Arezou Khosroshahi

Consensus statement on the pathology of IgG4-related disease.

IgG4-related disease is a newly recognized fibro-inflammatory condition characterized by several features: a tendency to form tumefactive lesions in multiple sites; a characteristic histopathological appearance; and—often but not always—elevated serum IgG4 concentrations. An international symposium on IgG4-related disease was held in Boston, MA, on 4–7 October 2011. The organizing committee comprising 35 IgG4-related disease experts from Japan, Korea, Hong Kong, the United Kingdom, Germany, Italy, Holland, Canada, and the United States, including the clinicians, pathologists, radiologists, and basic scientists. This group represents broad subspecialty expertise in pathology, rheumatology, gastroenterology, allergy, immunology, nephrology, pulmonary medicine, oncology, ophthalmology, and surgery. The histopathology of IgG4-related disease was a specific focus of the international symposium. The primary purpose of this statement is to provide practicing pathologists with a set of guidelines for the diagnosis of IgG4-related disease. The diagnosis of IgG4-related disease rests on the combined presence of the characteristic histopathological appearance and increased numbers of IgG4+ plasma cells. The critical histopathological features are a dense lymphoplasmacytic infiltrate, a storiform pattern of fibrosis, and obliterative phlebitis. We propose a terminology scheme for the diagnosis of IgG4-related disease that is based primarily on the morphological appearance on biopsy. Tissue IgG4 counts and IgG4:IgG ratios are secondary in importance. The guidelines proposed in this statement do not supplant careful clinicopathological correlation and sound clinical judgment. As the spectrum of this disease continues to expand, we advocate the use of strict criteria for accepting newly proposed entities or sites as components of the IgG4-related disease spectrum.

Recommendations for the nomenclature of IgG4-related disease and its individual organ system manifestations

John H. Stone, Arezou Khosroshahi, Vikram Deshpande, John K. C. Chan, J. Godfrey Heathcote, Rob Aalberse, Atsushi Azumi, Donald B. Bloch, William R. Brugge, Mollie N. Carruthers, Wah Cheuk, Lynn Cornell, Carlos Fernandez-Del Castillo, Judith A. Ferry, David Forcione, Gunter Kloppel, Daniel L. Hamilos, Terumi Kamisawa, Satomi Kasashima, Shigeyuki Kawa, Mitsuhiro Kawano, Yasufumi Masaki, Kenji Notohara, Kazuichi Okazaki, Ji Kon Ryu, Takako Saeki, Dushyant Sahani, Yasuharu Sato, Thomas Smyrk, James R. Stone, Masayuki Takahira, Hisanori Umehara, George Webster, Motohisa Yamamoto, Eunhee Yi, Tadashi Yoshino, Giuseppe Zamboni, Yoh Zen, and Suresh Chari

Rituximab therapy leads to rapid decline of serum IgG4 levels and prompt clinical improvement in IgG4-related systemic disease

OBJECTIVE Patients with IgG4-related systemic disease (IgG4-RSD) frequently show an incomplete response to treatment with glucocorticoids and traditional disease-modifying antirheumatic drugs (DMARDs). B lymphocyte depletion is a therapeutic strategy known to be effective for pemphigus vulgaris, an autoimmune condition mediated by IgG4 autoantibodies. This study was performed to assess the clinical and serologic responses to B lymphocyte depletion therapy with rituximab in patients with IgG4-RSD. METHODS Four patients with IgG4-RSD were treated with 2 intravenous doses (1 gram each) of rituximab. Clinical improvement was assessed by monitoring the tapering/discontinuation of prednisone and DMARDs, and by measuring the serum concentrations of B lymphocytes, immunoglobulins, and IgG subclasses before and after therapy. RESULTS Clinical features of IgG4-RSD in these 4 patients included autoimmune pancreatitis, sclerosing cholangitis, lymphoplasmacytic aortitis, salivary gland involvement, orbital pseudotumor, and lacrimal gland enlargement. The 3 patients with elevated serum IgG and IgG4 levels at baseline had a mean IgG concentration of 2,003 mg/dl (normal range 600-1,500 mg/dl) and a mean IgG4 concentration of 2,160 mg/dl (normal range 8-140 mg/dl). Among these patients, the serum IgG4 concentrations declined by a mean of 65% within 2 months of rituximab administration. All 4 patients demonstrated striking clinical improvement within 1 month of the initiation of rituximab therapy, and tapering or discontinuation of their treatment with prednisone and DMARDs was achieved in all 4 patients. A decrease in IgG concentration was observed for the IgG4 subclass only. CONCLUSION Treatment with rituximab led to prompt clinical and serologic improvement in these patients with refractory IgG4-RSD, and is a viable treatment option for this condition. The decline in serum IgG4 concentrations was substantially steeper than that of the autoantibody concentrations in immune-mediated conditions in which rituximab is effective, such as in rheumatoid arthritis. In addition, the reduction in IgG-subclass levels appeared to be specific for IgG4. The swift improvement of IgG4-RSD suggests that rituximab achieves its effects in IgG4-RSD by depleting the pool of B lymphocytes that replenish short-lived IgG4-secreting plasma cells.

