Non-Polio Enteroviruses Isolated by Acute Flaccid Paralysis Surveillance Laboratories in the Russian Federation in 1998-2021: Distinct Epidemiological Features of Types

More than 100 types of non-polio enteroviruses (NPEVs) are ubiquitous in the human population and cause a variety of symptoms ranging from very mild to meningitis and acute flaccid paralysis (AFP). Much of the information regarding diverse pathogenic properties of NPEVs comes from the surveillance of poliovirus, which also yields NPEV. The analysis of 265 NPEV isolations from 10,433 AFP cases over 24 years of surveillance and more than 2500 NPEV findings in patients without severe neurological lesions suggests that types EV-A71, E13, and E25 were significantly associated with AFP. EV-A71 was also significantly more common among AFP patients who had fever at the onset and residual paralysis compared to all AFP cases. In addition, a significant disparity was noticed between types that were common in humans (CV-A2, CVA9, EV-A71, E9, and E30) or in sewage (CVA7, E3, E7, E11, E12, and E19). Therefore, there is significant evidence of non-polio viruses being implicated in severe neurological lesions, but further multicenter studies using uniform methodology are needed for a definitive conclusion.

Dynamics of Soluble Forms of the Immune Checkpoint Components PD-1/PD-L1/B7-H3, CD314/ULBP1, and HLA-G in Peripheral Blood of Melanoma Patients Receiving Blockers of Programmed Cell Death Protein PD-1

The content of the soluble forms of immune checkpoint components sPD-1, sPD-L1 in blood serum, and sB7-H3, sCD314, sULBP1, sHLA-G in blood plasma of 30 melanoma patients receiving immunotherapy with anti-PD-1 antibodies (nivolumab, pembrolisumab) was measured before and in 4 and 8 weeks after the start of immunotherapy. The control group comprised 70 practically healthy donors. Standard immunoassay kits were used. In melanoma patients, the levels of sPD-L1 and sB7-H3 were significantly higher than in the control group (p<0001), sPD-1 level did not differ from the control, while sCD314 and sHLA-G levels were insignificantly decreased. During therapy, opposite changes in the levels of markers in individual patients were observed, and frequently after the initial increase (or decrease) after the first 4 weeks normalization did occur in the further 4 weeks. No statistically significant associations between the initial levels of markers and direction of their changes during treatment were found, but some trends indicating to the potential benefits from assessment of soluble forms of immune checkpoint proteins for evaluation and monitoring of the efficiency of the therapy with immune checkpoint blockers were revealed: significant decrease of sB7-H3 and sPD-1 levels in the course of treatment, higher initial sPD-1 level in patients with future progression than in those with stabilization or partial effect, and lower progression frequency in patients with increasing sPD-1 and sPD-L1 levels than in those with decreasing markers levels.

Soluble forms of PD-1/PD-L immune checkpoint receptor and ligand in blood serum of breast cancer patients: association with clinical pathologic factors and molecular type of the tumor

Results of enzyme-linked immunosorbent assay of the soluble forms of PD-1/PD-L immune checkpoint receptor and ligand (sPD-1 and sPD-L1) in pretreatment blood serum of 88 breast cancer patients at various disease stages aged 30-83 years are presented. The control group included 55 practically healthy women aged 19-82 years. Serum sPD-1 and sPD-L1 levels in breast cancer patients highly significantly (p<0.0001) differ from control and these changes are opposite: soluble receptor level is more than 6-fold decreased, while soluble ligand concentration - 5.5 fold increased. Both markers separately, as well as their ratio demonstrate very high sensitivity (94-100%) and specificity (95-100%) in relation to healthy control. No statistically significant associations of sPD-1 and sPD-L1 levels with clinical stage, individual TNM system criteria, tumor histological structure, grade, receptor status, and molecular type were established. In particular, no significant peculiarities of the markers' levels in triple negative breast cancer successfully treated with anti-PD-1/PD-L1 preparations were revealed. Long-term follow-up and dynamic studies of sPD-1 and sPD-L1serum levels in the course of treatment are required for evaluation of their independent from clinical and morphological factors prognostic significance and the possibility of application as low invasive tests for prediction and monitoring of corresponding targeted therapy efficiency.

Prognostic significance of VEGF signaling system components and matrix metalloproteinases in blood serum of gastric cancer patients

Analysis of long-term treatment results of 77 primary gastric cancer patients at stage I-IV of the tumor process followed during 1 - 41 months (median - 6.4 months) from the onset of specific treatment are presented depending on the basal levels of VEGF, soluble forms of its receptors (sVEGFR1, sVEGFR2) and matrix metalloproteinases (MMP-2, 7, 9) in blood serum. Overall survival assessed by Kaplan-Meyer analysis and with the help of Cox multiparametric regression model was applied as the criterion of prognostic value. It was found that at high (≥ 420 pg/ml) serum VEGF, the overall survival of patients with gastric cancer was statistically significantly lower than at the marker's levels below 420 pg/ml (p<0.011): 3-year's survival comprised 46,3±12,5% and 88,2±7,8% respectively. Median survival of patients with high VEGF level comprised 21.7 months, of those with low VEGF was not achieved during the whole follow-up period. Serum sVEGFR1, sVEGFR2, MMP-2, 7 and 9 levels were not significantly associated with the overall survival of patients included in this study. Only index M of TNM system and serum VEGF level demonstrated an independent prognostic value in multiparametric model (p=0.036). Thus, it was confirmed that VEGF signaling pathway plays an important role in gastric cancer, and its components - in the first place, VEGF A - are substantial factors of disease prognosis, and can also be useful for monitoring of treatment efficiency.

