Primary IgA Nephropathy in North India: Is it Different?
Primary IgA Nephropathy in North India: Is it Different?
Background Immunoglobulin A (IgA) nephropathy is the most common glomerulonephritis worldwide, but has a variable geographic distribution. The bulk of the disease burden is borne by Asian countries. However, its exact prevalence or clinicopathologic spectrum in India is not well documented.
Methods This cross sectional study analysed the renal biopsy findings and clinical features at presentation in 66 patients of primary IgA nephropathy diagnosed over a period of 2 years (2007–2008). The results were compared with studies from other centres in the country and elsewhere.
Results IgA nephropathy comprised 8.1% of all native kidney biopsies. The mean age of the patients was 29.9 years with a male:female ratio of 4.4:1. Most patients presented with renal failure and a significant percentage (23%) also had nephrotic range proteinuria. Renal biopsies were classified by the Haas classification and were further scored by the MEST scoring system of the Oxford classification. By Haas classification, 41 cases (62%) showed advanced sclerotic lesions of class V. Active crescents (cellular or fibrocellular) were seen in 42% of cases, and 26% of cases showed endocapillary proliferation. Serum creatinine values were highest in the presence of proliferative lesions. MEST scoring of the Oxford classification was not applicable in approximately 18% of cases because of the presence of advanced sclerotic lesions. On immunofluorescence, the majority of the cases showed both mesangial and membranous positivity for IgA antisera. Electron microscopy revealed para-mesangial location of immune complex deposition in the majority of the cases. It also showed glomerular basement membrane abnormalities in two cases.
Conclusion Comparison of clinical and pathological features revealed that this disease presents as an advanced disease in much younger individuals in this study compared to other studies. Elucidation of the underlying factors may have immense therapeutic implications.
Immunoglobulin A (IgA) nephropathy was first described by Berger and Hinglais in 1968. Since then, studies worldwide have proved it to be the most common glomerulonephritis in the world. The bulk of the disease burden is borne by Asians and whites, as compared to blacks from the USA and South Africa. In addition, Polynesians from New Zealand have a low frequency of the condition, whereas native Americans from New Mexico and Australian aborigines have a high frequency. The incidence quoted in the literature in France, Germany, and Italy varies from 15 to 40 new cases per million population per year.
In Asia, Singapore, Japan, and China have a very high prevalence of IgA nephropathy. Studies from Japan recorded a prevalence of up to 50%. In a Japanese study by Okada et al, hypertension was found in 9.8% and focal glomerulosclerosis on morphology in 52.9% of their adult cohort. In a study from the North West Frontier province of Pakistan, the prevalence of the disease was 20.83% (25/120) of all renal biopsies, with only 4% of patients having nephrotic range proteinuria. Few studies have been published in the literature from the Indian subcontinent which quote a variable prevalence of 5.45–16% of all cases of glomerulonephritis from different regions. Moreover, many studies from Asia report pure mesangiopathy to be the most common lesion in IgA nephropathy. On the other hand, western literature quotes focal proliferative lesions to be the most common histological lesion.
Our current knowledge of IgA nephropathy in India is based on multiple small studies on native renal biopsies, the first one of which was by Bhuyan et al in 1992, which reported a prevalence of 7.24% in New Delhi. Three years later, Sehgal et al from northern India quoted a prevalence of 10.4%. Most of the other studies were from southern India, which has a demographic profile that is different from the northern part of the country. The largest of these was a 27 year (1986–2002) retrospective review of the pattern of IgA nephropathy at a single centre (Vellore). Of the 5415 native renal biopsies, 8.6% showed IgA nephropathy, which were further subclassified using the modified World Health Organization classification. Recent studies by Vanikar et al from western India and Chandrika et al from southern India recorded that 14% and 16% of their kidney biopsies, respectively, showed IgA nephropathy, which is much lower than the prevalence of 50% in Japan.
The present study was conducted in a tertiary care centre in north India—a multi-specialty, 1700 bed teaching hospital with an active nephrology unit and a pathology department which performs histopathology, electron microscopy, and immunofluorescence on nearly 500 native kidney biopsies a year. Unlike corporate hospitals, a major proportion (80%) of patients visiting this hospital are of low socioeconomic status and consequently may present late in the course of the disease because of a lack of awareness about their health. All patients with glomerular haematuria, proteinuria or renal failure are biopsied, unless there are specific contraindications. However, we record that the clinicopathologic pattern of IgA nephropathy in the north of India is quite different from the rest of the world. In this study we analysed 66 cases of primary IgA nephropathy and examined correlation between biopsy findings and clinical features at presentation. The results obtained were compared with the studies from other centres (in India, other Asian countries, and western countries).
