Chemokine Levels among Patients with Middle East Respiratory Syndrome Coronavirus Infection

Middle East respiratory syndrome coronavirus (MERS-CoV) is associated with significant morbidity and mortality due to intense pulmonary inflammation. Enhanced chemokine-mediated leukocyte infiltration in lungs has been linked with unfavorable outcomes with respect to the disease. This cross-sectional study assessed the levels of chemokines among 46 MERS-CoV-infected patients (19 asymptomatic and 27 symptomatic) and 52 healthy controls using a customized Luminex human chemokine magnetic multiplex panel. The plasma levels of interferon-inducible protein (IP)-10 (568.5 ± 114.7 vs. 55.19 ± 5.85 pg/mL; p < 0.0001), macrophage inflammatory protein (MIP)-1 alpha (MIP-1A) (30.78 ± 2.81 vs. 18.16 ± 0.91 pg/mL; p < 0.0001), MIP-1B (36.63 ± 4.25 vs. 25.26 ± 1.51 pg/mL; p < 0.003), monocyte chemoattractant protein (MCP)-1 (1267 ± 309.5 vs. 390.0 ± 35.51 pg/mL; p < 0.0002), and monokine-induced gamma interferon (MIG) (28.96 ± 3.93 vs. 16.29 ± 1.69 pg/mL; p < 0.001), interleukin (IL)-8 (147.9 ± 21.57 vs. 84.63 ± 10.62 pg/mL; p < 0.004) were significantly higher in symptomatic patients than healthy controls. Likewise, the levels of IP-10 (247.6 ± 80.09 vs. 55.19 ± 5.85 pg/mL; p < 0.0002) and MCP-1 (650.7 ± 149 pg/mL vs. 390 ± 35.51 pg/mL; p < 0.02) were also significantly higher in asymptomatic patients compared to healthy controls. However, no differences were observed in the plasma levels of MIP-1A, MIP-1B, MIG, and IL-8 between asymptomatic patients and uninfected controls. Conversely, the mean plasma levels of regulated on activation normal T cell expressed and secreted (RANTES) (3039 ± 301.0 vs. 4390 ± 223 pg/mL; p < 0.001) and eotaxin (176.9 ± 30.20 vs. 296.2 ± 28.11 pg/mL; p < 0.01) were significantly lower in symptomatic MERS-CoV-infected patients compared to healthy controls. Likewise, the levels of eotaxin (162.7 ± 21.60 vs. 296.2 ± 28.11 pg/mL; p < 0.01) were also significantly lower in asymptomatic patients. Interestingly, the level of MCP-1 (2139 ± 548.2 vs. 776.5 ± 165.3 pg/mL; p < 0.004) was significantly higher in deceased symptomatic patients compared to recovered symptomatic patients. MCP-1 was the only chemokine associated with a higher risk of mortality. Symptomatic MERS-CoV-infected patients had a significant elevation of plasma chemokines and elevated MCP-1 levels were found to be associated with fatal outcomes.

Differential expression of carcinoembryonic antigen-related cell adhesion molecule-5 (CEACAM5) and dipeptidyl peptidase-4 (DPP4) with detection of Middle East respiratory syndrome-coronavirus in peripheral blood

BACKGROUND

Middle East respiratory syndrome-coronavirus (MERS-CoV) utilizes CD26 (dipeptidyl peptidase-4) and CD66e or CEACAM5 (carcinoembryonic antigen-related cell adhesion molecule 5) receptors for cell infection. Peripheral blood mononuclear cells (PBMCs) play a critical role in mounting adaptive immune response against the virus. This study was performed to assess the expression of CD26 and CD66e on PBMCs and their susceptibility to MERS-CoV infection.

METHODS

Surface expression of CD26 and CD66e receptors on PBMCs from MERS-CoV patients (n = 20) and healthy controls (n = 20) was assessed by flow cytometry and the soluble forms were determined by enzyme-linked immunosorbent assay (ELISA). MERS-CoV UpE and Orf1a genes in PBMCs were detected by using Altona diagnostics reverse transcription polymerase chain reaction (RT-PCR) kit.

RESULTS

Mean fluorescent intensity (MFI) of CD66e was significantly higher on CD4 + lymphocytes (462.4 ± 64.35 vs 325.1 ± 19.69; p < 0.05) and CD8 + lymphocytes (533.8 ± 55.32 vs 392.4 ± 37.73; p < 0.04) from patients with MERS-CoV infection compared to the normal controls. No difference in MFI for CD66e was observed on monocytes (381.8 ± 40.34 vs 266.8 ± 20.6; p = 0.3) between the patients and controls. Soluble form of CD66e among MERS-CoV patients was also higher than the normal controls (mean= 338.7 ± 58.75 vs 160.7 ± 29.49 ng/mL; p < 0.01). Surface expression of CD26 on PBMCs and its soluble form were no different between the groups. MERS-CoV was detected by RT-PCR in 16/20 (80%) patients from whole blood, among them 8 patients were tested in PBMCs, 4/8 (50%) patients were positive.

