Anti-Jka (JK1)

Blood Group: Kidd

Common:  23% Caucasians, 8% Blacks, 27% Asians are Jk(a-b+) and at risk for developing anti-Jka [1].

Causes HDN: Yes
Critical Titer: 1:16
Information:
The cases where anti-Jka has caused a problem are few and far between. Of the 4 cases of HDN from anti-Jka mentioned in the article, only 2 required exchange transfusion. After two intrauterine deaths from anti-Jka, the authors treated the infant with immediate exchange transfusion upon birth. [4] 


While anti-Jka is usually mild, it can cause severe HDN. In this article, despite exchange transfusion at 3 days old, the infant developed kernicterus. The authors again recommend early exchange transfusions with anti-Jka to avoid Kernicterus. [3]


Kidd antibodies are frequently difficult to detect. This makes them hazardous in transfusion medicine. They are a suspected common cause of delayed hemolytic transfusion reactions. [1]


Kidd antigens are also found on the kidneys [1]. With anti-Jka, titers vary over time or may completely disappear, but they are known to surge at a second exposure to cause delayed hemolytic transfusion reaction (DHTR) [5].


In one article, out of 20 cases of anti-Jka, 16 required monitoring with titers only, while 4 were followed with more diagnostic tests. One pregnancy with the highest titer of 1:32 had an elevated MCA PSV and needed 4 IUTs. A second pregnancy with titers 1:32 had an infant who needed phototherapy to read the HDN. None of the other 18 infants required any therapy for HDN. The article concluded that the 1 severe case of HDN was correctly identified by following titers and MCA scans as used for montioring anti-D. The authors reported that the criteria used for monitoring anti-D affected pregnancies were effective in detecting severe HDN due to anti-Jka. [2]


Articles:

1 - https://www.ncbi.nlm.nih.gov/books/NBK2272/
2 - https://www.ncbi.nlm.nih.gov/pubmed/19370894
3 - http://onlinelibrary.wiley.com/doi/10.1111/j.1423-0410.1959.tb04028.x/full
4 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1848545/pdf/canmedaj00916-0033.pdf
5 - http://pathology.ucla.edu/workfiles/Education/Transfusion%20Medicine/5B-Blood-Kidd-luPPT.75184755.pdf
6 - http://www.nejm.org/doi/pdf/10.1056/NEJM196706292762609
7 - https://www.ncbi.nlm.nih.gov/pubmed/13669426
8 - http://indianpediatrics.net/dec1998/dec-1251-1253.htm
9 - https://www.ncbi.nlm.nih.gov/pubmed/7382958
10 - https://www.ncbi.nlm.nih.gov/pubmed/2584811
11 - https://www.ncbi.nlm.nih.gov/pubmed/557194