β-glucan in the lymph nodes in sarcoidosis and in Kveim-Siltzbach test reagent

Diagnostic yield of the Kveim test in sarcoidosis patients

BACKGROUND AND AIM

Sarcoidosis is a granulomatous disorder of unknown etiology characterized by the existence of non-caseating granulomatous inflammation. Diagnosis can be challenging due to the presence of comprehensive clinical, laboratory, and radiologic manifestations. We have evaluated the diagnostic yield of the Kveim test and compared this test with the other conventional laboratory modalities. Our aim was to reach the highest level of diagnostic confidence acknowledging the absolute uncertainty in diagnosis with the current diagnostic enterprises.

METHODS

Medical records of 300 sarcoidosis patients were reviewed. Patients were classified into two categories as the conventional laboratory and the Kveim test group to compare the diagnostic yield.

RESULTS

Sensitivity of the Kveim test was 76.4% while the conventional laboratory tests provided a 64% diagnostic yield.  The conventional tests had a low diagnostic rate in the early disease stages. Kveim test revealed a high yield diagnosis for all stages of sarcoidosis. Integrated assessment of the two modalities reached a 96.8% sensitivity and a 94,6% specificity.

CONCLUSIONS

Conventional laboratory modalities were useful for the assessment of disease activity and identification of organ involvement. Kveim test revealed a significant diagnostic yield for all stages of sarcoidosis. The lowest output was achieved in stage IV patients due to the waning of active granulomatous inflammation.  The highest diagnostic sensitivity was obtained by an integrated analysis of the conventional laboratory and the Kveim test results for all aspects of sarcoidosis.

CD4+ T cells in the lungs of acute sarcoidosis patients recognize an Aspergillus nidulans epitope

Löfgren’s syndrome (LS) is an acute form of sarcoidosis characterized by a genetic association with HLA-DRB1*03 (HLA-DR3) and an accumulation of CD4⁺ T cells of unknown specificity in the bronchoalveolar lavage (BAL). Here, we screened related LS-specific TCRs for antigen specificity and identified a peptide derived from NAD-dependent histone deacetylase hst4 (NDPD) of Aspergillus nidulans that stimulated these CD4⁺ T cells in an HLA-DR3–restricted manner. Using ELISPOT analysis, a greater number of IFN-γ– and IL-2–secreting T cells in the BAL of DR3⁺ LS subjects compared with DR3⁺ control subjects was observed in response to the NDPD peptide. Finally, increased IgG antibody responses to A. nidulans NDPD were detected in the serum of DR3⁺ LS subjects. Thus, our findings identify a ligand for CD4⁺ T cells derived from the lungs of LS patients and suggest a role of A. nidulans in the etiology of LS.