Assistant professor, Madras Medical College
CMV infection can closely mimic a flare of autoimmune rheumatic disease, particularly in immunosuppressed patients. Both conditions may present with fever, cytopenia, pulmonary, gastrointestinal, neurological, or mucocutaneous manifestations. Clinical assessment for disease activity elsewhere, along with immunological markers, can provide clues toward an autoimmune flare. CMV PCR, antigenemia, and tissue-based testing help support the diagnosis of active or tissue-invasive CMV disease. Recognizing the distinction is important because autoimmune flares require immunosuppression, whereas CMV infection requires antiviral therapy. A careful assessment of the overall clinical context is therefore essential to avoid inappropriate treatment.
Introduction
Cytomegalovirus (CMV) infection may range from an asymptomatic infection in healthy individuals to severe systemic disease involving the hematopoietic system, gastrointestinal tract, nervous system, and lungs in immunosuppressed individuals. Patients with autoimmune rheumatic diseases (AIRD) are at increased risk of severe CMV infection or reactivation due to the underlying disease as well as treatment with immunosuppressive medications. In addition, CMV infection may trigger a flare of the underlying rheumatic disease. Distinguishing CMV infection or reactivation from an autoimmune disease flare can therefore be challenging for the treating clinician.
CMV as a Masquerader
CMV infection generally presents as an acute illness with constitutional symptoms, sometimes accompanied by cytopenia, pneumonitis, transaminitis, or colitis. Distinguishing CMV infection from a flare of the underlying rheumatic disease requires careful assessment for clinical features of disease activity elsewhere, along with relevant laboratory and immunological markers of disease activity. The various clinical manifestations of CMV and the corresponding rheumatological conditions they may mimic, along with clues to distinguish between them, are summarized in the table below.
|
Organ system |
CMV manifestation |
Rheumatic disease manifestation it may mimic |
Features favouring CMV over autoimmune flare |
|
1. Skin / mucosa |
Painful oral or genital ulcers, necrotic or ulcerative cutaneous lesions, and occasionally lesions resembling vasculitis |
SLE mucocutaneous flare or vasculitic ulcers |
Deep, painful, necrotic ulcers are more suggestive of CMV than typical lupus oral ulcers. Skin biopsy with CMV inclusions or immunohistochemistry (IHC) can establish the diagnosis. |
|
2. Hematologic |
Leukopenia, thrombocytopenia, anemia, or pancytopenia, often accompanied by fever and malaise |
SLE-associated cytopenias, autoimmune cytopenia, or disease-related marrow abnormalities |
CMV-related cytopenia tends to occur with an acute febrile illness, constitutional symptoms, and/or other organ involvement. Atypical lymphocytes may be present. In contrast, SLE-related cytopenia is more suggestive when accompanied by other evidence of lupus activity, such as low complement levels or raised anti-dsDNA titres. |
|
3.Nervous system |
Encephalitis, polyradiculopathy, multifocal neuropathy, and immune or axonal neuropathies; rarely, other focal neurological manifestations |
Neuropsychiatric SLE or vasculitic neuropathy |
Acute or subacute neurological deterioration with concurrent CMV mucocutaneous or systemic manifestations should raise suspicion of CMV. CSF studies, MRI, and neurophysiological testing may help in diagnosis. Detection of CMV in the CSF provides stronger evidence than blood PCR. |
|
4. Lung |
Pneumonitis with fever, hypoxemia, and diffuse or bilateral ground-glass or interstitial infiltrates |
SLE pneumonitis, connective-tissue-disease-associated ILD exacerbation, or diffuse alveolar hemorrhage (DAH) due to vasculitis |
CMV is more likely with acute deterioration, fever, cytopenia, transaminitis, and evidence of active CMV infection. SLE pneumonitis or ILD flare is supported by simultaneous systemic autoimmune activity elsewhere or immunological evidence of a flare, such as falling complement levels and rising anti-dsDNA titres. |
|
5. Gastrointestinal |
Esophagitis, gastritis, enteritis or colitis, ulceration, and gastrointestinal bleeding |
Lupus enteritis or mesenteric vasculitis, inflammatory bowel disease flare, or vasculitic gastrointestinal involvement |
CMV is favoured by fever and acute systemic illness. Endoscopy with biopsy demonstrating CMV inclusions or IHC, or tissue PCR in the appropriate setting, is more convincing than blood PCR alone. |
|
6. Liver |
CMV hepatitis or transaminitis |
Lupus-associated hepatitis, autoimmune hepatitis, or nonspecific transaminitis during a systemic flare |
Acute transaminitis accompanied by fever and atypical lymphocytes may favour CMV. |
|
7. Eye |
Retinitis, especially in severely immunosuppressed patients |
Neuro-ophthalmic or vasculitic manifestations of SLE or other systemic rheumatic diseases |
Funduscopic examination showing characteristic retinal lesions, supported by CMV PCR of aqueous or vitreous fluid when required, can help establish the diagnosis. |
Investigations
1. Tissue biopsy – Demonstration of CMV in tissue by histopathology, immunohistochemistry, or tissue PCR provides strong evidence of tissue-invasive CMV disease. It is particularly useful in gastrointestinal, skin, or other organ-specific disease, but may not be feasible in all settings.
