Neutrophil CD64 is upregulated in RA patients with lymphoma but not in other solid cancers.

OBJECTIVE: To evaluate the utility of quantifying CD64 expression on neutrophils in rheumatoid arthritis patients with malignancy, especially its diagnostic role in lymphoma. METHODS: We used flow cytometry to quantify CD64 expression on neutrophils from patients diagnosed with malignancy during the follow-up period prior to initiating treatment. RESULTS: Neutrophils from 18 patients with lymphoma expressed significantly higher levels of CD64 (9635.6 ± 2123.7 molecules/cell) than those from 32 patients with other solid cancers (carcinoma) (1250.5 ± 91.1 molecules/cell) (p < 0.001). When the cutoff value was set at 2060 molecules/cell, the sensitivity and specificity of CD64 for diagnosing lymphoma was 88.9% and 94.4%, respectively. CONCLUSIONS: The quantitative measurement of neutrophil CD64 by flow cytometry may be useful as a subsidiary diagnostic marker in patients with suspected lymphoma. Although neutrophil CD64 is currently a well-known marker of infection, it is necessary to bear in mind that lymphoma is also a candidate in differential diagnosis when CD64 expression on neutrophils is upregulated.

Neutrophil CD64 for monitoring the activity of nontuberculous mycobacteria infection in patients with rheumatoid arthritis.

OBJECTIVE: To evaluate the utility of neutrophil CD64 as a marker for monitoring the activity of nontuberculous mycobacteria (NTM) infection in patients with rheumatoid arthritis (RA). METHODS: We compared neutrophil CD64 expression in nine RA patients with NTM infection in the active and inactive phase of NTM disease chronologically. "Active phase" was here defined as present in patients admitted to hospital to receive intensive treatment for NTM, as well as outpatients with an infectious episode showing positive acid- and alcohol-fast bacillus (AFB) staining of sputa (Grade 2-3) who needed to start treatment for NTM with a multiple antibiotics regimen. The cut-off value for CD64 positivity was 2000 molecules/cell. RESULTS: Neutrophils from patients with active-phase NTM infection expressed high levels of CD64 with a mean ± SEM of 7335 ± 784 molecules/cell. However, during the inactive phase of disease, this was significantly lower (1481 ± 103 molecules/cell, p < 0.001). The sensitivity and specificity of neutrophil CD64 to detect active-phase NTM infection was 96.3% and 84.6%, respectively. Expression of neutrophil CD64 was not affected by disease activity of the RA itself. CONCLUSIONS: Neutrophil CD64 is useful for monitoring disease activity in NTM infection of patients with RA.

Association of human leukocyte antigen with interstitial lung disease in rheumatoid arthritis: a protective role for shared epitope.

INTRODUCTION: Interstitial Lung Disease (ILD) is frequently associated with Rheumatoid Arthritis (RA) as one of extra-articular manifestations. Many studies for Human Leukocyte Antigen (HLA) allelic association with RA have been reported, but few have been validated in an RA subpopulation with ILD. In this study, we investigated the association of HLA class II alleles with ILD in RA. METHODS: An association study was conducted on HLA-DRB1, DQB1, and DPB1 in 450 Japanese RA patients that were or were not diagnosed with ILD, based on the findings of computed tomography images of the chest. RESULTS: Unexpectedly, HLA-DRB1*04 (corrected P [Pc] = 0.0054, odds ratio [OR] 0.57), shared epitope (SE) (P = 0.0055, OR 0.66) and DQB1*04 (Pc = 0.0036, OR 0.57) were associated with significantly decreased risk of ILD. In contrast, DRB1*16 (Pc = 0.0372, OR 15.21), DR2 serological group (DRB1*15 and *16 alleles) (P = 0.0020, OR 1.75) and DQB1*06 (Pc = 0.0333, OR 1.57, respectively) were significantly associated with risk of ILD. CONCLUSION: HLA-DRB1 SE was associated with reduced, while DR2 serological group (DRB1*15 and *16) with increased, risk for ILD in Japanese patients with RA.

Diffuse chronic leptomeningitis with seropositive rheumatoid arthritis: report of a case successfully treated as rheumatoid leptomeningitis.

A case of biopsy-confirmed chronic leptomeningitis complicating rheumatoid arthritis in a 53-year old female is reported. Her symptoms included weight loss, severe depression, and pyrexia. Magnetic resonance imaging was useful in diagnosis. Intravenous methylprednisolone was prescribed (1 g/day for 3 days), followed by prednisolone (initial dose of 30 mg daily), and this treatment was effective. Her IgG-index, serum levels of soluble interleukin-2 receptor and ferritin, and cerebrospinal level of interleukin-6 paralleled her clinical course.