The effects of angiotensin-converting enzyme gene polymorphism on the progression of immunoglobulin A nephropathy in Malaysian patients

INTRODUCTION

Angiotensin-converting enzyme (ACE) gene polymorphism, especially the deletion/deletion (DD) genotype, is associated with the disease progression of immunoglobulin A (IgA) nephropathy patients in various studies from both Asia Pacific and European populations. However, recent studies within the same populations were unable to reproduce the same results. Hence, we had studied the distribution of the DD genotype, the association between ACE gene polymorphism and the disease progression, and the factors (other than ACE gene polymorphism) which were involved in the disease progression of our local patients.

METHODS

This was a cross-sectional study of biopsy-proven IgA nephropathy patients attending the Nephrology Clinic, Hospital Universiti Kebangsaan Malaysia. Both biochemical and urine tests at the time of first presentation were compared to those at the time of the study, and the disease progression was analysed. The ACE gene polymorphism was identified via PCR-amplification technique, and patients were then categorised into the DD and the non-DD groups for detailed analysis. Histological severity of each renal biopsy was scored according to the predetermined criteria and medications used were recorded. The association between the gene polymorphism and disease progression was then determined. The patients who were stable or had renal function deterioration, were respectively regrouped into Groups 1 and 2, to identity those factors (other than ACE gene polymorphism), which were involved in the disease progression.

RESULTS

60 patients with adequate renal histopathological examination were recruited. Their mean age was 40.9 +/- 12.3 years and the follow-up duration was 4 +/- 3 years (range 6 months-20 years). More than two-thirds of them were treated with ACE inhibitors or angiotensin receptor blockers and 8.3 percent received the combination treatment. The DD genotype was noted in 13.3 percent of study patients, insertion/insertion in 48.3 percent and insertion/deletion genotype in 38.3 percent. Although the estimated glomerular filtration rate (eGFR) of both groups were the same during their initial presentation, the DD patients had more severe disease compared to the non-DD patients at the time of the study. Their serum creatinine and eGFR was 178 (IQR 31.3) micromol/L and 42.1 +/- 31.1 ml/min/1.73 square metres, whereas the non-DD patients had serum creatinine and eGFR of 79 (IQR: 88.3) micromol/L and 76.6 +/- 42.1 ml/min/1.73 square metres, respectively (p-value is less than 0.01). The DD patients were also found to have more severe vascular damage in their renal biopsies compared to the non-DD patients. The annual rate of decline in eGFR was not significantly different between the two groups. It was -5.7 +/- 2.2 ml/min/1.73 square metres/year for the DD group and -4.8 +/- 2.0 ml/min/1.73 square metres/year for the non-DD group (p-value is equal to 0.5). They also had severe proteinuria with UPCI of 0.09 (IQR 0.2) g/mmol creatinine vs. 0.04 (IQR 0.10) g/mmol creatinine (p-value is less than 0.01). The study also confirmed that patients who had higher systolic blood pressure, greater proteinuria and longer follow-up duration had significant renal function deterioration compared to those who did not.

CONCLUSION

The DD genotype, although found in a minority of the patients, might have adversely affected the disease progression of our IgA nephropathy patients. Higher systolic blood pressure, greater proteinuria and longer follow-up duration were the other prognostic factors in IgA nephropathy patients. However, appropriate treatment, especially prompt use of renin-angiotensin-aldosterone system blockade, should stabilise the disease regardless of their genotype.

Gender differences in the clinical and serological features of systemic lupus erythematosus in Malaysian patients

An analysis of the clinical and serological features of 12 male and 122 female patients with SLE was done to determine whether sex related differences exist. We found a lower incidence of mucocutaneous symptoms and arthritis but an increased incidence of discoid lesions, pleuritis and pericarditis in males at disease onset. During the disease course, there was a lower incidence of arthritis, a similar prevalence of mucocutaneous symptoms but an increased incidence of pleuritis in males with a trend towards renal involvement. These findings were however not statistically significant except for the higher incidence of thrombosis among males. Serologically, both groups showed similar frequencies of autoantibodies and hypocomplementaemia. Although the study was small, it was shown that several sex-related differences in the clinical and serological features exist in Malaysian SLE patients.

