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Production of cytokines in unstimulated and mitogen-stimulated cultures were evaluated by ELISPOT in 34 SLE patients with low to moderate disease activity and 23 healthy controls. Significantly reduced production of IFN gamma, IL4 and IL12 and significantly increased production of IL6, IL10 and TNF alpha were found in patients with SLE. Regression analysis revealed that production of all six cytokines tended to decrease with increasing disease activity, but negative correlation with SLEDAI was significant (p < 0.05) only for PHA-stimulated IL4, unstimulated and PHA-stimulated IL10 and SAC-stimulated IL6. Negative correlation of stimulated and unstimulated IL6 and TNF alpha production with anti-DNA antibody levels were also significant.

We report six Chinese boys with hypogammaglobulinaemia. All but one had very low or undetectable circulating B-lymphocytes, two had reversed CD4/CD8 ratios (in one of whom this latter became normal), one had reduced lymphocyte proliferative responses to concanavalin A and pokeweed mitogen and three had deficient responses to OKT3. Generation of antibody-secreting cells in response to pokeweed mitogen was markedly defective in all patients. Co-cultures of purified lymphocyte subsets from the patients with those of normal donors revealed that in addition to B-cell deficiency seen in all patients, two had T-helper cell deficiency and two had T-suppressor cell hyperactivity. One of the latter patients was treated with cimetidine in an attempt to ablate histamine type 2 receptor-bearing suppressor cells: the absolute number of such cells was temporarily reduced but there was no concurrent correction of the functional hyperactivity. These studies point to the variable nature of T-regulatory cell deficiencies in hypogammaglobulinaemia.

In order to establish normal reference ranges of serum immunoglobulin G subclasses for different age groups in Chinese, we measured the four IgG subclasses by radial immunodiffusion using polyclonal antisera in 350 normal healthy subjects (148 males and 202 females) recruited from the community. There was no significant sex difference for all the four IgG subclasses. Using Box-Cox transformation, we constructed smooth age-dependent percentile curves for the four IgG subclasses. For the 50th percentile values, the plateaus for IgG1 to IgG4 are respectively 970 mg/dl at 13 years old, 481 mg/dl at 18, 48 mg/dl at 17 and 80 mg/dl at 13. Methodology, reagents, environmental and genetic factors might be responsible for the observed difference among the various reports. The IgG2 level in our Chinese population seemed to be higher than that in Caucasians, which might account for the very low incidence of invasive Haemophilus influenzae type b disease among the Chinese. Our IgG1 level also plateaued later and at a higher level than that in other studies.

A study was conducted on 751 healthy children from child health clinics, kindergartens and schools, and 80 normal adults to establish reference ranges for serum immunoglobulins (Ig) G, A and M concentrations in normal Chinese. Serum IgG, IgA and IgM concentrations were determined by nephelometry. Serum IgG and IgA were shown to have a significant rise during the preschool age as well as at puberty with a plateau phase in between. This biphasic maturation profile has not been reported in Caucasians and the reasons for the observed difference have yet to be elucidated. Serum IgM concentrations were shown to be higher in females than in males, reaching significance in most age groups beyond 4 years of age. The difference between the two sexes in Chinese was of similar magnitude as that reported for Blacks and Caucasians, that is, 30%. Our findings support the hypothesis that the human X chromosome may carry quantitative genes for IgM.

In "standardized" one-way mixed lymphocyte cultures, a pool of blood lymphocytes from randomly chosen Chinese subjects was a significantly stronger stimulus to Caucasian responder lymphocytes than was a pool of allogeneic cells from Caucasians. In contrast, Chinese lymphocytes did not respond more strongly to Caucasian cells than to Chinese cells. This could not be explained by an inherent racial difference in the capacity of blood lymphocytes to undergo blastogenesis. The implications of these findings for organ transplantation and routine testing of cell-mediated immune function are discussed.