NRL of Immunology

Head of NRL of Immunology

Prof. Maria Nikolova, MD, DSc

email: This email address is being protected from spambots. You need JavaScript enabled to view it.

tel. 02 943 56 36

 

Research staff:

  • Assoc. prof. Georgi Nikolov, MD, PhD - clinical immunologist
  • Assoc. prof. Radoslava Emilova, PhD
  • Assistant prof. Yana Todorova, PhD
  • Gabriela Radulova - biologist
  • Radostina Dimotrova - biologist
  • Slaveika Metodieva - laboratory technician
  • Tsvetelina Kesova - laboratory worker

 

Laboratory samples are accepted

between 8:00 a.m. and 12:00 p.m.

Venous blood samples are collected between 9:00 a.m. and 12:00 p.m.

Consultations:

Monday - Wednesday: 8.30 a.m. – 10.30 a.m.

sign-up in advance

NRLI performs highly specialized phenotypic and functional studies of the immune system with focus on secondary immunodeficiencies and infections. A significant part of the research is related to the immune monitoring of HIV+ patients and the recovery of immune response in the course of antiretroviral therapy.

NRLI offers a range of methods for complex evaluation of the immune system, including humoral and cellular components, natural and acquired immune response. Precise quantitative flow cytometry analysis of T-, B- and NK-lymphocytes and their subpopulations, quantification of antigen-specific response in chronic infections (HIV, EBV, CMV, HBV, tuberculosis), functional studies of phagocytes, determination of sensitization to allergens by in vitro allergen-specific activation of basophils, quantitative measurement of CD34+ stem cells, phenotyping of leukosis and lymphomas. In vitro diagnosis of latent and active tuberculosis infection as well as monitoring of antituberculosis therapy by QuantiFERONTBGoldIn-Tube and T.SPOT.TB is also available.

Since the beginning of 2020, NRLI offers a range of tests for evaluation of SARS-CoV-2 specific antibody and T-cell response. The proposed tests are extremely useful for evaluation of patients with primary and secondary immune deficiencies, chronic viral infections and unexplained fever, "chronic fatigue syndrome", malignancies and allergies.

Research studies performed at NRLI are related to the homeostasis and regeneration of lymphocyte subsets, the regulation of the immune response and its disorders in chronic infections, the possibilities for immunomodulation of adaptive and natural immune response. NRLI has established collaborations with the Medical Universities in Sofia, Plovdiv, the Biology Department of Sofia University, the institutes of Microbiology and Molecular Biology at the Bulgarian Academy of Sciences, etc. A long-term collaboration exists with the National Institute of Health and Medical Research of France (INSERM), the Medical Faculty of UPEC and the Department of Clinical Immunology of the University Hospital A. Mondor”, Creteil, France, as well as the Immunology Department of Tor Vergata University in Rome, Italy. The laboratory staff has co-authored over 200 scientific publications in Bulgarian and international scientific journals.

INSTRUCTIONS FOR THE COLLECTION, PACKAGING AND TRANSPORT OF TEST SAMPLES (PDF, 173KB)

 

Diagnostic tests offered at NRLI (PDF, 125KB)

 