Abstract and Introduction
Abstract
Background Immunoglobulin A (IgA) nephropathy is the most common glomerulonephritis worldwide, but has a variable geographic distribution. The bulk of the disease burden is borne by Asian countries. However, its exact prevalence or clinicopathologic spectrum in India is not well documented.
Methods This cross sectional study analysed the renal biopsy findings and clinical features at presentation in 66 patients of primary IgA nephropathy diagnosed over a period of 2 years (2007–2008). The results were compared with studies from other centres in the country and elsewhere.
Results IgA nephropathy comprised 8.1% of all native kidney biopsies. The mean age of the patients was 29.9 years with a male:female ratio of 4.4:1. Most patients presented with renal failure and a significant percentage (23%) also had nephrotic range proteinuria. Renal biopsies were classified by the Haas classification and were further scored by the MEST scoring system of the Oxford classification. By Haas classification, 41 cases (62%) showed advanced sclerotic lesions of class V. Active crescents (cellular or fibrocellular) were seen in 42% of cases, and 26% of cases showed endocapillary proliferation. Serum creatinine values were highest in the presence of proliferative lesions. MEST scoring of the Oxford classification was not applicable in approximately 18% of cases because of the presence of advanced sclerotic lesions. On immunofluorescence, the majority of the cases showed both mesangial and membranous positivity for IgA antisera. Electron microscopy revealed para-mesangial location of immune complex deposition in the majority of the cases. It also showed glomerular basement membrane abnormalities in two cases.
Conclusion Comparison of clinical and pathological features revealed that this disease presents as an advanced disease in much younger individuals in this study compared to other studies. Elucidation of the underlying factors may have immense therapeutic implications.
Introduction
Immunoglobulin A (IgA) nephropathy was first described by Berger and Hinglais in 1968. Since then, studies worldwide have proved it to be the most common glomerulonephritis in the world. The bulk of the disease burden is borne by Asians and whites, as compared to blacks from the USA and South Africa. In addition, Polynesians from New Zealand have a low frequency of the condition, whereas native Americans from New Mexico and Australian aborigines have a high frequency. The incidence quoted in the literature in France, Germany, and Italy varies from 15 to 40 new cases per million population per year.
In Asia, Singapore, Japan, and China have a very high prevalence of IgA nephropathy. Studies from Japan recorded a prevalence of up to 50%. In a Japanese study by Okada et al, hypertension was found in 9.8% and focal glomerulosclerosis on morphology in 52.9% of their adult cohort. In a study from the North West Frontier province of Pakistan, the prevalence of the disease was 20.83% (25/120) of all renal biopsies, with only 4% of patients having nephrotic range proteinuria. Few studies have been published in the literature from the Indian subcontinent which quote a variable prevalence of 5.45–16% of all cases of glomerulonephritis from different regions. Moreover, many studies from Asia report pure mesangiopathy to be the most common lesion in IgA nephropathy. On the other hand, western literature quotes focal proliferative lesions to be the most common histological lesion.
Our current knowledge of IgA nephropathy in India is based on multiple small studies on native renal biopsies, the first one of which was by Bhuyan et al in 1992, which reported a prevalence of 7.24% in New Delhi. Three years later, Sehgal et al from northern India quoted a prevalence of 10.4%. Most of the other studies were from southern India, which has a demographic profile that is different from the northern part of the country. The largest of these was a 27 year (1986–2002) retrospective review of the pattern of IgA nephropathy at a single centre (Vellore). Of the 5415 native renal biopsies, 8.6% showed IgA nephropathy, which were further subclassified using the modified World Health Organization classification. Recent studies by Vanikar et al from western India and Chandrika et al from southern India recorded that 14% and 16% of their kidney biopsies, respectively, showed IgA nephropathy, which is much lower than the prevalence of 50% in Japan.
The present study was conducted in a tertiary care centre in north India—a multi-specialty, 1700 bed teaching hospital with an active nephrology unit and a pathology department which performs histopathology, electron microscopy, and immunofluorescence on nearly 500 native kidney biopsies a year. Unlike corporate hospitals, a major proportion (80%) of patients visiting this hospital are of low socioeconomic status and consequently may present late in the course of the disease because of a lack of awareness about their health. All patients with glomerular haematuria, proteinuria or renal failure are biopsied, unless there are specific contraindications. However, we record that the clinicopathologic pattern of IgA nephropathy in the north of India is quite different from the rest of the world. In this study we analysed 66 cases of primary IgA nephropathy and examined correlation between biopsy findings and clinical features at presentation. The results obtained were compared with the studies from other centres (in India, other Asian countries, and western countries).
