Immune System Explained for Grand Rapids, MI Residents

Understanding how your immune system works can help you make better decisions about your health, especially in a city like Grand Rapids, Michigan, where we experience cold winters, seasonal flu, and changing environmental allergens throughout the year.

Grand Rapids is served by major health systems such as Corewell Health (formerly Spectrum Health), Trinity Health Grand Rapids, Metro Health – University of Michigan Health, and Mercy Health, as well as public health support from the Kent County Health Department and Grand Rapids Public Health. These organizations play an important role in helping residents protect and support their immune health.

What Is the Immune System?

Your immune system is a complex network of organs, cells, and proteins that protects you from infection caused by:

  • Bacteria
  • Viruses (like the flu and common cold)
  • Fungi
  • Parasites

When your immune system encounters a microbe and successfully fights it off, it “remembers” it. Special white blood cells, called memory B-lymphocytes and T-lymphocytes, store this information. If the same microbe enters your body again, your immune system can usually recognize and destroy it quickly—often before you feel sick.

However, some infections like the common cold and influenza (flu) need to be fought many times. That’s because there are many different viruses and strains. Catching one type of cold or flu does not give you immunity to all others. This is one reason annual flu vaccination is recommended in Michigan, especially before the winter season in Grand Rapids.

Main Parts of the Immune System

White Blood Cells

White blood cells are the key players in your immune system. They are:

  • Made in your bone marrow
  • Circulated through your blood and lymphatic system
  • Constantly patrolling your body for foreign invaders

Types of important white blood cells include:

  • Lymphocytes
    • B-cells – make antibodies
    • T-cells – help coordinate the immune response and kill infected cells
    • Natural killer (NK) cells – attack virus-infected and cancer cells

When white blood cells detect microbes, they launch an immune attack.

Antibodies

Antibodies (also called immunoglobulins) are proteins made by B-cells that help your body fight microbes and the toxins (poisons) they produce. They work by:

  • Recognizing antigens (unique markers) on the surface of microbes or in the toxins they produce
  • Binding to these antigens
  • Marking the microbes or toxins for destruction by other parts of the immune system

This process is a key part of how vaccines and natural immunity work.

Complement System

The complement system is a group of proteins in your blood that “complement” the work of antibodies. When activated, complement proteins:

  • Help destroy microbes directly
  • Attract immune cells to the site of infection
  • Promote inflammation to fight infection

The Lymphatic System

The lymphatic system is a network of delicate tubes and organs throughout the body. It plays several important roles:

  • Managing fluid levels in the body
  • Absorbing some fats from the intestine
  • Reacting to bacteria and other microbes
  • Helping deal with cancer cells
  • Clearing out cell waste products that could otherwise cause disease

The lymphatic system includes:

  • Lymph vessels – tubes that carry lymph, a clear fluid containing infection-fighting white blood cells
  • Lymph nodes (lymph glands) – small, bean-shaped structures that:
    • Filter lymph
    • Trap microbes and foreign particles
    • Are often the sites where immune responses are activated

In Grand Rapids, swollen lymph nodes are commonly seen in primary care and urgent care clinics during cold and flu season, especially in the neck and under the jaw.

The Spleen

The spleen is a blood-filtering organ located in the upper left side of your abdomen. It:

  • Removes microbes from the blood
  • Destroys old or damaged red blood cells
  • Produces important immune components, including antibodies and lymphocytes

People without a spleen (due to surgery or disease) often need extra vaccinations and close follow-up with their doctors in Grand Rapids to prevent serious infections.

Bone Marrow

Bone marrow is the soft, spongy tissue inside your bones. It produces:

  • Red blood cells – carry oxygen
  • White blood cells – fight infection
  • Platelets – help your blood clot

Bone marrow health is essential for a strong immune system. Certain conditions treated in Grand Rapids oncology and hematology clinics (for example, at Corewell Health and Metro Health) can affect bone marrow function and weaken immunity.

Thymus

The thymus is a small gland located behind your breastbone. It:

  • Filters and monitors your blood content
  • Produces T-lymphocytes (T-cells), which are critical for coordinating immune responses and killing infected or abnormal cells

The thymus is most active in childhood and gradually becomes less active with age, which is one reason older adults in Grand Rapids may be more vulnerable to infections and benefit from recommended vaccinations.

