[Castleman's disease, pathophysiology, advances in diagnosis and treatment]. / Enfermedad de Castleman, fisiopatología, avances en el diagnóstico y tratamiento.

Castleman's disease (CD) encompasses a heterogeneous set of reactive lymphoproliferative processes that share well-defined histologic features. CD is considered a rare or minority disease. The incidence of CD is not fully known, although it is estimated at less than 1 per 100,000 inhabitants. It has a bimodal distribution (30-40 years and then 60-80 years). The incidence is similar in both sexes, although the unicentric variant seems to have a slight predominance in women with a 2:1 ratio. CD is classified into a hyalinovascular form (this being the most frequent) and a plasmocellular form, related to the HIV and VHH-8 viruses, which together with other autoimmune mechanisms develop hyperproduction of interleukin-6 (IL-6) by B lymphocytes. There are different lines of treatment, where the use of anti IL-6 stands out, being siltuximab the most used as orphan drug in this pathology.

Characterisation of the coexistence between sarcoidosis and Sjögren's syndrome. Analysis of 43 patients.

OBJECTIVES: To characterise the key epidemiological, clinical, immunological, imaging, and pathological features of the coexistence between sarcoidosis and Sjögren's syndrome (SS). METHODS: All centres included in two large multicentre registries (the Sjögren Syndrome Big Data Consortium and the Sarco-GEAS-SEMI Registry) were contacted searching for potential cases of coexistence between SS and sarcoidosis seen in daily practice. Inclusion criteria were the fulfilment of the current classification criteria both for SS (2016 ACR/EULAR) and sarcoidosis (WASOG). The following features were considered for evaluating a coexisting immunopathological scenario between the two diseases: non-caseating granulomas (NCG), focal lymphocytic sialadenitis (FLS) and positive anti-Ro antibodies. RESULTS: We identified 43 patients who fulfilled the inclusion criteria (38 women, with a mean age of 53 years at diagnosis of SS and of 52 years at diagnosis of sarcoidosis). In 28 (65%) cases, sarcoidosis was diagnosed concomitantly with SS, or during the follow-up of patients with an already diagnosed SS, while in the remaining 15 (35%), SS was diagnosed during the follow-up of an already diagnosed sarcoidosis. Patients in whom sarcoidosis was diagnosed first showed a lower mean age (43.88 vs. 55.67 years, p=0.005) and were less frequently women (73% vs. 96%, p=0.04) in comparison with those in whom sarcoidosis was diagnosed concomitantly with SS, or during the follow-up of an already diagnosed SS. We identified the following immunopathological scenarios: a combination of NCG involving extrasalivary tissues and anti-Ro antibodies in 55% of patients, a coexistence of both pathological scenarios (extrasalivary NCG and FLS in MSGB) in 42% (with positive anti-Ro antibodies in two thirds of cases), and NCG involving salivary glands and anti-Ro antibodies in 3% of cases. CONCLUSIONS: We have characterised the largest reported series of patients who fulfilled the current classification criteria for both SS and sarcoidosis. This implies that sarcoidosis (and not just the presence of isolated NCG on salivary gland biopsy) may, like other systemic autoimmune diseases, coexist with SS, and that a sarcoidosis diagnosis does not preclude the development of SS in the future.