Polyarteritis nodosa (PAN) and Hep B link?

[CBG23]

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So, I am a bit confused about this point: Apparently in ~30% of cases, a patient with PAN will have chronic Hepatitis B and test positive for immune complexes made up of HBsAg and Anti-HBsAg - Just double checked this point in Big Robbins.

This doesn't quite make sense. I thought individuals who can develop Anti-HBsAg will clear the virus and NOT develop chronic HBV infection, whereas those who fail to make Anti-HBsAg WILL develop chronic hep B. So how can someone with chronic hep B have immune complexes made up of Anti-HBsAg/ HBsAg?

 

[OveractiveBrain]

So, I am a bit confused about this point: Apparently in ~30% of cases, a patient with PAN will have chronic Hepatitis B and test positive for immune complexes made up of HBsAg and Anti-HBsAg - Just double checked this point in Big Robbins.

This doesn't quite make sense. I thought individuals who can develop Anti-HBsAg will clear the virus and NOT develop chronic HBV infection, whereas those who fail to make Anti-HBsAg WILL develop chronic hep B. So how can someone with chronic hep B have immune complexes made up of Anti-HBsAg/ HBsAg?

Hep A is the Acute form of Hepatitis ('everyone' gets only the acute infection)
Hep C is the Chronic form of Hepatitis ('everyone' gets only the chronic infection)
Hep B is the Both form of Hepatitis; you can get the acute or the chronic carrier state.

Hep B is dependent on how strong your immune system is.

Strong Immune System = Severe Symptoms and Cleared Infection (Acute). If Hep B infects a healthy adult, with an intact immune system, there is a vigorous reaction to the infection, which is cleared. The result is massive hepatic damage (to kill the virus you must kill the infected cells, which happen to be all hepatocytes). The patient will get anorexic, jaundiced, suffer abdominal pain, and other liver symptoms. Clearing the infection too well can lead to fulminant hepatic failure.

Weak immune System = Mild Symptoms and a Chronic Infection. If Hep B infects a weak adult (HIV/AIDS, on immunosuppresion) or infects a wee little baby without an immune system (vertical transmission) the infection cannot be cleared. No clearing of infection. No hepatic damage. No symptoms. However, the infection is still there and gets weeded, rooted in to the hepatocytes and floats around in the blood. There is no cure for the chronic carrier state (save the antivirals and Interferons for Medicine or even Hematology rotations), and these patients have similar hepatic risks as chronic Hep C-ers.

So how can someone with chronic hep B have immune complexes made up of Anti-HBsAg/ HBsAg?

To answer the original question: If you've got a virus chronically in you, you will develop antibodies to it. There aren't enough antibodies to clear the infection, just some foreign particles inciting an immune response. Its why they sometimes get yellow (like when they drink alcohol); the virus is still there, there is still an immune response, there is still inflammation. Thats why chronic hep Bers, like Chronic Hep Cers, have the same inflammatory risks (cirrhosis and Hepatocellular Carcinoma)

 

[thechad]

Weak immune System = Mild Symptoms and a Chronic Infection. If Hep B infects a weak adult (HIV/AIDS, on immunosuppresion) or infects a wee little baby without an immune system (vertical transmission) the infection cannot be cleared. No clearing of infection. No hepatic damage. No symptoms. However, the infection is still there and gets weeded, rooted in to the hepatocytes and floats around in the blood. There is no cure for the chronic carrier state (save the antivirals and Interferons for Medicine or even Hematology rotations), and these patients have similar hepatic risks as chronic Hep C-ers.

Perfectly healthy adults can contract chronic hepatitis from Hep B.

 

[OveractiveBrain]

Perfectly healthy adults can contract chronic hepatitis from Hep B.

Don't confuse the novice learner. Anything can be anything, and almost anything CAN happen. Of course. For understanding, for helping the novice grasp a concept, it is easier to first speak in absolutes, and allow the rest of their medical education (clerkships, residency, fellowships, and continuing ed) to flush it out.

Likewise, while it CAN happen, what is more LIKELY to happen is what I've written. Again, taking confusion out simplifies the answer. While not being 100% correct, it certainly conveys understanding.

 

[DoctwoB]

So, I am a bit confused about this point: Apparently in ~30% of cases, a patient with PAN will have chronic Hepatitis B and test positive for immune complexes made up of HBsAg and Anti-HBsAg - Just double checked this point in Big Robbins.

This doesn't quite make sense. I thought individuals who can develop Anti-HBsAg will clear the virus and NOT develop chronic HBV infection, whereas those who fail to make Anti-HBsAg WILL develop chronic hep B. So how can someone with chronic hep B have immune complexes made up of Anti-HBsAg/ HBsAg?

I think overactive brain's response missed the point. Unless I'm wrong, you're asking how chronic hepB can cause PAN (or glomerulonephritis) secondary to HBsAg-HBsAb complex deposition when development of HBsAb antibodies indicates immunity or clearance of HBV (according to first aid).

I think the answer is that anti-HepBsAg antibodies do confer immunity in sufficient quantities, but one might mount an HBsAb response sufficient enough to cause PAN but not sufficient enough to clear the infection.

 

[OveractiveBrain]

I think overactive brain's response missed the point.

Uh...

To answer the original question: If you've got a virus chronically in you, you will develop antibodies to it. There aren't enough antibodies to clear the infection, just some foreign particles inciting an immune response.

I presumed some one could go from "there are antibodies to antigens" to "there are antibodies to antigens that can get stuck in the kidney"

Whenever there is an error in reasoning, its best to step back and start from what you think they SHOULD know, then move forward, simply correcting the mistake doesn't get at the reason why they made the mistake, and no learning occurs. Offended? Too bad. I'm long winded.

I think the answer is that anti-HepBsAg antibodies do confer immunity in sufficient quantities, but one might mount an HBsAb response sufficient enough to cause PAN but not sufficient enough to clear the infection.

And no. If you had IgG HBsAB and no presence of IgM HBsAB and no HbeAg, HbxAg, HbcAg, then you have successfully cleared the infection, and no increased amount of antibody is necessary (until encountering an acute innoculation, where IgG may go up a tid bit). You are immune. This happens when the immune response is strong.

If you are a chroni carrier, on initial infection you were unable to mount a sufficient response, and now you are constantly going to make antibodies to the infection that is constantly there. You never (ok, not never, but feel that almost never) mount enough to clear the infection again. You'll have IgG HBsAb and IgM HBsAB, and still the antigen floating around. Its the fact that there is chronic antigens + chronic antibodies that make chronic Ag-Ab complexes that get deposited. The constant production of antibodies leads to immune deposition and hepatocellular dysfunction.

 

[UAAWolf]

Don't confuse the novice learner. Anything can be anything, and almost anything CAN happen. Of course. For understanding, for helping the novice grasp a concept, it is easier to first speak in absolutes, and allow the rest of their medical education (clerkships, residency, fellowships, and continuing ed) to flush it out.

Likewise, while it CAN happen, what is more LIKELY to happen is what I've written. Again, taking confusion out simplifies the answer. While not being 100% correct, it certainly conveys understanding.

In our micro class, we definitely learned that Hep B isn't limited to immunocompromised. I think your mnemonic is good but not fully correct

 

[thechad]

Don't confuse the novice learner.

Don't confuse people with inaccurate information.