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La etiopatogenia de las vasculitis no es del todo bien conocida, involucrándose la participación de factores ambientales en individuos genéticamente predispuestos 1,2. La expresión histológica renal de la vasculitis sistémicas es una glomerulonefritis necrotizante pauciinmune (GNP) 3. Nosotros describimos dos casos de vasculitis familiar en dos hermanos procedentes de medio rural.
To the editor: Etiopathogenesis of vasculitis is not fully understood, and environmental factors have been implicated in genetically predisposed individuals.1,2 The histological renal expression of systemic vasculitis is apauci-immune necrotizing glomerulonephritis (PNG).3 Two cases of familial vasculitis in two brothers living in a rural environment are reported here.
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To the editor: Etiopathogenesis of vasculitis is not fully understood, and environmental factors have been implicated in genetically predisposed individuals.1,2 The histological renal expression of systemic vasculitis is apauci-immune necrotizing glomerulonephritis (PNG).3 Two cases of familial vasculitis in two brothers living in a rural environment are reported here.
CASE 1
A 63-year-old male, a shepherd living in a rural environment. He consulted in 1988 for an impaired general status, and laboratory tests revealed oliguric acute renal failure. Histological analysis of renal biopsy found a necrotizing vasculitis with extracapillary proliferative glomerulonephritis. The patient was treated with corticosteroids and oral cyclophosphamide. No renal function improvement occurred, and renal replacement therapy was required until the patient died in 2003.
CASE 2
A 72-year-old male, a farmer living in a rural environment. In April 2004 he complained of cough, expectoration, fatigue, and anorexia. His family history revealed that the patient reported as case 1 was his brother. His parents had died at an advanced age, and he had two sisters with type 2 diabetes mellitus, one of them with a history of pulmonary tuberculosis.
Based on his personal history, clinical signs, and renal function impairment, a renal biopsy was performed,
which confirmed the presence of PNG in the setting of a systemic vasculitis associated to P-ANCA (positive anti-MPO, titer 442 U/mL).
DISCUSSION
Pauci-immune necrotizing glomerulonephritis with extracapillary proliferation is the renal pathological expression of systemic vasculitis. This group of diseases is characterized by inflammation of small and medium-sized
blood vessels, and includes Wegener¿s granulomatosis (WG), microscopic polyangeitis (MPA), Churg-Strauss
syndrome, or vasculitis limited to the kidney.3
Their etiopathogenesis is unknown. Occurrence of these diseases in several members of a same family has suggested that genetic factors could contribute to its occurrence.1 We report two cases of PNG as a renal manifestation of systemic vasculitis in two brothers. In case 2, the disease started when the first patient had already died. The presence on the same disease in two brothers could support the genetic component in the etiopathogenesis of vasculitis.
Some researchers have attempted to find associations of vasculitis with HLA genes.1 Recent studies found a positive association with HLA DR1, particularly in patients with WG, and negative associations with HLA DR3,
particularly in Churg-Strauss granulomatosis and polyarteritis nodosa.1, 4 Our patient had the haplotype A1, B8 B35 Cw4 Cw7 DR3 and DR5 DQ2. Case 1 haplotype is unknown because the patient died before the second patient experienced the disease.
It has also been suggested that environmental factors could contribute to disease development in genetically
predisposed individuals.2 Patients reported here lived in a rural environment, and some environmental component may possibly have contributed to occurrence of the same disease in both patients.
In conclusion, these two cases of PNG as an expression of systemic vasculitis in two brothers living in a similar environment could support the suggested hypothesis of an influence of environmental factors on the etiopathogenesis of vasculitis in genetically predisposed individuals.
CASE 1
A 63-year-old male, a shepherd living in a rural environment. He consulted in 1988 for an impaired general status, and laboratory tests revealed oliguric acute renal failure. Histological analysis of renal biopsy found a necrotizing vasculitis with extracapillary proliferative glomerulonephritis. The patient was treated with corticosteroids and oral cyclophosphamide. No renal function improvement occurred, and renal replacement therapy was required until the patient died in 2003.
CASE 2
A 72-year-old male, a farmer living in a rural environment. In April 2004 he complained of cough, expectoration, fatigue, and anorexia. His family history revealed that the patient reported as case 1 was his brother. His parents had died at an advanced age, and he had two sisters with type 2 diabetes mellitus, one of them with a history of pulmonary tuberculosis.
Based on his personal history, clinical signs, and renal function impairment, a renal biopsy was performed,
which confirmed the presence of PNG in the setting of a systemic vasculitis associated to P-ANCA (positive anti-MPO, titer 442 U/mL).
DISCUSSION
Pauci-immune necrotizing glomerulonephritis with extracapillary proliferation is the renal pathological expression of systemic vasculitis. This group of diseases is characterized by inflammation of small and medium-sized
blood vessels, and includes Wegener¿s granulomatosis (WG), microscopic polyangeitis (MPA), Churg-Strauss
syndrome, or vasculitis limited to the kidney.3
Their etiopathogenesis is unknown. Occurrence of these diseases in several members of a same family has suggested that genetic factors could contribute to its occurrence.1 We report two cases of PNG as a renal manifestation of systemic vasculitis in two brothers. In case 2, the disease started when the first patient had already died. The presence on the same disease in two brothers could support the genetic component in the etiopathogenesis of vasculitis.
Some researchers have attempted to find associations of vasculitis with HLA genes.1 Recent studies found a positive association with HLA DR1, particularly in patients with WG, and negative associations with HLA DR3,
particularly in Churg-Strauss granulomatosis and polyarteritis nodosa.1, 4 Our patient had the haplotype A1, B8 B35 Cw4 Cw7 DR3 and DR5 DQ2. Case 1 haplotype is unknown because the patient died before the second patient experienced the disease.
It has also been suggested that environmental factors could contribute to disease development in genetically
predisposed individuals.2 Patients reported here lived in a rural environment, and some environmental component may possibly have contributed to occurrence of the same disease in both patients.
In conclusion, these two cases of PNG as an expression of systemic vasculitis in two brothers living in a similar environment could support the suggested hypothesis of an influence of environmental factors on the etiopathogenesis of vasculitis in genetically predisposed individuals.