Soluble B7-H3 in Ovarian Cancer and Its Predictive Value

The content of the soluble form of protein of the key point of immunity B7-H3 (sB7-H3) in the blood plasma of 75 patients with epithelial ovarian cancer before treatment was measured by ELISA. It is known that B7-H3 belongs to the immunoglobulin superfamily (B7 molecule family) and is involved in the regulation of the immune response mediated by T cells. The sB7-H3 concentration correlated with the clinical and morphological parameters of ovarian cancer. The content of sB7-H3 was higher at the later stages of the disease, in the presence of ascites, and in patients with poorly differentiated ovarian cancer. It was revealed that increased plasma content of sB7-H3 in patients with epithelial ovarian cancer is associated with unfavorable prognosis of the disease. Therefore, sB7-H3 can be used as a prognostic marker in ovarian cancer patients.

Clinical and prognostic significance of the soluble form of the VISTA immunity control point in patients with primary bone tumors

The data of a comparative enzyme-linked immunosorbent assay of the content of the soluble form of the immunity checkpoint VISTA in the blood serum of 30 healthy donors (control group), 79 patients with primary malignant (osteosarcoma - 30, chondrosarcoma - 31, chordoma - 14) and 14 borderline (giant cell tumor) bone neoplasms are presented. In the general group of patients with malignant neoplasms of bones, the median sVISTA content in blood serum is statistically significant lower than in the control (p = 0.040). In patients with bone tumors and healthy donors over 18 years of age, there was a decrease with age in serum sVISTA levels. There were no significant differences in sVISTA concentration between patients with osteosarcoma, chondrosarcoma and healthy donors. Only in patients with chordoma were sVISTA levels statistically significant lower than in controls (p = 0.013). In the groups of patients with chondrosarcoma and osteosarcoma of the bone, there were no significant associations between the serum sVISTA content and the main clinical and morphological characteristics of the disease. In patients with osteosarcoma, no relationship was found between sVISTA levels and overall survival rates, while in patients with bone chondrosarcoma, there was a tendency towards a favorable prognosis with a high content of the marker in the blood serum.

Vascular Endothelial Growth Factor and Soluble Forms of Its Receptors 1 and 2 in Gastric Cancer

Comparative evaluation of blood content of VEGF, sVEGFR1, and sVEGFR2 in 104 primary gastric cancer patients and 65 healthy persons was performed and associations of these markers with the principal clinical and morphological characteristics of gastric cancer were analyzed. The median levels of VEGF and sVEGFR1 in gastric cancer patients significantly surpassed the control: by 1.5 (p<0.001) and 1.2 times (p<0.01), respectively. On the contrary, sVEGFR2 level in patients was below the control (p<0.001). The best sensitivity-specificity ratio (64 and 65%, respectively) was observed for VEGF at 347 pg/ml cut-off value, which is insufficient for the use of this parameter as a clinically valuable serological marker for gastric cancer. No significant associations of these markers with the disease stage, depth of primary tumor invasion, its histological type, grade, or localization were found. The serum level of VEGF in patients with metastases to more than 7 regional lymph nodes (N3) was significantly higher than in patients without lymph node metastases (N0). Blood content of sVEGFR1 in patients with distant metastases (М+) was lower than in patients without distant metastases (М0). Thus, VEGF and its receptors circulating in the peripheral blood do not play significant diagnostic role in gastric cancer, but could be useful in monitoring and prognosis of the efficiency of antiangiogenic therapy.

Immunosuppression Factors PD-1, PD-L1, and IDO1 and Colorectal Cancer

Due to the low efficiency of immunotherapy for colorectal cancer (CRC), it is extremely promising and relevant to study the mechanisms of immunosuppression. In this work, a comprehensive study of the expression of soluble and tissue forms of PD-1 and PD-L1 in blood serum and tumors of patients with CRC, as well as IDO1 in tumors was performed for the first time. The diagnostic and prognostic significance of the studied parameters was determined. A statistically significant decrease in the number of soluble forms of PD-1 and PD-L1 in the blood serum and the association of the number of PD-L1+ cells in the stroma of tumors with the CRC stage were established. The absence of correlations between soluble and tissue forms of the studied proteins was shown, indicating the presence of independent mechanisms of immunosuppression in CRC, which may explain the ineffectiveness of immunotherapy for this type of tumor.