The association of the HLA class II antigens with clinical and autoantibody expression in Malaysian Chinese patients with systemic lupus erythematosus

The frequency of the HLA class II antigens/alleles (HLA-DR, DQ and DP) were studied in 70 Malaysian Chinese patients with systemic lupus erythematosus (SLE) to examine the contribution of these genes to disease susceptibility, their clinical expression and Immunological responses. This was done using modified PCR-RFLP technique. These samples were then compared with 66 ethnically matched controls. We found a strong association of the DQA1*0102 (p corr = 0.032, rr = 3.39), DQB1*0501 (p corr = 0.003, rr = 4.55), *0601 (p corr = 0.006, rr = 4.22) and DPB1* 0901(p corr = 0.02, rr = 4.58) with SLE. Clinically, we found a strong association of DR2 and DQA1*0301 with renal involvement and DQA1*0102 with alopecia. Immunologically, statistical analysis (Chi-square test ) showed a strong association of DQA1*0102 with anti-Ro/La antibodies while DQA1*0301 was observed to be strongly associated with antibodies to ds DNA. DQA1*0102 was found more frequently in those with a later disease onset (30 years of age or above). From these data we suggest that the HLA class II genes play a role in conferring disease susceptibility and clinical and immunological expression.

HLA antigens in Malay patients with systemic lupus erythematosus: association with clinical and autoantibody expression

BACKGROUND

Studies have shown that certain genes within the major histocompatibility complex predispose to systemic lupus erythematosus (SLE) and may influence clinical and autoantibody expression. Thus, we studied the frequency of HLA-DR, -DQA, -DQB and -DPB alleles in ethnic Malays with SLE to determine the role of these genes in determining disease susceptibility and their association with clinical and immunological manifestations.

METHODS

Fifty-six Malay SLE patients were enrolled into the study. Demographic, clinical and immunological findings were obtained from medical records. HLA-DR, DQ and DP typing were done using modified PCR-RELP. Controls were from ethnically-matched healthy individuals.

RESULTS

We found a strongly significant association of the DR2 and DQB1 *0501 and DQB1*0601 (pcorr = 0.03, rr = 3.83, pcorr = 0.0036, rr = 4.56 and pcorr = 0.0048 and rr = 6.0, respectively). There was also a weak increase of DQB1*0.201 and DPB1*0.0901 with a weak decrease of DQA1*0601 and DQB1*0503 and *0301 which were not significant after corrections for multiple comparisons were made. There was a significant positive association of DR2 and DQB1*0501 with renal involvement and DR8 with alopecia. A nonsignificant increase of DQB1*0503 in patients with photosensitivity was noted. Significant autoantibody associations were also found: DQB1*0601 with anti-Sm/RNP, DR2 with antiSSA (Ro)/SSB (La), and DR2, DQB1*0501 and *0601 with antibodies to ds DNA. There was no specific DR, DQ or DP associations with age of disease onset (below 30 years or those at or above 30 years).

CONCLUSION

Our data suggests the role of the HLA class II genes in conferring SLE susceptibility and in clinical and autoantibody expression.

Lymphocyte subsets in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by increased B cell activity and depressed T cell function. However, the contribution of the immunoregulatory system to its pathogenesis is still unclear. The recent development in the production of monoclonal antibodies and the availability of bench-top flow cytometers have allowed rapid quantitation of peripheral blood lymphocyte subsets. We analysed the distribution of the lymphocyte subsets in 24 patients with active SLE and 18 with inactive SLE. The distribution of immunoregulatory cells in 72 normal volunteers was used as control. Statistical analysis showed that there were significant differences between both the SLE groups and the normal controls, for total lymphocytes, T cells, B cells, T helper cells, T suppressor cells, T helper/suppressor ratio and natural killer cells. There was a significant difference for T helper cells between active and inactive SLE. T helper cells levels were found to be low in inactive SLE and lower in active SLE. It appears that treatment-induced remissions did not restore the levels of immunoregulatory cells to normal. Thus, T helper cell levels reflect disease activity and longitudinal assays of T helper cells may serve as an indicator of disease reactivation.

