The study population is patients with liver cirrhosis undergoing liver transplantation; In this study, the sample will be selected from cirrhosis patients undergoing liver transplantation in Taleghani (Tehran), Imam Khomeini (Tehran) and Abu Ali Sina hospitals(Shiraz).

This study uses the recorded information of patients with cirrhosis who have undergone liver transplantation so far and have inclusion criteria and no exclusion criteria. First, we extract demographic and clinical and pathophysiological information of patients, including age, sex, BMI, cause of cirrhosis, medical status at the time of liver transplantation, history of abdominal surgery, portal vein thrombosis, and waiting time for liver transplantation. In the next step, we examine the serum level of vitamin D in different age and sex groups and determine the prevalence of vitamin D deficiency for each group. It should be noted that in this study, the serum level of 25-hydroxy vitamin D below 20 ng/mL will be considered an insufficient level.

In the next step, in patients 12 years of age and older, according to serum bilirubin, serum creatinine, serum sodium and INR, we calculate the MELD-Na score and evaluate it with the serum level of vitamin D or 25-hydroxy vitamin D. We also use PELD scores in patients younger than 12 years of age, which consist of age, serum albumin, total bilirubin, INR, and stunted growth.

Follow-up will be done by calling the patients and recruitment every 3 month. ACR or acute cell rejection is usually suspected after elevated liver enzymes (serum aminotransferases, alkaline phosphatase, gamma glutamyl transpeptidase) or bilirubin (30). The incidence of ACR and Overall survival (OS) will be considered as the end point of the first phase of the study, and finally the incidence of 25-hydroxy vitamin D before transplantation with MELD-Na or PELD score will be examined. ACR and OS, we deal with statistical tests.

In the second phase of the study, which is a clinical trial, 50 sample patients with vitamin D deficiency will be selected from Taleghani Hospital; After transplanting, we will inject 300,000 units of vit D IM and compare their ACR and OS levels with those who have been deficient in vitamin D but whose vitamin D status has not improved. It is worth mentioning that in the second phase of the study, patients will be followed up to 3 months after liver transplantation.

Inclusion Criteria:

• ESLD underwent liver transplantation
• Creatinine, bilirubin and INR measured
• Measured liver enzymes such as serum aminotransferases, alkaline phosphatase, gamma glutamyl transpeptidase / or bilirubin

Exclusion Criteria:

• People with acute liver failure
• People who have had multiple organ transplants
• Primary graft non-function (PNF) individuals