Interleukin-28B genotyping profile is expressed in HCV-infected patients into favorable CC genotype and unfavorable TT genotype. The former CC genotype might be defensive against disease progression and development of diabetes, while the later TT genotype might be a risk factor for the appearance of T2DM, fibrosis, and cirrhosis.
In this study, 160 patients who were positive for chronic HCV, 107 males and 53 females, aged between 20 and 70 years, were divided into two groups; 80 CHC patients without diabetes at the time of sample collection and 80 CHC patients with T2DM and were subdivided by Fibro-Scan into mild and advanced fibrosis.
As shown in Table 1, age showed a significantly higher difference in diabetes with compensated cirrhosis versus non-diabetes with compensated cirrhosis (p < 0.001), and that may be attributed to the fact that included diabetes patients were older than the non-diabetes with range [45–70 years versus 20–64 years] and mean ± SD (57.58 ± 4.39 vs. 40.79 ± 11.65; p < 0.001, respectively); this factor could potentially contribute to the development of T2DM and disease progression in advanced fibrosis.
BMI showed a significantly higher difference in diabetes patients with fibrosis than non-diabetes with fibrosis (p = 0.001) because people with T2DM usually suffer from fatness and show an inactive manner of living . This matched with studies on T2DM in healthy individuals as well as diseased patients with genotypes other than HCV genotype 4 . The amplified prevalence of diabetes in chronic liver disease is limited to HCV, and this relationship may be due to glucose intolerance in these patients . Furthermore, high BMI, getting old and genomic factors such as a family history of T2DM, may lead to the development of T2DM and make difficulties in evaluating the pathogenic role of the virus C as a causative organism which enhances the development of T2DM .
Table 2 demonstrates that more than half of included patients have CT genotype expression. Although many studies had been done in IL-28B (rs12979860) in Egypt and around the world [27,28,29,30], the analysis of the prevalence of different genotypes CC, CT, and TT of IL-28B rs12979860 among all populations diseased and healthy is scarce and needs more evaluation. However, a study done by Thomas et al. reported the distribution of the C allele showed a lower frequency among Africans than Europeans and was more prevalent in Asians .
In the non-diabetic group, the genotype CC represented (36.3%), CT (43.7%), and TT (20%); these results are near to those of Bakr et al. and similar to El-Awady et al. [32, 33]. On the other hand, the CC genotype was significantly lower in CHC patients with diabetes (13.7%). In contrast to, the non-CC genotypes (CT/TT) showed a higher significant difference in CHC patients with diabetes than without diabetes [CT 58.8% vs. 43.7%, TT 27.5% vs. 20%, respectively] (p = 0.03, and χ2 = 6.14).
When we compared the allele frequency between two groups in this study, the favorable C allele was more in the non-diabetes group (58.7%) than in the diabetes group (47.5%). In contrast, the non-favorable T allele was lower in the non-diabetes (41.3%) compared to the diabetes group (52.5%) with statistically significant difference (p = 0.04, and χ2 = 2.48) (Table 2). These results were in concurrence with El-Awady et al. .
The level of CC genotype in the non-diabetes group was higher in fibrosis than in compensated cirrhosis [45.0% vs. 27.5%, respectively], but statistically insignificant (p = 0.27). At the same time, the level of CC genotype in the diabetes group was the worst either with fibrosis and/or compensated cirrhosis [15%, vs. 12.5%, respectively]. So, the reduction in CC genotype had been linked to the stage of fibrosis and the presence of diabetes. On the contrary, the non-CC genotypes were higher in the diabetes group with fibrosis and compensated cirrhosis but statistically insignificant (p = 0.32), as presented in Table 3.
Diabetes is accompanied by increased fibrosis in patients with HCV, but possibly it is due to the frequent occurrence of diabetes in patients with cirrhotic liver disease . The association of T2DM with the increased disease severity may be due to inflammation caused by the activity of the virus, duration of the disease, insulin secretion, insulin resistance, and the effect of other risk factors of T2DM .