Other Physical Defenses Against Microbes

In addition to the immune system, your body has several built-in physical and chemical barriers:

  • Skin – a waterproof barrier that:
    • Blocks many microbes from entering
    • Produces oils with bacteria-killing properties
  • Lungs
    • Mucus (phlegm) traps foreign particles
    • Tiny hairs called cilia move mucus upward so it can be coughed out
  • Digestive tract
    • The mucous lining contains antibodies
    • Stomach acid can kill many microbes
  • Body fluids
    • Saliva, tears, and skin oils contain enzymes that reduce infection risk
  • Urinary tract and bowel
    • Constant flushing helps remove microbes

In West Michigan’s colder months, dry indoor air can irritate these protective barriers, which is why staying hydrated and using humidifiers (when appropriate) can help support respiratory defenses.

Fever: An Immune System Response

A fever (rise in body temperature) is often a sign that your immune system is responding to infection. Fever can:

  • Help kill or slow the growth of some microbes
  • Trigger and speed up the body’s repair processes

However, very high fevers or fevers in young children, older adults, or people with chronic health conditions should be evaluated by a healthcare professional. In Grand Rapids, you can seek care from your primary care provider, urgent care clinics, or local hospital emergency departments if you are concerned about a fever.

Common Immune System Problems

It is common for people to have either an overactive or underactive immune system.

Overactive Immune System

An overactive immune system can lead to:

Allergic Diseases

These occur when the immune system makes an overly strong response to normally harmless substances (allergens), such as pollen, foods, medications, or insect stings.

Common allergic conditions include:

  • Food allergies
  • Medication allergies
  • Stinging insect allergies
  • Anaphylaxis – a life-threatening allergic reaction that requires emergency care
  • Hay fever (allergic rhinitis)
  • Sinus disease
  • Asthma
  • Hives (urticaria)
  • Dermatitis and eczema

In Grand Rapids, spring and fall pollen, mold from damp leaves, and indoor allergens during winter can all trigger allergies and asthma. Local allergists and clinical immunology specialists can help diagnose and manage these conditions.

Autoimmune Diseases

In autoimmune diseases, the immune system mistakenly attacks normal parts of the body. These conditions range from common to rare and include:

  • Type 1 diabetes
  • Rheumatoid arthritis
  • Systemic lupus erythematosus (lupus)
  • Multiple sclerosis (MS)
  • Autoimmune thyroid disease
  • Systemic vasculitis

Many autoimmune conditions are managed long term with specialists such as rheumatologists and neurologists at Grand Rapids hospitals and specialty clinics.

Underactive Immune System (Immunodeficiency)

An underactive immune system (immunodeficiency) does not function correctly and makes people more vulnerable to infections. It can be:

  • Inherited (primary immunodeficiency)
    • Examples:
      • Common variable immunodeficiency (CVID)
      • X-linked severe combined immunodeficiency (SCID)
      • Complement deficiencies
  • Acquired (developing later in life), such as:
    • Due to medications like corticosteroids or chemotherapy
    • Caused by diseases like HIV/AIDS or certain cancers
    • Following organ transplantation, where immune-suppressing drugs are needed to prevent rejection

In severe cases, immunodeficiency can be life-threatening. People with frequent, severe, or unusual infections in Grand Rapids are often referred to clinical immunology/allergy specialists for evaluation and treatment.

Immunoglobulin (Antibody) Therapy

Some people cannot make enough antibodies on their own, or their antibodies do not work properly. They may need immunoglobulin replacement therapy (IRT).

What Is Immunoglobulin?

Immunoglobulin (Ig), commonly known as antibodies, is made from plasma, the liquid part of blood that contains important proteins. Immunoglobulin therapy helps:

  • Replace missing or defective antibodies
  • Support the immune system in fighting infections

Intravenous Immunoglobulin (IVIg)

Traditionally, immunoglobulin therapy in the United States has been given:

  • Through a drip into a vein
  • In a hospital or infusion center
  • Known as intravenous immunoglobulin (IVIg) therapy

Grand Rapids residents may receive IVIg at hospital-based infusion centers associated with Corewell Health, Trinity Health Grand Rapids, or other local providers.

Subcutaneous Immunoglobulin (SCIg)

Now, immunoglobulin can also be given:

  • Into the fatty tissue under the skin
  • Often at home after proper training
  • Known as subcutaneous immunoglobulin (SCIg) therapy

SCIg is similar to IVIg in effectiveness and is also made from plasma. It may offer benefits such as:

  • More stable antibody levels
  • Greater flexibility and independence for some patients

Many health services, including those in West Michigan, now offer SCIg therapy to eligible patients with specific immune conditions. If you are interested in this type of treatment, talk with your:

  • GP / primary care provider
  • Clinical immunology/allergy specialist

They can help determine whether IVIg or SCIg is appropriate for you and coordinate care with local infusion centers.