Publications with impact factor in the last 10 years

  1. Marcus, ….,Nikolova, M., Muhtarova, M., Kantarjiev, T.,… Johnston, L.HIV serostatus knowledge and serostatus disclosure with the most recent anal intercourse partner in a European MSM sample recruited in 13 cities: Results from the Sialon-II study. (2017) BMC Infectious Diseases, 17 (1) (IF 3.01)
  2. Mirandola, M. …Nikolova, M., Muhtarova, M., Kantarjiev, T., ..Noack, P., Peeling, R., Johnston, L. Socio-demographic Characteristics, Sexual and Test-Seeking Behaviours Amongst Men Who have Sex with Both Men and Women: Results from a Bio-behavioural Survey in 13 European Cities (2017) AIDS and Behavior, 21 (10), pp. 3013-3025. (IF 3.89)
  3. Amicosante, M., ….,Nikolova, M., … Fuentes-Alcala, Z.Current use and acceptability of novel diagnostic tests for active tuberculosis: A worldwide survey [Uso atual e aceitabilidade de novos testes diagnósticos para tuberculose ativa: Um inquérito mundial](2017) Jornal Brasileiro de Pneumologia, 43 (5), pp. 380-392. (IF 2.6)
  4. Yancheva N , Strashimirov D , Hrischev V , Tchervenyakova T, Nikolova M , Aleksiev I Three cases of non-Hodgkin's lymphoma in HIV-infected Bulgarian patients. Infez Med. 2018 Jun 1; 26 (2):155-159.
  5. Ivanova, I.I., Mihaylova, N.M., Manoylov, I.K., Makatsori, D., Lolov, S., Nikolova, M.H., Mamalaki, A., Prechl, J., Tchorbanov, A.I. Targeting of Influenza Viral Epitopes to Antigen-Presenting Cells by Genetically Engineered Chimeric Molecules in a Humanized NOD SCID Gamma Transfer Model (2018) Human Gene Therapy, 29 (9), pp. 1056-1070.
  6. Николов Г.С., Тодорова Я.Д., Николова М.Х., Емилова Р.Г.,Христова Д.М., Костова-Шахид П.Й. , Петрунов Б.Н Субпопуляции Т-регуляторных клеток у пациентов с IGE- обусловленной аллергией журнал микробиологии, эпидемиологии и иммунобиологии. 2019; (6) DOI: https://doi.org/10.36233/ 0372-9311-2019-6-65-71
  7. R Emilova , V Manolov, Y Todorova , N Yancheva , I Alexiev , M Nikolova Elevated Labile Iron Levels in CD4 and CD8 T Cells From HIV Positive Individuals With Undetectable Viral Load AIDS Research and Human Retroviruses DOI: 10.1089/AID.2020.0010 (IF 1.823)
  8. I Alexiev, E Golkocheva-Markova, A Kostadinova…. Maria Nikolova. The prevalence of hepatitis B and C co-infections among people with HIV-1 in Bulgaria: 2010-2015 Future Virology Vol. 14, No. 12 Short Communication Published Online:30 Jan 2020 https://doi.org/10.2217/fvl-2019-0092 (IF: 1.83)
  9. Nikolova, Y. Todorova, R. Emilova et al. Induction of humoral and cellular immune responses to COVID‐19 mRNA and vector vaccines: A prospective cohortstudy in Bulgarian healthcare workers. J Med Virol. 2022; 1–11. IF 2.33
  10. Todorova, R Emilova, V Milanov, E Bachijska J Atanasova, A Bajkova, M Nikolova Eicosanoid and cytokine levels differentiate between stages of MTB infection. 2022 Folia Medica, vol. 65, no. 3, pp. 399-406. https://doi.org/10.3897 /folmed.65.e80599 (Q4, IF 0.54)
  11. R Emilova, Y Todorova, M Aleksova, I Alexiev, L Grigorova, R Dimitrova, N Yancheva, M Nikolova. Reactive oxygen species (ROS) features on t-cell subpopulations in people living with HIV. HIV Glasgow, 23–26 October 2022, Glasgow, UK / Virtual (wiley.com) JIAS 25, IssueS6 Supplement: Q1, IF 5.39
  12. Elitsa Golkocheva-Markova, Ani Kevorkyan, Ralitsa Raycheva, Chiydem Ismailova, Viliana Yoncheva, Tencho Tenev, Radoslava Emilova, Lyubomira Grigorova, Ivan Baltadzhiev, Radka Komitova. Assessment of hepatitis E seropositivity among HIV-infected patients in Bulgaria. The Brazilian Journal of Infectious Diseases, 26, Issue 1, 2022, 102329. Q3, IF 3.257