2. CMV PCR – Quantitative PCR for CMV DNA in blood is widely used to detect and monitor CMV replication. A positive blood PCR supports CMV infection but does not, by itself, prove tissue-invasive disease. PCR from the relevant specimen, such as CSF or tissue, is more useful when organ-specific CMV disease is suspected.
3. CMV antigenemia – Detection of CMV pp65 antigen in peripheral blood leukocytes can indicate active CMV replication. It may be useful for diagnosis and monitoring, although its use is limited by technical requirements and availability.
CMV serology (IgG/IgM by ELISA) has limited utility in diagnosing active CMV infection. IgG positivity usually reflects previous exposure, while IgM may be positive in the absence of active disease and should not be used alone to diagnose CMV reactivation or tissue-invasive disease. CMV PCR or antigenemia, and whereever appropriate, tissue-based diagnosis, are preferred.
Treatment
1. Intravenous ganciclovir – First-line treatment for severe or tissue-invasive CMV disease. Dose adjustment is required in renal impairment, and blood counts should be monitored because of the risk of neutropenia and other cytopenias.
2. Oral valganciclovir – Preferred over oral ganciclovir because of its better oral bioavailability. It is commonly used in patients who are clinically stable and able to take oral medication.
3. Foscarnet – Used in patients with ganciclovir-resistant CMV or significant ganciclovir-related toxicity, particularly severe myelosuppression. Its use is limited by nephrotoxicity and electrolyte disturbances, so renal function and electrolytes require close monitoring.
Treatment is minimum 2 weeks and generally continued until there is clinical improvement and an adequate virologic response. The duration is individualized according to the site and severity of disease and the patient’s immune status.
Conclusion
Distinguishing a disease flare from CMV infection is both important and challenging. A disease flare may require intensification of immunosuppressive therapy, whereas CMV infection requires antiviral treatment. Also, CMV detection alone does not always establish CMV disease in absence of appropriate symptoms and signs. In practice, the distinction is often based on the overall clinical context, including evidence of disease activity elsewhere, immunological markers such as low complement levels or rising anti-dsDNA titres, and evidence of CMV infection from appropriate clinical specimens, including tissue-based testing or PCR when indicated.
Suggested reading
1. Choo, H.M.C., Cher, W.Q., Kwan, Y.H. et al. Risk factors for cytomegalovirus disease in systemic lupus erythematosus (SLE): a systematic review. Adv Rheumatol 59, 12 (2019).
2. Ranjan S, Dubey M, Panda AK. Cytomegalovirus infection and its association with systemic lupus erythematosus: Systematic review and meta-analysis. Lupus. 2026;35(5):446-457.
3. Oka H, Sumitomo S, Miyakoshi C and Ohmura K (2026) Tissue-invasive CMV disease is associated with poor prognosis during remission induction therapy for autoimmune inflammatory rheumatic diseases. Front. Immunol. 17:1696516. doi: 10.3389/fimmu.2026.1696516.
4. Shimada, T., Higashida-Konishi, M., Izumi, K. et al. Risk factors associated with cytomegalovirus reactivation in patients receiving immunosuppressive therapy for rheumatic diseases: a retrospective study. Sci Rep 12, 20926 (2022). https://doi.org/10.1038/s41598-022-25451-4.
5. Karimi E, Moradi Z, Soroureddin S, Nouri O, Tamartash Z, Kavosi H. Cytomegalovirus Infection Mimics Manifestations of Underlying Diseases in Patients With Autoimmune Disorders: A Case Report and Literature Review. Immun Inflamm Dis. 2026 Mar;14(3):e70377. doi: 10.1002/iid3.70377. PMID: 41847937; PMCID: PMC13098031.
6. Sumethkul K, Kitumnuaypong T, Bupparenoo P, Angthararak S. CMV infection in active systemic lupus erythematosus: clinical characteristics, prognosis and treatment outcomes. BMC Rheumatol. 2025 Nov 12;9(1):134. doi: 10.1186/s41927-025-00592-x. PMID: 41225686; PMCID: PMC12613559.
7. Lourenço MH, Borralho J, Silva I, Alves J, Sampaio R, Mansinho K, Branco JC. Cytomegalovirus and rheumatic diseases: cases-based review. ARP Rheumatol. 2023 Jul-Sep;2(3):269-274. English. PMID: 37839034.
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