TY - JOUR T1 - A clinicopathological review of interstitial pneumonia with marked IgG<sub>4</sub> positive plasma cells infiltration JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - P5117 AU - Satoshi Ikeda AU - Tomohisa Baba AU - Machiko Arita AU - Tamiko Takemura AU - Takashi Ogura AU - Tadashi Ishida Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/P5117.abstract N2 - Background; There are few reports describing IgG4-related interstitial pneumonia (IP). Moreover, the clinical features of IgG4-related pulmonary disease without extra-thoracic manifestations are not well defined.Objectives; The aims of the present study were to clarify the clinical characteristics and pathological findings of IP with marked IgG4 positive plasmacyte infiltration and to determine whether these cases should be diagnosed as a subtype of IgG4-related disease or not.Methods; From 2001 to 2012 inclusive, 15 patients (pts) were diagnosed by surgical lung biopsy with IP with marked plasmacyte infiltration. Among them, 7 pts were enrolled into our study, in whom immunostaining confirmed IP with marked IgG4 positive plasmacyte infiltration (IgG4+ plasma cells / IgG+ plasma cells &gt; 40%).Results; All 7 pts were male and had a history of smoking. Serum IgG4 level range was from 217 to 1070 mg/dl and antinuclear antibodies were highly positive in 5 pts. Histopathologically, NSIP pattern was found in 6 pts. Eosinophilic infiltration, obliterative phlebitis and storiform fibrosis were not evident. Lymphoid follicle with germinal center was observed in all cases. Five of 7 pts met the criteria for lung dominant connective tissue disease proposed by Fisher. Clinical response to corticosteroid therapy was good in all cases, but lung cancer developed in 3 pts.Discussions; The clinical efficacy of corticosteroid-therapy and high frequency of lung carcinoma was noteworthy. These cases may involve an independent disease group separate from typical IgG4-related disease or connective tissue disease associated with interstitial pneumonia. ER -