# Low antibodies and infection risk for years after anti-CD20 and bispecific antibodies

Source: https://onco.cc/terms/lymphoma-living-infection-years-after/  
OnCo record `lymphoma-living-infection-years-after` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Treatments that remove B cells also remove the cells that make antibodies, and the effect can last for years after the last dose. Most people need nothing more than ordinary vigilance, but some need preventive antibiotics or infusions of donor antibodies, and a fever at any point in that period is an emergency rather than a nuisance.

## Summary

**Why it lasts.** Rituximab and obinutuzumab deplete normal B cells along with the lymphoma, as do the bispecific antibodies and the engineered T-cell therapies that target the same protein. Lymphoma Action says that after engineered T-cell therapy B cell levels are likely to be low for a long time, sometimes several years, and that because B cells make antibodies, a low B cell count and low antibody levels raise the risk of infection. The same mechanism follows repeated courses of rituximab, and maintenance treatment extends it.

**What is done about it.** Lymphoma Action says most people with lymphoma do not need immunoglobulin replacement. Where antibody levels are low, preventive antibiotics are usually enough. Replacement is likely only when antibody levels are low and the person has had severe or repeated infections, often needing hospital admission, despite preventive antibiotics. It is given either into a vein every three to four weeks, taking four to six hours for the first doses and two to three hours later, or as a weekly injection under the skin which many people are taught to give themselves. A vaccine challenge test, usually with the pneumococcal vaccine followed by a blood test a few weeks later, is sometimes used to decide whether it is needed.

**The part a reader will not be told twice.** After engineered T-cell therapy, Lymphoma Action says a person may lose immunity to illnesses they were vaccinated against in the past, and the team may recommend repeating those vaccinations. Around one person in four has low blood counts lasting several months after the treatment.

**What to do about it day to day.** Lymphoma Action's infections page lists the signs worth knowing: a temperature above 38 degrees Celsius, a temperature below 35 degrees, pain, redness, discharge, swelling or heat around a wound or an intravenous line, chills and sweating, shivering even without a fever, feeling generally unwell, confused or disoriented, a cough or coloured phlegm, diarrhoea, vomiting, burning when passing urine, headache with new neck stiffness and discomfort in bright light, and new pain anywhere. Its instruction is to contact the team immediately for any of them, even a minor one, and not to wait to see if it worsens. The charity also describes the medical card the team can give you, which records your treatment, your risk of a low white cell count and who to ring, and says to carry it and take it to hospital.

**Vaccination.** The Green Book says that many live vaccines are contraindicated in people who are immunosuppressed, and that for those due to begin immunosuppressive treatment, inactivated vaccines should ideally be given at least two weeks before it starts; where that is not possible, vaccination may be carried out at any time and re-immunisation considered after treatment has finished and recovery has occurred. That is the sentence behind the hurried vaccination appointment in the first fortnight after a lymphoma diagnosis, and behind the instruction to check with the team before any vaccine afterwards.

## Fields

- Kind: Term
- Last checked: 2026-10-01
- Also known as: Hypogammaglobulinaemia after rituximab; Infection risk after CAR-T; Immunoglobulin replacement lymphoma; B-cell aplasia

## Sources

- Lymphoma Action: immunoglobulin replacement therapy: https://lymphoma-action.org.uk/information-and-support/lymphoma-treatment/immunoglobulin-replacement-therapy
- Lymphoma Action: infections, risk and prevention: https://lymphoma-action.org.uk/information-and-support/side-effects-lymphoma-and-treatment/infections-risk-and-prevention
- Lymphoma Action: CAR-T cell therapy: https://lymphoma-action.org.uk/information-and-support/lymphoma-treatment/car-t-cell-therapy
- Lymphoma Action: neutropenia (low neutrophils): https://lymphoma-action.org.uk/information-and-support/side-effects-lymphoma-and-treatment/neutropenia-low-neutrophils
- Immunisation against infectious disease (the Green Book), chapter 7: immunisation of individuals with underlying medical conditions: https://assets.publishing.service.gov.uk/media/5e18a52940f0b65dc1918763/Greenbook_chapter_7_Immunsing_immunosupressed.pdf
- NICE CG151: neutropenic sepsis: https://www.nice.org.uk/guidance/cg151

## Connected records

- cancers: [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/), [Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)](https://onco.cc/cancers/malt-lymphoma/), [Follicular lymphoma](https://onco.cc/cancers/follicular-lymphoma/), [Hodgkin lymphoma](https://onco.cc/cancers/hodgkin-lymphoma/), [Mantle cell lymphoma](https://onco.cc/cancers/mantle-cell-lymphoma/), [Marginal zone lymphoma](https://onco.cc/cancers/marginal-zone-lymphoma/), [Nodal marginal zone lymphoma](https://onco.cc/cancers/nodal-marginal-zone-lymphoma/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/), [Primary mediastinal (thymic) large B-cell lymphoma](https://onco.cc/cancers/primary-mediastinal-b-cell-lymphoma/), [Relapsed and refractory classical Hodgkin lymphoma](https://onco.cc/cancers/relapsed-refractory-hodgkin-lymphoma/), [Splenic marginal zone lymphoma](https://onco.cc/cancers/splenic-marginal-zone-lymphoma/), [Waldenström macroglobulinaemia](https://onco.cc/cancers/waldenstrom/)
- technologies: [Bispecific antibodies](https://onco.cc/technologies/bispecific-antibody/), [CAR-T cell therapy](https://onco.cc/technologies/car-t/)
- terms: [Febrile neutropenia](https://onco.cc/terms/febrile-neutropenia/), [Hypogammaglobulinaemia and infection risk after B-cell therapies](https://onco.cc/terms/hypogammaglobulinaemia/), [Immunoglobulin replacement after CAR-T, bispecifics and long anti-CD20 treatment](https://onco.cc/terms/lymphoma-tx-immunoglobulin-replacement/), [Infection prophylaxis in lymphoma: PJP, herpes, fungal risk and vaccination](https://onco.cc/terms/lymphoma-tx-pjp-and-infection-prophylaxis/), [Neutropenia](https://onco.cc/terms/neutropenia/), [Transplant or CAR-T at second line in diffuse large B-cell lymphoma](https://onco.cc/terms/lymphoma-decision-transplant-or-car-t/), [Vaccinations around lymphoma treatment: the ones to have first, and the ones not to have at all](https://onco.cc/terms/lymphoma-living-vaccinations/)

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