Rituximab for the Treatment of Igg4-related Disease: Lessons From 10 Consecutive Patients

AbstractPatients with IgG4-related disease (IgG4-RD) typically have elevated serum concentrations of IgG4 and share histopathologic features that are similar across affected organ(s). IgG4-RD patients frequently require prolonged treatment with glucocorticoids and are often unable to taper these medications. Traditional disease-modifying antirheumatic drugs (DMARDs) are generally ineffective. We assessed the clinical and serologic responses to B lymphocyte depletion therapy in 10 consecutive patients with steroid- and DMARD-refractory IgG4-RD.Ten patients with IgG4-RD were treated with rituximab (RTX) (2 infusions of 1000 mg, 15 days apart). Clinical improvement was assessed by monitoring the patient’s ability to taper prednisone to discontinuation and to stop DMARDs; by serial measurements of total IgG and IgG subclasses; and by follow-up radiologic assessments guided by the patient’s particular pattern of organ involvement. We also developed and retrospectively applied the IgG4-RD Disease Activity Index and Flare Tool.Organ involvement included the pancreas, biliary tree, aorta, salivary glands (submandibular and parotid), lacrimal glands, lymph nodes, thyroid gland, and retroperitoneum. Nine of 10 patients demonstrated striking clinical improvement within 1 month of starting RTX. One patient with advanced thyroid fibrosis associated with Riedel thyroiditis and a history of disease in multiple other organ systems did not have improvement in the thyroid gland, but the disease did not progress to involve new organs. All 10 patients were able to discontinue prednisone and DMARDs following RTX therapy. Significant decreases in IgG concentrations were observed for the IgG4 subclass only. Four patients were re-treated with RTX after 6 months because of either symptom recurrence and increasing IgG4 concentration at the time of peripheral B cell reconstitution (n = 2) or because of physician discretion (n = 2). Repeated courses of RTX maintained their effectiveness and resulted in further decreases in IgG4 concentrations. In patients who had an increased IgG4 concentration at the time of presentation, the level of serum IgG4 appeared to be a reliable measure of disease activity.IgG4-RD is an idiopathic, multiorgan inflammatory disease in which diverse organ manifestations are linked by characteristic histopathologic and immunohistochemical features. Treatment with RTX led to prompt clinical and serologic improvement in refractory IgG4-RD in all patients with active inflammation. Serial treatments with RTX may lead to progressive declines in serum IgG4 concentrations and better disease control. Serum IgG4 concentrations may remain low, and clinical disease activity may remain quiescent even after B cell reconstitution in a significant proportion of patients.

A critical role for the programmed death ligand 1 in fetomaternal tolerance.

Fetal survival during gestation implies that tolerance mechanisms suppress the maternal immune response to paternally inherited alloantigens. Here we show that the inhibitory T cell costimulatory molecule, programmed death ligand 1 (PDL1), has an important role in conferring fetomaternal tolerance in an allogeneic pregnancy model. Blockade of PDL1 signaling during murine pregnancy resulted in increased rejection rates of allogeneic concepti but not syngeneic concepti. Fetal rejection was T cell– but not B cell–dependent because PDL1-specific antibody treatment caused fetal rejection in B cell–deficient but not in RAG-1–deficient females. Blockade of PDL1 also resulted in a significant increase in the frequency of IFN-γ–producing lymphocytes in response to alloantigen in an ELISPOT assay and higher IFN-γ levels in placental homogenates by ELISA. Finally, PDL1-deficient females exhibited decreased allogeneic fetal survival rates as compared with littermate and heterozygote controls and showed evidence of expansion of T helper type 1 immune responses in vivo. These results provide the first evidence that PDL1 is involved in fetomaternal tolerance.

