Biomedical subjects
Publications and source records attributed to L M Noh.
We describe a Malay girl with disseminated cryptococcosis affecting the lungs, liver, lymph nodes and bones. The diagnosis was made by culture of the bone marrow. Tests of immune function showed that she was HIV-negative but the CD4 percentage was persistently low. Idiopathic CD4+ T-lymphocytopenia was diagnosed. The child died despite two courses of anti-fungal therapy.
A 3-month-old Malay male infant presented with multiple infections (candidiasis, Pseudomonas aeruginosa, Cytomegalovirus), persistent pneumonia, intractable diarrhoea and failure to thrive. There was lymphopaenia affecting both T and B subsets. He developed Graft versus Host disease weeks following transfusion with non irradiated blood. In spite of aggressive microbicidal and supportive therapy including regular immunoglobulin infusions, the child succumbed to infection before a bone marrow transplant could be instituted.
X linked agammaglobulinemia (XLA) is rarely reported from developing countries especially from South East Asia. It appears that X linked agammaglobulinemia is less common in certain ethnic groups. It is very uncommon in black people in USA and South Africa. In multiracial Malaysia we have documented five XLA in Malays and Indians but not in the Chinese that constitute about 31% of the population. First degree relatives afflicted with XLA or other primary immunodeficiencies occurred more often in our study. All showed lung involvement although the etiologic organisms involved were atypical, being Gram negative.
Three different methods to measure the oxidative respiratory burst of neutrophils were performed. Of the three, the chemiluminescence technique was observed to be the most sensitive among them. The strong statistical correlation and an acceptable agreement between chemiluminescence with that of the killing assay provides evidence for using the chemiluminescence assay as an alternative method of detecting gross defects of neutrophil respiratory burst killing assays.
Variable parameters in chemiluminescence assay, one of the methods used to assess the functional capacity of neutrophils, were evaluated for suitable adaptation locally. The use of pooled normal human serum as compared to single normal human serum in opsonizing particles for phagocytosis was found to exhibit lower chemiluminescence activity (reduction range of 30%-50%). A similar degree of depression was observed when the particles were opsonized using normal human serum in comparison to that using autologous serum. Different intensity of chemiluminescence was also noted when the opsonized particle used was the Oxford strain of Staphylococcus aureus (NCTC 6571) in contrast to a strain of Staphylococcus aureus isolated from a patient. The results obtained warrant clinicians to deliver appropriate samples as best they can when the chemiluminescence assay is requested.
A 20-month-old Indian boy presented with recurrent pyogenic infections and failure to thrive. His IgG and IgA levels were low, but his IgM was elevated. He also had undetectable isohaemagglutinin titre and neutropenia, both parameters being poor prognostic indicators in this very rare primary immunodeficiency state--antibody deficiency with hyper IgM. Our patient subsequently succumbed to Pseudomonas aeruginosa septicaemia and meningitis inspite of aggressive antibiotic and intravenous gammaglobulin therapy. To the best of our knowledge, this is the first such case to be documented in Malaysia.
A case of chronic mucocutaneous candidiasis in a Malaysian child who subsequently developed disseminated tuberculosis and toxoplasmosis is described. The phenotype of her peripheral blood mononuclear cells showed discordance for her T cell markers. The presence of a subpopulation of CD2-/CD3+ mononuclear cells leading to an immunodeficiency state is consistent with failure of activation of CD2-mediated alternative pathway resulting in immunodeficiency. Such abnormal CD2-/CD3+ subpopulations have been described in lepromatous leprosy and foetal abortuses.
We have used the mixed leukocyte reaction assay (MLR) to compare the non-specific suppressor activity of fresh and short-term cultured peripheral blood rosetted lymphocytes from human umbilical cord blood. To a one way MLR between adult responders and irradiated adult stimulator cells, we added adult or cord blood mononuclear cells. Cord-blood derived mononuclear cells were more potent suppressors of the MLR than the adult peripheral blood mononuclear cells. When the fresh cord blood T cell fraction was separated from non-T cells by rosetting, the frequency and capacity of suppression fell, suggesting a role of non-T cells in this phenomenon. However, short-term culture (up to nine days) of cord blood derived T cells in the absence of mitogen resulted in a significant increase in their suppressive characteristics. Maternal cells were not used in any of these assays and the suppression was non specific. There was no HLA restriction to the response. The cord blood lymphocytes responded poorly to alloantigen when compared to the adult lymphocytes. In addition, there was a correlation between the allogeneic proliferative response and the suppressive capacity of the cord blood cells. Such a correlation was not found with the adult peripheral blood lymphocytes.