Prognostic significance of soluble forms of immune checkpoint PD-1/PDL1 receptor and ligand in blood plasma of gastric cancer patients

Analysis of long-term treatment results of 101 primary gastric cancer patients at various stages of the tumor process followed during 1 - 41 months (median - 6,4 months) from the onset of specific treatment are presented depending on the levels of soluble forms (s) of PD-1 receptor and its ligand PD-L1 in blood plasma. Overall survival assessed by Kaplan-Meyer analysis and with the help of Cox multiparametric regression model was applied as the criterion of prognostic value. It was found that at high (≥ 35 pg/ml) sPD-L1 levels in blood plasma, the overall survival of patients with gastric cancer was statistically significantly lower than at the marker's levels below 35 pg / ml (p <0.045): 1-year survival comprised 78 and 96%, 2-year - 52 and 78%; 3-year - 40 and 61% at high and low sPD-L1 respectively. Median survival of patients with high plasma sPD-L1 comprised 29 months, of those with low sPD-L1 was not achieved during the whole follow-up period. This trend was observed not only in the total group of stage I-IV gastric cancer patients, but also in patients at the early stages of the disease, though sPD-L1 did not show an independent prognostic value in multiparametric model. At the same time, the overall survival of patients with gastric cancer did not depend on the baseline levels sPD-1 in blood plasma. Thus, soluble ligand sPD-L1 can be considered as a potentially valuable factor for prognosis of gastric cancer patients' survival, and, probably, of anti-PD-1/PD-L1 treatment efficiency, but further studies and patients' monitoring are required to prove this statement.

Soluble forms of immune checkpoints in ovarian cancer

The data of a complex immunoassay comparative study of the content of soluble forms of sPD-1, sPD-L1, sNKG2D, sNKG2DL1, sB7-H3 and sHLA-G in the blood plasma of 75 patients with epithelial ovarian cancer and 20 healthy donors of the control group are presented. The diagnostic significance of the studied proteins was determined. The study showed that the profile of soluble immunity checkpoints differs when malignant ovarian pathology occurs. There was a statistically significant decrease in the content of sPD-L1, sNKG2DL1, sB7-H3, and sHLA-G in the blood plasma of patients compared with the control group. Differences were found in the content of the studied markers depending on the histological type of tumors. Correlations between the soluble forms of some of the studied proteins are shown, indicating the presence of independent mechanisms of immune regulation in ovarian cancer, which may explain the insufficient effectiveness of the existing immunotherapy for this type of tumor. The results obtained will undoubtedly facilitate the development of new effective methods for the diagnostics and therapy of ovarian cancer.

Comparative analysis of the levels of soluble forms of receptor and ligand of the immunity control point PD-1/PD-L1 in the blood serum of patients with typical bone osteosarcoma and chondrosarcoma

Results of ELISA investigation of the pretreatment sPD-1 and sPD-L1 content in blood serum of 133 bone neoplasms patients aged 6-70 years and 57 practically healthy control persons aged 12-70 years are described. In 14 patients the neoplasms were of a benign character, in 16 - borderline giant-cell bone tumor was diagnosed, and in 103 - malignant bone lesions including 39 osteosarcomas and 42 chondrosarcomas were revealed. The sPD-1 receptor concentrations in blood serum did not differ between control healthy persons and primary bone tumor patients, while serum sPD-L1 level in bone tumor patients was statistically significantly increased (p<0.0000001). By means of ROC curve construction a cut-off sPD-L1 level of 16.5 pg/ml was found that imposed 75,9% sensitivity and 75,4% specificity in relation to healthy control. However, the frequency of sPD-L1 levels exceeding 16.5 pg/ml was approximately similar in benign, borderline and malignant bone tumor patients. Analysis of the pattern of sPD-1 and sPD-L1 circulation in the peripheral blood of patients with the most prevalent malignant bone tumors - osteosarcoma and chondrosarcoma - demonstrated that in both sarcoma types sPD-L1 level was significantly higher than in control, but in patients with chondrogenic tumors the soluble ligand sPD-L1 dominates in the circulation, while in those with osteogenic tumors - sPD-1 receptor prevails. In particular, sPD-1 level is statistically significantly higher in patients with typical osteosarcoma than in those with typical chondrosarcoma (p=0.002437), and sPD-L1/sPD-1 concentration ratio in chondrosarcoma is highly significantly more than 2-fold higher than in osteosarcoma (0.81 and 0.35 respectively; p=0.000284). The sensitivity of sPD-L1 ≥16.5 pg/ml test in typical osteosarcoma patients' group comprised only 70.2%, and in those with typical chondrosarcoma - 84.6%. Serum sPD-1 and sPD-L1 concentrations in osteosarcoma and chondrosarcoma patients were not associated with the indices of tumor advancement, its histological grade, localization in the osseous system, and type of affected bone. Thus, it can be concluded that the ratio between circulating soluble forms of the receptor and the ligand of PD-1/PD-L signaling pathway differs between patients with chondrogenic and those with osteogenic tumors, sPD-L1 being diagnostically valuable mostly for chondrogenic bone neoplasms.

