgM) and 3.9% responded only with the IgG isotype. The IFT-positive and CFT-negative were 5.2% and the IFT-negative and CFT-positive 4%. In 7.9% no antibody rises were detected by CFT or by IFT despite virus isolation. Results from IFT may permit the interpretation of low CF titers. In contrast to CFT, IFT makes possible the differentiation between vaccinated and unvaccinated persons because vaccinated persons regularly produce IgM antibodies against all strains of the vaccine.     

侵袭性真菌深部感染的早期实验室诊断

目的探讨假丝酵母菌甘露聚糖抗原和假丝酵母菌IgG/IgM抗体、曲霉半乳甘露聚糖抗原和烟曲霉IgG抗体在侵袭性真菌病早期临床诊断中的应用价值。方法收集已确诊侵袭性假丝酵母菌病患者18例,侵袭性烟曲霉病患者6例,单纯细菌感染患者20例,浅部真菌感染患者20例,健康体检者(正常对照组)20例,通过酶联免疫吸附法(ELISA)检测患者血清甘露聚糖和假丝酵母菌IgG/IgM抗体以及曲霉半乳甘露聚糖抗原和烟曲霉IgG抗体浓度,计算各指标的灵敏度、特异度、阳性预测值、阴性预测值和受试者工作特征(ROC)曲线下面积。结果甘露聚糖抗原和假丝酵母菌IgG/IgM抗体联合测定的敏感度为66.7%,特异度为83.3%,阴性预测值为100.0%,阳性预测值为85.7%,ROC曲线下面积为0.992(95%CI:0.974~1.000);半乳甘露聚糖抗原和烟曲霉IgG抗体联合测定的敏感度为66.7%,特异度为95.0%,阴性预测值为98.2%,阳性预测值为100.0%,ROC曲线下面积为0.978(95%CI:0.934~1.000)。结论甘露聚糖抗原和假丝酵母菌IgG/IgM抗体、半乳甘露聚糖抗原和烟曲霉IgG抗体联合检测对深部真菌感染的早期诊断具有重要意义。     

Immunodiagnosis of Dengue Virus Infection Using Saliva

Keeping in view the complications and the case fatality associated with dengue virus, several serologic tests have been developed. However, the major drawback of these serologic tests is the need for a venous blood sample obtained by invasive venipuncture. As a noninvasive alternative, saliva provides a body fluid that contains antibodies of diagnostic importance. Hence, the detection of DEN-specific IgM and IgG antibodies in serum and saliva from 80 patients was compared. Salivary IgM antibodies were detected in 100% of the serum IgM-positive samples and in 30% of the serum samples that were negative for IgM antibodies. Salivary IgG antibodies were detected in 93.3% of the serum samples that were positive for anti-dengue IgG antibodies and in none of the serum IgG-negative cases. None of the specimens from the healthy controls showed the presence of IgM or IgG antibodies. The detection of both IgG and IgM antibodies in saliva correlated well with the serum IgG and IgM detection by the ELISA test (r = 0.6322 and r = 0.4227). Detection of salivary IgM antibodies by ELISA showed 100% sensitivity, 70% specificity, 90.9% positive predictive value, and 100% negative predictive value. The detection of IgG in saliva proved to be a promising tool as the sensitivity, specificity, positive predictive value, and negative predictive value were found out to be 93.3%, 100%, 100%, and 83.3%, respectively. Thus, from this study we conclude that the detection of DEN-specific salivary IgG and IgM antibodies are useful markers for dengue infection.     

肺炎支原体IgG类抗体亲和力检测的实验研究与临床应用

目的探讨肺炎支原体IgG类抗体亲和力检测在肺炎支原体感染诊断中的意义。方法用被动颗粒凝集试验(PPA)和间接免疫荧光法(IFA)检测儿童上呼吸道感染者血清IgM类抗体水平,同时用IFA法检测其IgG类抗体的亲和力,并对检测结果进行相关性分析和一致性检验。结果在IgM类抗体检测上PPA法检出阳性率(60/120)高于IFA法(49/120),两法检测结果缺乏一致性。而IFA法检测IgG类抗体阳性的97例中,有22例检出低亲和力IgG类抗体,其中20例同时检出IgM类抗体,两法检测结果具有显著的相关性(P<0.001)和较好的一致性(0.7>Kappa>0.4)。结论肺炎支原体低亲和力IgG类抗体检测有与IgM类抗体检测类似的早期诊断价值,可与IgM类抗体联合检测用于区分近期感染、感染后复发或再次感染。     

Comparative study of cell-immunoenzymatic methods for the estimation of IgG and IgM anti-Brucella antibodies in the diagnosis of human brucellosis

Two methods which employ whole cells are described and compared for the detection of human IgG and IgM anti-brucella antibodies. Dot ELISA and ELISA were shown to be suitable for a screening diagnosis of human brucellosis. Titres of antibodies obtained by dot ELISA showed 100% coincidence for IgG and 97% for IgM, compared with agglutination and complement fixation tests; when ELISA was used 11% positive sera were not detected. The comparison of these two methods with the conventional serological test kit indicated that both dot ELISA and ELISA were sensitive, reproducible and specific for the quantification of IgG and IgM antibrucella antibodies.     

