PCH Help!

[BB1956]

I have a patient with a history of Non-Hodgkins Lymphoma. She has been fairly asymptomatic for the past few years. Recently she began showing signs of anemia. DAT testing revealed a negative IgG but positive C3.

The oncologist suspected a cold agglutinin or PCH and tested for Cold Agglutinins for 3 consecutive months through the winter and all were negative, Mycoplasma testing was negative. He then ordered Donath-Landsteiner testing, I/i antigen testing and P antigen testing.

We performed a modified cold panel using cord cells pooled from 3 patients and the only result which was positive was the 4C inbcubation with the cord cells 2+. There was no hemolysis with the Donath-Landsteiner testing and the patient typed P1 negative. Does anyone have any insight on what could be causing this patient to hemolyze?

The oncologist reports her hemolysis has improved as the weather has warmed. Appreciate your help or suggested testing.

[David Saikin]

Complement positive DAT - my experience with lymphoma pts is that in the latter stages of their disease they get a+DAT (though not always complement +). Has her DAT gotten weaker as her hemolysis as decreased?

[Malcolm Needs ☆]

I do not think for one second that this patient has PCH (sounds like the physician was clutching at straws when he/she ordered that particular test - and, incidentally, asking for a P1 antigen test was a waste of time), but, when you did it, did you add fresh complement (the indirect D-L test), rather than rely on the patient's own complement (the direct D-L test).

Many people do rely on their patient's own complement, but, in a rip roaring PCH, this complement is used up, and the direct D-L test will give a false negative result.

Did you perform a thermal amplitude test to 30oC?