[Novel miRNAs as Potential Regulators of PD-1/PD-L1 Immune Checkpoint, and Prognostic Value of MIR9-1 and MIR124-2 Methylation in Ovarian Cancer]

Ovarian cancer (OC) is mostly detected at late stages weighed down with metastasis, and the five-year survival rate of patients is only 30%, which dictates the necessity to develop gentler and more selectively targeted drugs that current chemotherapeutic agents. The search for factors that can influence on the activity of the PD-1/PD-L1 immune checkpoint signaling pathway in tumors is relevant, and micro RNAs (miRNAs) play an important role in it. Over the past 5 years, only a few miRNAs (miR-34a, miR-145, and miR-424), which have a regulatory effect on the PD-1/PD-L1 system in OC patients, have been discovered. In present work, the methylation levels of 13 miRNA genes in 26 primary tumors and 19 peritoneal metastases of OC patients were determined and compared with the level of the soluble form of PD-L1 (sPD-L1) in the blood plasma of the same patients. It was shown that the methylation levels of five miRNA genes (MIR124-2, MIR34B/C, MIR9-1, MIR9-3, and MIR339) in tumors are in direct correlation with the sPD-L1 level in the blood plasma. In addition, when analyzing these five genes, a significant association of the methylation level of the MIR9-1 gene with a decrease in the three-year relapse-free survival, and a trend for decrease in the three-year survival rate with the methylation level of the MIR124-2 gene of OC patients were determined. Thus, the first data suggesting the role of inhibitors of the sPD-L1 immune checkpoint for five miRNAs (miR-124, miR-34b, miR-34c, miR-9, miR-339) and the possibility of using hypermethylated MIR9-1 and, presumably, MIR124-2 genes as independent prognostic markers of poor disease-free survival in OC patients were obtained.

[The content of the soluble forms PD-1 and PD-L1 in blood serum of patients with gastric cancer and their relationship with clinical and morphological characteristics of the disease.]

Results of comparative ELISA investigation of pretreatment sPD-1 and sPD-L1 content in blood plasma of 100 gastric cancer patients at various disease stages aged 25 to 81 years are presented. Control group included 60 practically healthy donors aged 18 - 68 years. Plasma sPD-L1 concentrations did not differ between gastric cancer patients and control group, and sPD-1 levels were statistically significantly lower in patients than in healthy donors (p<0.0001). Positive correlation (R=0.38; p=0.003) was revealed between plasma sPD-1 и sPD-L1 levels in control group and negative (R= -0.26; p=0,009) - in gastric cancer patients. ROC curve revealed the best sPD-1 cut-off level (< 21 pg/ml) with 77% sensitivity and 63.3% specificity, which is not sufficient for its application as diagnostic marker. Statistically significant increase of plasma sPD-L1 from stage I to stage IIIC (R=0.50; p=0.000011) was found. Analysis of associations between the evaluated markers' levels and indices of gastric cancer expansion according to TNM system revealed statistically significant positive associations of plasma sPD -L1 levels with T (tumor invasiondepth) and N (number of affected lymph nodes) indices: R=0.33; p=0.00093, and R=0.27; p=0.0099 respectively. sPD-L1 level was significantly increased in patients with low differentiated adenocarcinoma and cricoid-cell cancer as compared to highly differentiated adenocarcinoma (p=0.02 and p=0.004 respectively); in patients with cricoid-cell cancer it was also higher than in those with moderately differentiated adenocarcinoma (p=0.043) and undifferentiated cancer (p=0.049). Plasma sPD-1 level did not depend on disease stage, TNM system indices and tumor histological structure. Thus, soluble ligand sPD-L1, but not its receptor sPD-1, plasma level is increased in patients with unfavorable clinical and morphological characteristics, may be regarded as potentially valuable prognostic factor for gastric cancer patients' survival, and probably as a predictor of anti - PD-1/PD-L1 treatment efficiency.

Case of Poliomyelitis Caused by Significantly Diverged Derivative of the Poliovirus Type 3 Vaccine Sabin Strain Circulating in the Orphanage

Significantly divergent polioviruses (VDPV) derived from the oral poliovirus vaccine (OPV) from Sabin strains, like wild polioviruses, are capable of prolonged transmission and neuropathology. This is mainly shown for VDPV type 2. Here we describe a molecular-epidemiological investigation of a case of VDPV type 3 circulation leading to paralytic poliomyelitis in a child in an orphanage, where OPV has not been used. Samples of feces and blood serum from the patient and 52 contacts from the same orphanage were collected twice and investigated. The complete genome sequencing was performed for five polioviruses isolated from the patient and three contact children. The level of divergence of the genomes of the isolates corresponded to approximately 9–10 months of evolution. The presence of 61 common substitutions in all isolates indicated a common intermediate progenitor. The possibility of VDPV3 transmission from the excretor to susceptible recipients (unvaccinated against polio or vaccinated with inactivated poliovirus vaccine, IPV) with subsequent circulation in a closed children’s group was demonstrated. The study of the blood sera of orphanage residents at least twice vaccinated with IPV revealed the absence of neutralizing antibodies against at least two poliovirus serotypes in almost 20% of children. Therefore, a complete rejection of OPV vaccination can lead to a critical decrease in collective immunity level. The development of new poliovirus vaccines that create mucosal immunity for the adequate replacement of OPV from Sabin strains is necessary.