CONCLUSION

Increased expression levels of CD66e (CEACAM5) may contribute to increased susceptibility of PBMCs to MERS-CoV infection and disease progression.

Assessment of Th1/Th2 cytokines among patients with Middle East respiratory syndrome coronavirus infection

Middle East respiratory syndrome coronavirus (MERS-CoV) is a member of the beta-coronavirus genus of zoonotic origin that emerged in the Arabian Peninsula and is associated with significant morbidity and mortality. This study was conducted to assess the plasma levels of cytokines to evaluate the Th1/Th2 status among 46 MERS-CoV-infected patients (19 asymptomatic and 27 symptomatic) and 52 normal healthy controls using a customized luminex kit. Comparative analysis of data between MERS-CoV-infected patients and normal healthy controls revealed that although no difference was observed between asymptomatic MERS-CoV patients and controls, the mean plasma levels of interleukin (IL)-10 (44.69 ± 40.04 pg ml-1 versus 14.84 ± 6.96 pg ml-1; P < 0.0001), IL-4 (22.46 ± 8.02 pg ml-1 versus 16.01 ± 9.97 pg ml-1; P < 0.0001), IL-5 (10.78 ± 2.86 pg ml-1 versus 8.06 ± 1.41 pg ml-1; P < 0.0001) and IL-13 (14.51 ± 3.97 pg ml-1 versus 11.53 ± 4.16 pg ml-1; P < 0.003) in MERS-CoV symptomatic patients were significantly higher than the normal controls. The mean plasma levels of interferon (IFN)-γ and IL-12 were no different among the study groups. The cytokine profile among symptomatic MERS-CoV-infected patients was skewed to a Th2 type immune response.

Assessing the Detection of Middle East Respiratory Syndrome Coronavirus IgG in Suspected and Proven Cases of Middle East Respiratory Syndrome Coronavirus Infection

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory disease with significant mortality. Two testing methods are currently used for MERS-CoV diagnostics: nucleic acid detection (the gold standard) and serological analysis. In this study, we evaluated the detection of MERS-CoV-IgG in suspected and proven cases of MERS-CoV infection. We enrolled 174 patients: 113 had respiratory symptoms/suspected MERS-CoV infection, 31 had confirmed influenza A or B infection, 23 had a recent confirmed MERS-CoV infection, and 7 had confirmed MERS-CoV infection 1 year before. All underwent MERS-CoV RNA and MERS-CoV-IgG testing. Thirty patients were found to be MERS-CoV RNA positive; however, during serological analysis, only 6 (3.4%) patients were positive for MERS-CoV-IgG, 1 (0.6%) patient was equivocal, and 167 (96%) patients were negative. Among the serological positives, four were recently MERS-CoV RNA positive and two were MERS-CoV RNA negative. No cross-reactivity to influenza A or B was detected. Based on the lack of correlation between nucleic acid and serological analysis, we conclude that MERS-CoV-IgG testing may not be suitable for diagnosing acute infection or estimating its prevalence during an outbreak. In addition, our findings show that MERS-CoV-IgG may not have significant value in determining disease severity or prognosis.

Disruption of a conserved CAP-D3 threonine alters condensin loading on mitotic chromosomes leading to chromosome hypercondensation

The condensin complex plays a key role in organizing mitotic chromosomes. In vertebrates, there are two condensin complexes that have independent and cooperative roles in folding mitotic chromosomes. In this study, we dissect the role of a putative Cdk1 site on the condensin II subunit CAP-D3 in chicken DT40 cells. This conserved site has been shown to activate condensin II during prophase in human cells, and facilitate further phosphorylation by polo-like kinase I. We examined the functional significance of this phosphorylation mark by mutating the orthologous site of CAP-D3 (CAP-D3(T1403A)) in chicken DT40 cells. We show that this mutation is a gain of function mutant in chicken cells; it disrupts prophase, results in a dramatic shortening of the mitotic chromosome axis, and leads to abnormal INCENP localization. Our results imply phosphorylation of CAP-D3 acts to limit condensin II binding onto mitotic chromosomes. We present the first in vivo example that alters the ratio of condensin I:II on mitotic chromosomes. Our results demonstrate this ratio is a critical determinant in shaping mitotic chromosomes.