IgG4-related disease (IgG4-RD) is a fascinating clinical entity proposed by Japanese investigators, and includes a wide variety of diseases, formerly diagnosed as Mikulicz's disease (MD), autoimmune pancreatitis (AIP), interstitial nephritis, prostatitis, retroperitoneal fibrosis, etc. Although all clinicians in every field of medicine may encounter this new disease, a unifying diagnostic criterion has not been established. In 2011, the Japanese IgG4 team, organized by the Ministry of Health, Labor and Welfare (MHLW) of Japan, published comprehensive diagnostic criteria for IgG4-RD. Several problems with these criteria have arisen in clinical practice, however, including the difficulty obtaining biopsy samples from some patients, and the sensitivity and the specificity of techniques used to measure serum IgG4 concentrations. Although serum IgG4 concentration is an important clinical marker for IgG4-RD, its diagnostic utility in differentiating IgG4-RD from other diseases, called IgG4-RD mimickers, remains unclear. This review describes the current optimal approach for the diagnosis of IgG4-RD, based on both comprehensive and organ-specific diagnostic criteria, in patients with diseases such as IgG4-related pancreatitis (AIP), sclerosing cholangitis, and renal, lung and orbital diseases.

IgG4-related disease is a new disease classification established in Japan in the 21st century. Patients with IgG4-related disease display hyper-IgG4-gammaglobulinemia, massive infiltration of IgG4+ plasma cells into tissue, and good response to glucocorticoids. Since IgG4 overexpression is also observed in other disorders, it is necessary to diagnose IgG4-related disease carefully and correctly. We therefore sought to determine cutoff values for serum IgG4 and IgG4/IgG and for IgG4+/IgG+ plasma cells in tissue diagnostic of IgG4-related disease. Patients and Methods. We retrospectively analyzed serum IgG4 concentrations and IgG4/IgG ratio and IgG4+/IgG+ plasma cell ratio in tissues of 132 patients with IgG4-related disease and 48 patients with other disorders. Result. Serum IgG4 >135  mg/dl demonstrated a sensitivity of 97.0% and a specificity of 79.6% in diagnosing IgG4-related disease, and serum IgG4/IgG ratios >8% had a sensitivity and specificity of 95.5% and 87.5%, respectively. IgG4+cell/IgG+ cell ratio in tissues >40% had a sensitivity and specificity of 94.4% and 85.7%, respectively. However, the number of IgG4+ cells was reduced in severely fibrotic parts of tissues. Conclusion. Although a recent unanimous consensus of all relevant researchers in Japan recently established the diagnostic criteria for IgG4-related disease, findings such as ours indicate that further discussion is needed.

IgG4-RD, a novel disease involving many immune-system components

Multicentric Castleman's disease (MCD) is a polyclonal lymphoproliferative disorder that manifests as marked hyper-γ-globulinemia, severe inflammation, anemia, and thrombocytosis. Recently, Takai et al. reported a new disease concept, TAFRO syndrome, named from thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly. Furthermore, Kojima et al. reported Japanese MCD cases with effusion and thrombocytopenia (Castleman-Kojima disease). Here, we report two cases of MCD associated with marked pleural effusion, ascites, and thrombocytopenia, and discuss the independence of the TAFRO syndrome (Castleman-Kojima disease). Case 1: A 57-year-old woman had fever, anemia, anasarca, and some small cervical lymphadenopathy. Although she had been administered steroid therapy, and full-coverage antibiotics, her general condition, including fever, systemic inflammation, and anasarca, deteriorated steadily. We administered chemotherapy [CHOEP (cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisolone) regimen], but despite a transient improvement, she died due to septic shock. Case 2: A 73-year-old man with a history of aplastic anemia and remission presented with fever, severe inflammation, and anasarca. Prednisolone was administered (15 mg daily), and his hyperinflammation once improved. Nevertheless, his general condition, including pleural effusion and ascites, worsened, and C-reactive protein and interleukin-6 levels showed marked increases. The patient died due to multiorgan failure. Cases of TAFRO syndrome (Castleman-Kojima disease) are still rare. Therefore, it is necessary to conduct multicenter clinical surveys including similar cases, such as ours, to reach a consensus regarding diagnostic criteria, therapeutic strategy, and pathophysiological etiology for this syndrome.

ABSTRACT:Multidrug resistance protein 1 (MRP1) confers drug resistance and also mediates cellular efflux of many organic anions. MRP1 also transports glutathione (GSH); furthermore, this tripeptide stimulates transport of several substrates, including estrone 3-sulfate.