Polymorphism of interleukin 28B gene in human immunodeficiency virus infected individuals

Abstract

Zaraza virusom ljudske imunodeficijencije (HIV) povezuje se s progresivnom deficijencijom imunološkog sustava. CD4+ T-limfociti su osnovna subpopulacija stanica koju virus ljudske imunodeficijencije zaražava te tijekom infekcije dolazi do deplecije ovih stanica u krvi HIV-pozitivnih osoba što služi kao prognostički parametar za progresiju HIV-bolesti. Interferoni λ inhibiraju replikaciju različitih virusa. Polimorfizam jednog nukleotida rs12979860 u promotoru gena za interleukin-28B (jedan od interferona λ) utječe na koncentraciju tog citokina u organizmu. Osobe koje su C homozigoti imaju veće koncentracije IL-28B te sporiju progresiju bolesti. Cilj ovog istraživanja je odrediti povezanost između polimorfizma gena za IL-28B i imunološkog statusa HIV-om zaraženih osoba. Ispitanike sam podijelila u tri skupine prema apsolutnom broju CD4+ T-limfocita te metodom PCR-a u stvarnom vremenu odredila polimorfizam gena za IL-28B. Prva skupina su osobe koje su pri ulasku u kliničku skrb, te minimalno godinu dana nakon toga imale > 500 CD4+ limfocita / μl krvi. Druga skupina su osobe koje su u kliničku skrb ušle s 500 CD4+ limfocita / μl krvi nakon početka terapije antiretrovirusnim lijekovima. Treća skupina su osobe koje su pri ulasku u kliničku skrb, te nakon minimalno godinu od započinjanja antiretroviralne terapije imale < 200 CD4+ limfocita / μl krvi. C homozigoti su najčešća skupina u prvoj i trećoj skupini ali i u čitavoj populaciji (50,5 %). Heterozigoti su prisutni u populaciji sa 36,7 % i najčešći je genotip u drugoj skupini ispitanika. T homozigoti su prisutni u populaciji sa 12,8 %, i najrjeđi je genotip u sve tri skupine. Nema statistički značajnih razlika između pojedinih skupina ispitanika. Istraživanje je pokazalo da nema povezanosti između progresije bolesti i IL-28 genotipa u HIV zaraženih osoba.Infection with the human immunodeficiency virus (HIV) is associated with progressive deficiency of the immune system. CD4+ T-lymphocytes are the primary targets of HIV which leads to depletion of this cell population in HIV-infected individuals which serves as a prognostic marker for HIV disease progression. Interferons λ inhibt the replication of different viruses. Single-nucleotide polymorphism (SNP) of interleukin 28B (IL-28B, one of λ interferons) affects the concentration of that interleukin in the organism. C homozygotes have higher concentrations of that interleukin and therefore slower disease progression. The aim of this study is to determine the corellation between IL-28B SNP and immunological status of HIV-infected individuals. I have divided the patients into three groups considering their CD4+ count and using a real-time PCR test determined their IL-28B genotype. First group consisted of patients who had > 500 CD4+ lymphocytes / μl at entrance to care and at least for one year after. In the second group were patients who had 500 lymphocytes / μl and stayed as high for at least a year. Third group had patients who entered clinical care with < 200 CD4+ lymphocytes / μl at and remained so for at least a year. C homozygotes are most frequent in entire study group (50,5 %) as well as in the first and third group of patients. Heterozygotes were present in 36,7 % in the entire study group and were the most frequent in second group of patients. T homozygotes were the least frequent in an entire study population and all three groups. There were no statistically significant differences in genotype distribution between groups so this study showed that there is no corelation between disease progression and IL-28B genotype in HIV-infected individuals