  13. Lazova, S.; Dimitrova, Y.; Hristova, D.; Tzotcheva, I.; Velikova, T. Cellular, Antibody and Cytokine Pathways in Children with Acute SARS‐CoV‐2 Infection and MIS‐C—Can We Match the Puzzle? Antibodies 2022, 11, 25. Q2 IF 1.67
  14. Nadya Ivanova-Aleksandrova, Heliana Dundarova, Boyko Neov, Radoslava Emilova, Irina Georgieva, Rayna Antova, Krasimir Kirov, Jiri Pikula, Kateřina Zukalová & Jan Zukal. Ectoparasites of Cave- Dwelling Bat Species in Bulgaria. 2022. Proceedings of the Zoological Society, 1-6. Q3, IS 0.71
  15. Bolyarova-Konova, L. Stefanov, Z. Kolarov, R. Grozdanova, and M. Nikolova, “Anti-cyclic Citrullinated Peptide Antibody and Rheumatoid Factor and the Relationship between Periodontitis and Rheumatoid Arthritis”, C. R. Acad. Bulg. Sci., vol. 75, no. 3, pp. 451–457, Mar. 2022. , IF 0.33
  16. Eleonora Kaneva, Georgi Nikolov, Yana Kandova, Bogdan Petrunov. A seroepidemiological investigation of toxocariasis in forestry workers in Bulgaria. Comptes rendus de l’Acad´emie bulgare des Sciences, 2022; Tome 75, No 5, 686-693. Q3, IF 0.33
  17. I Rainova, R Harizanov, I Kaftandjiev, N Tsvetkova, R Enikova, M Videnova, E Kaneva and Y Todorova. Prevalence of Toxoplasma gondii among different groups of patients in Bulgaria and algorithm for diagnosis of toxoplasmosis, applied in the National Reference Laboratory for Diagnosis of Parasitic Diseases, Bulgaria. World Journal of Advanced Research and Reviews, 2022, 14(03), 116– 123, eISSN: 2581-9615
  18. Emilova, R., Todorova, Y., Aleksova, M., Dimitrova, R., Alexiev, I., Grigorova, L., Yancheva, N., & Nikolova, M. (2022). Determination of intracellular reactive oxygen species in T-cell subsets of HIV+ patients on continuous cART. Problems of Infectious and Parasitic Diseases, 50(1), 5–11. Q4
  19. Георги Николов. Алергенни протеинови семейства. Алергии Хиперсензитивност Астма, 2022, том 18, № 2: 44-53.
  20. M Aleksova, Y Todorova, R Emilova, M Baymakova, N Yancheva, M Nikolova. Pre-existing immunity to beta-coronaviruses HKU1 and OC43 may affect susceptibility to SARS-CoV-2 infection Acta Microbiologica Bulgarica. 38 / 4 (2022), 294 – 300.
  21. Ngoc, K., Trifonova, I., Nikolova, M., Emilova, R., Todorova, Y., Gladnishka, T., Christova I., 2022. Association between Serum Concentrations of IL-6 and IL-10 and COVID-19 Severity. Acta Microbiologica Bulgarica, vol. 38, no. 4, pp. 289-93. (Q4, IF20220.17)
  22. Trifonova, I., Ngoc, K., Nikolova, M., Emilova, R., Todorova, Y., Gladnishka, T., Christova, I., 2023. Patterns of cytokine and chemokine expression in peripheral blood of patients with COVID-19 associated with disease severity. International Journal of Immunopathology and Pharmacology, vol. 37, pp. 1–12. Doi. 10.1177/03946320231163681 (Q2, IF 3.22)
  23. Aleksova, M., Todorova, Y., Emilova, R., Baymakova, M., Yancheva, N., Andonova, R., Zasheva, A., Grifoni, A., Weiskopf, D., Sette, A., Nikolova, M., 2023. Virus-Specific Stem Cell Memory CD8+ T Cells May Indicate a Long-Term Protection against Evolving SARS-CoV-2. Diagnostics, vol. 13, 1280. https://doi.org/10.3390/diagnostics 13071280. (Q2, IF 3.71)
  24. Todorova, Y., Emilova, R., Koleva, V., Ivanov, I., Stoikov, I., Nikolova, M., 2023. Expression of membrane-bound β-Klotho on peripheral blood CD4+ and CD8+ T lymphocytes of healthy subjects. Biotechnology & Biotechnological Equipment, vol. 37, no. 1, 2199887, DOI: 10.1080/13102818.2023.2199887 (Q3, IF2023 1.63)
  25. Vangelov, D., Aleksova, M., Todorova, Y., Emilova, R., Kapincheva, N., Yancheva, N., Koleva, V., Nikolova, M., 2023. Immune Response to SARS-COV-2 in Patients with Chronic HIV Infection. Probl Infect Parasit Dis, vol. 51, no. 1, pp. 5–11. (Q4)
