Dapsone-induced methemoglobinemia in pediatric oncology patients: case examples.

Over the last 25 years, significant advances have been made in supportive care of the immunocompromised patient. One significant advance is the use of trimethoprim-sulfamethoxazole (TMP-SMZ) in the prevention of Pneumocystic carinii pneumonia (PCP). Although TMP-SMZ remains the drug of choice for PCP prophylaxis, children who develop or have a history of adverse reactions must be prescribed an alternative treatment. In these instances, medications such as dapsone, aerosolized pentamidine, or atovaquone are prescribed. This report discusses four children with sulfa allergy who were prescribed dapsone and later developed methemoglobinemia. Although methemoglobinemia is associated with dapsone, there was no reference found regarding this link in the pediatric oncology literature. The purpose of these clinical examples is to alert the pediatric nurse and advanced practitioner to the association of dapsone and methemoglobinemia.

Detection of cytomegalovirus antigens in phagocytosed serum complexes from a patient with rheumatoid arthritis, vasculitis, peripheral neuropathy, cutaneous ulceration, and digital gangrene.

A patient with rheumatoid arthritis, vasculitis, peripheral neuropathy, cutaneous ulceration, and digital gangrene was studied. Circulating immune complexes were detected by C1q binding although serum complement levels were within the normal range. Immunofluorescent staining of buffy coat cells with specific antisera showed the presence of IgG and IgM in phagocytosed inclusions but complement C3 was not detected. A monoclonal antibody specific for cytomegalovirus detected antigens in phagocytosed inclusions on one occasion. These results may suggest that cytomegalovirus antigens are a hitherto unidentified component of serum complexes in patients with rheumatoid arthritis and may contribute to the pathogenesis of the vasculitic complications of rheumatoid arthritis by participating in immune complex formation.

Do polyclonal rheumatoid factors carry an 'internal image' of cytomegalovirus, Epstein-Barr virus and nuclear antigens?

Rabbit antisera have been prepared against isolated rheumatoid factors (RF's). It was considered that RFs are anti-idiotype antibodies and that the anti-RF antisera had anti-anti-idiotype specificity. Furthermore, it was considered that the RF's carry an "internal image" of the putative "antigen X" and that the rabbit antisera would have specificity for this "antigen-X". Reactions of the rabbit antisera with the early and late antigens of CMV, EBV antigens and nuclear antigens suggest that there may be an "internal image" of these antigens in rheumatoid factor molecules and that they all may be related to the immunogenesis of RF.

Aetiology of rheumatoid arthritis: an attempt to transmit an infective agent from patients with rheumatoid arthritis to baboons.

Thirty baboons were injected intravenously and intra-articularly with material from the joints of 19 patients with active rheumatoid arthritis or with control material. Fifteen of the 30 animals received synovial fluid cells or synovial membrane cells from 3 patients with seronegative arthritis. Ten animals received pooled cells from a total of 16 cases of seropositive arthritis. Five animals were given nonrheumatoid cells. No signs of arthritis were recognised in the 27 surviving animals during 3 years of observation. No significant biochemical, haematological, or serological changes occurred during this period, and no gross or microscopic evidence of synovial or systemic disease was found post mortem.

Viruses and lymphocytes in rheumatoid arthritis. II. Examination of lymphocytes and sera from patients with rheumatoid arthritis for evidence of retrovirus infection.

The possible involvement of retroviruses in the aetiology of rheumatoid arthritis (RA) was investigated. Retrovirus antigens were not expressed on rheumatoid synovial and peripheral blood lymphocytes as judged by membrane immunofluorescence, radioimmunoassay, and complement-mediated cytotoxicity. The specific antiretroviral (anti-RD-144 and anti-SSAV) sera used in this study were produced in rabbits immunised with viral antigens grown in a homologous system (rabbit cells and medium supplemented with normal rabbit serum), avoiding non-specific immunofluorescence previously detected with donated antiretroviral sera. Immune complexes lodged in the rheumatoid synovial membranes did not contain, and other cells within the membranes did not express, retroviral antigens. Antibodies cross-reacting with primate retrovirus antigens were sought in sera from patients with 'autoimmune' diseases by means of solid phase radioimmunoassay. There were no retrovirus antibodies in the 3 groups of patients studied, that is, those with rheumatoid arthritis, systemic lupus erythematosus, and with non-RA conditions. Absorption of rheumatoid factor did not alter this conclusion. These results give little support to the hypothesis that activation of endogenous human retroviruses or an infection with horizontally transmitted retroviruses is associated with the rheumatoid process.

Rheumatoid polyarthritis after rubella.

A 21-year-old woman developed persistent polyarthritis indistinguishable from rheumatoid arthritis after rubella. The arthritis persisted for approximately 30 months and was associated with high levels of antibody to rubella virus and with rheumatoid factor. The antibody titres declined pari passu with clinical improvement which progressed to complete resolution. Fractionation of serial serum specimens showed a substantial and persistent IgM antibody response to rubella virus. Rubella antigen was not demonstrated in the synovial exudate.

