Human CCL3L1 gene expression in blood donors infected with HIV-1

— The CCL3L1 gene is very important in regulating of immunity against of pathogens. CCL3L1 inhibits HIV-1 replication by competing with CCR5 co-receptors, which are essential receptors for virus entry into target cells. The aim of the study, which was done in Thi-Qar province from February 2022 to February 2023, was to monitoring the immune status by estimate the gene expression of the CCL3L1 gene in people infected with HIV-1 compared to the group of control. Where 30 samples were collected from infected people and 30 samples from non-infected people as a control group. There was an increased level of gene expression in patients, where it was (17.02778) compared to the control group, which was (1.428108) using qPCR. There is a need for more molecular studies and follow-up of genetic and immunological changes in infected patients.


I. INTRODUCTION
Chemokine ligand 3 like-1 (CCL3L1) codes the CCL3L1 protein [1], located on human chromosome 17 [2], which is the most powerful efficacious chemokine for HIV-1 suppression [1], it is plays an important role in regulatory of immune and host protective by production macrophage inflammatory proteins (MIP)-1α which has a role in decrease the expression of CCR5 co-receptor for entry HIV into cells [3]. There is association between CCL3L1 expression and altered exposure to HIV-1. CCL3L1 is critically important in HIV-1 pathogenesis. More chemokines mean less HIV-1 replication, suggesting that variances in the gene copies of immune response underlie different responses to infectious diseases. The CCL3L1 expression levels are correlated with the number of copies for CCL3L1 gene [4].The presence of a segment redundancy hotspot causes CCL3L1 copy number to fluctuate widely. The chemokine co-receptor (CCR5) is naturally linked to CCL3L1. In addition to influencing HIV-1 susceptibility and possibly blocking HIV-1 entry by conquering required coreceptors, copy number variation (CNV) of CCL3L1 is also closely related with HIV-1 exposure. When CCL3L1 was low copy number that enhanced infection with HIV-1, as well as rapid progression to AIDS and death. CCR5 coreceptor ligand CCL3L1 has genetic variations that affect its expression and function [2]. The CCL3L1 variant range of CCL3L1 transcripts has been documented from 0 to 14 transcripts in many different populations. CCL3L1 copy numbers varied from 0 to 8 for the Malaysian and Indian populations and from 0 to 10 for the Chinese [3], where both the HIV-positive Malays and Indians had CN status at two, while the CN status of the Chinese had four [1], whereas most Europeans have between 0 to 5 copies [5].
African people have significant greater copies of CCL3L1 compared to people from other continents populations, suggesting this gene confers resistance to HIV infection in these people [4]. HIV favorably selects people with a low concentration of the CCL3L1 gene [6]. Given that individuals have fewer copies CCL3L1 in population have an increase risk of infection with HIV as well as predisposition to the rapid development of AIDS, individuals with lower two of copies were more likely to be infected with HIV. For over 15 years of infection, however, the copy number of CCL3L1 did not play a role in identifying infections. Additionally, the variation of CCL3L1 have little influence on HIV-1 loading level, this difference in the CCL3L1 version number does not appear to be the case the reason that regulates the diagnosis of chronic infection with HIV although it is related with exposure to HIV infection [2].
Check CCL3L1 version in adolescents with early HIV infection Chronic stage without AIDS is no variance in CNV of CCL3L1 distribution among infection with HIV-1 and control subjects it has also been reported that children with upper copy counts have a lower risk of transmitting HIV-1 from mother of infection [7].
CNV of CCL3L1 rate in the Indian population ranges from 1-6, risk of infected with HIV-1 was found to be associated with people who have less than two copies compared to those who have two or more copies [8]. The aim of current study to monitoring the immune status by estimate the gene expression of the CCL3L1 gene in people infected with HIV compared to group of control.

A. Samples
One ml of whole blood samples were collected from 30 individuals infected with HIV-1 and 30 individuals noninfected as control group, these samples were placed in EDTA tubes containing 1 ml of TransZol, in the main donation center in Thi-Qar province, from February 2022 to February 2023.

B. Methods
All samples were screening by using ELISA assay. Positive samples were collected from infected patients after their consent. Human RNA was isolated from 1ml of whole blood samples using the (TransGen biotech, Cat.No:ET101,China). Due to the company's guidelines.

IV. DISCUSSION
Since gene expression was further directly related to molecular function, studying gene expression variation within or among social people can yield more information about how human genes have evolved to perform their functions [11]. Gene expression levels do not differ significantly between one group of the population and another, with the exception of a few genes that show varying levels of expression between a particular population [12].
Molecular analyzes revealed that genes with high variability in expression within the population are associated with some human diseases, and among these diseases is HIV-1 infection, especially the first phase enter of virus into host cell [13]. This confirms what Kaslow et al., [14], mentioned that there are certain genetic factors affecting exposure to infection with HIV-1 or the progress of AIDS, The clinical progression of HIV-1 infection was also noted to vary greatly between individuals. While some people with HIV develop AIDS very quickly, others are able to bring their virus under control and maintain a relatively stable immune system. Certain genes have been implicated in susceptibility to HIV/AIDS through genetic association analyses of AIDS patients.
Those genes control how HIV-1 enters cells and how the response to the virus, and significantly influence the susceptibility of individuals and populations to HIV-1 [15].
One such gene is CCL3L1, which is highly variable due to the presence hotspot of segmental duplication [2]. It is a host factor that interacts with many HIV-1 genes, controls enter of virus and inhibits duplication, and shows high variability in expression between individuals [13]. CCL3L1 prevents the virus from entering cells by competing with HIV-1 for the CCR5 receptor [16].
Through the current study regarding the gene expression of the CCL3L1 gene between the infected group and the control group, it was found that there are clear expression levels of a gene among the infected compared to the control group using qPCR technique, this is consistent with Pilotti et al., [9] who mentioned increase expression of the CCL3L1 gene due to HIV-1.It also agrees with [13], described a 3-fold increase in the expression of CCL3L1 gene.
However, the result of the current study differedform other studies that reported that there was no variance in CCL3L1 levels among people HIV-1 patients and the control group [17].
Perhaps the reasons for the discrepancy in the results of these studies are due to the method of collecting or preparing samples, the use of inappropriate amounts of cDNA , or the inappropriate rounding to the nearest value as an integer [18]. Or the difference in the method of examination, as Urban et al., [17], mentioned and there is a significant correlation between CCL3L1 levels among people living with HIV-1 compared to the paralogue ratio test (PRT) control group, but there is no significant correlation when using the qPCR technique. However, qPCR is sometimes useful in studying gene expression [19,20].
Or, samples of studies that indicated there is no association between the CCL3L1 and the HIV-1 may have been taken in the late stages of infection, as there is no effect of the CCL3L1 on the HIV-1 in infected people for over 15 years [2].

V. CONCLUSION
It was found in current study there was an increase in CCL3L1 gene expression in patients compared to the control group using qPCR. There is a need for more molecular studies and follow-up of genetic and immunological changes in infected patients.

CONFLICT OF INTEREST
Authors declare that they have no conflict of interest.