Basic Characteristics of HIV-infected Individuals
In this study, plasma samples from 15 individuals in the early treatment stage and 18 individuals in the delayed treatment stage were selected for analysis and comparison. The median age of the patients in the early treatment group was 28 years (interquartile range (IQR], 26–36 years), and that of the delayed treatment group was 32 years (interquartile range [IQR], 28–38.5 years]. All selected patients were male, except for one candidate. Men engaging in same-sex relations (MSM) accounted for the highest transmission rate. There was no significant difference in the viral load or lymphocyte counts before and after early or delayed treatment (Table 1).
Table 1
Basic characteristics of HIV-infected individuals.
Characteristic
|
AHI
n = 15
|
CHI
N = 18
|
P-value
|
Age, years
|
28(26,36)
|
32(28,38.5)
|
0.319
|
Sex, n (%)
|
|
|
|
Male
|
14 (93)
|
18 (100)
|
NA
|
Female
|
1 (7)
|
0 (0)
|
NA
|
Baseline: plasma viral load, (HIV RNA copies/ml)
|
24559 (2788,79646)
|
22500 (6675,75591)
|
0.857
|
ART: plasma viral load, (HIV RNA copies/ml)
|
TND
|
TND
|
1.000
|
Co-morbidities (%)
|
|
|
|
Syphilis
|
4(33)
|
5(33)
|
NA
|
HBV
|
0(0)
|
0(0)
|
NA
|
Syphilis + HBV
|
0(0)
|
3(20)
|
NA
|
Transmission category, n (%)
|
|
|
|
Hetero
|
2 (17)
|
2 (13)
|
NA
|
MSM
|
9 (75)
|
11 (73)
|
NA
|
PWID
|
1 (8)
|
0 (0)
|
NA
|
Unknown
|
0 (0)
|
2 (13)
|
NA
|
Baseline: CD4 + T cell count (cells/µL)
|
358.29 (263.4,497.3)
|
296 (225,366.4)
|
0.148
|
cART (96 w): CD4 + T cell count (cells/µL)
|
637.76 (499.14,954.43)
|
563.72 (466.52,687.68)
|
0.357
|
Baseline: CD8 + T cell count (cells/µL)
|
997.51 (659.5,1628)
|
735.37 (515.8,1002)
|
0.075
|
cART (96 w): CD8 + T cell count (cells/µL)
|
801.43 (544.59,855.84)
|
906.41 (675.38,1223.20)
|
0.139
|
cART Treatment, n (%)
|
|
|
|
cART (AZT/3TC/NVP)
|
0 (0)
|
9 (60)
|
NA
|
cART (TDF/3TC/EFV)
|
100 (0)
|
5 (33)
|
NA
|
Regimen adjustment*
|
0 (0)
|
1 (6)
|
NA
|
Notes: Data are presented as medians with IQRs. Participant characteristics were analyzed using the Mann-Whitney U test. Statistical significance was set at P < 0.05. Abbreviations: AHI, acute HIV infection; CHI, chronic HIV infection. |
To determine the patterns of inflammatory cytokine levels under natural conditions (before treatment), we first examined those with significantly altered levels (Table S1). We found that the levels of PD-L1, IL-8, EGF, G-CSF, granzyme B, IFN-b, IL-12p70, IL-15, IL-17A, IL-17E, IL-1b, IL-33, IL-5, TGF-a, VEGF, and FGF basic were significantly lower than the normal levels. As expected, some cytokines with significantly elevated levels may be constitutional components of the cytokine storm (P < 0.05). Higher levels of eotaxin, MIP-3b, MCP-1, MIP-1a, IP-10, Fit-3 ligand, GM-CSF, IFN-a, IL-10, IL-1ra, IL-3, IL-4, PDGF-AB/BB, TNF-a, TRAIL, and fractalkine are shown in Table S1.