Vaccine-associated paralytic poliomyelitis in the Russian Federation in 1998-2014

OBJECTIVES

Different polio vaccination schemes have been used in Russia: oral polio vaccine (OPV) was used in 1998-2007 and inactivated polio vaccine (IPV) followed by OPV in 2008-2014. This article presents the characteristics of vaccine-associated paralytic poliomyelitis (VAPP) cases in Russia during this period.

METHODS

VAPP cases were identified through the acute flaccid paralysis surveillance system, classified by the National Expert Classification Committee. Criteria for a 'recipient VAPP' (rVAPP) case were poliomyelitis symptoms 6-30days after OPV administration, isolation of the vaccine virus, and residual paralysis 60days after disease onset. Unvaccinated cases with a similar picture 6-60days after contact with an OPV recipient were classified as 'contact VAPP' (cVAPP) cases.

RESULTS

During 1998-2014, 127 VAPP cases were registered: 82 rVAPP and 45 cVAPP. During the period in which only OPV was used, rVAPP cases prevailed (73.8%); cases of rVAPP were reduced during the sequential scheme period (15%). Poliovirus type 3 (39.5%) and type 2 (23.7%) were isolated more often. Vaccine-derived poliovirus types 1, 2, and 3 were isolated from three cases of cVAPP. The incidence of VAPP cases was higher during the period of OPV use (1 case/1.59 million OPV doses) than during the sequential scheme period (1 case/4.18 million doses).

CONCLUSION

The risk of VAPP exists if OPV remains in the vaccination schedule.

Regulatory Proteins of Epithelial-Mesenchymal Transition and Some Components of VEGF Signaling Pathway in Breast Cancer

Immunohistochemical method was used to assay for Snail family regulatory proteins of epithelial-mesenchymal transition, their NF-κB coactivator, and the components of VEGF signaling pathway (VEGF and its receptors VEGFR1 and VEGFR2) in 157 specimens of breast tumors. Most tumors did not express SNAI1, while 65% tumors demonstrated mid- or high-level SNAI2 expression. There were significant correlations between the expression of SNAI1, SNAI2, and their NF-κB co-activator. Correlation was also detected between expression of Snail and VEGFR1 protein families in the tumors. In addition, the study revealed tumoral co-expression of SNAI2 and VEGFR2. The data attest to coordinated activation of regulatory proteins of epithelial-mesenchymal transition and the major components of VEGF signaling pathway in breast tumors.

Regulatory Proteins of Epithelial-Mesenchymal Transition and Some Components of VEGF Signaling Pathway in Breast Cancer

Immunohistochemical method was used to assay for Snail family regulatory proteins of epithelial-mesenchymal transition, their NF-κB coactivator, and the components of VEGF signaling pathway (VEGF and its receptors VEGFR1 and VEGFR2) in 157 specimens of breast tumors. Most tumors did not express SNAI1, while 65% tumors demonstrated mid- or high-level SNAI2 expression. There were significant correlations between the expression of SNAI1, SNAI2, and their NF-κB co-activator. Correlation was also detected between expression of Snail and VEGFR1 protein families in the tumors. In addition, the study revealed tumoral co-expression of SNAI2 and VEGFR2. The data attest to coordinated activation of regulatory proteins of epithelial-mesenchymal transition and the major components of VEGF signaling pathway in breast tumors.

[VACCINE-ASSOCIATED PARALYTIC POLIOMYELITIS IN RUSSIAN FEDERATION DURING THE PERIOD OF CHANGES IN VACCINATION SCHEDULE (2006-2013 yy.)]

The results of virologic testing of clinical materials and epidemiological analysis of vaccine-associated paralytic poliomyelitis (VAPP) cases obtained in 2006-2013 during AFP surveillance are presented. Among the 2976 cases of AFP 30 cases were VAPP. 15 cases were observed in OPV recipients, whereas 15 cases were observed in non-vaccinated contacts. The age of the patients varied from 4 months to 5.5 years (13.6 ± 12.4 months old). Children younger than 1 year constituted 63.3% of the group; boys were dominant (73.3%); 53.3% of children were vaccinated with OPV; the time period between receipt of OPV and onset of palsy was from 2 to 32 days (18.7 ± 8.2). Lower paraparesis was documented in 48.3% of patients; lower monoparesis in 37.9%; upper monoparesis, in 6.9%; tetraparesis with bulbar syndrome, in 6%. The majority of the patients (85.7%) had an unfavorable premorbid status. The violations of the humoral immunity were found in 73.9% cases: CVID (52.9%), hypogammaglobulinemia (41.2%); selective lgA deflciency (5.9%). In 70.6% cases damage to humoral immunity was combined with poor premorbid status. The most frequently observed (76%, p < 0.05) represented the single type of poliovirus--type 2 (44%) and type 3 (32%). All strains were of the vaccine origin, the divergence from the homotypic Sabin strains fell within the region of the gene encoding VPI protein, which did not exceed 0.5% of nucleotide substitutions except vaccine derived poliovirus type 2--multiple recombinant (type 2/type 3/ type 2/type 1) with the degree of the divergence of 1.44% isolated from 6-month old unvaccinated child (RUS08063034001). The frequency of the VAPP cases was a total of 1 case per 3.4 million doses of distributed OPV in 2006-2013; 2.2 cases per 1 million of newborns were observed. This frequency decreased after the introduction of the sequential scheme of vaccination (IPV, OPV) in 2008-2013 as compared with the period of exclusive use of OPV in 2006-2007: 1 case per 4.9 million doses, 1.4 cases per million newborns and 1 case per 1.9 million doses, 4.9 cases per 1 million newborns, respectively. The study has been financed from Russian Federation budget within the framework of the Program for eradication of poliomyelitis in the Russian Federation, WHO Polio eradication initiative, WHO's European Regional Bureau, Russian Foundation for Basic Research (project No. 15-15-00147).