Assay of IgA to Shigella flexneri during shigellosis

Abstract An enzyme-linked immunosorbent assay (ELISA) to Shigella flexneri 2a whole bacterium was used to determine IgM, IgG and IgA serum titers in 50 acute-phase shigellosis patients and 37 controls, i.e., hospital patients without known recent infections. Compared to controls, the shigellosis patients displayed statistically raised average serum titers to S. flexneri in all 3 above immunoglobulin classes, most notably IgA, which displayed an average 42-fold increase. Specific IgM and IgG were 5- and 16-fold higher, respectively. All sera displayed statistically raised titers in at least one immunoglobulin class. A Widal agglutination detected a 7-fold increase in serum titers; this was comparable to the IgM ELISA. Statistical analysis showed that the intra-assay error of the ELISA varied from 5 to 14%, depending on the absorbance from which titers were calculated. A second ELISA was performed on the above shigellosis sera to determine titers to purified lipopolysaccharide (LPS): a statistical correlation was found between these and the above values for all 3 immunoglobulin classes. We conclude that the use of S. flexneri whole bacterium as an antigen in an IgA ELISA is a statistically valid and convenient parameter for monitoring shigellosis, comparable to the use of LPS as antigen, and more sensitive than IgM or IgG ELISAs or agglutinations.     

Comparison of diagnostic performances of ten different immunoassays detecting anti-CCHFV IgM and IgG antibodies from acute to subsided phases of Crimean-Congo hemorrhagic fever

Crimean-Congo Hemorrhagic Fever Virus (CCHFV) is a geographically widespread tick-borne arbovirus that has been recognized by the WHO as an emerging pathogen needing urgent attention to ensure preparedness for potential outbreaks. Therefore, availability of accurate diagnostic tools for identification of acute cases is necessary.A panel comprising 121 sequential serum samples collected during acute, convalescent and subsided phase of PCR-proven CCHFV infection from 16 Kosovar patients was used to assess sensitivity. Serum samples from 60 healthy Kosovar blood donors were used to assess specificity. All samples were tested with two IgM/IgG immunofluorescence assays (IFA) from BNITM, the CCHFV Mosaic 2 IgG and IgM indirect immunofluorescence tests (IIFT) from EUROIMMUN, two BlackBox ELISAs for the detection of CCHFV-specific IgM and IgG antibodies (BNITM), two Anti-CCHFV ELISAs IgM and IgG from EUROIMMUN using recombinant structural proteins of CCHFV antigens, and two ELISAs from Vector-Best (IgM: μ-capture ELISA, IgG: indirect ELISA using immobilized CCHFV antigen). Diagnostic performances were compared between methods using sensitivity, specificity, concordance and degree of agreement with particular focus on the phase of the infection.In early and convalescent phases of infection, the sensitivities for detecting specific IgG antibodies differed for the ELISA test. The BlackBox IgG ELISA yielded the highest, followed by the EUROIMMUN IgG ELISA and finally the VectorBest IgG ELISA with the lowest sensitivities. In the subsided phase, the VectorBest IgM ELISA detected a high rate of samples that were positive for anti-CCHFV IgM antibodies. Both test systems based on immunofluorescence showed an identical sensitivity for detection of anti-CCHFV IgM antibodies in acute and convalescent phases of infection.Available serological test systems detect anti-CCHFV IgM and IgG antibodies accurately, but their diagnostic performances vary with respect to the phase of the infection.     

Application of released proteins (RPs) of Yersinia Enterocolitica for serological diagnosis of yersiniosis. I. Antigen for ELISA

The usefulness of the released proteins (RPs) prepared in our laboratory from the strain Y. enterocolitica for the serological diagnosis of yersiniosis was estimated. Yersinia enterocolitica 0:8 was cultured under calcium deficient conditions and the virulence factors were isolated from the culture supernatant. The purified proteins were solubilized using sodium dodecyl sulfate. The results of ELISA using released proteins obtained in our laboratory as the antigen were compared to the results of commercial ELISA-Mikrogen and ELISA-Euroimmun. One hundred serum samples obtained from patients suspected in clinical investigations for jersiniosis were tested. Comparison of the frequency of detecting in particular ELISA antibodies to Yersinia showed a high (> 85%) agreement of the results in all of the immunoglobulin classes. The highest sensitivity (97.4%) and specificity (95.4%) was displayed by the ELISA with our antigen in relation to the ELISA-Mikrogen when determining antibodies of IgM class.