We studied the prevalence of antinuclear (ANA), anti-double stranded DNA (dsDNA), anti-Sm and anti-RNP antibodies in a group of 93 blood donors (age range: 18-58 years). Antinuclear and anti-ds DNA antibodies were detected by immunofluorescence (IF) using HEp2 cells and Crithidia luciliae as substrates, respectively, while anti-Sm and anti-RNP antibodies were assayed by ELISA. ANA was found in 6.5% while anti-dsDNA antibodies were not detected in any of the subjects. The 98th percentile was used as cut off where values greater than 0.651 for anti-Sm and 0.601 for anti-RNP antibodies were taken to be positive. This gives a frequency of 1.1% for both antibodies. There was no significant association of antibody positivity with sex or race. We conclude that certain autoantibodies are present in low titres in the normal Malaysian Individuals, at a different frequency compared to other studies probably due to genetic, ethic or environmental factors.
A study of 101 sera from 69 Malay, 14 Chinese and 18 Indian healthy adult Malaysians was undertaken to determine the frequency of antinuclear antibodies (ANA), antimitochondrial antibodies (AMA), antismooth muscle antibodies (SMA) and antiparietal cell antibodies (APCA). There were 67 females and 34 males with a mean age of 31.7 years (+/-8.6). ANA was assayed by immunofluorescence (IF) using both mouse liver and HEp-2 cell substrates. AMA, SMA and APCA were also tested by IF using composite sections from mouse liver, kidney and stomach substrates. Analysis showed 6.9% were positive for ANA at a titre of 1:40 with HEp-2 while only 1.9% were detected using mouse liver. 9.9% had detectable AMA from titres 1:10 to 1:90. None of them had detectable SMA and only 1 (0.09%) had APCA at a titre of 1:80. This study suggests that a diagnosis of an autoimmune disorder has to be cautiously made taking into consideration that autoantibodies are present in low titres in the healthy population.
Autoantibodies have been known to be detected during pregnancy. The occurrence of autoantibodies during pregnancy was studied in a group of 146 healthy pregnant women from Jan-March 1995. Serum samples were tested for antinuclear (ANA), anti-ds DNA, anti-mitochondrial, anti-smooth muscle and anti-parietal cell antibodies employing the technique of indirect immunofluorescence. Sera from 66 non-pregnant women were used as controls. Among the pregnant group, 2 (1.4%) were found to have ANA positivity in comparison to none in the control group. This difference was found to be not statistically significant. Only 1 (0.7%) was positive for anti-mitochondrial antibody in the pregnant group compared to one in the control group (p > 0.05). However, anti-ds DNA, anti-smooth muscle and anti-parietal cell antibodies were not detected in both groups. All those positive for autoantibodies were in their 2nd trimester. When these cases were followed-up at the end of their pregnancy, none had complicated pregnancies nor infant abnormalities. Our findings suggest that (a) the occurrence of autoantibodies in pregnant women was not significantly different from non-pregnant controls and that (b) maternal autoantibodies did not appear to cause complications during pregnancy or infant morbidity.
Thirty-six patients with lupus nephritis (LN) attending the Nephrology Clinic, Hospital Kuala Lumpur were studied for the prevalence of anticardiolipin antibody (ACA) isotypes (IgG and IgM) and other associated antibodies, antinuclear antibody (ANA) and anti-ds DNA antibody and to determine the possible association between serological and clinical parameters. The study population consisted of 20 (55.6%) Malays, 15 (41.7%) Chinese and 1 (2.8%) Indian with a mean age of 31.4 +/- 11.3 years, range 14 to 60 years. The female to male ratio was 11:1. The average time between diagnosis and blood sampling was 4.4 years (range 0.25 to 15 years). Increased ACA levels were found in 20 (55.6%) patients where raised IgG ACA and IgM ACA were observed in 20 (55.6%) and 2 (5.6%) cases respectively. ANA and anti-ds DNA antibodies were detected in 22 (61.1%) and 4 (11.1%) individuals respectively, with the majority (82%) showing a speckled pattern of nuclear staining. However, neither the IgM ACA nor IgG ACA showed any significant association with thrombosis or any other clinical parametres. Our preliminary study indicates that ACA is a frequent finding in lupus nephritis and that the IgG isotype is more prevalent.
Study site: nephrology Clinic, Hospital Kuala Lumpu