Immunology Review: Your Comprehensive Guide to HIV

In immunology, the human immunodeficiency virus (HIV) is a huge topic. So, in this lecture, you can expect a couple of things:

  • The definition of HIV
  • What viral load is
  • How HIV is different from AIDS
  • How HIV progresses into AIDS
  • The diagnostic tests for HIV
  • The signs and symptoms
  • How to educate clients with HIV
  • Pharmacology

There are a lot of things to tackle so let’s begin.

An Introduction

Human immunodeficiency virus is considered one of the most interesting topics in nursing school and is also a favorite when it comes to major exams. Diagnosing HIV can be quite complicated, especially during the initial stages when the client has just been infected with the virus.

Keep in mind that HIV transmission is through blood and body fluids – mainly semen and vaginal secretions. But blood is the main component for contracting the virus. And HIV can be transmitted to other people through all of its stages. However, the transmission would depend on the viral load; the higher the viral load, the higher chances of having HIV.

The Viral Load

Having mentioned the viral load, what is it, exactly?

On the first day of getting HIV, the client will have a very high viral load. During this period, the virus is already attacking the body, but the body doesn’t have an idea on how to defend itself from such virus.

Naturally, the body develops antibodies from the B cells or plasma cells. These antibodies inform the body that there are viruses and bacteria that have entered the system and need to be attacked and destroyed by the white blood cells. Technically, antibodies are tags that prompt white blood cells to certain harmful elements inside the body.

With the viral load of HIV, it will take time for the system to communicate that the body is already positive for HIV and this is because of the high antibody tolerance to the virus. One can expect that the viral load is constantly high in the first two to four weeks since the virus was contracted.

By that time, the body will not have enough antibodies and a robust defense system to fight off the virus.

The Window Period

Another term that you will encounter when it comes to HIV is an acute retroviral syndrome or the window period.

So, for the first two to four weeks, the body does not know that it already has HIV. Even the ELISA test, the test to know if there is the presence of antibodies against HIV is also unsure if there’s HIV.

Therefore, the first two to four weeks is what is termed as the window period or the period wherein the acute retroviral syndrome kicks in. During this period, the client will come in with flu-like symptoms – night sweats, fever, and muscle aches.

The medical team would think that the client just has a viral infection because the ELISA test will come back negative for HIV because, during the window period, the antibodies that determine the presence of HIV are not detected. The problem is, the majority of HIV clients who show signs and symptoms, are already positive with the virus but there is just not enough antibodies to prove the diagnosis.

The result might be a negative HIV, but can be positive for viral meningitis or flu, and it’s all because of the ELISA test, a rapid test usually used by medical institutions, provided negative results.

Initial Signs and Symptoms

After a couple of months, the antibodies against HIV have already been produced and has gone up, at the same time, the viral load is staying steady. The moment the client gets sick for whatever reason, the viral load will jump up because the body’s immune system is now compromised, and that’s when the signs and symptoms of HIV kick in.

At this point, another ELISA test is done to check if the person has HIV. The test will now show that the antibodies against HIV are increased and that’s when it will yield a positive result. Once the ELISA test confirms HIV, the client will still be subjected to a couple of diagnostic tests, which we will go through in a bit.

So remember, during the window period (two to four weeks), there would be flu-like symptoms, but the ELISA test will show negative results for antibodies against HIV. It is only after a couple of months when the body becomes sick again that these antibodies are detected.

Three Essential Lab Tests for HIV

There are three different confirmatory tests for HIV – the ELISA test, the Western blot, and the viral load test. And these tests follow a sequence.

1. The ELISA test

So, the first test in your diagnostic sequence is the ELISA test.

The ELISA test does not determine if a client has the virus; which is why, even if the viral load is high in the beginning, the ELISA test will not show a positive result. What the ELISA test determines is how the body is responding to the antibodies that are created against HIV.

The antibodies will not show during the first two to four weeks after having the virus because the body is still figuring out how to deal with the virus. By the time that the body has figured out how and has created enough antibodies, the time has already passed.