The relation of T2DM and IL-28B genotype and the degree of severity of fibrosis in CHC patients with CC genotype compared to patients with non-CC genotypes (CC 12.5% vs. CT 52.5% vs. TT 35%, respectively) is shown in Table 3. The reduction in favorable CC genotype was substantial in the diabetic group with compensated cirrhosis, opposite to the increasing unfavorable TT genotype in the same diabetic group. Nonetheless, we cannot judge whether this connection between diabetes and genotype was primary or secondary to the effect of CHC on the liver and general metabolism.
Chang et al. and Eurich et al. tried to comprehend the role of IL-28B rs12979860 genotype in the progression of cirrhosis in CHC patients. They detected that the unfavorable TT genotype in IL-28B rs12979860 had been linked with disease progression and possibly HCC [34, 36]. However, Agundez et al. and De la Fuente et al. found that the IL-28B rs12979860 genotype distribution was similar in CHC patients and that of patients with HCC [37, 38]. Marabita et al. concluded that the IL-28B genotype did not influence developing cirrhosis, whereas factors like age, male gender, and HCV genotype 3 are triggers to hasten disease progression .
A significant relation has been detected between the ALT level and the genotype; the CC genotype showed the lowest level of ALT in comparison to the CT/TT genotype (p < 0.001), as presented in Table 4. ALT levels were increased in the TT genotype and mixed CT genotype, which were elevated in the diabetes group with cirrhosis. LSD between ALT and each genotype was highly significant [CC vs. CT p = 0.002], [CC vs. TT p = < 0.001] & [CT vs. TT p = 0.004].
On the contrary, Agundez et al. found a higher level of ALT with the CC genotype patients . This opposite relation might be attributed to the different HCV genotype 1 and the effect of viral genotype on ALT level . Also, Al-Swaff reported the high ALT values were mainly present in the early and late stages of inflammation .
A different viral genotype 1 was included in their studies than the common genotype 4 in our country, alcohol drink, and alcoholic cirrhosis, which could make different results as assessed by Schreiber et al., who detected a low predictive value of IFN-λ3 genotypes regarding HCV genotype 2 and 3 in their study. Alcohol drink and alcoholic cirrhosis still could present in those with CHC, and their results showed an effect of the non-favorable TT genotype on fibrosis progression .
Both ALT and HCV RNA viral load by PCR were much lower in patients with IL-28B genotype CC compared to other genotypes. In other words, the patients with non-CC genotype are associated with more inflammatory changes. These results conflicted with the results of the study by Tadeusz et al., who found no correlation between the viral load and the genotype [CC, CT, or TT] of the patients .
In the present study, the reduction in CC genotype in diabetes group versus non-diabetes group may be explained by the multivariate logistic regression analysis that showed different cofactors together combined with hepatitis C such as viral load, ALT, IL-28B genotypes, diabetes and age, might interplay as predictors for CHC disease progression from fibrosis to cirrhosis among diabetes group collectively, [viral load p < 0.001], [ALT p < 0.001], [genotype CC vs. CT p = 0.02], [genotype CC vs. TT p = 0.04], [T2DM p = 0.03] and [age p = 0.04], or independent predictors of disease severity which is highly significant with viral Load & ALT (p < 0.001), then genotype CC versus CT (p = 0.02) and T2DM (p = 0.03) in that manner consequently as shown in Table 5.
Strengths of the study
It is a new innovative study and a rare one in Egypt that studies the role of genetics in CHC progression and development of T2DM in CHC patients. This study is a preliminary study that pinpoints the importance of genetics in assessing either disease development (T2DM) or disease progression (CHC).
Limitations of the study
Regarding our study's constraints, the study is specific to a certain governorate. It cannot be generalized all over Egypt or even beyond the research setting at certain universities and hospitals. The study was done on a small sample size of patients that was limited to the power of the study. Also, no documents to decide precisely whether diabetes occurred before or after HCV disease, as most patients with diabetes and HCV may stay undiagnosed for a time and also, not all CHC patients developed diabetes. The Egyptian populations are infected mostly with HCV genotype 4 more than 90% ; so, we can consider this research applicable for genotype 4 and not an extension to any other research directed to a specific racial group other than Egyptians. Finally, the homeostatic model assessment "HOMA" test for assessing β-cell function and IR was not asked.