Late presentation of HIV-infection is one of the most serious challenges in providing medical care to HIV-infected patients, because delay in detection and treatment of HIV-infection leads to a gradual decrease in the number of CD4+lymphocytes and the threat of infectious complications and tumor processes.
 Objective of this study is to find out the features of HIV-infection in people with late presentation of the disease, to evaluate the effectiveness of treatment and factors influencing the emergence of severe opportunistic infections on the background of dolutegravir-based antiretroviral therapy regimens. To achieve this goal, a cohort retrospective study was conducted, during which data from 210 outpatient records were analyzed.
 Analysis of opportunistic infections depending on the level of lymphocytes at the time of registration showed that in 123 (58.6%) of 210 late presenters, opportunistic infections were diagnosed at lymphocytes level below 200 cells/mL, in 22 people, while severe opportunistic infections were registered at a lymphocytes level above 500 cells/mL.
 Analysis of the clinical effectiveness of antiretroviral therapy showed that while taking the drugs, some patients continued to develop severe opportunistic infections such as tuberculosis, oropharyngeal candidiasis and severe bacterial diseases. An analysis of the Kaplan-Meier survival curve showed that there is a significant relationship between low baseline lymphocytes counts and the development of late opportunistic infections during treatment.
 Thus, the majority of HIV-infected patients were diagnosed with wasting syndrome, profound immunosuppression, severe opportunistic infections, and their combination at the time of registration. In some patients, severe late opportunistic infections were diagnosed with a satisfactory lymphocytes count above 500 cells/mL and subsequently on antiretroviral treatment. A low baseline lymphocytes count was identified as a risk factor for the development of severe opportunistic infections on antiretroviral therapy.