Antibodies are created by the B cells. And these B cells or plasma cells shoot tags or spray paint the infecting organism for the white blood cells to attack at.

HIV Mechanism of Attack

Before going on to the next types of diagnostic tests, we’ll quickly go through how HIV attacks the body, primarily, the CD4 cells. The CD4 cells are types of white blood cells that HIV attaches to.

Once HIV has attached itself to the CD4 cell, it infuses its DNA inside the cell and is now in control of the army composed of the following:

  • B cells
  • Natural killer cells
  • Macrophages

The CD4 cell is considered as the general that commands the abovementioned elements to fight off harmful elements in the body. The moment HIV becomes in-charge of the CD4 cells, the army goes into limbo and will no longer become active.

ELISA Test: Labeling Antibodies

For antibodies to label HIV, it usually takes anywhere between three to 12 weeks. Sometimes, HIV labeling can take up to 36 weeks; that’s how long antibodies can build up. Normally, the ELISA test will pick up antibodies in the first two to four weeks. And in labeling antibodies, there are results like false negative and false positive. How do these results happen?

False Negative

A false negative result for an HIV client means that the virus is there, but the client will have a low antibody screening result. This is called false negative because, it’s too early to tell if the client does or does not have HIV, especially if the ELISA test is done before the window period.

Low antibodies do not immediately rule out HIV infection. The body is just taking time adjusting to the presence of the virus and creating an antibody immune response to appropriately label the bad guys.

Therefore, checking for antibodies before the two to four-week marker will yield a false negative results.

False Positive

On the other hand, a false positive means that there are increased antibodies but can be due to reasons like:

  • The client has hepatitis.
  • The client is a newborn mom.
  • The client is an IV drugs user.
  • The client has a history of malaria.

Due to the extensive causes of high antibodies, the ELISA test will yield a false positive result. This happens because the ELISA test does not specifically test on the type of virus that’s causing the increase in antibodies. That is why having a positive ELISA test is still considered false positive unless other diagnostic tests are done.

Why use the ELISA test?

The reason why the ELISA test is a popular method used to determine HIV is because it’s inexpensive and can be done rapidly.

If the ELISA test shows a positive result, the next step in the diagnostic sequence is the Western blot.

2. The Western Blot Test

The Western blot test is more accurate than the ELISA test because it specifically looks for the HIV antibody serum created by the plasma cells. The Western blot test usually detects around two to four antibodies to provide a positive result. Basically, this is the test to confirm the presence of HIV.

Aside from confirming the infection, the Western blot test also provides information on the status of the CD4 cells and how long has it been since the client has the virus in his or her system.

3. The Viral Load Test

The viral load test is the final diagnostic test in this sequence that is done during HIV treatment to determine if the viral load has gone down or is rebounding.

If the client has a negative result with the ELISA test, it is important to remind him or her to do a follow-up especially after the two to the four-week marker to verify further signs and symptoms.

HIV Progression

How far long your client has HIV? How bad is it? What’s the progression status? To answer all of these questions, we have to concentrate on the CD4 cells and the viral load which are two different things.

As mentioned, the CD4 cells are the generals that instruct the white blood cells what to do and what to attack to efficiently defend the body from intruders. The normal CD4 cell count is usually more than 500. At this range, the body still has HIV and is defending itself from bacteria, viruses, and other elements that can affect the body’s health.

HIV to AIDS

If the body’s CD4 cells start to drop below 200, that’s when the major signs and symptoms of HIV comes out and is also the moment when the client is diagnosed with AIDS. Technically, everyone who have had AIDS are diagnosed with HIV. But not everyone with HIV has AIDS because there are clients who stay above the 200 CD4 cell count and they do not develop signs and symptoms.

Dropping below the Therapeutic Range

The moment the body’s CD4 cells drop to 200 and below, a cascading series of events happen, mainly:

  1. Opportunistic Infection

Opportunistic infections are those infections that are already inside the system for a while and have seen the opportunity to attack the body because the CD4 cells have dropped below the therapeutic level. Because there are not enough soldiers or policemen patrolling and stopping crime, the body will now be overwhelmed with bad guys that cause sickness.

