BACKGROUND: The mitotic spindle apparatus (MSA) is a unique structure of microtubules and associated proteins involved in the segregation and reorganisation of chromosomes during cell division. Autoantibodies to the MSA (anti-MSA) are reported to occur rarely, but are easily identified during the immunofluorescent detection of anti-nuclear antibodies (ANA), and are generally reported as part of that investigation. AIMS: As the clinical significance of these antibodies is unknown, our aim was to identify the clinical features of subjects identified with anti-MSA, and in a subset investigate the co-association with organ specific anti-thyroid antibodies. METHODS: All ANA results from the three major immunology laboratories serving South Australia between January 1993 and June 1998 were retrospectively reviewed to identify anti-MSA subjects. Clinical details were extracted from hospital or general practice records using a standard proforma. Thyroid autoantibodies were measured using standard technique. A control group of consecutive ANA positive, anti-MSA negative individuals had anti-thyroid antibodies measured. Statistical comparison used chi2 test. RESULTS: Fifty-five subjects (43F) were identified with mean age 59.8 (range 17-91); 39 had specific diagnoses, with 16 identified as part of non-specific investigations. 'Arthritis' broadly accounted for the largest group, transient inflammatory arthritis n=7, degenerative joint disease n=6, rheumatoid arthritis n=5. Adenocarcinoma and mesothelioma accounted for one case each. Thirty-two subjects had anti-thyroid antibodies tested, with ten of 21 and two of 11 positive among the groups with anti-MSA titre >1:80 and <1:40 respectively, chi2=2.7, p=0.1. Anti-thyroid antibodies were detected more frequently among the high titre anti-MSA group (ten of 21) compared with high titre positive ANA, negative anti-MSA group (two of 11), RRisk 4.4, chi2=5.34, p=0.02. CONCLUSION: This study confirmed the relative rarity of anti-MSA and that its association is primarily with rheumatic diseases. The coincidence of mesothelioma is novel with only two previous reports of malignancy and anti-MSA. The co-association of high titre anti-MSA and thyroid autoantibodies suggest that the latter should be a follow up investigation if the former is identified as part of an investigative screen.
BACKGROUND: The mitotic spindle apparatus (MSA) is a unique structure of microtubules and associated proteins involved in the segregation and reorganisation of chromosomes during cell division. Autoantibodies to the MSA (anti-MSA) are reported to occur rarely, but are easily identified during the immunofluorescent detection of anti-nuclear antibodies (ANA), and are generally reported as part of that investigation. AIMS: As the clinical significance of these antibodies is unknown, our aim was to identify the clinical features of subjects identified with anti-MSA, and in a subset investigate the co-association with organ specific anti-thyroid antibodies. METHODS: All ANA results from the three major immunology laboratories serving South Australia between January 1993 and June 1998 were retrospectively reviewed to identify anti-MSA subjects. Clinical details were extracted from hospital or general practice records using a standard proforma. Thyroid autoantibodies were measured using standard technique. A control group of consecutive ANA positive, anti-MSA negative individuals had anti-thyroid antibodies measured. Statistical comparison used chi2 test. RESULTS: Fifty-five subjects (43F) were identified with mean age 59.8 (range 17-91); 39 had specific diagnoses, with 16 identified as part of non-specific investigations. 'Arthritis' broadly accounted for the largest group, transient inflammatory arthritis n=7, degenerative joint disease n=6, rheumatoid arthritis n=5. Adenocarcinoma and mesothelioma accounted for one case each. Thirty-two subjects had anti-thyroid antibodies tested, with ten of 21 and two of 11 positive among the groups with anti-MSA titre >1:80 and <1:40 respectively, chi2=2.7, p=0.1. Anti-thyroid antibodies were detected more frequently among the high titre anti-MSA group (ten of 21) compared with high titre positive ANA, negative anti-MSA group (two of 11), RRisk 4.4, chi2=5.34, p=0.02. CONCLUSION: This study confirmed the relative rarity of anti-MSA and that its association is primarily with rheumatic diseases. The coincidence of mesothelioma is novel with only two previous reports of malignancy and anti-MSA. The co-association of high titre anti-MSA and thyroid autoantibodies suggest that the latter should be a follow up investigation if the former is identified as part of an investigative screen.