Glomerulonephropathy in ankylosing spondylitis

Aim:  Renal abnormalities have been reported in ankylosing spondylitis (AS). The purpose of this study was to elucidate the nature of glomerulonephropathy in AS. Methods:  Two hundred and sixty-six patients with definite AS diagnosed at Taipei Veterans General Hospital, Taiwan, were enrolled. Urinary analysis and renal biopsy were performed in this study. The nature of glomerulonephropathy in AS was analyzed. Results:  Twelve out of 266 (4.5%) patients had AS-associated nephropathy manifesting as haematuria alone (11 patients) or haematuria and proteinuria (1 patient). Renal biopsy in seven patients showed IgA nephropathy in two cases, mesangial nephropathy with isolated C3 deposits in three cases, and IgM nephropathy in two cases, one of which had accompanied infectious endocarditis. Conclusion:  AS-associated nephropathy is not uncommon and mesangial nephropathy is the most common form. Microscopic haematuria and proteinuria are the most common manifestations of renal involvement.