Antineutrophilic cytoplasmic antibody-associated vasculitis with hypocomplementemia has a higher incidence of serious organ damage and a poor prognosis

A relationship between antineutrophilic cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and complement has been shown, and complement has an important role in the pathogenesis of AAV. The clinical characteristics of AAV with hypocomplementemia still remain unclear.We conducted an observational study of 81 patients with AAV (median onset age 71 years; 58% female). Using medical records, we analyzed the patients' baseline variables, laboratory data, clinical symptoms, and therapeutic outcomes after treatments including episodes of relapses, initiation of dialysis, and death. We defined hypocomplementemia as the state in which at least one of the following was lower than the lower limit of the normal range: complement 3 (C3), complement 4 (C4), and total complement activity (CH50).Sixteen patients (20%) had hypocomplementemia at their diagnosis of AAV. Compared to the AAV patients without hypocomplementemia (n = 65), those with hypocomplementemia had significantly higher rates of the occurrence of skin lesions (8 [50%] vs. 8 [12%], P = 0.002), diffuse alveolar hemorrhage (DAH) (6 [38%] vs. 5 [8%], P = 0.006), and thrombotic microangiopathy (TMA) (3 [19%] vs. 0 [0%], P = 0.007). The AAV patients with hypocomplementemia had significantly lower platelet levels (16.5 × 10 vs. 24.9 × 10 cells/μL, P = 0.023) compared to those without hypocomplementemia. More positive immune complex deposits in renal biopsy specimens were seen in the AAV patients with hypocomplementemia than in those without hypocomplementemia (4 [80%] vs. 2 [18%], P = 0.036). Assessed by a log-rank test, hypocomplementemia at disease onset was significantly associated with death (P = 0.033).Hypocomplementemia in AAV at the disease onset was a risk factor for the serious organ damage, and a life prognostic factor. It is thus very important to pay attention to the levels of complement at the diagnosis of AAV.

Lupus Nephritis IgG Induction of Calcium/Calmodulin-Dependent Protein Kinase IV Expression in Podocytes and Alteration of Their Function

OBJECTIVE

Kidney podocytes and their slit diaphragms prevent urinary protein loss. T cells from patients with systemic lupus erythematosus display increased expression of calcium/calmodulin-dependent protein kinase IV (CaMKIV). The present study was undertaken to investigate the role of CaMKIV in podocyte function in lupus nephritis (LN).

METHODS

We treated kidney podocytes with IgG derived from healthy individuals or patients with LN and then analyzed gene expression using a DNA microarray. The localization of IgG in podocytes was analyzed by immunofluorescence staining, with or without silencing of neonatal Fc receptor (FcRn). In addition, we silenced CAMK4 in podocytes and analyzed the expression of selected genes. We also examined the expression of CD86 in kidney podocytes from MRL/lpr, MRL/lpr.camkiv(-/-), and MRL/MPJ mice by in situ hybridization.

RESULTS

We found that exposure of podocytes to IgG resulted in entry of IgG into the cytoplasm. IgG entered podocytes via the FcRn because less IgG was found in the cytoplasm of podocytes treated with FcRn small interfering RNA. DNA microarray studies of podocytes exposed to LN-derived IgG revealed up-regulation of genes related to the activation of immune cells or podocyte damage. Interestingly, CD86 expression decreased after silencing CAMK4 in podocytes. Also, in situ hybridization experiments showed that the expression of CD86 was reduced in podocytes from MRL/lpr.camkiv(-/-) mice.

CONCLUSION

LN-derived IgG enters podocytes and up-regulates CAMK4, which is followed by increased expression of genes known to be linked to podocyte damage and T cell activation. Targeted inhibition of CAMK4 in podocytes may prove to be clinically useful in patients with LN.

A case of lacrimal sarcoidosis following interstitial pneumonia: imaging and management

A 60-year-old Japanese man developed a fever and dry cough. Although chest CT showed interstitial pneumonia, the primary disease was not revealed. The interstitial pneumonia was improved by treatment with oral prednisolone following methylprednisolone pulse therapy. After the discontinuation of prednisolone he developed swelling of the eyelids and polyarthralgia. Orbital magnetic resonance imaging showed enlargement of the bilateral lacrimal glands. (67)Gallium scintigraphy showed abnormal uptake of the bilateral lacrimal glands and pulmonary hilum. A lacrimal gland biopsy showed noncaseating granulomatous infiltration with occasional multinucleated giant cells consistent with sarcoidosis. His symptoms improved by treatment with oral prednisolone and triamcinolone injection into the lacrimal glands.

RS3PE Syndrome with Iliopsoas Bursitis Distinguished from an Iliopsoas Abscess Using a CT-guided Puncture

A 55-year-old man was diagnosed with remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome. Contrast-enhanced computed tomography for cancer screening showed a mass with low-density centers with an enhanced rim in the left iliopsoas muscle. We suspected an iliopsoas abscess and performed computed-tomography-guided puncture of the mass. Both Gram staining and the culture of the fluid were negative. We diagnosed the patient with RS3PE syndrome with iliopsoas bursitis and administered low-dose corticosteroids without antibiotics. The symptoms, including left hip pain, quickly disappeared following treatment. Clinicians should be aware that iliopsoas bursitis may resemble an iliopsoas abscess. As a result, it is important to make an accurate differential diagnosis.

Hemophagocytic syndrome and inflammatory myopathy with abundant macrophages in a patient with adult-onset Still's disease

We herein describe a 71-year-old woman with adult-onset Still's disease (AOSD) who developed fever, myalgia, and pancytopenia. The bone marrow aspiration and muscle biopsy revealed hemophagocytic syndrome (HPS) and inflammatory myopathy with abundant macrophages (IMAM). Immunostained specimens were positive for expression of retinoic acid-inducible gene-I (RIG-I), which recognizes viral RNA in infiltrated mononuclear cells as well as muscle tissues. These findings suggest that RIG-I may be involved in induction of HPS and IMAM in AOSD.