Levels of Few Cytokines Decreased Significantly through 96 weeks of Anti-HIV Therapy
First, we aimed to directly observe the changes in cytokine levels before and after antiretroviral therapy. Upon comparing the results of the natural infection group with those of the long-term (96 weeks) anti-HIV treatment group in early and delayed treatment stages, we found that MIP-3b, fractalkine, IL-10, IP-10, GM-CSF, Fit-3 ligand, and TRAIL were significantly reduced after long-term highly active antiretroviral therapy (HAART) (Fig. 1, A-G). Early treatment could be effective in alleviating the risk of inflammatory cytokine storms [1]. MIP-3b, fractalkine, IL-10, GM-CSF, and Fit-3 ligand showed significantly reduced expression during the early treatment stages (Fig. 1A–C, E, F). IP-10 levels decreased more significantly in the delayed treatment group (P < 0.001). TRAIL expression was significantly reduced only in the delayed treatment group (P < 0.05). Although early treatment can be effective in reducing the levels of some cytokines, the results are not the same for all cytokines. Moreover, early antiretroviral therapy (ART) is ineffective in eliminating HIV-induced immune responses [6].
To determine changes in the levels of different cytokines during this process, we collected samples at four time points (0, 24, 48, and 96 weeks). First, we used GEE to analyze all 33 samples, both acute and chronic. After 96 weeks of antiretroviral therapy, the levels of a few cytokines, including IL-1ra, TRAIL, eotaxin, MIP-3b, fractalkine, IP-10, Fit-3 ligand, GM-CSF, granzyme B, IL-10, TNF-α, and IL-1a, changed significantly (P < 0.05). Eotaxin levels increased dramatically after treatment, whereas those of the other cytokines decreased significantly (P < 0.05) (Table S2). To further examine the performance of the cytokines, we conducted an analysis (Wilcoxon test) for the early or delayed treatment separately to examine the changes from 0 to 96 weeks. Notably, the levels of all cytokines mentioned above decreased significantly within 24 weeks (Fiebig III) in the early treatment group (Fig. 2A–J). Some cytokines rebounded after 24 weeks (Figure D-J). However, MIP-3b, IP-10, IL-10, GM-CSF, fractalkine, IL-1a, and Fit-3 ligand still showed reduced levels after 96 weeks of treatment compared to those at the beginning of the treatment (Fig. 2A–G). In the delayed treatment group, MIP-3b, IP-10, and IL-10 levels continuously decreased (Fig. 2A–C). In addition, GM-CSF and TRAIL levels decreased significantly after 96 weeks of treatment (Fig. 2D, I). Despite these changes, most cytokines did not exhibit any obvious variations during the entire process.
Few Cytokines could be Restored to Normal with Anti-HIV Therapy
As antiretroviral therapy could significantly reduce the levels of some cytokines, we sought to determine the cytokines whose levels returned to normal. We found that TRAIL, fractalkine, Fit-3 ligand, IL-10, and IL-1a levels recovered to normal levels compared to those under normal conditions at 96 weeks (Fig. 3, A-E).The levels of granzyme B were significantly lower than normal levels after 96 weeks of treatment (Fig. 3, J), although these levels were low from the onset. The levels of MIP-3b, GM-CSF, IL-1ra, and IP-10 were significantly higher than normal levels (Fig. 3F–I). However, we found that variations during the early and delayed treatment stages did not correspond. The GM-CSF levels returned to normal after 96 weeks of treatment in the chronic group and remained high in the early treatment group (P < 0.001).
Classification of Cytokines associated with HIV Infection Demonstrated using Cytokine Networks
As antiretroviral therapy alone cannot alter cytokine levels, we sought to examine how cytokines function together during HIV infection. Using the information collected earlier, we separated cytokines into two groups: those with higher-than-normal levels (Fig. 4) and those with lower-than-normal levels (Fig. 5). In this process, we selected cytokines whose levels were higher or lower than normal but did not return to normal after 96 weeks, to fit into these networks. This was performed to determine how these crucial cytokines interact with each other to maintain the immune condition from recovering to normal. Each group was further separated into four specific circumstances: acute _UTx, acute _Tx, chronic _UTx, and chronic _Tx. The selected cytokines were closely associated with each other, creating a significant HIV-related immune environment. To clarify this, we further grouped cytokines according to their functionality (Table 2). Deciphering how these cytokines function may aid in developing a more detailed anti-HIV therapy for better recovery.
