Polyarteritis nodosa (PAN), also known as panarteritis nodosa, represents a form of necrotizing vasculitis that predominantly affects medium-sized vessels, although it is not restricted to them and can also involve smaller vessels. The clinical presentation is heterogeneous and characterized by a significant number of patients exhibiting general symptoms, including asthenia, fever, and unintended weight loss. Although PAN can involve virtually any organ, it preferentially affects the skin, nervous system, and the gastrointestinal tract. Orchitis is a rare but specific manifestation of PAN. The absence of granulomas, glomerulonephritis, and anti-neutrophil cytoplasmic antibodies serves to distinguish PAN from other types of vasculitis. Major complications consist of hemorrhagic and thrombotic events occurring in mesenteric, cardiac, cerebral, and renal systems. Historically, PAN was frequently linked to hepatitis B virus (HBV) infection, but this association has dramatically changed in recent years due to declining HBV prevalence. Current epidemiological research often identifies a connection between PAN and genetic syndromes as well as neoplasia. This article provides a comprehensive review of PAN, specifically focusing on the progression of its clinical manifestations over time.

Lupus nephritis (LN) is a frequent manifestation of systemic lupus erythematosus, and fewer than half of patients achieve complete renal response with standard immunosuppressants. Identifying noninvasive, blood-based immune alterations associated with renal injury could aid therapeutic decisions. Here, we used mass cytometry immunophenotyping of peripheral blood mononuclear cells in 145 patients with biopsy-proven LN and 40 healthy controls to evaluate the heterogeneity of immune activation and identify correlates of renal parameters. Unbiased analysis identified 3 immunologically distinct groups of patients that were associated with different patterns of histopathology, renal cell infiltrates, urine proteomic profiles, and treatment response at 1 year. Patients with enriched circulating granzyme B ⁺ T cells showed more active disease and increased numbers of activated CD8 ⁺ T cells in the kidney, yet they had the highest likelihood of treatment response. A second group characterized by a high type I interferon signature had a lower likelihood of response to therapy, while a third group appeared immunologically inactive but with chronic renal injuries. The major immunologic axes of variation could be distilled down to 5 simple cytometric parameters that recapitulate several clinical associations, highlighting the potential for blood immunoprofiling to translate to clinically useful noninvasive metrics to assess immune-mediated disease in LN.

The vast majority of patients with systemic lupus erythematosus (SLE) complain about fatigue. They also report fatigue as one of their most debilitating symptoms. Yet, in clinical practice, fatigue is only rarely assessed and remains poorly understood. The purpose of this study is to validate the Fatigue Assessment Scale (FAS) and assess the impact of disease activity on fatigue in SLE. A cross-sectional single-center study of patients was included in the Swiss SLE Cohort Study. The FAS and the Short Form 36 (SF-36) were administered to SLE patients and controls with primary Sjogren’s syndrome (pSS) and healthy volunteers (HV) attending our clinic. Disease activity in SLE was captured at the same time as patient-reported outcomes using the SLE Disease Activity Index score with the Safety of Estrogens in SLE National Assessment modification (SELENA-SLEDAI) and the physician’s global assessment. We explored the internal consistency, reproducibility, construct validity, and convergence of the FAS, in comparison to the vitality subscale (VT) of the SF-36. We examined the association of FAS with demographics, disease type, SLE disease activity, and clinical features. Of the 73 SLE subjects, 89% were women and 77% were Caucasians. The median age was 43 years, and 23 (32%) patients had active SLE. Demographics in pSS and HV were similar. Within the SLE group, FAS displayed good internal consistency (Cronbach’s alpha = 0.93), unidimensionality, and test-retest reliability (ICC = 0.90). FAS and VT correlated well. The total FAS was highest in active SLE and pSS and higher in non-active SLE compared to HV. The FAS is a promising tool to measure fatigue in SLE. Patients with SLE display a significantly higher level of fatigue than HV, which is even more pronounced in active disease and comparable to fatigue levels measured in pSS.

Lupus nephritis (LN) is a frequent manifestation of systemic lupus erythematosus, and fewer than half of patients achieve complete renal response with standard immunosuppressants. Identifying non-invasive, blood-based pathologic immune alterations associated with renal injury could aid therapeutic decisions. Here, we used mass cytometry immunophenotyping of peripheral blood mononuclear cells in 145 patients with biopsy-proven LN and 40 healthy controls to evaluate the heterogeneity of immune activation in patients with LN and to identify correlates of renal parameters and treatment response. Unbiased analysis identified 3 immunologically distinct groups of patients with LN that were associated with different patterns of histopathology, renal cell infiltrates, urine proteomic profiles, and treatment response at one year. Patients with enriched circulating granzyme B ⁺ T cells at baseline showed more severe disease and increased numbers of activated CD8 T cells in the kidney, yet they had the highest likelihood of treatment response. A second group characterized primarily by a high type I interferon signature had a lower likelihood of response to therapy, while a third group appeared immunologically inactive by immunophenotyping at enrollment but with chronic renal injuries. Main immune profiles could be distilled down to 5 simple cytometric parameters that recapitulate several of the associations, highlighting the potential for blood immune profiling to translate to clinically useful non-invasive metrics to assess immune-mediated disease in LN.