  26. Alexiev, I., Shankar, A., Pan, Y., Grigorova, L., Partsuneva, A., Dimitrova, R., Gancheva, A., Kostadinova, A., Elenkov, I., Yancheva, N., Grozdeva, R., Strashimirov, D., Stoycheva, M., Baltadzhiev, I., Doichinova, T., Pekova, L., Kosmidis, M., Emilova, R., Nikolova, M., Switzer, W.M., 2023. Transmitted HIV Drug Resistance in Bulgaria Occurs in Clusters of Individuals from Different Transmission Groups and Various Subtypes (2012–2020). Viruses, vol. 15, 941. https://doi.org/10.3390/v15040941 (Q1, IF20235.71)
  27. Todorova, Y., Emilova, R., Milanov, V., Bachiyska, E., Atanasova, Y., Baikova, A., Nikolova, M., 2023. Eicosanoid and cytokine levels differentiate between stages of MTB infection. Folia Medica, vol. 65, no. 3, pp. 399-406. https://doi.org/10.3897/folmed.65.e80599 (Q4, IF20230.54)
  28. Manolov, V., Georgiev, O., Vasilev, V., Emilova, R., Petrova, I., Hadjidekova, S., Angov, G., Kunchev, T., Tzatchev, K., Traykov, L. and Pencheva, V. 2023. Iron Metabolism Dysregulation and Atherosclerotic Changes in Obstructive Sleep Apnoea, Proceedings of the Bulgarian Academy of Sciences. Sofia, Bulgaria, 76(10), pp. 1625–1632. doi: 10.7546/CRABS.2023.10.17. (Q3, IF2023 0.38)
  29. Nikola Ralchev, Nikola Kerekov, Nikolina Mihaylova, Mariann Kremlitzka, Diana Hristova, Julian Dzhorev, Anna Erdei, Andrey Ivanov Tchorbanov, Targeted suppression of Dpt-specifik B cells in humanized Rag2-yc-mouse model of HDM allergy,Scandinavian Jurnal of Immunology, (Q3, IF 3.889) 
  30. Nikolova D., Todorova Y., Hammoudeh Z., Rukova B., Emilova R., Aleksova M., Koleva V., Nikolova M. Gene Expression Changes as Biomarkers of Immunosenescence in Bulgarian Individuals of Active Age. (2025) Biomedicines, 13 (3), art. no. 721 DOI: 10.3390/biomedicines13030721(Q1, IF20233.9)
  31. Nikolov G., Emilova R., Todorova Y., Milcheva D., Nikolova M. Mast cells, the effector cells of IgE-mediated allergy (2025) Problems of Infectious and Parasitic Diseases, 53 (2), pp. 27 - 34, Cited 0 times. DOI: 10.58395/292bv823 (Q4)
  32. Petrov S., Bozhkova M., Ivanovska M., Kalfova T., Dudova D., Nikolova R., Vaseva K., Todorova Y., Aleksova M., Nikolova M., Taskov H., Murdjeva M., Maes M.Comparable Immune Alterations and Inflammatory Signatures in ME/CFS and Long COVID (2025) Biomedicines, 13 (12), art. no. 3001, Cited 0 times. DOI: 10.3390/biomedicines13123001 (Q1, 3.9)
  33. Dudova D., Bozhkova M., Petrov S., Nikolova R., Kalfova T., Ivanovska M., Vaseva K., Nikolova M., Ivanov I.N.Insights into the Complex Biological Network Underlying Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. (2026) International Journal of Molecular Sciences, 27 (1), art. no. 268 DOI: 10.3390/ijms27010268. (Q1, IF 9)
  34. Vangelov D., Emilova R., Todorova Y., Yancheva N., Dimitrova R., Grigorova L., Alexiev I., Nikolova M. T-Lymphocyte Phenotypic and Mitochondrial Parameters as Markers of Incomplete Immune Restoration in People Living with HIV+ on Long-Term cART. (2025) Biomedicines, 13 (8), art. no. 1839 DOI: 10.3390 /biomedicines 13081839 (Q1, IF 9)
  35. Mihaylova N.M., Manoylov I.K., Nikolova M.H., Prechl J., Tchorbanov A.I. DNA and protein-generated chimeric molecules for delivery of influenza viral epitopes in mouse and humanized NSG transfer models. (2024) Human Vaccines and Immunotherapeutics, 20 (1), art. no.2292381. DOI: 10.1080/21645515.2023.2292381(Q1, IF20243.5)
  36. Partsuneva A., Gancheva A., Dimitrova R., Grigorova L., Kostadinova A., Nikolova M., Emilova R., Yancheva N., Grozdeva R., Alexiev I.Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in Bulgaria. (2025) Microorganisms, 13 (5), art. no. 1108, DOI 10.3390/microorganisms13051108. (Q1, IF20244.1)
