RESEARCH - Occurrence of HSV-1-induced pneumonitis in patients under standard immunosuppressive therapy

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BMC Pulm Med. 2009 May 18;9:22.

Occurrence of HSV-1-induced pneumonitis in patients under standard

immunosuppressive therapy for rheumatic, vasculitic, and connective

tissue disease.

Witt MN, Braun GS, Ihrler S, Schmid H.

Department of Nephrology, Medical Policlinic, University of Munich,

Munich, Germany.

BACKGROUND: Herpes simplex virus type-1 (HSV-1) has been described to

cause respiratory tract infections in critically ill patients or in

individuals that are immunocompromised. It is a continuing matter of

debate under which circumstances HSV-1 is a relevant pathogen for

pneumonitis. While its role during critical illness has been

investigated by prospective interventional studies, comparatively

little systematic data is available on the role of HSV-1 for

pneumonitis in outpatients with autoimmune disease under a maintenance

regimen of immunosuppression.

METHODS: We retrospectively reviewed the charts of approximately 1400

patients with rheumatoid arthritis, vasculitis, and systemic lupus

erythematosus (SLE) that were followed at the outpatient clinic of a

German University hospital during the years 2000-2007. Episodes of

admission to a ward resulting in the diagnosis of

pneumonia/pneumonitis were identified, and the type of pneumonia and

clinical features retrospectively studied.

RESULTS: 63 patients with rheumatoid arthritis, vasculitis, or SLE

were admitted to a ward and diagnosed to have pneumonia/pneumonitis.

Using bronchoscopy a total of 6 cases of pulmonary infection

associated with HSV-1 in the lower respiratory tract were identified.

Among those, 2 cases suggested a causative role of HSV-1 as the sole

agent causing pneumonitis that proved clinically responsive to

antiviral treatment. In the remaining 4 cases HSV-1 appeared as a

bystander of bacterial infection. Maintenance therapy with

leflunomide, which inhibits HSV-1 assembly in vitro, was associated

with a milder course of pneumonitis in one patient. Detection of HSV-1

was associated with stronger immunosuppressive regimens and vasculitic

disease.

CONCLUSION: The present study analyzed the frequency and hallmarks of

cases of HSV-1 associated pneumonitis that occurred in a comparatively

large cohort of patients with rheumatologic autoimmune diseases. In an

area of controversy, this study provides further evidence that HSV-1

causes isolated pneumonitis in the immunocompromised. The study may

provide an estimate on the frequency of relevant HSV-1 infection and

bacterial agents in outpatients with autoimmune disease.

PMID: 19450259

http://www.ncbi.nlm.nih.gov/pubmed/19450259

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