When MS Antibody Levels Drop: What Patients Should Know

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Key Takeaway

Longer treatment (3+ years), older age (50+), and having low antibody levels raise the chances of low protective antibodies and serious infections for people on ocrelizumab or ofatumumab.

What They Found

Researchers looked at 911 real-world MS patients treated with ocrelizumab or ofatumumab and found about 1 in 10 (9.8%) developed low levels of IgG, a key antibody that helps fight infections—think of IgG like part of your body's defense shield.Being 50 years or older, being White (Caucasian), and being on these therapies for three years or more each independently increased the chance of that weaker antibody shield.About 8% of people had a serious infection that needed hospital care or major treatment; the risk was higher if someone already had low antibodies (HGG) or low lymphocyte counts (another part of the immune system).Other factors tied to higher infection risk were having used other MS treatments before and having a progressive form of MS, which often means the disease is more advanced or steadily getting worse.When the researchers compared the two drugs directly and adjusted for patient differences, they found no clear difference between ocrelizumab and ofatumumab in how often low antibodies or serious infections happened—so the risks seemed similar for both drugs.

Who Should Care and Why

MS patients taking ocrelizumab or ofatumumab should care because the study shows some people may lose part of their infection protection over time—like a flashlight battery slowly dimming—especially after about three years.Older adults (50+) and White patients may be more likely to have this drop in antibodies, so they may need closer monitoring or extra caution with situations that raise infection risk (crowds, sick contacts).Caregivers should pay attention to signs of infection (fever, cough, new pain) and know that prior immune system tests or past MS treatments can change infection risk, so they can advocate for timely medical care.Healthcare providers can use these findings to check antibody levels (IgG) and white blood cell counts before and during treatment, and consider extra precautions like vaccines or different monitoring plans for higher-risk patients.Patients with progressive MS or who have used multiple MS drugs before should be especially watchful, because they had higher rates of serious infections in this study—meaning their daily care may need stronger infection prevention steps.

Important Considerations

This study looked back at medical records (retrospective) rather than following people forward, so it can show links but not prove one thing caused another.Most patients in the study were treated in routine care and were majority White and middle-aged, so results may not apply exactly the same to younger people or other ethnic groups.The study did not find differences between the two drugs after matching patients, but individual risk still varies—so any treatment decisions should be discussed with your neurologist who knows your personal health story.

Categories:

Treatment Updates Clinical Trials MS Progression

Article Topics:

Ocrelizumabdisease-modifying therapieshypogammaglobulinemiainfectionmultiple sclerosisofatumumab

Whether you’ve recently been diagnosed with Multiple Sclerosis (MS) or are seeking to broaden your understanding of this complex, neurodegenerative disease, navigating the latest research can feel overwhelming. Studies published in respected medical journals like Multiple sclerosis (Houndmills, Basingstoke, England) often range from early-stage, exploratory work to advanced clinical trials. These evidence-based findings help shape new disease-modifying therapies, guide symptom management techniques, and deepen our knowledge of MS progression.

However, not all research is created equal. Some clinical research studies may have smaller sample sizes, evolving methodologies, or limitations that warrant careful interpretation. For a more comprehensive, accurate understanding, we recommend reviewing the original source material—accessible via the More Details section above—and consulting with healthcare professionals who specialize in MS care.

By presenting a wide range of MS-focused studies—spanning cutting-edge treatments, emerging therapies, and established best practices—we aim to empower patients, caregivers, and clinicians to stay informed and make well-informed decisions when managing Multiple Sclerosis.

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