  37. Hristova D., Decheva A., Donchev D., Vangelov D., Donev V., Nikolov G., Nikolova M.(2024) Problems of Infectious and Parasitic Diseases, 52 (3), pp. 47 - 57, DOI: 10.58395/fxa59569(Q4)
  38. Vangelov D., Emilova R., Todorova Y., Alexiev I., Yancheva N., Gadher S.J., Nikolova M. Genetic Signatures of Immune Recovery in People Living with HIV on Long-Term Contemporary Antiretroviral Therapy. (2025) AIDS Research and Human Retroviruses, 41 (8), pp. 414 - 417, DOI: 10.1089/aid.2024.0111(Q3, IF20241.3)
  39. Donev V., Emilova R., Todorova Y., Nacheva J., Stefanova T., Nikolov G., Nikolova M.Immunotherapeutic potential of Bulgarian intravenous immunoglobulin (Immunovenin-intact 5% IgG) (2025) Pharmacia, 72. DOI: 10.3897/pharmacia.72. e149467(Q2, SCS2.5)
  40. Donev V., Todorova Y., Emilova R., Nikolov G., Nikolova M. Extensive characterization of COVID-19 convalescent plasma from Bulgarian donors. (2024) Biotechnology and Biotechnological Equipment, 38 (1), art. no. 2432986, DOI: 10.1080/13102818.2024.2432986 (Q3, IF 1.4)
  41. Emilova R., Todorova Y., Nikolova M. Attitude and knowledge of HIV infection among health personnel in Bulgaria. (2025) Problems of Infectious and Parasitic Diseases, 53 (1), pp. 15 - 22, DOI: 10.58395/de3b1827(Q4)
  42. Petrov S., Bozhkova M., Ivanovska M., Kalfova T., Dudova D., Todorova Y., Dimitrova R., Murdjeva M., Taskov H., Nikolova M., Maes M.Comprehensive Immunophenotyping of Monocytes and Dendritic Cells Suggests Distinct Pathophysiology in Chronic Fatigue Syndrome and Long COVID. (2026) International Journal of Molecular Sciences, 27 (10), art. no. 4488, DOI: 10.3390 /ijms27104488(Q1, IF20244.9)
  43. Vangelov D., Emilova R., Todorova Y., Blazheva S., Alexiev I., Doichinova Ts., Nikolova M.phenotypic and metabolic features of CD4 and CD8 T cells of an elite controller – a case report. (2026) Problems of Infectious and Parasitic Diseases, 54 (1), pp. 31 - 39.DOI: 10.58395/en47mb37 (Q4)
  44. Dudova, D.; Bozhkova, M.; Petrov, S.; Nikolova, R.; Kalfova, T.; Ivanovska, M.; Vaseva, K.; Nikolova, M.; Ivanov, I.N. Insights into the Complex Biological Network Underlying Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Int. J. Mol. Sci. 2026, 27, 268. https://doi.org/10.3390/ijms 27010268 (Q1; IF=4.9)
  45. Petrov, S.; Bozhkova, M.; Ivanovska, M.; Kalfova, T.; Dudova, D.; Nikolova, R.; Vaseva, K.; Todorova, Y.; Aleksova, M.; Nikolova, M.; et al. Comparable Immune Alterations and Inflammatory Signatures in ME/CFS and Long COVID. Biomedicines 2025, 13(12), 3001; https://doi.org/10.3390/biomedicines13123001 (Q1; IF=3.9)
  46. Bozhkova, M., Raycheva, R., Petrov, S., Dudova, D., Kalfova, T., Murdjeva, M., Taskov, H., & Shivarov, V. (2025). Humoral and Memory B Cell Responses Following SARS-CoV-2 Infection and mRNA Vaccination. Vaccines, 13(8), 799. https://doi.org/10.3390/vaccines13080799 (Q1; IF=3.4)
  47. Petrov, S.; Bozhkova, M.; Ivanovska, M.; Kalfova, T.; Baldzhieva, A.; Todev, A.; Kirova, D.; Kicheva, Y.; Stoynov, S.; Murdjeva, M.; et al. Immunophenotyping and Functional Characterization of NK Cells in SARS-CoV-2 Infection. Immuno 2025, 5, 35. https://doi.org/10.3390/immuno5030035 (Q2; IF= 2.5)
  48. Petrov S., Taskov H., Murdjeva M. Guardians of immunity: NK cell-mediated defense in COVID-19 and post-COVID scenarios. Folia Medica. 2024; 66 (1): 12-18. https://doi.org/10.3897/folmed.66.e113356 (SJR2023=0.217, Q4)
  49. Todorova, Y.; Dimitrova, R.; Kalfova, T.; Petrov, S.; Bozhkova, M.; Ivanovska, M.; Dudova, D.; Murdjeva, M.; Taskov, H.; Maes, M.; et al. Treg and Oxidative Stress Biomarker Profiles in Long COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Int. J. Mol. Sci. 2026, 27, 9422. https://doi.org/10.3390/ijms27219422