Clinician Awareness of RBC Health and Related Laboratory Measurements

Biree Andemariam, MD: I’ll direct this toward Nirmish. What do you think is the general level of awareness of red blood cell health? There are all the parameters and laboratory testing we’ve talked about, whether it’s experimental as part of clinical trials or standard-of-care labs that might be available. What’s the general awareness of clinicians regarding these tests and their importance?

Nirmish Shah, MD: It’s a growing field of understanding, but we don’t have a general awareness across the board. If you talk to most sickle cell [disease] providers, the focus is still getting them on the standard-of-care and approved medicines, which aren’t really in tune with red blood cell health “at this point.” Elna and Matt [Heeney] have both brought up that the standard of care is to look at the standard blood markers. It’s not to look, as Matt said, at these new lab tests because we just don’t have enough data yet—yet is the key part. As we get that data, we’ll be able to say, “This is what seems encouraging. I’m going to continue to show this.” [As it becomes] more widely available, then the sickle cell community will be able to lean on a test like that. Of course, if there’s a medicine that’s focused on red blood cell health, then [we can] use that as a tool to understand how much that medicine is helping.

Biree Andemariam, MD: That’s super helpful. I want to close this section by talking a little about how we would discuss red blood cell health and parameters and laboratory tests with patients and their families. You’ve touched on this, Nirmish. Elna, how would you begin to introduce the concept of these red blood cell health parameters to patients and families going beyond the usual hemoglobin, MCV [mean corpuscular volume], and MCH [mean corpuscular hemoglobin] and see into the haemolytic markers. Patients are getting comfortable with that, but how do you start to talk about 2,3 DPG [diphosphoglyceric acid]…and all that?

Elna Saah, MD: Yes, that’s been interesting. I’m partnering 1 of our labs that does functional red cell and biological markers. It’s very important to start by anchoring the patients on what’s important in their number. You have a hemoglobin of 7 or 8 g/dL. That number is important. We want to get it to 9 or 10 g/dL, get it 1 or 2 g/dL above, so you feel better. This takes care of the fatigue. However, it’s not only that number but also what happens with that number. What does the red blood cell do when it’s doing its job? When you take it out of the circulation from the lungs, where the oxygen is rich, and you get it to the tissues, what does that number do? What happens to your red blood cell? Does it squeeze in or squeeze out? Does it get in or does it get stuck, or occluded?

I try to let them know that we also want to figure out what’s happening at that stage. That’s when we introduce these indirect assessments of biological markers. I’ll say to them, “If your cell gets there—to the tissues, to your muscles, to the finger beds—does it get more sickly? Does it go from the potato shape and get more sickly? Is it able to come back?” I let them know that I need to figure out if there’s a lot of fluid in the cell. Does your cell get dehydrated to the point where it cannot come back? Does it get crystallized? I say that we have this test, so we can see how far out the stretch goes. How far out does it elongate and adapt? What point does it get there?

The other thing I bring up, when we’re talking about the role of the white blood cells and all the other things is how we can test and see what other cells are doing to increase the stickiness, to increase the likelihood of this cell getting stuck in the tissues. We have ways. There are other studies. We encourage biological studies and biobanking so we can investigate these things. Look at the point of sickling, the elongation index, microfluidics, and cell concentration. When we put it that way, we have a slightly higher chance of success with our patients participating in research studies to validate these biomarkers. I tell them that I don’t want to be here in Atlanta [Georgia] thinking, “This is what I need to do.” We need to have enough information so that everybody does it. We’re not really looking at the number as hematologists, but we’re looking at what the cell needs to do its job.

Biree Andemariam, MD: I agree with you 100%. Patients and family members encourage their loved ones with sickle cell disease to participate in these biomarker studies. They’re important. Elna, your description of how you’d present emerging functional studies to patients and families in the community is spot-on.

Transcript edited for clarity