Tumor associated proteases -- prognostic markers of colorectal cancer

Associations between matrix metalloproteinase (MMP) 2, 7, 9, tissue MMP inhibitor TIMP- I and plasminogen activation system components (uPA, tPA and PAl-1) plasma and/or tumor levels in colorectal cancer (CRC) patients were evaluated in order to reveal their potential clinical implications. Two groups of CRC patients monitored for 5 or 10 years were enclosed in the study. Earlier, corresponding markers 'levels were measured in their plasma and/or tumors by immunoenzymatic techniques. High tumor PAl-I (> or =1 4,0 ng/mg protein) was demonstrated to be a significant, but not independent unfavorable prognostic factor for 5 and I10 years overall survival. Its role was mostly pronounced in stage II1 patients. High preoperative plasma MMP-7 and TIMP-I levels (cut-offs - 4,0 and 347 ng/ml respectively) were shown to be independent unfavorable prognostic factors, and univariate analysis revealed unfavorable prognostic value of high tumor MMP-7 content (> or =7,8 ng/mg protein) in patients with disseminated process.

Prognostic role of tumor-associated proteases in colorectal cancer

The relationship between the tumor and plasma levels of tumor-associated proteases - components of plasminogen activation system (uPA, tPA, and PAI-1), matrix metalloproteinases (MMP) 2, 7, 9 and their inhibitor (TIMP-1) - and the survival rate of patients with colorectal cancer was analyzed in order to evaluate the clinical significance of these markers. The study was carried out in two groups of patients, observed for 5 and 10 years, in whom the levels of these proteins were previously measured by enzyme immunoassays. High level of PAI-1 in the tumor (≥4.0 ng/mg protein) was found to be a significant, but not independent unfavorable prognostic factor for overall 5- and 10-year survival. The role of this factor was mainly significant in patients with stage III disease. High preoperative plasma levels of MMP-7 and TIMP-1 (threshold values 4.0 and 347 ng/ml, respectively) were independent unfavorable prognostic factors, while in unifactorial analysis, high level of MMP-7 (≥7.8 ng/mg protein) in the tumors of patients with disseminated process was olso an unfavorable prognostic factor.

[Optimization of preoperative preparation of patients with acute intestinal obstruction]

Water and electrolyte imbalance is considered to be the mainstay of preoperative treatment of patients with acute intestinal obstruction. The correct preoperative preparation defines the anaesthesia course, which requires the team work of surgeon and aneasthesiologist. The benefits of such an approach is confirmed by the retrospective analysis of 84 case histories, operated on the reason of the acute intestinal obstruction. The rational combination of colloid and crystalloid solutions was jointly selected, which allowed to decrease the need of vasopressor use and minimized the ICU and overall hospital stay.

Matrix metalloproteinases 2, 3, 13 and their type 2 tissue inhibitor in tumors and plasma of patients with colorectal cancer

Enzyme immunoassay studies revealed increased content of matrix metalloproteinases 2, 3 and 13 in tumors compared to the adjacent histologically unchanged mucosa in 70-90% patients with colorectal cancer, while the increase in the content of type 2 metalloproteinase tissue inhibitor did not reach the level of statistic significance. Plasma concentrations of these proteins did not correlate with the corresponding values in the tumors and did not surpass the normal levels, while their decrease after removal of the primary tumor was observed only in patients with initially high levels of this parameter.

[Testing of sewage water in orphanage for younger children as a way of surveillance for circulation of polioviruses]

Ability to test sewage water for surveillance on circulation of polioviruses was assessed. Stool samples from children living in orphanage for younger children were collected monthly. Simultaneously, samples of sewage water from orphanage's collector and community collector, in which sewage from neighborhood dwellings is dumped, were collected by snap sample and sorption methods. Rate of isolation of polio--and nonpolioenteroviruses (NPEV) from stool samples for 6 months was 44%; rate of isolation from sewage water for the same period was 79% for sorption method and 50% for snap sample method. Between viruses circulating in orphanage, NPEV of different serotypes predominated (99 isolates out of 170). Domination of polioviruses in isolates from sewage samples obtained by sorption method (23 strains out of 32) can be associated with properties of the sorbent. Number of poliovirus strains and NPEV isolated by snap sample method was equal. Season fluctuations in proportion of stool and sewage samples containing viruses coincided. Comparison of efficacy of the methods during total study period (14 samplings) did not reveal significant difference in rate of virus isolation (in orphanage's collector--72% and 50% for sorption and snap sample collection methods respectively; in community collector--31% for both methods). Detection of type 1 poliovirus with changed antigenic properties in one stool sample and one sewage water sample argue for possibility to detect in sewage minor quantity of virus excreting by one person. Thus testing of sewage water provides information on viruses circulating in the community of children. Study of stool samples revealed high rate of poliovirus isolation (up to 32%) including nonvaccinated children.

