Assessment of pathologically diagnosed patients with Castleman's disease associated with diffuse parenchymal lung involvement using the diagnostic criteria for IgG4-related disease.
BACKGROUND
IgG4-related disease (IgG4RD) is a recently recognized disease entity. Differentiating IgG4RD from plasma cell type Castleman's disease (PCD) is important but also difficult using only pathological findings. In addition, little is known about the association between these two diseases with diffuse parenchymal lung involvement.


METHODS
We analyzed the serum IgG4 levels and the ratio of IgG4/IgG-positive plasmacytes in the lung and lymph node specimens of eight patients previously pathologically diagnosed of PCD with diffuse parenchymal lung involvement (DL-PCD). We also compared the clinical and laboratory findings observed in these patients.


RESULTS
Six of the eight patients exhibited abundant IgG4-positive plasmacytes in the lung and lymph node tissues and elevated serum IgG4 levels, thereby fulfilling the diagnostic criteria of IgG4RD with DL (DL-IgG4RD) in addition to having obstructive phlebitis and massive lymphoplasmacytic infiltration with fibrosis. However, three of these six patients exhibited higher levels of serum interleukin-6 and were still diagnosed with DL-PCD. Accordingly, three of these eight patients were considered as IgG4RD with DL (DL-IgG4RD), and the other five patients were ultimately given a diagnosis of DL-PCD. These two diseases have different characteristics in terms of age, symptoms, serum levels of C-reactive protein, and IgA, complicating allergic disorders, response to corticosteroids, and prognosis.


CONCLUSIONS
This is the first report to show a high prevalence of DL-IgG4RD in DL-PCD patients, although additional large investigations are necessary. Clinical and laboratory findings are important for distinguishing between these two diseases in other organs, as previously described.
Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu, Fukuoka, 807-8555, Japan.
Takaaki
T
Ogoshi
Takashi
T
Kido
Kazuhiro
K
Yatera
Keishi
K
Oda
Toshinori
T
Kawanami
Hiroshi
H
Ishimoto
Noriho
N
Sakamoto
Arisa
A
Sano
Chiharu
C
Yoshii
Shohei
S
Shimajiri
Hiroshi
H
Mukae
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology / Q000628:therapy; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D005871:Castleman Disease / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology / Q000628:therapy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis* / Q000097:blood; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000097:blood; D008168:Lung / Q000276:immunology* / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology / Q000628:therapy; D008198:Lymph Nodes / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells / Q000276:immunology* / Q000473:pathology; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D015415:Biomarkers; C508600:IL6 protein, human; D007074:Immunoglobulin G; D015850:Interleukin-6