Mortality in Malaysians with systemic lupus erythematosus

One hundred and two patients attending the systemic lupus erythematosus (SLE) clinic of the Department of Medicine, Universiti Kebangsaan Malaysia, were studied retrospectively to determine their survival rates and causes of death. There were 21 deaths. The 1, 5, and 10 year survival rates were 93%, 86% and 70% respectively. There was a bimodal pattern of mortality with more patients dying in the first 2 years or after 5 years of disease. Infection was the direct cause of death in 52% and contributed to a further 19% of deaths. Patients with lupus nephritis had a higher relative risk (RR) of death (RR = 4.34, p < 0.02) although there was no significant increase in risk with any particular histological type on biopsy. Cerebral lupus (RR = 3.08, p < 0.001) and methylprednisolone treatment (RR = 6.24, p < 0.001) were also associated with increased risk of death. Increased awareness of infection and earlier use of antibiotic therapy may improve survival of patients suffering from SLE.

Risk factors for infection in Malaysian patients with systemic lupus erythematosus

To determine the incidence, types and risk factors for infection in systemic lupus erythematosus (SLE) patients in Kuala Lumpur, Malaysia, we retrospectively reviewed the medical records of 102 patients with definite SLE attending a specialist clinic. Details of major infections (pneumonia or severe infection requiring intravenous therapy) and minor infections, and their time of onset in relation to immunosuppressive therapy and disease flares were recorded. There were 77 major and 163 minor infections during 564 patient-years of follow-up. In the month following a course of pulse methylprednisolone, the incidence of major infection was 20 times higher and the incidence of minor infection was 10 times higher than at other periods (p < 0.0001). In the month after disease flare, the incidence of major infection was 10 times higher and the incidence of minor infection six times higher than at other times (p < 0.0001). After allowing for methylprednisolone therapy and disease flares, there was no increase in the rate of infections during treatment with azathioprine, oral or intravenous cyclophosphamide. There was no effect of renal involvement on infection rate.

Pyomyositis revisited

Pyomyositis, purportedly a common tropical infection affecting mainly healthy adults and children, appears to be most uncommon in this region. We report a case of pyomyositis caused by a Methicillin-resistant Staphylococcus aureus (MRSA) in a previously healthy army officer. This case serves to illustrate the difficulty in recognising this disease entity, which is why many cases may have been missed. With the increasing incidence of MRSA nosocomial infections, the emergence of MRSA in a hitherto community-acquired infection poses a major concern especially since intravenous drug abuse and acquired immune deficiency syndrome (AIDS) are on the rise in our country. We hope to inculcate greater awareness of this infection.

Brain calcification in patients with cerebral lupus

Cerebral lupus (CL) is a common cause of morbidity and mortality in patients with SLE. The brain CTs of 27 consecutive adult patients with SLE and various neurological presentations were reviewed. The median age and duration of neurological symptoms at the time of the brain CT were 30 years (range = 14-51 years) and six days (range = 1 day-22 years), respectively. Eleven patients (41%) had normal CTs. The abnormalities in the remaining patients could be divided into six categories: (a) cerebral atrophy alone (two patients); (b) calcification alone (three patients); (c) infarct(s) alone (five patients); (d) cerebral atrophy and calcification (three patients); (e) cerebral atrophy and infarct(s) (one patient) and (f) cerebral atrophy, calcification and infarct(s) (two patients). Altogether eight patients (30%) (age range = 17-47 years) had intracerebral calcification: the globus pallidus was involved in all, putamen in two, head of the caudate nucleus in one, thalamus in one, centrum semiovale in two and cerebellum in three patients. Two patients had extensive calcifications of most of the basal ganglia, centrum semiovale and cerebellum. There was no relationship between the presence/degree of calcification and age of patients/duration or type of neurological presentation. The pathogenesis of cerebral calcification in CL is unknown. Cerebral lupus must now be included in the differential diagnosis of intracerebral calcification.

Djenkol bean poisoning (djenkolism): an unusual cause of acute renal failure

This report describes a patient with acute renal failure that resulted from the ingestion of djenkol beans. Features of acute djenkolism include nausea, vomiting, bilateral loin pain, gross hematuria, and oliguria. The blood urea level was 16.2 mmol/L and the serum creatinine was 460 mumol/L. Phase contrast microscopy of the urinary sediment indicated that the hematuria was nonglomerular. Ultrasound of the kidneys showed slightly enlarged kidneys with no features of obstruction. Renal biopsy showed acute tubular necrosis similar to the single animal study reported in the literature. With conservative therapy, which included rehydration with normal saline and alkalinization of the urine with sodium bicarbonate, the acute renal failure resolved. Based on its chemistry, djenkol bean-associated acute renal failure may be analogous to acute uric acid nephropathy.

