IBD prevalence in Bedouin Arab population is increasing . ASCA and ANCA are very well-studied markers in CD and UC as diagnostic markers or as a predictor for disease phenotype. No data were reported regarding these serological markers in the Arab Bedouin population.
We investigated the frequency of these markers and its association with the disease phenotype. This is the first report of IBD serologic markers Arab Bedouin IBD patients in southern Israel.
ASCA are known to be predominantly associated with CD and ANCA with UC.
In our study we found the frequency of 52% of ASCA in CD patients. Among the UC patients, we also found a frequency of 36% of atypical ANCA, whereas the frequency of pANCA was 24% of the UC cohort.
The frequency range of ASCA and ANCA are so wide and different in literature and in different population. The frequency of ASCA in CD patients and ANCA in UC patients may reach 80% in some reports [9,10,11,12,13,14].
In this study, we found a high frequency of ASCA and pANCA. However, in our cohort the most frequent ANCA type was the atypical ANCA and not the pANCA.
There are only few reports in the Arab world regarding serological markers in IBD among the Arab population; a study of IBD in children from Saudi Arabia found a prevalence of 35% of ASCA in CD patients and 28% of pANCA in UC .
Bread and beer are important sources of Saccharomyces cerevisiae yeast, only scant paper published regarding the relationship between the diet and ASCA frequency. However, no support of relationship between bread consumption and ASCA frequency was found in the scientific literature .
An important part of the nutrition among the BA is bread, which is included in the daily nutrition , and a low percentage of alcohol, we found a relative high frequency of ASCA among CD patients, the possible relationship between high consumption of bread and frequency of ASCA among this population is still to investigate in the future.
On the basis of the results of the present study, no relationship was found between the ASCA positivity and the disease phenotype characteristics in the CD patient’s cohort.
Also, in previous literature there are a large number of reports regarding the relationship between ASCA and CD phenotype; however, the results are controversial and vary among the previously reported studies, some of them found an association between ASCA positivity and early disease onset, longer disease duration, ileal involvement, complicated disease and IBD-related surgery [13,14,15,16,17,18]. Other several independent studies found no association between these parameters and ASCA positivity , it is therefore, important to mention is that these studies were heterogeneous in term of design, inclusion criteria, number of patients and other parameters of methodology . In our work, the patients with positive ASCA were younger; however, it’s still none statistically significant. In our cohort we didn’t find a relationship between ASCA positivity and gender, family history of IBD, smoking, disease location, anti-TNF treatment or surgery.
While it is possible that there is no relationship between ASCA and disease phenotype in our population, from another view the no relationship perhaps could be linked to the small number of IBD patients in this specific population. It has also been suggested that to investigate this issue in this specific population in the future, when the number of IBD patients is larger, which could make the relationship clearer.
According to our results, the most common type of ANCA in Arab Bedouin IBD patients is the atypical ANCA, which was common by 36%. Several previous reports indicated a high frequency of atypical ANCA in other populations [26, 27]. In the present research the frequency of pANCA was 24%. This, therefore, translate into 60% of our UC cohort tested positive for pANCA or Atypical ANCA. In comparing our results with those in previous literature particularly Arab children in Saudi children, which showed a 28% frequency of pANCA , the frequency of pANCA and atypical ANCA is high in our cohort. To the best of our knowledge there are no other reports from Arab population in the Arab World.
In contrast to the more accurate results seen in our UC cohort, we have demonstrated that male patients are more likely to have negative ANCA or cANCA rather than atypical or pANCA. Of the ten patients who had negative ANCA or positive cANCA, nine of them were male (90%), however only 3 of 15 patients (20%) with positive pANCA or atypical ANCA were male (p = 0.002).
Atypical ANCA testing might be a helpful test for differentiating UC from CD in this specific population. Previous study suggested that atypical p-ANCA is a useful parameter to differentiate UC from CD .
In one hand, we have reported before, that the IBD among Bedouin Arab is increasing , which is attributed to change of lifestyle, including urbanization and modernization with a western lifestyle, particularly change of hygiene and nutrition. In the other hand we found a high prevalence of ASCA and ANCA positivity in the specific population. The Bedouin Arab in southern Israel are a very young society, 60% of the population are younger than age 19 . The compensation of these factors let us expecting continuation increase of IBD incidence and prevalence in the future. The importance of this study might be the detecting a high frequency of serologic markers and its implication as diagnostic markers or as marker, which could differentiate between CD and UC.
The present study is limited by the small number of patients, the use of only the ASCA IgG type and the lack of control group.