Immunisation and the Immune System

Immunisation (vaccination) works by copying the body’s natural immune response.

How Vaccines Work

A vaccine contains a small amount of a specially treated virus, bacterium, or toxin (or a piece of it). When it is injected or given orally:

  1. Your body recognizes it as foreign.
  2. Your immune system makes antibodies and memory cells against it.
  3. Later, if you are exposed to the real virus, bacterium, or toxin, your immune system recognizes it and attacks quickly.

This usually prevents you from getting sick—or makes the illness much milder.

In Grand Rapids, vaccines are available through:

  • Primary care clinics and pediatric offices
  • Pharmacy-based clinics
  • Kent County Health Department
  • Community immunisation events and school-based programs

HALO: Factors That Guide Your Immunisation Needs

The immunisations you may need are based on your Health, Age, Lifestyle, and Occupation (HALO).

Health

Some health conditions or factors can make you more vulnerable to vaccine-preventable diseases, such as:

  • Heart, lung, spleen, or kidney conditions
  • Diabetes
  • Asthma
  • Down syndrome
  • HIV or other conditions that weaken the immune system
  • Premature birth

People in Grand Rapids with these conditions may benefit from additional or more frequent immunisations, such as pneumonia or influenza vaccines.

Age

At different ages, you need protection from different diseases. National immunisation schedules recommend vaccines for:

  • Babies and children
  • Adolescents
  • Adults
  • Older adults

Older adults in West Michigan are especially encouraged to receive vaccines against flu, COVID-19, pneumonia, and shingles.

Lifestyle

Lifestyle choices can affect your immunisation needs. You may need additional vaccines if you:

  • Travel overseas to certain regions
  • Are planning a family or are pregnant
  • Are sexually active with new or multiple partners
  • Smoke
  • Play contact sports that might expose you to someone else’s blood

Travel clinics and primary care offices in Grand Rapids can provide guidance and travel-related vaccines.

Occupation

Some jobs increase your risk of exposure to infections, including:

  • Healthcare (hospitals, outpatient clinics, nursing homes)
  • Childcare and education
  • Aged care facilities
  • Emergency services (police, fire, EMS)
  • Sewerage repair and maintenance

If you work in these fields in Grand Rapids, discuss your immunisation needs with your employer and your doctor. Some employers help cover the cost of required or recommended vaccinations.

Local Immune Health Considerations in Grand Rapids, MI

Living in Grand Rapids and the broader West Michigan region brings specific immune-related concerns:

  • Cold winters and indoor crowding increase the spread of respiratory infections like colds, flu, and COVID-19.
  • Seasonal allergies can be triggered by tree pollen in spring, grass pollen in early summer, and weed pollen and mold in fall.
  • Great Lakes climate can contribute to damp conditions, which may increase mold exposure in some homes and workplaces.

Supporting your immune system here often includes:

  • Staying up to date on flu, COVID-19, and other recommended vaccines
  • Practicing good hand hygiene and respiratory etiquette
  • Managing allergies and asthma with help from local specialists
  • Maintaining a healthy lifestyle (sleep, nutrition, exercise), especially during long winters

Where to Get Help in Grand Rapids, MI

If you have concerns about your immune system, frequent infections, allergies, or autoimmune disease, contact:

  • Your GP / primary care provider
  • A specialist (ask for a referral), such as:
    • Dermatologist
    • Rheumatologist
    • Clinical immunology/allergy specialist
  • Local health systems and clinics, including:
    • Corewell Health (Spectrum Health)
    • Trinity Health Grand Rapids
    • Metro Health – University of Michigan Health
    • Mercy Health
  • Kent County Health Department and Grand Rapids Public Health for:
    • Immunisation clinics
    • Community health programs
    • Public health information

These resources can help you understand your immune health, access appropriate testing and treatment, and stay up to date on vaccinations recommended for Grand Rapids, Michigan residents.

Key Points

  • The main parts of the immune system include white blood cells, antibodies, the complement system, lymphatic system, spleen, bone marrow, and thymus.
  • White blood cells are the primary defenders, constantly searching for and attacking harmful microbes.
  • The lymphatic system helps manage body fluids, react to bacteria, deal with cancer cells, and filter harmful substances.
  • It is common to have an overactive (allergies, autoimmune diseases) or underactive (immunodeficiency) immune system.
  • Allergic diseases are very common and can be effectively managed with help from local healthcare providers in Grand Rapids.
  • Immunoglobulin therapy and vaccination are important tools for supporting and strengthening the immune system in people with specific conditions.