Association of HLA-DR3, DR4, and B27 gen in autoimmune hepatitis patients

AIH so far thought to be an auto-immune disease. One of the genetic predisposing factors is thought to be HLA-DR3 and DR4 genes. The present study aimed at investigation the frequencies of HLA-DR3, DR4 and HLA-B27 genes among the Real-time PCR were used for the HLA-genes. The age of the patients were ranged from 7- 69 years in AIH group and from 8-67 years in healthy controls group. On the context of genotyping of HLA- genes, DR3, DR4, and B27 were found to be differed in their frequencies significantly among AIH patients that creating high etiological fraction of 0.504, 0.583, and 0.129 respectively compared to healthy controls, with odd ratio (OR) 7.35 for DR3, high OR 8.0 for DR4 and 2.23 for B27. The frequencies of these genes in AIH patients, highly significant differed between patient group, for DR3 compared to healthy group which 58.3% and 16% respectively, and very high significantly differed between patient group for DR4 compared to healthy group which 66.7% and 20% respectively, while no significant differed between patient group compared to healthy group for B27 which 23.3% and 12% respectively.


Introduction
In current study the age range of 7-69 years in autoimmune hepatitis patients with mean age (40.6), this result was just similar to that of Mauss et al., (2013). Moreover, it was, for some extent comparable to (39.2±11.2) years reported by (1).
Thus in Iraq the incidence of AIH is in younger age patients which might be attributed to environmental factors, malnutrition and stress or even due to the fact that the life span of Iraqi are lower than that for European (2).
The female was predominant in this study (68.3%) and this comparable with other studies where women represent (73.4%) in (3), Also the ratio of male to female which was (1:2.8) in this work which is nearly comparable to that of (1:2.7) reported by (4). However, the ratio 1:2.4 and 1:3 had been reported by abroad studies (4).
These variations may be related to the differences in race and genetic factor in addition to environmental differences. The explanation for predominance of AIH among females more than males may be due to the effect of hormonal differences which activate Th2 and subsequently enhance autoantibodies production (5).
In general, regarding the laboratory diagnosis of autoimmune diseases, the detection of autoantibodies alone doesn't mean the presence of neither the disease, nor it is absence exclude it so far. However, these tests, i.e., autoantibodies detection, may accomplish the clinical feature of the case, as do the biochemical tests. The routinely used tests during the course of autoimmune hepatitis were investigated in this study (6).
To shed light the supportive value of these autoantibodies and on possible association with more candidate genetic factors, as well median concentration of this autoantibody (p < 0.001) among autoimmune hepatitis patient and the level of ANA antibodies among AIH patients in this study was (75%) have referred to the positive level of ANA antibodies in 76% of patients with AIH group (7).
Al have reported similar results, where the ANA was 80% positive and (2009). However, lower frequencies have been reported by (2013), where it occurred in only (17.6%) and where it occurred in only (13.33%) in AIH patients (8).
There were significant differences in the median concentration of this autoantibody (p < 0.005) between autoimmune hepatitis patient and healthy control (9).
As with the occurrences of other autoantibodies during the course of diverse autoimmune diseases, such materials may be/may be not developed, and if developed, there is a certain extent at which they produced. In other words, some controversial between different studies regarding the presence of anti-SLA, some are in concordance with ours like this differences may be due to small number of samples (10). The significant differences of LKM among AIH patients (p= 0.01) when compared with health control group in this study is disagree with this difference because the small sample size and variation of prevalence of auto-immune diseases among AIH patients in this study (11).

Materials and Methods
Two study groups have been enrolled in this study, the first was composed of Sixty Iraqi autoimmune hepatitis patients, include (19) males and (41) females, had been clinically diagnosed as autoimmune hepatitis by physicians, biochemical tests, and immune assay tests, with an age range of (7-69) years with an a mean age ( 40.6 ) year old. The second group was consisted of 50 healthy control individuals (15 males and 35 females) for age (10-67) years old, sex and ethnic back ground (Iraqi Arabs) were selected who had no history or clinical evidence of hepatitis or any chronic disease and obvious abnormalities according to laboratory findings of biochemical tests and immune assay tests who were considered as control. Individuals of both groups were subjected for the occurrence of HLA-DR3, HLA-DR4, and HLA-B27 as well as described by (12). A real time PCR was used to amplify the gene using the primer mentioned in table (1)

Result and discussion
As shown in table (2) the current study revealed an age range of 7-69 years in autoimmune hepatitis patients with mean age (mean= 40.6 ± SD 14.9), whereas the age range of healthy group were (10-67) years with mean age (36.7 ± SD 15.0), which selected matched and this result are comparable to Mauss (14). Moreover, it was observed in this study, that the mean age of the disease was (40.6) years which, is to some extent comparable to (39.2±11.2) years reported by Mauss (15). Thus in Iraq the incidence of AIH is in younger age patients which might be attributed to environmental factors, malnutrition and stress or due to the fact that the life span of Iraqi are lower than that for European (16). Also table (2) showed there was no obvious statistical significant difference in mean age between cases and controls.
Data of the current study showed a female predominance, where the female/male showed 41(68.3%)/19(31.7%) for the case group while the mal showed 16(32%) and 19(31.7%) for the control and case, this comparable with Baranov and Sabri (17,18). variations in age may be related to the differences in race and genetic factor in addition to environmental differences.
The explanation for predominance of AIH among female more than females may be due to the effect of hormonal differences which activate Th2 and subsequently enhance autoantibodies production (19).
There are specific alleles of HLAclass II that associated with susceptible for development of the AIH disease. The frequency distribution of class II HLA-DR3, DR4 & B27 alleles for patients as compared with healthy control group in (%, OR, P, EF) are shown in (table 3). These results are in compatible with Amarapurkar (24) who studied HLA Genotyping autoimmune hepatitis in western India and attended strongly significant association of autoimmune hepatitis was found amongst HLA-B27 (25).