Having an opportunistic infection is one huge indication that CD4 cells have dropped drastically and has progressed into AIDS.

  1. Viral Infection (Herpes)

Herpes doesn’t always mean genital; it can also mean oral if they contract type 2 herpes. Having herpes is another indication that the CD4 cells are below the therapeutic range.

  1. Kaposi’s Sarcoma

Kaposi’s sarcoma is a condition where blotches that look like pepperoni can be seen all over the body.

It would take more than ten years for the CD4 cells to drop below 200 and proceed to the AIDS category. The progression is slow and can become slower if the client is given an antiviral medication called HAART.

Arriving at an AIDS Diagnosis

For a person to be diagnosed with AIDS, the following has to happen first:

  • Positive HIV result through one of these tests – ELISA, Western blot, viral load.
  • CD4 cells that are less than the 200 therapeutic mark.
  • Having an opportunistic or viral infection.

The Two Most Important Nursing Interventions with HIV

In any type of diagnosis, the most important nursing interventions involve education and pharmacology.

Educating HIV Clients

Under education, there are three things that you have to keep in mind:

  1. Prevention

The most important part of client education is prevention. As a nurse, you want to prevent the spread of HIV to other people because clients can get infected at any stage, and there’s no cure for HIV. The only thing that medical providers can do with HIV clients is to slow down the progression of the infection to not reach the AIDS category.

Prevention through ABCs

So, how can you prevent the spread and transmission of HIV?

According to the AIDS Council, there are three ways to prevent HIV from getting transmitted:

  • A – Abstinence
  • B – Be faithful
  • C – Condoms
  1. Body Fluids Transmission

Educate your clients that body fluids transmission is the primary cause of getting HIV. There are two types of risk for transmission – highest and lowest.

  • Highest risk – through semen and blood
  • Lowest risk – vaginal secretions, breast milk, amniotic fluid, and saliva

For instance, your pregnant client is infected with HIV. The chances of the baby getting infected with the virus are slim. With saliva, it is said that a person needs to drink around two gallons of saliva to get infected with HIV.

  1. Modes of Transmission

As said, the highest and most potent way to get HIV is through semen and blood. How are they transmitted?

  1. Having sex – either male to female or anal sex
  2. Parenteral route – for IV drug users who are used to sharing needles
  3. Perinatal – through the womb with a probability risk of around 8% to 25%; not as high as with a sexual or parenteral route

When educating, remind clients to:

  • Abstain, be faithful, and use condoms.
  • Don’t share needles.
  • Be careful when using needles.

HIV Pharmacology – The HAART

Since HIV is incurable, the only thing that one can do is to prevent its progression to AIDS, and this can be done through HAART.

The HAART is an expensive but effective medication regimen that stands for High Active Anti-Retroviral therapy. What the HAART does is that it breaks up the virus to prevent it from attacking the body; like dismantling an empire by going against the virus and stopping it from progressing.

The HAART tells the virus to stop attacking the CD4 cells through replication and pirating. You have to remember that HAART does not kill the virus but only stops it from doing what it does to the CD4 cells.

Caution with HAART

Drug resistance is the biggest caution that you have to remember when dealing with HAART. If the client does not adhere to the regimen, drug resistance will occur. Therefore, you have to advise your client not to miss a dose or not to take less than the recommended prescription.

A Summary

What are the important things that you have to remember regarding HIV?

  1. HIV can progress into AIDS if the CD4 cells go below 200.
  2. Blood and semen are the main culprits for contracting HIV.
  3. When a client has a high viral load with low antibodies, they are usually within the window period having the anti-retroviral
  4. The anti-retroviral syndrome is that moment when clients will develop flu-like symptoms but will not show signs of HIV antibodies during an ELISA test.

Immunology Lecture

For those who are interested in an extensive immunology lecture, we have a video and an article on that. We highly recommend that you drop by our website and YouTube channel to get a hold of that comprehensive discussion.

