In a study to identify the role of ITPA rs1127354 in prediction of cytopenia in 149 Egyptian patients with chronic hepatitis C treated with combined pegylated interferon α and ribavirin, we find that pegylated interferon a2a was associated with higher frequency of anemia (P>0.05) and less thrombocytopenia (P=0.0004) and leukopenia (P>0.05) compared to INF a2b. However, when we compare the percent of cytopenia in relation to the type of interferon and genotypes of ITPA rs1127354, we find that CC can significantly predict more anemia and less thrombocytopenia in type a2a and not a2b. This means that the predictability of CC genotype of ITPA of rs1127354 regarding ribavirin induced anemia and the concomitant increase in platelet count is limited to INF a2a.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3086671/
Dear Mostafa,
It is highly dependent to sample size of each group. If the sample size in the a2a group was higher than that of the a2b group, it is rational to observe more associations in the a2a group however the sample size 149 is low and as a result such evidences are not conclusive.
Regards,
Heidar
Dear Heidar Sharafi
The number of patients treated with peg INF a2a were 86 (7 non CC and 79 CC) and a2b was 63 (5 non CC and 58 CC).
The alternative factor might be the low number of patients with non CC genotypes of ITPA rs1127354 which was 12 in our study, the distribution of the minor allele was 4%