Clinical and immunologic manifestations of mixed connective tissue disease in a Miami population compared to a Midwestern US Caucasian population.
OBJECTIVE
A cross-sectional study of mixed connective tissue disease (MCTD) was performed to determine if there were identifiable differences in the clinical expression of MCTD associated with race or ethnicity.


METHODS
Miami, Florida, and Midwestern US (Missouri) Caucasian MCTD cohorts were studied. Clinical and laboratory features of the 2 MCTD cohorts were compared. A concurrently collected cohort of Sm-positive patients with systemic lupus erythematosus (SLE) was studied as a control. Disease activity and severity and functional status were measured. CD4+CD25(high)-expressing T-regulatory cells were enumerated and serum soluble L selectin was measured as biomarkers of disease activity.


RESULTS
The Miami and Missouri Caucasian MCTD groups, while differing from the SLE group, were largely similar; however, gastroesophageal reflux, sclerodactyly, and malar rash were significantly more frequent in the Missouri MCTD group and alopecia was more frequent in the Miami MCTD group. Significant clinical and laboratory differences were found between the Miami MCTD and Miami SLE groups despite similar disease duration, activity, severity and functional status. Raynaud's phenomenon (RP), hand swelling, synovitis, myositis, and sclerodactyly were all significantly more common in RNP-positive MCTD versus Sm-positive SLE subjects. CONCLUSION Ethnic differences were observed in the frequency of end-organ involvement in the Miami MCTD versus the Missouri Caucasian MCTD groups. Clinical and laboratory features of all MCTD groups were clearly different from the SLE group, despite similar disease activity, disease severity, and functional status. Disease activity measures appeared to behave similarly as valid measures of disease activity in SLE and MCTD.
Maldonado
Marcos E
ME
Division of Rheumatology and Immunology, Department of Medicine, University of Miami Miller School of Medicine; and the Miami VA Medical Center, Miama, Florida 33136, USA.
Perez
Magdalena
M
Pignac-Kobinger
Judith
J
Marx
Emily Triana
ET
Tozman
Elaine M
EM
Greidinger
Eric L
EL
Hoffman
Robert W
RW
D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000208:ethnology; D000368:Aged; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005431:Florida / Q000453:epidemiology; D006630:Hispanic or Latino / Q000208:ethnology; D006801:Humans; D019041:L-Selectin / Q000097:blood*; D008180:Lupus Erythematosus, Systemic / Q000208:ethnology / Q000276:immunology*; D008875:Middle Aged; D008923:Missouri / Q000453:epidemiology; D008947:Mixed Connective Tissue Disease / Q000208:ethnology* / Q000276:immunology*; D012720:Severity of Illness Index; D050378:T-Lymphocytes, Regulatory; D044465:White People / Q000208:ethnology
D019041:L-Selectin