Kim Kardashian has launched a desperate appeal in a bid to find an Armenian bone marrow donor for her sick cousin.

The pregnant reality TV star has penned an emotional plea on her blog to help her cousin Cici, who has stopped responding to chemotherapy treatment as she battles cancer.

In the post, Kardashian explains, "This is difficult for me to write, but we really need your help. My cousin, Cici, has been battling cancer for 17 years. She's been going through chemo for such a long time, but now the cancer is not responding to the chemo and she needs a bone marrow stem cell transplant. This necessary procedure would hopefully give our Cici many more years to live!

"What makes this more difficult is that the donor must be of Armenian descent because Cici is Armenian. We are asking every Armenian who reads this message to reach out to the bone marrow registry and sign up so that we can find a match for Cici."

Kardashian assures fans donating bone marrow is "not as scary as it sounds" and has urged her followers to do all they can to raise awareness of Cici's plight.

She adds, "Please help our family's plea by signing up and pray that we all can save Cici's life! Thank you guys!!! Please keep Cici in your prayers."

Her sister Khloe has taken to her Twitter.com page to echo Kim's plea and reveals the famous family has been tested as potential bone marrow donors - but were not compatible.

In a series of posts, she writes, "I have never met any person in my life who lives life to the fullest every single day! That's my cici! Always smiling. We have been praying for 17 years Cici and God has been so great to us! We have been tested. Matches aren't easy to come by."