Person walking a tightrope symbolizing the balance between autoimmune treatment and infection risk.

Unmasking Legionella: When Autoimmune Treatments Open the Door to Infection

Lena Kashyap in Health & Wellness November 2025 • 4 min read.

"A Case Study on the Risks of Immunosuppression and the Critical Need for Vigilant Monitoring"

In the complex landscape of autoimmune disease management, clinicians often walk a tightrope, balancing the need to suppress the immune system to alleviate symptoms against the potential for opportunistic infections to take hold. Immunosuppressive medications, while effective in controlling autoimmune activity, can leave patients vulnerable to a range of pathogens, turning life-saving treatments into double-edged swords.

This article delves into a compelling case study that highlights the risks associated with immunosuppression. It chronicles the experience of a 38-year-old woman with systemic lupus erythematosus (SLE) who developed a disseminated Legionella pneumophila infection following treatment with prednisolone, hydroxychloroquine, and azathioprine. Her journey underscores the critical importance of vigilant monitoring and prompt intervention in patients receiving immunosuppressive therapies.

By examining the clinical course, diagnostic challenges, and treatment strategies employed in this case, we aim to shed light on the intricate relationship between autoimmune disease, immunosuppression, and infection. This exploration serves as a reminder of the need for personalized approaches to patient care, where the benefits of treatment are carefully weighed against the potential risks.

The Case: A Perfect Storm of Immunosuppression and Infection

Person walking a tightrope symbolizing the balance between autoimmune treatment and infection risk.

The patient, a 38-year-old woman with systemic lupus erythematosus (SLE), had been receiving long-term treatment with prednisolone and azathioprine. While these medications effectively managed her autoimmune disease, they also weakened her immune defenses, creating an environment ripe for infection. Over time, she developed a series of complications, starting with enteritis and progressing to proximal muscle weakness.

As her condition deteriorated, she was hospitalized and treated with various medications, including pyridostigmine and IV fluids. However, her condition continued to worsen, marked by high-grade fever, a generalized vesicular rash, and proximal muscle weakness. Further investigation revealed a heart rate of 100 beats/min, a body temperature of 39°C, and blood pressure of 90/60mm Hg.

Skin examination displayed generalized discrete erythematous papules and macules with dry necrotic crust on the scalp, trunk, facial area, and extremities.
She also had plaques measuring 15 x 15cm on both inner thighs.
Abdominal examination displayed mild tenderness and distension.
A skin biopsy revealed varicella zoster virus, leading to a diagnosis of varicella zoster virus infection.

Further complicating matters, the patient was found to have a high viral load of cytomegalovirus (CMV) and was diagnosed with leucopenia. She was treated with a combination of antiviral and antibacterial agents, including ganciclovir, piperacillin/tazobactam, meropenem, and cefepime. Despite these efforts, her condition remained precarious. Ultimately, bacterial broad-range 16S ribosomal RNA sequencing revealed Legionella pneumophila. The initial antimicrobial regimen was promptly changed to azithromycin.

Lessons Learned: Vigilance and Personalized Care

This case underscores the critical need for vigilance and personalized care in patients receiving immunosuppressive therapies. Clinicians must carefully weigh the benefits of treatment against the potential risks, and they must closely monitor patients for signs of opportunistic infection. Prompt diagnosis and treatment are essential to prevent serious complications and improve patient outcomes. Understanding the intricate interplay between immunosuppression and infection is paramount in ensuring the safety and well-being of individuals with autoimmune diseases.

About this Article -

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Everything You Need To Know

Why are individuals with autoimmune diseases more prone to infections when taking medications like prednisolone, hydroxychloroquine, and azathioprine?

In managing autoimmune diseases like systemic lupus erythematosus (SLE), immunosuppressive medications such as prednisolone, hydroxychloroquine, and azathioprine are used to control the overactive immune response. However, these medications weaken the body’s natural defenses, making patients more susceptible to opportunistic infections. Vigilant monitoring for signs of infection is essential to balance the therapeutic benefits against the increased risk of infection.

What does the case of the 38-year-old woman with systemic lupus erythematosus (SLE) and disseminated Legionella pneumophila infection tell us about the risks associated with immunosuppressive therapies?

The presented case study underscores the heightened risk of disseminated Legionella pneumophila infection in individuals undergoing immunosuppressive therapies for autoimmune diseases. The 38-year-old woman with systemic lupus erythematosus (SLE) treated with prednisolone, hydroxychloroquine, and azathioprine, developed this severe infection, highlighting the need for clinicians to be vigilant about potential opportunistic infections in immunosuppressed patients.

What early symptoms might indicate an infection in a patient being treated with immunosuppressants like prednisolone and azathioprine?

Early signs of infection in immunosuppressed patients can be subtle and easily overlooked. In the reported case, the patient initially presented with enteritis and proximal muscle weakness. As the condition progressed, high-grade fever and a generalized vesicular rash also developed. These symptoms, combined with the patient's history of immunosuppressive treatment, should prompt clinicians to consider opportunistic infections and initiate appropriate diagnostic testing and intervention.

What specific diagnostic tests were crucial in identifying the infections in the described systemic lupus erythematosus (SLE) patient, and why is comprehensive testing so important in such cases?

In this instance, diagnostic testing included a skin biopsy, which revealed varicella zoster virus infection, and bacterial broad-range 16S ribosomal RNA sequencing, which ultimately identified Legionella pneumophila. It is important to note that the patient also had a high viral load of cytomegalovirus (CMV) and was diagnosed with leucopenia. The diagnostic approach should be tailored to the patient's clinical presentation and risk factors, with consideration given to both common and opportunistic pathogens.

What was the initial treatment approach for the immunocompromised patient, and why was it changed after the identification of Legionella pneumophila?

The patient was initially treated with antiviral and antibacterial agents, including ganciclovir, piperacillin/tazobactam, meropenem, and cefepime to combat the varicella zoster virus infection, cytomegalovirus and potential bacterial infections. However, upon identification of Legionella pneumophila through bacterial broad-range 16S ribosomal RNA sequencing, the antimicrobial regimen was promptly changed to azithromycin, which is specifically effective against Legionella. The choice of treatment depends on the identified pathogen and its antimicrobial sensitivities.