Immunology Part 2: White Blood Cell Review in a Nutshell

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In this lecture, we will talk about immunology, mainly focusing on the white blood cells (WBC) which are considered as the body’s military base or police department.

Within the military, different positions are particularly tasked with responsibilities, ranging from detectives, investigators, patrol officers, sergeants, and captains. Similarly, white blood cells also have these types of components which we will all go through thoroughly to properly identify their jurisdictions and functions.

WBC Key Players

First, we’ll have a quick introduction of each key player and elaborate later on. What are the primary components of white blood cells?

  1. Neutrophils – involved in the body’s inflammatory response that composes 55% – 70% of the entire white blood cell army.
  2. Monocytes – made up of macrophages and phagocytes. Monocytes are five to six percent of the body’s white blood cell count and are responsible for devouring bacteria and viruses, much like Pac-man.
  3. Lymphocytes – known as the body’s natural killers or mercenaries, lymphocytes are about 30% – 40% of white blood cells. There are two types of cells involved with lymphocytes, namely:
  • B cells – also known as plasma cells that shoot antibodies, labeling the invader as a foreign element which needs to be destroyed by other cells like the T cells
  • T cells – tagged as the mercenaries or natural killers of the body, T cells are divided into two groups – CD4 cells and CD8 cells. The CD4 cells are the cells that HIV overrides. On the other hand, the CD8 cells attack the antibodies marked by the B cells, killing the infecting bacteria.
  1. Eosinophils and basophils – make up one to two percent of the white blood cells, the eosinophils and basophils are mainly responsible for the body’s allergic response.

The Thymus Gland

Aside from the five important components of white blood cells, we will also cover the thymus – a gland that is critical in the final stage of white blood cell development. The thymus is like a boot camp for the majority of the blood cells, mainly the T cells’ last phase of training.

Once the white blood cells are created, they are stored in the barracks – the spleen. The spleen not only serves as the storage for WBCs but it also is the graveyard for hemoglobin and platelets.

White blood cells “patrol” along the highways of the lymphatic tissue as well as the bloodstream. So that, if ever there are invaders, the white blood cells will easily be prompted and will be activated to take on whatever threat present in the system. For this reason, whenever a person is deemed sick, blood culture is taken to determine what kind of infection the body has.

Five Components Elaborated

As mentioned earlier, we will discuss every white blood cell component that we have identified above.

  1. Neutrophils

If there’s inflammation happening within the body, you can count on neutrophils to act on them. Neutrophils make up 55% up to 70% of the body’s WBC army. Under this category, there are two different types – the segmentals and the baby bands.

Segmentals are the upper-class men in the army that are tasked to fight off bacteria and viruses that cause infection which lead to inflammation. On the other hand, the baby bands are immature segmentals that are also created to ward off the threat inside the body but are too small and underdeveloped to do so.

  1. Monocytes

Monocytes make up five to six percent of white blood cells and are divided into macrophages and phagocytes. Monocytes are the patrol officers inside the body that go around the system, destroying and devouring viruses and bacteria that can cause infections.

While macrophages and phagocytes are categorically the same when it comes to responsibilities, macrophages are more elite than phagocytes; much like a sergeant to a cop. You can consider monocytes as Pac-man because of their nature of “eating up” harmful threats.

  1. Lymphocytes

The lymphocytes are the main patrollers of the lymphatic tissues and the bloodstream, making up 30% to 40% of the body’s WBCs. These patrollers are known as the natural killer cells because of their Terminator-like properties that will eliminate any intruder in their path. The lymphocytes are composed of the B cells and the T cells.

The B Cells

As mentioned above, the B cells are the plasma cells that are like little plasma guns which shoot tags (antibodies) all over an in invading bacteria, marking it and prompting the other white blood cells to get rid of it. To explain further, let’s create a simple scenario:

Imagine robbers invading a bank. The other white blood cells – segmentals, macrophages, T cells – show up like a SWAT team. To be able to differentiate the robbers from the hostages, the B cells will “spray” or mark them as the threat using antibodies, and because of this action taken by the B cells, the SWAT team will immediately recognize who to eliminate.

