The Role of Viruses in Systemic Lupus Erythematosus

Hepatitis B virus surface antigen in glomerular immune complex deposits of patients with systemic lupus erythematosus

In view of a high prevalence of hepatitis B virus infection in the Malaysian population, indirect immunofluorescence examination for hepatitis B surface antigen (HBsAg) was routinely performed on renal biopsy specimen at the University Hospital, Kuala Lumpur, over a 3-year period. Examination of renal tissue from 259 patients, including 47 with systemic lupus erythematosus (SLE), revealed 43 cases with HBsAg in glomerular immune complexes. A significantly high proportion (30/43) of these were SLE patients. The deposits were granular in nature, situated in both the capillary walls and mesangium and associated with immunoglobulin deposition. Morphological patterns of lupus nephritis involved were focal proliferative (one case), diffuse proliferative (23 cases) and membranous (six cases). None of these patients showed clinical evidence of liver disease. The significance of these findings remains uncertain, but the possibility exists that the hepatitis B virus may have a role in the pathogenesis of SLE in the tropics where both SLE and HBs antigenaemia are common.

Reactivities of systemic lupus erythematosus sera with cellular and virus antigen preparations

Sera of patients with systemic lupus erythematosus (SLE) showed significantly higher complement fixation reactivities with 8 of 10 virus antigen preparations compared to sera of normal subjects, including virus workers, confirming earlier observations. However, one-third of SLE sera were also reactive with cellular antigens, prepared in a manner identical to viral antigens, but from cells not infected with virus. By contrast, only one of 49 normal sera showed reactivity with one of nine cellular antigens, at a minimal titer. Apparently heightened reactivities of SLE sera with virus antigens could be explained in many instances on the basis of reactions with cellular antigens. Serum reactivities with nonviral tissue antigens in SLE must be considered in interpretation of immunologic studies related to viruses and SLE.

Effect of inherited deficiency of the fifth component of complement on arthritis induced in mice by Mycoplasma pulmonis

Mycoplasma pulmonis inoculated parenterally into mice deficient in the fifth component of complement (C5) caused a chronic arthritis of significantly greater magnitude than in immunologically normal mice. During the chronic phase of arthritis M pulmonis organisms were isolated from the joints and organs of C5 deficient mice more frequently and in larger numbers than from immunologically normal mice. The implications of the results are discussed in relation to the pathogenesis of M pulmonis induced arthritis and human connective tissue diseases.

Type C oncornavirus studies in systemic lupus erythematosus

The following paper critically reviews published evidence that concerns the occurence of viruses in patients with systemic lupus erythematosus. Special emphasis is placed on the recent studies that implicate type C oncornaviruses. Evidence from our laboratory regarding the occurence of type C viruses in these patients is predominantly negative. It is concluded that the pathogenesis of systemic lupus erythematosus is almost certainly multifactorial and that the part that viruses play remains hypothetical.