HSP70 antibodies in 80 patients with "clinically certain" Meniere's disease.

OBJECTIVES: We tested the claim that a significant proportion of patients with Meniere's disease have antibodies to heat shock protein 70 (HSP70) antigen, which may lead to defective endolymphatic sac function and vertigo attacks. METHODS: Serum samples were taken from 80 subjects with a "certain" diagnosis of Meniere's disease (American Academy criteria plus electrocochleographic confirmation of endolymphatic hydrops with tone burst stimuli) and were tested for HSP70 antibodies with the OTOblot (hsp70) Western blot assay. The response was recorded as negative, positive, or equivocal. Samples from 80 sex- and age-matched blood donors were used as controls. RESULTS: Of 80 patients with "clinically certain" Meniere's disease, 14 were positive for HSP70 antibodies or equivocal; of 80 controls, 10 were positive or equivocal. There was no significant difference (p=0.239). There was no correlation with bilateral disease, "activity" of Meniere's disease, or stage of Meniere's disease. CONCLUSIONS: Patients with an unequivocal diagnosis of Meniere's disease do not have a significantly raised incidence of HSP70 antibodies.

Antineutrophil cytoplasmic antibody measurement: advantages and disadvantages of a capture PR3 ELISA and a direct PR3 ELISA.

AIM: To compare the performance of a capture proteinase 3 enzyme linked immunosorbent assay (PR3 ELISA) with a direct PR3 ELISA in the measurement of PR3 antineutrophil cytoplasmic antibodies (ANCA). METHOD: The performance of both assays systems was compared using two sets of sera. Sera from patients (n = 49) suffering from Wegener's granulomatosis (WG) and fulfilling the American College of Rheumatology classification criteria (or a modification of those criteria that allowed for ANCA positivity) were used along with sera from a group of patients (n = 48) considered to have a clinically false positive PR3 ANCA result when measured by routine direct ELISA. RESULTS: Using the assay specific cut-offs, the direct ELISA gave a positive result in 92% on repeat testing and the capture ELISA a positive result in 84% of sera from patients with WG. The capture ELISA was negative in 75% of patients considered to have a false positive PR3 ANCA on initial testing by direct ELISA (27% were negative on repeat testing by direct ELISA). The mean concentration of PR3 ANCA in WG patient sera measured by the capture ELISA was significantly higher than that measured by the direct ELISA. The capture PR3 ELISA had a broader analytical range which was also reflected in PR3 ANCA concentrations measured in serial serum samples from WG patients. CONCLUSION: In this study the direct PR3 ELISA performed better as a screening test for PR3 ANCA compared with the capture PR3 ELISA, mainly because the cut-off for the capture ELISA needed to be set higher to avoid non-specific binding. In contrast, the improved analytical range of the capture ELISA made it a potentially more useful method for monitoring serial PR3 ANCA concentrations. In specific serum samples the capture ELISA was better able to discriminate 'false positive' PR3 ANCA.

Anti-cyclic citrullinated antibodies: complementary to IgM rheumatoid factor in the early diagnosis of rheumatoid arthritis.

AIMS: To compare the diagnostic sensitivity of anti-cyclic citrullinated (CCP) antibodies and rheumatoid factor (RF) in rheumatoid arthritis (RA) within a general hospital setting. METHOD: Using the American College of Rheumatology (ACR) classification criteria as a gold standard, the frequency of RF and anti-CCP antibody positivity was compared between two groups of RA patients: those with disease duration less than 2 years (early RA, ERA) and those with disease duration more than 2 years (late RA, LRA). RESULTS: In ERA, the diagnostic sensitivity of RF and anti-CCP antibodies was 57% and 79% respectively. In LRA, it was 81% and 84% respectively. CONCLUSION: Anti-CCP antibodies are 20% more sensitivity than RF in the diagnosis of early RA.