Abstract: Clinical and Immunologic Manifestations of Mixed Connective Tissue Disease in a Miami Population Compared to a Midwestern US Caucasian Population

Clinical and Immunologic Manifestations of Mixed Connective Tissue Disease in a Miami Population Compared to a Midwestern US Caucasian Population

MARCOS E. MALDONADO, MAGDALENA PEREZ, JUDITH PIGNAC-KOBINGER, EMILY TRIANA MARX, ELAINE M. TOZMAN, ERIC L. GREIDINGER, and ROBERT W. HOFFMAN

ABSTRACT.

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. (First Release Feb 1 2008; J Rheumatol 2008;35:429-37)

Key Indexing Terms:

MIXED CONNECTIVE TISSUE DISEASE
SYSTEMIC LUPUS ERYTHEMATOSUS
L-SELECTIN
T-REGULATORY CELLS
HISPANIC

From the Division of Rheumatology and Immunology, Department of Medicine, and the Department of Microbiology and Immunology, University of Miami Miller School of Medicine; and the Miami VA Medical Center, Miama, Florida, USA.

Supported by the University of Miami NIH General Clinical Research Center. Dr. Hoffman was supported by the National Institutes of Health (AR43308) the Department of Veterans Affairs, and the Lupus Foundation of America. Dr. Greidinger was supported by the Department of Veterans Affairs and the Lupus Research Institute.

M.E. Maldonado, MD, Assistant Professor of Medicine; M. Perez, MD, Research Associate; J. Pignac-Kobinger, MS, Research Associate; E.T. Marx, MD, Postdoctoral Fellow; E.M. Tozman, MD, Associate Professor of Medicine; E.L. Greidinger, MD, Assistant Professor of Medicine; R.W. Hoffman, DO, Professor of Medicine and Microbiology and Immunology, Chief, Division of Rheumatology and Immunology, Department of Medicine, University of Miami Miller School of Medicine.

Address reprint requests to Dr. R.W. Hoffman, Division of Rheumatology and Immunology, University of Miami Miller School of Medicine, 1120 NW 14th Street, Room 968, Miami, FL 33136. E-mail: rhoffman@med.miami.edu

Accepted for publication October 17, 2007.