Lymphopenia in systemic lupus erythematosus. Clinical, diagnostic, and prognostic significance

One hundred fifty-eight patients with active, untreated systemic lupus erythematosus (SLE) were studied from the time of diagnosis. Lymphopenia was present in 75%, and another 18% of those patients developed lymphopenia subsequent to disease reactivation. Lymphopenia of less than 1500 cells/microliter occurred more frequently than any of the preliminary criteria for the classification of SLE, and it was the most prevalent initial laboratory abnormality. Lymphocyte counts were significantly lower in lupus than in the other connective tissue diseases except mixed connective tissue disease and polymyositis.

Normotensive hyperreninemia in systemic lupus erythematosus. An indicator of tubular dysfunction

High plasma renin activity (PRA) was found in 16 of 42 randomly selected nonuremic systemic lupus erythematosus (SLE) patients. Mild hypertension was present in 3 of the 16.6 high-PRA and 10 normal-PRA patients were admitted to a metabolic ward. Salt restriction produced a disproportionate rise in both PRA and aldosterone, a decrease in glomerular filtration rate (GFR) and a slightly greater negative sodium balance in the group with high PRA. Potassium excretion was less than intake in both groups. Balance studies were performed in 6 additional high-PRA patients before and during indomethacin administration (150 mg/24 h). PRA and aldosterone were markedly suppressed by indomethacin. UnaV was significantly greater than in the control period despite of the 28% reduction in GFR. These results suggest that high PRA is secondary to impaired distal tubular sodium reabsorption. Such a defect could be responsible for the relatively low frequency of hypertension in lupus nephritis.

T-lymphocyte subpopulation in untreated SLE. Variations with disease activity

An active subpopulation of T lymphocytes characterized by their ability to form early rosettes with sheep erythrocytes (active E-RBL) was studied in the blood of 50 patients with untreated systemic lupus erythematosus (SLE) and in 50 normal controls. The findings were related to the absolute number of circulating lymphocytes and total E-receptor-bearing lymphocytes (total E-RBL). Lupus patients with active disease had markedly decreased absolute lymphocyte counts, but the decrease of both the total and the active E-RBL surpassed what would be expected from the lymphopenia. Patients with inactive disease had moderately decreased absolute lymphocyte counts with a marked and disproportionate decrease in total E-RBL and a moderate decrease in active E-RBL, which seemed to reflect only the absolute lymphopenia. Patients with active disease had significantly lower active E-RBL than those with inactive disease. The changes of these and other lymphocyte subpopulations in relation to disease activity in SLE may reflect the influence of factors leading to T-cell depletion and immaturity. Circulating thymic products may be one of those factors.

Immunochemical characterization of the anti-RNA antibodies found in scleroderma and systemic lupus erythematosus. II. Reactivity with hsa-coupled, uridine-containing, monophosphoric ribodinucleotides

Sera from patients with scleroderma have been found to have anti-RNA antibodies which react with human serum albumin (HSA)-coupled uridine and uridine monophosphate (UMP) and are inhibited by uracil, uridine and UMP. Scleroderma sera react uniformly with 5'-polyuridylic acid (poly(U)) and fail to react with polyadenylic, polyuridylic acid poly(A) - poly(U)) which is also indicative of their uracil specificity. Anti-RNA antibodies found in systemic lupus erythematosus (SLE) are immunochemically different from those found in scleroderma in that, instead of being uniformly specific to uracil, they are markedly heterogeneous and may react with uracil, uridine and/or UMP. SLE sera frequently react with poly(A) - poly(U), indicating also their ability to recognize the double helical structure of double-stranded RNA. Thirty-seven scleroderma and thirty-four SLE sera from as many patients with either of these conditions were tested against HSA-coupled, uridine-containing monophosphoric dinucleotides in an attempt to characterize further their anti-RNA antibodies. Scleroderma sera were found to react primarily with dinucleotides in which uridine was the base proximal to the carrier protein and, except for sera that also contained antibodies to adenosine which reacted with UpA, they failed to react with dinucleotides in which uridine was in a terminal position only. Reaction with dinucleotides in which uridine was proximal to the carrier protein could be inhibited by uracil but not by the corresponding terminal base. Some lupus sera were found to react with both dinucleotides that contain the same bases in opposite sequence, e.g. ApU and UpA, while others were found to react with only one of the sequences. They were also found to react more frequently with dinucleotides in which HSA was coupled to a base other than uridine, suggesting that the reaction is primarily due to anti-DNA antibodies. Because immunization with dinucleotides coupled to protein prepared by the same method we have used, yields higher specificity to the base attached to the carrier protein, our findings suggest that, in scleroderma, a single event, akin to that of immunization with a purified antigen, gives rise to the anti-RNA antibodies, whereas in systemic lupus erythematosus there is a considerably wider immunological aberration.