International consensus guidance statement on the management and treatment of IgG4-related disease

A. Khosroshahi, Z. S. Wallace, J. L. Crowe, T. Akamizu, A. Azumi, M. N. Carruthers, S. T. Chari, E. Della-Torre, L. Frulloni, H. Goto, P. A. Hart, T. Kamisawa, S. Kawa, M. Kawano, M. H. Kim, Y. Kodama, K. Kubota, M. M. Lerch, M. L€ ohr, Y. Masaki, S. Matsui, T. Mimori, S. Nakamura, T. Nakazawa, H. Ohara, K. Okazaki, J. H. Ryu, T. Saeki, N. Schleinitz, A. Shimatsu, T. Shimosegawa, H. Takahashi, M. Takahira, A. Tanaka, M. Topazian, H. Umehara, G. J. Webster, T. E. Witzig, M. Yamamoto, W. Zhang, T. Chiba, and J. H. Stone

A clinical overview of Igg4-related systemic disease

Purpose of reviewTo summarize the existing knowledge of various clinical presentations of IgG4-related systemic disease (IgG4-RSD) and to review the evolving list of organs affected by IgG4-RSD. Recent findingsThe term IgG4-RSD encompasses a variety of clinical entities once regarded as being entirely separate diseases. The list of organs associated with this condition is growing steadily. Tissue biopsies reveal striking histopathological similarity, regardless of which organ is involved, although subtle differences across organs exist. Diffuse lymphoplasmacytic infiltrates, presence of abundant IgG4-positive plasma cells and extensive fibrosis are the hallmark pathology findings. Tumorous swelling, eosinophilia, and obliterative phlebitis are other frequently observed features. Polyclonal elevations of serum IgG4 are found in most but not all patients. SummaryIgG4-RSD is an underrecognized condition about which knowledge is now growing rapidly. Yet there remain many unknowns with regard to its cause, pathogenesis, various clinical presentations, approach to treatment, disease monitoring, and long-term outcomes. A wide variety of organs can be involved in IgG4-RSD. Clinicians should be aware of this entity and consider the diagnosis in the appropriate settings.

Rituximab for IgG4-related disease: a prospective, open-label trial

Objectives To evaluate the efficacy of rituximab (RTX) in IgG4-related disease (IgG4-RD) in an open-label pilot trial. Methods We treated 30 IgG4-RD patients with two doses of RTX (1000 mg each). The participants were either treated with RTX alone (n = 26; 87%) or required to discontinue baseline glucocorticoids (GC) within 2 months (n = 4; 13%). Disease activity was measured by the IgG4-RD Responder Index (IgG4-RD RI) and physicians global assessment (PGA). Disease response was defined as the improvement of the IgG4-RD RI by two points. The primary outcome, measured at 6 months, was defined as: (1) decline of the IgG4-RD RI ≥2 points compared with baseline; (2) no disease flares before month 6; and (3) no GC use between months 2 and 6. Complete remission was defined as an IgG4-RD RI score of 0 with no GC use. Results Disease responses occurred in 97% of participants. The baseline IgG4-RD RI and PGA values, 11±7 and 63±22 mm, respectively, declined to 1±2 and 11±16 mm at 6 months (both p<0.00001). The primary outcome was achieved by 23 participants (77%). Fourteen (47%) were in complete remission at 6 months, and 12 (40%) remained in complete remission at 12  months. Among the 19 with elevated baseline serum IgG4, IgG4 concentrations declined from a mean of 911 mg/dL (range 138–4780 mg/dL) to 422 mg/dL (range 56–2410 mg/dL) at month 6 (p<0.05). However, only 8 (42%) of the 19 achieved normal values. Conclusions RTX appears to be an effective treatment for IgG4-RD, even without concomitant GC therapy. Trial registration number ClinicalTrials.gov identifier: NCT01584388.

Tocilizumab for the treatment of large-vessel vasculitis (giant cell arteritis, Takayasu arteritis) and polymyalgia rheumatica.

The interleukin‐6 pathway is up‐regulated in giant cell arteritis (GCA), Takayasu arteritis (TA), and polymyalgia rheumatica (PMR). We retrospectively assessed the outcomes of 10 patients with relapsing/refractory GCA, TA, or PMR treated with tocilizumab (TCZ).

Riedel's Thyroiditis and Multifocal Fibrosclerosis are part of the IgG4-related systemic disease spectrum

Riedels thyroiditis is a chronic fibrosing disorder of unknown etiology often associated with “multifocal fibrosclerosis.” IgG4‐related systemic disease is characterized by IgG4+ plasma cell infiltration and fibrosis throughout many organs. We hypothesized that Riedels thyroiditis is part of the IgG4‐related systemic disease spectrum.