[Tissue inhibitor of metalloproteinase-1 (TIMP-1) in colorectal cancer: correlation with clinico-morphological factors]

Tissue inhibitor of metalloproteinase-1 (TIMP-1) was identified by enzyme-linked immunosorbent assay in tumor, histologically-unchanged mucosa, and plasma from 100 colorectal cancer patients. A significant increase in TIMP-1 production of up to 27.4-times as high as in adjacent mucosa was found in 92%. That was most pronounced in cases of tumor extension through adjacent tissues and organs. The marker's level was excessively high in 8% only. It remained unchanged in 71% after excision of tumor. Yet, plasma levels of TIMP-1 were significantly higher in patients with distant metastases than in those with locally advanced process. No significant correlation between tumor and circulating TIMP-1 levels was established.

[Evolution of vaccine poliovirus strains]

The paper considers different aspects of the molecular evolution of poliovirus vaccine strains: mutational and recombinant variability; mechanisms of fixation of occurring genetic changes. Matters concerning the policy of vaccination of the population against poliomyelitis are covered.

Matrix metalloproteinases 7 and 9 and their types 1 and 4 tissue inhibitors in tumors and plasma of patients with colorectal cancer

Enzyme immunoassays showed significantly elevated content of matrix metalloproteinase 7 and type 1 tissue inhibitor of metalloproteinases in tumors compared to adjacent histologically unchanged mucosa of patients with colorectal cancer; the levels of metalloproteinase 9 and type 4 tissue inhibitor of metalloproteinases were virtually the same in the tumors and mucosa. Plasma concentrations of the studied proteins did not correlate with their levels in the tumor, did not surpass the normal, and did not decease after removal of the primary tumor in the majority of patients.

[Paralytic poliomyelitis in Russian Federation in 1998-2005]

From 1998 through 2005 3,294 cases of acute flaccid paralysis (AFP) including 93 cases with clinical picture of poliomyelitis were registered in Russian Federation. From the latter cases 91 were classified as vaccine-associated paralytic poliomyelitis (VAPP): 66 were VAPP cases in oral poliomyelitis vaccine (OPV) recipients and 25--VAPP cases in contacts. VAPP rate was 1 case per 1.6 million of distributed OPV doses, 1 case per 2.2 million doses for OPV recipients, and 1 case per 186,000 doses for recipients of 1st OPV dose in children aged < 1 year. Majority of VAPP cases in recipients occurred after 1st dose (89.4%) and in contacts--in non-vaccinated children (76%). Mean interval between OPV administration and onset of VAPP in recipients was 21 days. Children aged < 1 year were predominant among VAPP cases (92.4% among recipient VAPP cases, and 80% among contact VAPP cases). Majority of the patients had unfavorable health status including defects of immunity. Most of poliovirus strains isolated from VAPP cases belonged to type 3 (52.9%) whereas to type 2 and 1--29.8% and 17.4% of strains respectively. All VAPP cases were associated with vaccine-derived polioviruses. A highly diverged poliovirus type 1 (2.65% of nucleotide substitutions in VP1 region) was isolated from patient with contact VAPP. Formation of poliovirus-neutralizing serum antibodies in children with VAPP including persons with immunodeficiency reflects the ability of the organism to produce specific antiviral immune response.

[Global eradication of poliomyelitis: intralaboratory contamination with wild poliovirus in the implementation of the program for safe laboratory containment of wild-type polioviruses in the Russian Federation]

The paper describes a case of contamination of sewage samples by a wild poliovirus type 1 strain (Mahoney) in one of the virological laboratories of the Russian Federation. It discusses the possible sources and the mechanism of contamination, as well as the problems in the implementation of the program for safe laboratory containments of wild-type polioviruses.

Spread of vaccine-derived poliovirus from a paralytic case in an immunodeficient child: an insight into the natural evolution of oral polio vaccine

Sabin strains used in the manufacture of oral polio vaccine (OPV) replicate in the human organism and can give rise to vaccine-derived polioviruses. The increased neurovirulence of vaccine derivatives has been known since the beginning of OPV use, but their ability to establish circulation in communities has been recognized only recently during the latest stages of the polio eradication campaign. This important observation called for studies of their emergence and evolution as well as extensive surveillance to determine the scope of this phenomenon. Here, we present the results of a study of vaccine-derived isolates from an immunocompromised poliomyelitis patient, the contacts, and the local sewage. All isolates were identified as closely related and slightly evolved vaccine derivatives with a recombinant type 2/type 1 genome. The strains also shared several amino acid substitutions including a mutation in the VP1 protein that was previously shown to be associated with the loss of attenuation. Another mutation in the VP3 protein resulted in altered immunological properties of the isolates, possibly facilitating virus spread in immunized populations. The patterns and rates of the accumulation of synonymous mutations in isolates collected from the patient over the extended period of excretion suggest either a substantially nonuniform rate of mutagenesis throughout the genome, or, more likely, the strains may have been intratypic recombinants between coevolving derivatives with different degrees of divergence from the vaccine parent. This study provides insight into the early stages of the establishment of circulation by runaway vaccine strains.