Table 2
Classification and description of cytokines.
Classification
|
Cytokine Level
|
|
Presentation of Cytokine Functions
|
|
Th1/Th2
|
E
|
IL-4
|
Promotes Th2 lymphocyte proliferation and differentiation.
|
[30]
|
|
E
|
IL-10
|
Mainly Th1 proliferation, also with Th2 in specific condition; IL-6/IL-10 can lead to B-cell lymphoma.
|
|
D
|
Granzyme B
|
Produced by NK cells through ADCC function.
|
|
D
|
IL-12P70
|
IL-2/IL-12 significantly activates Th1 reaction.
|
[31]
|
D
|
IL-15
|
Potent testing Th1 activator.
|
[24]
|
D
|
IL-17E(IL-25)
|
Lead to Th2 reaction.
|
|
D
|
IL-5
|
Promotes B cell growth; Also called “Eo-CSF”.
|
|
Chemokine
|
E
|
Eotaxin (CCL11)
|
Natural antagonist of CCR2; Natural activator of CCR5.
|
[32]
|
|
E
|
MIP-3b
|
CCL19; C-C chemokine subfamily has potent antiviral ability.
|
|
E
|
MIP-1a
|
CCL3;
|
|
E
|
IP-10
|
CXCL10; extreme rise in HIV infection.
|
|
E
|
MCP-1
|
CCL2; targeting CCR1, CCR2, CCR5.
|
|
D
|
IL-8
|
CXCL8; specifically attracts neutrophil granulocytes.
|
|
CSF
|
E
|
FLT-3Ligand
|
Activates granulocyte with GM-CSF; AML deteriorate.
|
[33]
|
|
E
|
GM-CSF
|
Granulocytes and macrophages.
|
[34]
|
E
|
IL-3
|
Also called “Multi-CSF”.
|
|
D
|
G-CSF
|
Granulocyte stimulating factor.
|
|
IFN
|
E
|
IFN-a
|
Poor effect on HIV; promotes significant CD4 + T decrease.
|
|
|
D
|
IFN-b
|
Has shown some efficacy in treating COVID-19.
|
|
Inhibitor
|
E
|
IL-1ra
|
Can be induced by GM-CSF, IL-3, IL-5.
|
|
|
D
|
PD-L1
|
Immune checkpoint; proven crucial roles in both tumor immunity and viral immunity.
|
[35]
|
Pro-inflammatory
|
D
|
IL-17A
|
Primarily activating neutrophils.
|
|
|
D
|
IL-1b
|
IL-1 family member; Large damage of normal issue.
|
|
D
|
IL-33
|
IL-1 family member; IL-33 antibody can effectively reduce neutrophil amount.
|
|
TNF
|
E
|
TNF-a
|
TNFi can significantly reducing inflammatory syndrome.
|
|
|
E
|
TRAIL
|
TNF family has not shown strong killing effect on HIV-infected cells.
|
|
Growth Factor
|
E
|
PDGF-AB/BB
|
Imatinib, Sorafinib, Sunitinib play perfect antagonism effect.
|
[36]
|
|
D
|
TGF-a
|
Potent immune response suppressing factor; Promote regeneration of thymus epithelium after injury.
|
|
D
|
FGF Basic
|
Fibroblast growth factor; activates epithelium transcription factor.
|
|
D
|
EGF
|
Epithelial growth factor; cooperate with TGF and FGF.
|
|
D
|
VEGF
|
Vascular endothelial growth factor; also impacts on lymphatic vessel.
|
|
Abbreviations: E means “Elevated”; D means “Deficiency”. |