Immunological studies of the placenta in systemic lupus erythematosus.

An immunological study was made of the placentae from 5 mothers with lupus erythematosus. 3 of the 5 mothers had anti-DNA antibodies in their sera at the time of delivery and in one of these anti-DNA antibodies were detected in the cord blood. This patient had active renal disease and serological evidence suggestive of circulating immune complexes in her blood at the time of delivery. Immunofluorescence studies showed granular deposition of immunoglobulin and C3 on the trophoblast basement membrane similar to that previously described on the glomerular basement membrane in systemic lupus erythematosus. Anti-DNA antibodies were eluted from the placenta in this case. We suggest that immune complex deposition on the trophoblast basement membrane in patients with active systemic lupus erythematosus may play a part in the increased fetal mortality in this disease.

Further studies on the serological effects of C. parvum immunotherapy in cancer patients.

Previous serological studies undertaken in our laboratory have shown that the repeated administration of small doses of C. parvum to a small group of cancer patients resulted in a consistant increase in the levels of IgG (especially the IgG2b subclass), the development of antibodies to C. parvum and the transient appearance of 'rheumatoid factor like' substances in the serum (Br. J. Cancer, 32, 310, 1975). In the present paper we report the results of similar studies in small numbers of (a) inoperable bronchogenic carcinoma patients receiving combined C. parvum and cyclophosphamide therapy, and (b) brain glioma patients receiving intracerebral injection of C. parvum. As might be expected some of the serological changes observed in these patients were not as marked as previously noted. Nevertheless a number of the patients developed autoantibodies which were detectable by the latex and Ripley procedures but not by the Rose-Waaler test. There was no evidence of antinuclear factors by the fluorescence procedure.

IgG and IgA antigens in human renal basement membranes.

Cryostat sections of fresh human kidney studied by immunofluorescence were negative for IgG, IgA, IgM, Fc and Fab fragments of IgG, and kappa and lambda light chains. All of these conjugates except anti-IgM stained glomerular basement membranes and several other connective tissues if the cryostat sections were washed in phosphate-buffered saline (PBS) before being studied. Staining was inhibited by blocking reactions as well as by fixation before washing in PBS or by washing in non-ionized or hypotonic solutions. Results of several other aspects of this reaction are also reported.

The association of alpha2-macroglobulin with lymphocyte membranes in chronic lymphocytic leukaemia and other disorders.

The association of alpha2-macroglobulin (alpha2M) with the surface membranes of human peripheral blood lymphocyte preparations has been investigated by the direct immunofluorescent technique. The percentage (and total number) of lymphocytes with detectable alpha2M on their surface is significantly increased in chronic lymphocytic leukaemia. The incidence of alpha2M-positive cells in normal and pathological conditions closely parallels that observed with conjugated antiserum to the kamma and gamma light chains of human immunoglobulin. It bears no relationship however to the plasma alpha2M levels or to the age of the donor. Additional blocking studies with aggregated human IgG, soluble antigen-antibody complexes and the F(ab')2 moiety of the anti-alpha2M, and indirect immunofluorescent studies with the latter, indicate that the fluorescence observed is not due to interaction of the conjugated reagent with Fc or C3 receptors.

Co-cultivation of human cell lines with synovial fluids of patients with rheumatoid arthritis.

We have interpreted the above findings as implying that the changes seen may have arisen as a result of co-cultivation, albeit accidental, of Chang cells and cells derived from RA synovial tissue or fluid. A further obvious approach to this problem is to attempt deliberately to repeat the co-cultivation of Chang cells with RA synovial fluids.

Rheumatoid arthritis, rheumatoid factor, and tests for Australia or hepatitis-associated antigen.

False-positive results in tests for hepatitis-associated antigen using latex agglutination techniques may be due to rheumatoid factor in the serum. Possibly the use of IgM antibody in preparing the latex particles might diminish the occurrence of such reactions. No evidence was found for a relation between rheumatoid arthritis and a significant incidence of hepatitis-associated antigen detectable by countercurrent immunoelectro-osmophoresis.

Immunohistological and elution studies of the human placenta.

An immunohistological survey of 28 full-term human placentas has demonstrated deposits of IgG, beta1C, beta1E, and fibrinogen/fibrin in areas of fibrinoid necrosis and on the trophoblast basement membrane in approximately 35% of placental villi. Traces of IgM were detected at similar sites in 18 of 28 full-term placentas. In 11 specimens of immature placentas (10-18 wk gestation) traces of IgG and beta1C and deposits of fibrinogen/fibrin were also present, but IgM was not detected in this material. IgG was recovered in acidic eluates from an homogenized placenta which behaved as an antibody reactive with unidentified material present in fibrinoid deposits and on the thickened trophoblast basement membrane of some villi. It could not be determined whether this IgG was derived from the maternal or fetal circulation.