What is the IGHV4-34 Variant of Hairy Cell Leukemia?

You've probably heard of the Hairy Cell Leukemia Variant (HCLv), a rare type of HCL.

Another lesser-known type is the IGHV4-34 variant.

The IGHV4-34 variant can be positive for CD25, like classic HCL, but it is anything but classic. The IGHV4-34 variant is negative for the BRAF V600E mutation and requires a different treatment and management approach.

The IGHV4-34 variant often presents with severely enlarged spleens, lymphadenopathy (disease or swelling of the lymph nodes), low blood counts, and elevated leukemic cells. It shows a poor response to single-agent cladribine and pentostatin. The IGHV4-34 variant should not be treated with purine analog monotherapy; instead, purine analog chemotherapies should be combined with rituximab.

In late 2023, Dr. Robert Kreitman from the NCI-NIH gave a webinar presentation to our patient network where he discussed HCL, HCL variant and the IGHV4-34 variant.

Slides and a transcript of his presentation are available on our website:
https://www.hairycellleukemia.org/november-2023-webinar