Drug-induced antinuclear antibodies and lupus syndromes

Drugs capable of triggering the onset of systemic lupus erythematosus may be divided into those that do so by pharmacological properties of their own and those that do so by eliciting allergic reactions which bring about lupus. Drugs in the first group vary in their potency to activate lupus. They all elicit antinuclear antibodies in the majority of patients who receive them but they only cause lupus in a small percentage of patients. This dichotomy suggests that a predisposition is required for the development of lupus upon intake of these drugs. The mechanism whereby these drugs elicit antinuclear antibodies seems to relate to coupling to and/or modification of, nuclear antigens. The patterns of antinuclear antibodies elicited by these drugs in individuals who receive them correlate well with their known reactivity with various nuclear antigens.

Retinal microangiopathy in systemic lupus erythematosus

We performed complete ocular examination, including fluorescein angiography of the fundus, in 50 ambulatory patients with moderately active or inactive systemic lupus erythematosus; none had ocular symptoms. One patient had drusen and two patients had increased intraocular pressures with disk cupping attributable to orally administered corticosteroids. No patient had detectable abnormalities by ophthalmoscopic examination. Despite this apparently normal condition, fluorescein angiography revealed single or multiple microaneurysms in nine patients (13 eyes) and retinal capillary dilatations with leakage of fluorescein in six patients (six eyes). Both abnormalities occurred in two patients. These capillary changes in moderately ill patients with lupus erythematosus are probably the residue of previous acute vasculitis, perhaps due to immune-complex deposition.

Immunochemical characterization of the anti-RNA antibodies found in scleroderma and systemic lupus erythematosus. I. Differences in reactivity with Poly (U) and Poly-(A) Poly (U)

In a previous study, all 40 sera from patients with scleroderma, 20 of 40 sera from SLE patients, but none of 40 sera from normal controls, were found to have antibodies to ssRNA. All scleroderma sera were also found to react with HSA-coupled uridine and UMP and their reaction with HSA-coupled uridine and UMP and their reaction with ssRNA could be inhibited by uracil, uridine, and UMP. To characterize further these uracil-specific anti-RNA antibodies found in scleroderma and compare them with the anti-RNA antibodies found in SLE, we tested their reactivity with Poly (U) and with Poly (A)-Poly (U) and all but one failed to react with Poly (A)-Poly (U). This same serum was the only one in which the reaction with Poly (U) could not be inhibited with uracil. Reactivity of SLE sera was strikingly different from that found in scleroderma sera. Seventeen of 34 SLE sera studied reacted with ssRNA but only four of these reacted with Poly (U). Conversely, two SLE sera that reacted with Poly (U) did not react with ssRNA. Fifteen reacted with Poly (A)-Poly (U) and only two of these failed to react with ssRNA. Five SLE sera which were reactive with ssRNA did not precipitate with Poly (A)-Poly (U). All SLE sera which reacted with Poly (U) could be inhibited with uracil, although less effectively than in scleroderma. Reactivity with Poly (A)-Poly )U) was not inhibited with uracil nor with adenosine. These findings confirm that antibodies to RNA that are found in scleroderma are directed to uracil and thus specific to ssRNA, whereas RNA antibodies found in SLE sera are heterogeneous and directed to either the base, to the site of union of the base and sugar moiety to the ribose backbone, or to the helical structure of double stranded RNA. These differences and the respective antigenic specificities of these anti-RNA antibodies found in scleroderma and SLE may be theoretically important.

Systemic lupus erythematosus presenting as panniculitis (lupus profundus)

Six patients are described in whom panniculitis was a major manifestation of systemic lupus erythematosus. These patients were seen in a combined-clinics population of 270 patients with systemic lupus erythematosus for an incidence of approximately 2%. Panniculitis was the first symptom of systemic lupus erythematosus in three of these patients indicating that systemic lupus erythematosus should be considered as an underlying cause in patients with panniculitis or Weber-Christian's disease. Analysis of these six cases and those previously reported suggests that the addition of hydroxychloroquine to the treatment regimen may be beneficial in lupus panniculitis.

Uracil-specific anti-R.N.A. antibodies in scleroderma

Antibodies to single-stranded R.N.A. were found by counter immunoelectrophoresis in all of 40 sera from patients with scleroderma. These antibodies were specific to the uracil bases of R.N.A. Antibodies to R.N.A. were also found in 20 of 40 sera from patients with systemic lupus erythematosus (S.L.E.), but in none of forty controls. Antibodies to R.N.A. found in S.L.E. sera could be differentiated immunochemically from those found in scleroderma in that they were more heterogeneous and could react selectively with either uridine or uridine monophosphate. Antibodies ot D.N.A. were more frequent in S.L.E. than in scleroderma. That antibodies to D.N.A. are actually present in scleroderma and precipitin lines are not the result of cross reactivity with anti-R.N.A. antibodies is indicated by the finding that 10 of the 18 scleroderma sera which reacted with D.N.A. also reacted with thymidine, a base present in D.N.A. but not in R.N.A.