Alveolar septal deposition of immunoglobulin and complement parallels pulmonary hemorrhage in a guinea pig model of severe pulmonary leptospirosis.
Human patients suffering from leptospirosis present with a diverse array of clinical manifestations, including the more severe and often fatal pulmonary form of the disease. The etiology of pulmonary hemorrhage is unclear. Isolates of Leptospira acquired from patients suffering from pulmonary hemorrhage were used to develop a guinea pig model of pulmonary hemorrhage. Gross findings post-infection confirmed extensive hemorrhage in the lungs and on peritoneal surfaces as the likely cause of death. Immunohistochemistry confirmed the presence of large numbers of leptospires in kidney, liver, intestinal tissues, and spleen, but few inflammatory cells were seen. In marked contrast, few leptospires were detected in infected hemorrhagic lung tissue. Blood chemistries and hematology did not reveal the etiology of the hemorrhage observed. There was no chemical or microscopic evidence for disseminated intravascular coagulation. To ascertain an immunopathologic role during disease, immunofluorescence was performed on infected lung tissues and confirmed the presence of IgM, IgG, IgA, and C3 along the alveolar basement membrane. This suggests that an autoimmune process may be the etiology of fatal pulmonary hemorrhage in leptospirosis.
Division of Infectious Diseases, Department of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA. jnally@mednet.ucla.edu
Jarlath E
JE
Nally
Chavit
C
Chantranuwat
Xiao-Yang
XY
Wu
Michael C
MC
Fishbein
Martha M
MM
Pereira
João José Pereira
JJ
Da Silva
David R
DR
Blanco
Michael A
MA
Lovett
D000818:Animals; D001327:Autoimmune Diseases / Q000150:complications*; D003165:Complement System Proteins / Q000276:immunology / Q000378:metabolism; D004195:Disease Models, Animal; D006168:Guinea Pigs; D006470:Hemorrhage / Q000209:etiology* / Q000473:pathology; D007136:Immunoglobulins / Q000276:immunology / Q000378:metabolism; D007150:Immunohistochemistry; D007422:Intestines / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D007668:Kidney / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D007919:Leptospira / Q000276:immunology; D007922:Leptospirosis / Q000276:immunology* / Q000473:pathology; D008099:Liver / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D008171:Lung Diseases / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D008297:Male; D008854:Microscopy, Electron; D011650:Pulmonary Alveoli / Q000276:immunology / Q000473:pathology* / Q000648:ultrastructure; D013154:Spleen / Q000276:immunology / Q000382:microbiology / Q000473:pathology
D007136:Immunoglobulins; D003165:Complement System Proteins