Serodiagnosis of Mycobacterium avium complex pulmonary disease in the USA.

Diagnosis of Mycobacterium avium complex pulmonary disease (MAC-PD) can be difficult. A previous study from Japan reported the usefulness of a serodiagnostic test for MAC-PD. The objective of this study was to evaluate the usefulness of the test in similar patients in the USA. 100 patients with known or suspected MAC-PD and 52 healthy volunteers were enrolled into the study at National Jewish Health, Denver, CO, USA. Serum glycopeptidolipid core immunoglobulin A antibody levels were measured with an enzyme immunoassay (EIA) kit and routine clinical evaluations were performed. The patients were divided into two groups based on clinical evaluation: 87 patients with MAC-PD that met American Thoracic Society criteria, and 13 who did not meet the criteria. The sensitivity and specificity (cut-off point 0.3 U·mL(-1)) of the serodiagnostic test for diagnosing MAC-PD were 70.1% and 93.9%, respectively. Among the 44 patients in the MAC-PD group with two or more positive sputum cultures within the previous 6 months, sensitivity was 81.8%. The EIA kit demonstrated good sensitivity and specificity for the identification of MAC-PD, particularly in patients with two or more positive cultures, and may be useful for rapid MAC-PD diagnosis.

Response to cutaneous immunization with low-molecular-weight subunit keyhole limpet hemocyanin.

BACKGROUND: This study was carried out to determine whether humoral and cellular immune responses would be provoked by cutaneous administration of keyhole limpet hemocyanin (KLH) and in particular by scarification of the skin (SS). METHODS: This was an unblinded, single-center, 8-week pilot study in healthy young adults. Twenty-four subjects assigned to 4 groups completed the study. Each group was immunized twice, with a 3-week interval, either by SS or intradermally (ID), with an SS dose of 50 or 250 µg and an ID dose of 100 or 250 µg. Serum was collected for antibody assays at baseline and 3 weeks after both the first and second immunizations. Delayed-type hypersensitivity (DTH) testing was performed before the first immunization and 3 weeks after the second. RESULTS: In the 250-µg SS group, there was a significant increase from day 0 to day 47 in anti-KLH IgG (p = 0.02; day 0: 3.46 ± 5.49 mg/dl, day 47: 7.54 ± 8.87 mg/dl) and anti-KLH IgA (p = 0.04; day 0: 4.78 ± 9.15 mg/dl, day 47: 11.42 ± 13.62 mg/dl). One subject in each treatment group showed a positive DTH test result representing 20% (50-µg SS), 10% (250-µg SS), 25% (100-µg ID) and 20% (250-µg ID) of the subjects. CONCLUSIONS: It was possible to induce both humoral and cellular immune responses by SS administration despite the limited antigenic potency of the low-molecular-weight KLH preparation. This approach may be useful for studying the mechanisms of immune response in allergic skin diseases such as atopic dermatitis.