This scenario is a nice way to interpret how B cells work – an invading organism comes in, the B cells spray it with antibodies, alerting the other cells what to attack.

The T Cells

The T cells, on the other hand, are the killers of the viruses and bacteria. There are two divisions of the T cells – CD8 and CD4. The CD4 is the component that is primarily targeted by the human immunodeficiency virus (HIV); while the CD8 binds directly to the antigen to kill the invading bacteria.

CD8 binds with the antigen that the B cells have marked as the “bad guys.” Once spotted, the CD8 cells will pursue the target and wipe them out immediately.

CD4 cells have a number of responsibilities, namely:

  1. They are the commanding officers or the generals of the army – they call the shots or give orders on what to attack, when to attack, and who should do the attacking. So basically, the CD4 cells are in charge of the entire army of white blood cells.
  2. They summon the following WBC components:
  • B cells – plasma cells
  • Lymphocytes – natural killers
  • Macrophages

These summoned mercenaries take order from the CD4 cells on what to kill or eat.

HIV and the CD4 Cells

When a client has human immunodeficiency virus, the CD4 cells are compromised because the virus attaches itself to the CD4 cells and invades them by sending its DNA inside the CD4 cells. Once HIV has invaded the CD4 cell, it will take over command of the “mothership.”

Like that of sci-fi films, once the mothership has been captured and taken over by threats, the decisions will be altered, and the control of the entire army will be at the mercy of the invaders. This makes HIV smart because instead of destroying the one in charge, it re-hardwires its system through DNA invasion and takes control over the fleet, making HIV a scary form of virus.

What happens to the army of white blood cells? All these armies – B cells, lymphocytes, macrophages, will still be taking command from the CD4 cell that has now been infiltrated by HIV. Which is why, if there are other bacteria or viruses that enter the body, the army will not function properly or will not respond at all.

We have an entire lecture dedicated to HIV. You can visit SimpleNursing.com for a more comprehensive explanation regarding this topic.

  1. Eosinophils and Basophils

We have combined the two elements of WBCs – eosinophils and basophils because they are technically similar on targeting allergies. To remember this, think about, “Eww, baso allergies.” Basically, eosinophils and basophils only respond to allergies which is why there is just about one to two percent of them in the WBC army.

The Final Stage of WBC Development

As previously mentioned, the thymus is the area where white blood cells are developed completely; it’s the boot camp where they perfect their skills in warding off harmful elements that can inflict the body. The spleen is the barracks where they are stored and where they wait for further instructions.

Remember that the spleen is not just a storage but also a graveyard for hemoglobin and platelets, it is also where dying hemoglobin is converted into bilirubin before it is sent to the liver. The liver will put the bilirubin on the bile bus together with cholesterol and eventually drive them out of the body.

Jaundice with Newborns

Newborns have a lot of mixture of blood and hemoglobin that are broken down in the spleen. This increased level of hemoglobin is then taken to the newborn’s liver, and since the liver is not big enough to accommodate high levels of bilirubin, the bile bus becomes overloaded; thus, jaundice happens. Though this has nothing to do with the WBC immunology review, it is connected with the spleen’s responsibility.

To know more about the functions of the spleen and the breakdown of hemoglobin, you can check out our website at SimpleNursing.com.

The Highway Patrol

White blood cells patrol the lymphatic system and the bloodstream, making it easier for white blood cells to detect if there are threats inside the body. Which is why, whenever blood samples are taken and there is an increased level of white blood cells, medical professionals will immediately suspect the presence of an infection, whether it’s bacterial or viral.

The ways to determine increased white blood cells are through blood culture and lumbar puncture to take cerebrospinal fluid.

So, that’s it for our white blood cell elite squad lecture. We hope to see you again in our other lectures. Remember to visit us at SimpleNursing.com.