Retrospective analysis of a local cessation of vaccination against poliomyelitis: a possible scenario for the future

The global eradication of poliomyelitis will require substantial changes in immunization practices. One of the proposed scenarios includes cessation of vaccination with live oral poliovirus vaccine (OPV) and the creation of an OPV stockpile for emergency response in case of the reintroduction of poliovirus into circulation. We describe here a retrospective analysis of the cessation of OPV usage in a region of the Byelorussian Republic of the former Soviet Union in 1963 to 1966. During this period, a widespread circulation and evolution of independent lineages of vaccine-derived polioviruses took place in the region. Some of these lineages appeared to originate from OPV given to 40 children in the community during this period of essentially no vaccinations. The data demonstrate very high risks associated with both the local cessation of OPV vaccination and the proposed use of OPV to control a possible reemergence of poliovirus in the postvaccination period. The high transmissibility of OPV-derived viruses in nonimmune population, documented here, and the known existence of long-term OPV excretors should be also considered in assessing risks of the synchronized global cessation of OPV usage.

Poliomyelitis in Russia in 1998-1999

After introducing surveillance for poliomyelitis and AFP cases in the Russian Federation in 1998, 740 AFP cases have been registered in 1998-1999, and 18 of that number were considered as vaccine-associated paralytic poliomyelitis (VAPP). Of 18 cases 11 were classified as VAPP of vaccine recipients and confirmed by virus isolation; from two of the vaccine recipients virus was not isolated, and five were poliomyelitis cases in contact non-vaccinated children. In all the cases the disease was characterised with the typical clinical picture with residual pareses and paralyses. One case was fatal. Vaccine virus type 3 has been isolated from all the vaccine recipients. The MAPREC test has shown that the quality of monovaccine type 3 bulks used for vaccinating these children did not differ from the quality of other bulk vaccines produced by the Chumakov Institute of Poliomyelitis. Patients surveyed for gammaglobulin were positive. Polioviruses type 1 isolated from two of the contact cases had changed antigenic properties and were recombinants of types 1 and 2.

Long-term circulation of vaccine-derived poliovirus that causes paralytic disease

Successful implementation of the global poliomyelitis eradication program raises the problem of vaccination against poliomyelitis in the posteradication era. One of the options under consideration envisions completely stopping worldwide the use of the Sabin vaccine. This strategy is based on the assumption that the natural circulation of attenuated strains and their derivatives is strictly limited. Here, we report the characterization of a highly evolved derivative of the Sabin vaccine strain isolated in a case of paralytic poliomyelitis from a 7-month-old immunocompetent baby in an apparently adequately immunized population. Analysis of the genome of this isolate showed that it is a double (type 1-type 2-type 1) vaccine-derived recombinant. The number of mutations accumulated in both the type 1-derived and type 2-derived portions of the recombinant genome suggests that both had diverged from their vaccine predecessors approximately 2 years before the onset of the illness. This fact, along with other recent observations, points to the possibility of long-term circulation of Sabin vaccine strain derivatives associated with an increase in their neurovirulence. Comparison of genomic sequences of this and other evolved vaccine-derived isolates reveals some general features of natural poliovirus evolution. They include a very high preponderance and nonrandom distribution of synonymous substitutions, conservation of secondary structures of important cis-acting elements of the genome, and an apparently adaptive character of most of the amino acid mutations, with only a few of them occurring in the antigenic determinants. Another interesting feature is a frequent occurrence of tripartite intertypic recombinants with either type 1 or type 3 homotypic genomic ends.

[Mutation and recombination variability of vaccine polioviruses isolated in Belarus (1960-1999)]

One hundred and eight vaccine-derived strains of types 1, 2, and 3 poliovirus (25 PV1, 34 PV2, and 48 PV3) isolated in Belarus in 1960-1999 were analyzed by double restriction fragment length polymorphism assay (RFLP-1, -3D1). Forty-four (40.7%) of strains were genetically modified. Eight (7.4%) PV were modified by mutation, 16 (14.8%) by recombination, and 20 (18.5%) by both mutation and recombination. The genomes of 16 PV were analyzed by multiple RFLP technique covering VP1-, VP1/VP2A-, P2-, 3AC-, and 3D1-coding regions. The majority of recombinants were "simple" (with one crossing over site). One strain was "double" recombinant (two crossings over sites) and one more "multiple" recombinant (three crossing over sites). Partial nucleotide sequencing of some recombinant strains showed that the degree of these strains' divergence was less than 1% in comparison with the original vaccine viruses.