Acute renal failure in falciparum malaria

We report two patients who had cerebral malaria, heavy parasitemia, hyperbilirubinemia, hypercatabolism with rapid rises of blood urea and serum creatinine and acute renal failure. There was no evidence of intravascular hemolysis. Renal biopsy was consistent with acute tubular necrosis. Both patients responded to treatment with intravenous quinine and dialysis.

HLA antigens in Malay patients with systemic lupus erythematosus

Many studies have shown an association between human leucocyte antigens (HLA) and systemic lupus erythematosus (SLE) in the various study populations. Although SLE is not an uncommon disease in the Malaysian Archipelago, and appears to affect all three major racial groups equally (i.e. Southern Chinese, Malays and Southern Indians), very little information is available on the HLA profiles in the two latter groups. In phase I of our study of the HLA profiles in Malaysian SLE patients, the HLA phenotypes (class I: A, B, C; Class II: DR, DQ) of Malay patients with confirmed SLE and 91 normal Malay controls were determined using the microcytotoxicity assay. The strong association between DR (RR 3.28, P = 0.008) concurs with that reported among Chinese and Japanese populations. Moderate to strong associations with HLA-B 7 (RR 4.99, P = 0.02) and Cw 7 (RR 2.94, P = 0.003) were also found. We believe this is the first report of the association of HLA and SLE in the Malay population.

Cryptococcosis in a renal unit

Cryptococcosis is a known opportunistic infection in immunosuppressed hosts. We report our experience of all cases presenting to our Department between December 1975 and September 1988. Eight post-renal transplant patients and three systemic lupus erythematosus (SLE) patients were affected. All were receiving treatment with steroids, in association with either azathioprine or cyclosporin. The diagnosis of cryptococcal meningitis was initially based on a positive cerebrospinal fluid (CSF) cryptococcal antigen, by latex agglutination test, and subsequently confirmed by cultures. Common clinical presentations, in descending order of frequency, included headaches, fever, mental confusion, epilepsy and papilloedema. Meningism was not a prominent feature. CT brain scans were obtained in eight patients and one showed a focal lesion and one showed cerebral atrophy. Four patients also had an abnormal chest X-ray (CXR) and one had disseminated cryptococcosis. Amphotericin and 5-fluorocytosine were the mainstay of therapy, although ketoconazole alone was subsequently used in three selected patients with cure. Four early deaths occurred in patients with delayed diagnosis and treatment, usually in association with other severe concurrent infections. We conclude that awareness of cryptococcosis is essential in immunocompromised hosts presenting with headache with, or without, mental confusion or fever.

Spectrum of nocardiosis in renal patients

Nocardiosis is an increasingly recognised opportunistic infection in immunologically incompetent hosts but diagnosis is often delayed. Between December 1975 to October 1988, our two Nephrology Units have encountered five cases of nocardiosis occurring in two post-renal transplant patients, two patients with systemic lupus erythematous (SLE) and one patient with mesangiocapillary glomerulo--nephritis. All were on immunosuppressants at the time. The first three patients presented with predominant pulmonary disease and were cured by combined trimethoprim-sulphamethoxazole (cotrimoxazole) and doxycycline therapy. The patient with limited skin involvement responded to cotrimoxazole alone. However, the last patient with lymphocutaneous disease initially responded to cotrimoxazole (+ chloramphenicol) but developed acute-on-chronic renal failure and relapsed with dose reduction of cotrimoxazole. Alternative treatment with amikacin and doxycycline was instituted with good response. We shall review potential clues that may suggest the diagnosis of nocardiosis and discuss other effective antimicrobial agents.

Subclavian catheters as temporary vascular access

We reviewed our experience with subclavian vascular catheters (SVC) as temporary vascular access in the 18 month period 1 January 1984-30 June 1985. 37 consecutive patients using 49 vascular catheters received a total of 461 haemodialyses. Only 8 patients had acute renal failure. The rest were endstage renal failure (ESRF) patients awaiting definitive vascular access. Most of these latter patients were ambulant and were generally dialysed on an outpatient basis. 27 episodes of clinical septicaemia occurred and was the ONLY significant complication encountered. All but one patient responded to empiric therapy with cloxacillin +/- gentamicin and removal of the catheter. We conclude that SVC's are safe and suitable for use on an extended short-term basis especially in ESRF patients with vascular access problems.